Jt\ JIUU/A^^U.T
           United Nations
World         United States Army Corps of
Meteorological    Engineers, Environmental Protection
Organization     Agency, National Oceanic and
              Atmospheric Administration
May 1990
           Changing  Climate and the Coast

           Volume 2: Western Africa, the Americas,
           the Mediterranean Basin, and the Rest of Europe
                      Report to the Intergovernmental Panel on Climate Change
                        from the Miami Conference on Adaptive Reponses
                            to Sea Level Rise and Other Impacts
                                of Global Clini*tte Change

Library of Congress Cataloging-in-Publkation Data

Changing Climate and the Coast / edited by James G. Titus.
   Papers presented at workshop held in Miami, Fla, Nov 27-Dec 1,1989,
  sponsored by the US Environmental Protection Agency and others.
   Contents:  vol. 1.  Adaptive responses and their economic, environ-
  mental, and institutional implicationsvol. 2. Western Africa, the Ameri-
  cas, the Mediterranean basin, and the rest of Europe
   Includes bibliographical references.
   1. Global warmingCongresses.  2. Climatic ChangesCongresses.
  3. Sea levelCongresses.  I. Titus, James G.  II. United States Environ-
  mental Protection Agency.
  QC981.8X356C5S1990                                 90-2741
  333.91*7dc20                                          CIP


                      GLOBAL CLIMATE CHANGE
                             Edited by

                           James G. Titus
                  U.S. Environmental Protection Agency
                        with the assistance of

                          Roberta Wedge

                           Norbert Psuty
                          Rutgers University

                           Jack Fancher
             U.S. National Oceanic and Atmospheric Administration

                     HEADQUARTERS LIBRARY
                     WASHINGTON, D.C. 20460
 The opinions expressed herein are solely those of the authors and unless noted otherwise do not necessarily
 represent official views of any of the sponsoring agencies or the Intergovernmental Panel on Climate


                             TABLE  OF CONTENTS


    A.  WEST AFRICA	     1

      Adjustments to  the  Impact of  Sea  Level Rise  Along  the West  and
      Central African Coasts  	     3
      A.C.  Ibe

      The Gulf of  Benin:   Implications of Sea  Level  Rise for Togo  and
      Benin	    13
      Kolawole 5. Adam

      Coastal Erosion and  Management  Along the Coast  of Liberia  	    25
      Eugene H.  Shannon

      Impact of Sea Level  Rise on the Nigerian Coastal  Zone  	    49
      L.F.  Awosika,  A.C.  Ibe,  and M.A.  Udo-Aka

      Responses to the Impacts  of Greenhouse-Induced Sea Level  Rise  on
      Senegal	    67
      Isabelle Niang

      Response to Expected Impact of Climate  Change on  the  Lagoonal  and
      Marine Sectors of Cote D'lvoire 	    89
      Philibert Koffi Koffi,  Has sera  Kaba,  and Soko G.  Zabi

      Implications of Global  Warming  and  Sea  Level Rise for  Ghana  ....    93
      J.F.  Abban

      Sociocultural  Implications of Climate Change and  Sea Level Rise  in
      the West and Central  African Regions	103
      0.  Ojo


      Impacts of Global   Climate Change  in   the  Mediterranean  Region:
      Responses and Policy Options  	     115
      6.  Sestini

      Impacts  of Climate  Change  on  the  Socioeconomic  Structure  and
      Activities in the Mediterranean Region   	   127
      Ante Baric

  Venice:  An Anticipatory Experience of Problems Created by Sea Level
  Rise	  .  .  139
  A. Sbavaglia, C. Clini, F. De Siervo, and G. Ferro

  Implications of Sea Level  Rise for Greece	  .  161
  Hampik Maroukian

  Impacts of Sea Level Rise on Turkey	183
  Oguz Erol

  The  Influence  of  Sea  Level   Rise  on  the  Natural   and  Cultural
  Resources of the Ukrainian Coast  	  201
  Yurii D. Shuisky

  Coastal Morphology and Sea Level Rise Consequences in Tunisia  ...  211
  Ameur Oueslati

  Responses to  the  Impacts  of Greenhouse-Induced Sea  Level  Rise  on
  Egypt	225
  M. El-Raey

  Impacts of Sea Level  Rise  on Ports and Other Coastal Development  in
  Algeria	235
  El-Hafid Tabet-Aoul


  The Vulnerability of European Coastal Lowlands Along the North Sea
  and Atlantic Coasts to a Rise in Sea Level  	    241
  Saskia Jelgersma

  Impact  of  a Future  Sea  Level  Rise  in  the Polish  Baltic  Coastal
  Zone	247
  Karol Rotnicki and Ryszard K.  Borowka

  Adaptive Options and Implications of Sea Level Rise in England and
  Wales	265
  Ian R. Whittle

  Policy Analyses of Sea Level  Rise in the Netherlands   	  283
  J.G. De Ronde

  Impacts of and Responses to Sea Level Rise in Portugal	293
  Maria Eugenia S. De Albergaria Moreira


  Potential Impacts of Sea Level  Rise on the Coast of Brazil   ...    311
  Dieter Nuehe and Claudio F. Neves

  Potential Impacts of Sea  Level  Rise  on  the Guiana Coast:  Guyana,
  Surinam, and French Guiana  	  341
  J.R.K. Daniel

  Impacts of Sea Level Rise on the Argentine Coast	363
  Enrique J. Schnack, Jorge L. Fasano,  Nestor U. Lanfredi
    and Jorge L. Pousa

  Regional Implications of Relative Sea Level Rise and Global Climate
  Change Along the Marine Boundaries of Venezuela 	  385
  Ruben Aparicio-Castro, Julian Castaneda, and
   Martha Perdomo

  Impacts of and Responses to Sea Level Rise in Chile	399
  Belisario Andrade and Consuelo Castro

  Living Strategies and Relocation in Latin America 	  421
  Christina Massei


  Responding to Global Warming Along the U.S. Coast 	    433
  James G. Titus

  Sea Level Rise:  Canadian Concern and Strategies  	  457
  K.B.  Yuen

  The Lowlands of the Mexican Gulf Coast  	  469
  Mario Arturo Ortiz Perez, Carmen Valverde,
   Norbert P.  Psuty, and Luis M.  Mitre

  Raising Miami -- A Test of Political  Will	487
  Ted Miller and Mil Ham Hyman

  Accommodating  Sea   Level   Rise  in   Developing  Water   Resource
  Projects	501
  Robert H. Schroeder, Jr.




                                A. C.  IBE
        Coordinator, UNEP's Task on Implications of  Expected
      Climatic  Changes  on the  Coastal  and Marine Environment
                      of  West and Central  Africa
                 Nigerian Institute for  Oceanography
                          and  Marine  Research
                     Victoria  Island,  P.M.B.  12729
                             Lagos,  Nigeria

     The coasts  of West  and  Central  Africa,  stretching  from Mauritania to
Namibia, are mostly low plain, sandy, surf beaten,  and in many places,  subsiding.
The region has population of about 269 million, of which a large percentage live
along or near the  coasts.  All  but  4 of the 21 countries  presently  have their
capital  cities on the coast.  The lopsided history of urban development in the
region has  meant that most economic and social infrastructures  are  located in
these cities.  At present, erosion and concomitant flooding are prevalent along
the coasts  and have assumed disturbing proportions,  putting  life and property
continually  at risk.

     These problems would be exacerbated  by an  accelerated rise in sea level
that would  virtually  cripple most economic structures  and activities such as
ports, coastal roads,  air  fields, rail lines, fishing,  farming, oil  and mineral
production,  manufacturing, etc.  Settlements would be dislocated.  Surface and
groundwater  as well as flora and fauna of the region would be profoundly affected
as a result of increased salinization and added load of  sediment and pollutants.
Increased incidence of heat-related  diseases occurring with rising temperatures
would mean a drastic reduction in the well-being of humans, livestock,  and crops.
The enormity of the various expected impacts dictates that significant measures
be taken to  make the  coastal zone habitable.   Given the financial disabilities
of countries in  the  region,  only  well-planned  anticipatory actions by these
countries,  acting  preferably in concert,  can help avoid or minimize stress,
hazards, and resource losses from the expected changes.

West Africa


     Recognizing that the impact of the expected accelerated rise in sea level
along most low-lying coastlines of the world  would  lead to a disruption of life
and dislocation of socioeconomic structures and activities in such places, the
Ocean and Coastal Areas Programme Activity Center (OCA/PAC) of the United Nations
Environment Programme (UNEP)  set  up Task Teams in 1987 to  study the implications
of climate change on the coastal and marine environments of six of the regions
covered by UNEP's Regional  Seas Programme,  namely the Mediterranean, Caribbean,
South Pacific, Southeast Pacific, South Asian Seas,  and East Asian Seas regions.
In 1989,  two  more Task Teams  were  assembled for West and  Central  Africa and
Eastern Africa.  Other Task Teams (for the Black Sea and Kuwait region) are in
the process of  being established.   The ultimate  objective of these Task Teams
is to advise governments in the various regions on  how to respond appropriately
to the expected  impacts of increased  atmospheric temperatures and sea level rise.
The West  and  Central  African Task Team convened for  the  first  time in Lagos,
June 7-9, 1989.   This paper combines  the author's personal views on the problem
with those expressed by team members during that meeting.


     The West  and Central African (WACAF) region, comprising 21 countries between
Mauritania  and  Namibia, stretches approximately for almost 7,000  km between
latitudes 23 N and 28 S (Figure 1) with a total area of 9 10s  km2.

     Climatically (and by implication,  in terms of  vegetation) the WACAF region
falls within three main zones  (Figure 1):

     1.  North arid zone (semiarid and  arid zones);

     2.  Equatorial humid zone  (humid  and subhumid  zone);  and

     3.  South arid zone (semiarid and  arid zones).


     The evolution of the continental margin of West and Central Africa is linked
with separation of South American from Africa.   The dating  of this separation
is inexact as it consisted of a series of overlapping events.

     According to Emery et  al.  (1974),  the  earliest  of the events in the region
was the development of  small  basins  and troughs  (the Liberia and  Sierra Leone
Basins), when North America separated from Africa about 180 million years ago.
Then followed the separation  of South  America from Africa, which probably began
at the south and proceeded  northward occupying  a time  span of about 165 million
to 135 million years.  The general date of separation is indicated by the general
continuity of Precambrian and Paleozoic strata and structures in Africa and South
American and the disruption of Jurassic and  younger  structures.  This separation

        1.  Mauritania
        2.  Cape Verde
        3.  Senegal
     E  4.  Gambia
     *  5.  Guinea Bissau
     o  6.  Guinea
     z  7.  Sierra Leone
        8.  Liberia
        9. Cote d'lvoire
       10. Ghana
       11. Togo
     | 12. Benin
     n 13. Nigeria
     o-14. Cameroon
     m 15. Equatorial Guinea
       16. Sao Tome and Principe
       17. Gabon
     c 18. Congo
     J2 19. Zaire
     g 20. Angola
     w 21. Namibia
Northern    7
Figure  1.   Countries and zones of  the WACAF region.
led to the formation of the basins farther south (the Mossamedes, Cuanza, Congo-
Cabinda, Gabon,  Cameroun, Nigeria, Dahomey,  and Ivory Coast Basins).  Continued
separation of South America from Africa produced easily recognizable ocean-floor
provinces  (see  Emery et al.,  1974 for details).

     The coasts in the  West  and  Central  Africa region  are mostly  low plain,
sandy, and surf  beaten.   Four broad  types are recognized:  drowned coasts in the
northern area;  sand  bar or lagoon coasts  along  the  north of the Gulf of Guinea;
deltas associated with most of the major  rivers (e.g., Niger Delta) usually with
mangrove swamps and marshes;  and  coasts  with  sand  spits  (and  tombolos) formed
by accumulation of  longshore  transported sand in  bays  found in  the southern
parts of Angola.

     From  the   point   of view  of  their  geological   evolution  and  present
geomorphology, the coasts in the region are clearly vulnerable to sea level rise,
not only because they  are low-lying  but also  because the sedimentary basins that
dominate the coasts  are areas of subsidence.  These basins, formed by the rapid
deposition of sediments in a tectonic setting,  are  even in present times, still
undergoing dewatering and compaction.   In recent  times,  human  intervention by

Vest Africa

fluid extraction (including oil  and gas)  in the coastal zone has had the effect
of accelerating the subsidence due to natural causes.


Settlement and Population

     The WACAF region has  a  population  of about 269 million  and  with a rapid
annual growth rate of about 2.9%,  the population will most probably double itself
within the next two and a half decades.

     Due to the history of early contracts with  Europeans, most important cities
in the region are located on the coast.  Of the  21 countries, only 4 do not have
their capital cities in the coastal area.  These coastal  cities  are nearly always
synonymous  with  centers of  commerce,  industry,  and  politics  and have  thus
attracted very large populations.   For  example,  Lagos  (Nigeria)  is reputed to
have a population of over 8 million out of an estimated national  population of
100 million.  The story is much the same for Dakar, Abidjan,  Freetown, Banjul,


     Ports  and   harbors  as  transportation  access  facilities  for  maritime
activities provide  the lifeline  for socioeconomic development of the region and
are all located  in the coastal zone.  Most of these  ports and harbors are linked
by intricate road,  rail,  and  air  transport routes that complete the network for
the export-import trade that is  the linchpin of  most economies  in the region.
Coastal roads, some of  which are presently  under  threat from marine  erosion,
provide particularly easy access  between  the  countries  in the region, while air
transport offers a  means of rapid  movement  of goods and peoples  between the


     When compared  with  Europe or America,  the  West and Central  African region
is poorly industrialized, but the  pertinent  issue  is that the industries that
do exist  are  concentrated  mainly on or near the coast, most  often around the
capital cities.  Such industries include mining, oil  and  gas, petroleum products,
textiles, paper and pulp, timber, brewing, Pharmaceuticals,  plastics,  leather,
lumbering, and various manufacturing outfits.


     Agriculture is  the most  important industry in the West and Central African
zone.  About  70  to 80% of the  population  is engaged  in agriculture,  and the
economies of most countries in the region depend on it.  The  coastal areas are
becoming  increasingly  important to this industry   and  have  the  potential  of
increasing substantially their contribution to  agricultural  production.  About
60 to 80% of the food production of this zone comes from small farms.


     The crops and produce from  agriculture  of  this  zone may be classified as
follows (UNEP, 1984):

     1. Tree  and horticultural crops (oil  palm,  coconut,  citrus, avocado, pear,
        rubber,  kolanuts, sheanut,  cocoa,  coffee, pawpaw,  banana,  plantain,
        mango, pineapple);

     2. Cereals  (maize,  rice,  sorghum, millet);

     3. Root  crops  (cassava,  cocoyam, yam, sweet  potato,  ginger, tigernut);

     4. Vegetables and beans  (groundnuts, cowpea, phaseolus bean, melons); and

     5. Other crops  (sugarcane,  tobacco,  and cotton).

     Apart  from  crops,  the  coastal  and  forest  areas  have  a  low  livestock
population.   The main categories of livestock are large ruminants  (cattle and
camels), small ruminants (sheep and goats), equines (asses, mules, and horses),
pigs, and chicken.   The distribution of livestock  is uneven.  It is governed by
natural factors such as the presence of tse-tse  fly and historical and cultural
factors as well as vegetation types.

     Mariculture  and  aquaculture are becoming  increasingly popular in the coastal
zone of the West and Central  African region.   Captive breeding of economically
important species such as Chrvsicthy spp.,  Megalops spp., Clarias lazera, as well
as oyster  culture, are widely practiced in  Nigeria and Ghana with varying degrees
of success.   In Angola, the culture of mussels, Perna perna, is popular.

Forestry and Wildlife

     The West and Central  Africa region  is the home of the tropical rain forest
and mangroves of  great  biological  diversity,  but  the density and variation of
the forests  are greatly influenced  by climate,  especially rainfall.   The rain
forests and mangroves form the basis of an extensive lumbering industry.

     The region is  rich  in  wildlife,  which  is  an  important  source  of protein
and are hunted intensively, but  several  species are  on  the endangered list as
a result of  uncontrolled  harvesting and poor management.   The most important
wildlife include elephants, lions, buffalos, hartebeests, smaller antelopes of
different kinds,  warthogs, aardvarks,  civet, cats, chimpanzees, baboons, birds
of all types, and reptiles.

     The animal  species  found  in the mangroves are also found in other brackish
water, salted waters, and nearby forests.  The fauna consist of invertebrates,
molluscs, crabs,  prawns,  and  fish,  reptiles,  birds  (e.g., herons, storks, and
ibises), reptiles, and mammals (monkeys,  bush  pigs, and manatees).  Most of the
reptiles, birds,  and mammals are semi-aquatic.

West Africa

     In addition,  the  mangroves provide important spawning and breeding grounds
for a  variety  of  finfish  and shellfish that are the targets  of artisanal and
industrial fishery in the coastal zone.


     Despite deficient statistics,  several  resource surveys  in  the different
countries of the region show that respectable quantities of fish are harvested
in the region.   According  to  UNEP (1984), production figures show high harvests
in Angola, Cameroon, Ghana, Ivory  Coast, Nigeria, Namibia, Senegal, Sierra Leone,
and Zaire.  Namibia, with  761,000 metric tons in 1978, has the highest figures.

     The existence of upwelling zones in the region (both  permanent and seasonal)
is known  to  be the  basis  of the  rich fishery of the region.   Major permanent
upwelling zones occur near Mauritania and Senegal  as  well  as  off  the Congo,
Angola, and  Namibia,  whereas seasonal  upwelling occurs  in the  Gulf of Guinea
between Cote d'lvoire and Nigeria.  The  lagoons,  creeks,  and  bays along the
coasts are also areas of high productivity.

     Fish and  shrimp  are  the major resources of the region,  although  in some
countries such as Senegal, Sierra  Leone, Nigeria,  and  others, edible molluscs
from near-shore areas are harvested in considerable quantity.  The shrimps,
prawns, and oysters are now the targets of export trade in  the region.

Minerals  (Including 011 and Gas)

     A variety of minerals  ranging from  commonplace sand and  gravel  to gold,
diamonds,  and  petroleum  are mined from  the  coastal  zone  of this  region.
According to UNEP  (1984), the extent of mined resources, particularly  if revenues
from petroleum products are considered  as part of this grouping, is significant
in countries such  as Nigeria, Gabon,  Liberia, Guinea, Angola, and Sierra Leone;
their economies are best described as mineral economies.  For example, the export
of petroleum accounts for over 90% of the  export and foreign exchange earnings
of Nigeria.  Except for Gabon and Nigeria,  nonfuel  minerals  still  dominate the
economies of the other countries  listed above.

Water Resources

     The West  and Central  African region  is well-endowed in  terms  of rivers.
It is also blessed with heavy precipitation  (reaching 2,000 mm in  the south),
which means that  the  recharge potential of groundwater  aquifers is  very high.
Water  balance  maps depict  areas  of high  rainfall,  high  humidity,  and  low
temperature, i.e., Liberia, Sierra Leone,  and southeastern  Nigeria,  which have
the greatest water surplus  (amounting to the equivalent of  more than 1,000 mm
of rainfall).   In the more  arid  conditions of  the north, however,  rainfall
decreases to 50 mm and, under such  circumstances, aquifer recharge is very low.



     The West and Central  African coasts  are  the  scenes of high wave intensity.
This fact, along with other adverse geological  conditions (e.g., erodibility of
sediments,  subsidence),   and  detrimental  human  interference  in  the  natural
environment, have meant that erosion and concomitant flooding are prevalent along
the coasts of the region  (Ibe and Quelennec, 1989).  In some places, the flood
rates are so rapid that whole towns (e.g.,  Grand  Popo in the Benin  Republic and
Keta in Ghana)  have  virtually disappeared.   Elsewhere,  life and property have
been put to risk with resultant economic losses and social  misery.

     The region  in recent times has witnessed a prolonged  scourge of drought
and  desertification   with all  its  attendant  dislocation  of population  and
destabilization of socioeconomic activities.  Hunger and disease have afflicted
the populace as a result  of crop failures and losses in livestock.


     Different scenarios  of climate  change have  been put  forward and defended
by various authors, but the Task Team adopted as the basis for its deliberations
the  assumptions  accepted at the UNEP/ICSU/WMO  International Conference  in
Villach, October  9-15, 1985,  i.e.,  increased temperature  of 1.5-4.5C and sea
level rise of 20-140  cm before  the  end of  the  21st century.   (For the purpose
of the meeting,  temperature elevation of  1.5 and sea level  rise of 20 cm by the
year 2025 were accepted with the understanding  that these estimates may have to
be revised on the basis of new scientific evidence.)


     The problems of erosion and flooding presently  experienced  along the coasts
of the region will be exacerbated  by the predicted acceleration  in global  sea
level rise.  In  fact, worldwide  evidence points  to erratic  jumps in the rates
of shoreline retreat that  suggest sea level rise as a contributory factor (Pilkey
et al.,  1981).  Although the accepted predicted values may seem  small, its impact
along the low-lying and,  in many cases,  subsiding coasts in the region would be
immense, particularly when viewed from point of view of the Bruun  (1962) rule,
which predicts that a rise of 0.3 m  (1  ft)  of sea level  will cause a shoreline
recession of more than 30 m (100  ft) on low-lying coasts.  Subsidence phenomenon,
known to  be  active in major  coastal  sedimentary basins in the  region,  would
aggravate the situation.

     With the increase in ocean temperature, tropical storms are likely to extend
into some humid areas, and with rising sea level, the periodic flooding presently
being  experienced  in  vast  coastal   areas  will  become  more  frequent  and
devastating. This will virtually cripple most economic structures and activities
in the densely populated and highly urbanized settlements  proximal to the sea.
Ports,  coastal roads, and rail  lines will  be  knocked out of  action;  fishing,

West Africa

farming, oil  and mineral production,  and  manufacturing will  be interrupted;
people and businesses will be forced to relocate, etc.

     As  a  result  of increased  sea level  rise, surface  drinking water  and
groundwater  aquifers would  be  rendered unusable  as  sources  of  potable  and
irrigation water because of increased salinization and added loads of sediment
and pollutants.

     The fragile ecosystems of the  coastal  zone  will  be adversely affected by
inundation from the sea and may not be able to perform their traditional roles
as the spawning and breeding grounds of most finfish  and shell fish that are the
targets of artisanal and inshore industrial fishermen.

     A rise in sea level  will  also profoundly affect the flora and fauna of the
region as well  as the agriculture and livestock production.  Vegetation kill due
to salinity stress would result, as  is  presently being witnessed in the Mahin
area  on the  northwestern  flank of  the  Niger  Delta  (Ibe,  1988a,b).    The
distribution and composition  of  the  coastal vegetation would be affected with
salt-loving species increasing.  This may decrease suitable forage for livestock,
resulting  in  a  depression  of this  occupation among coastal  populations.   The
areas of saline soils would  increase, making them unsuitable for cultivation of
crops like maize, banana, pineapple, etc.  Coastal plantations would also suffer
from salinization.  Hunger,  already a problem in the region, would worsen.

     Apart from the impacts due  to  sea  level  rise,  other impacts derived from
a rise  in  temperature would  result.   Increased  humidity and temperature would
favor rapid multiplication of insects such  as  mosquitoes  and the tse-tse fly,
resulting  in  diseases such as  malaria  and trypanosomiasis  reaching  epidemic
proportions.  Temperature-sensitive  plant diseases and weeds would also increase
and cause greater damage  to crops.  Increased incidence of heat-related diseases
with rising temperatures would mean  a reduction in the well-being of humans and
livestock.  The general  level of discomfort and misery would be high.


     It is  imperative that countries in the region make some adjustments to cope
with the adverse conditions that would accompany the rise in  sea  level and higher
atmospheric temperatures. Given  the financial disabilities of countries in the
region in the face of these serious threats, well-planned anticipatory and, in
some cases,  reactive (including adaptive)  actions  need to be  pursued  by the
countries  acting  individually or in concert to  avoid  or minimize the stress;
hazards and resource losses  would be likely  to occur with the expected changes.

     In relation  to  sea  level rise, there  will  be  a  need  to  protect heavily
built-up areas  having high-value installations where  the option of relocation
is not  a reasonable  economic proposition.   But  while  many  of  the engineering
countermeasures are feasible for shoreline protection in the face of sea level
rise, they are economically impractical  in view of the financial  position of most



countries  in  the  region.   The approach here  should  be  toward the adoption of
low-cost,  low-technology, but effective measures such as permeable nonconcrete
floating breakwaters,  artificial  raising  of beach  elevations, installation of
rip raps,  timber groins, etc., from locally available materials.  Fortunately,
outside the urbanized  centers, the coasts are almost in pristine condition and
largely uninhabited except perhaps for small fishing settlements which, in any
case,  are  highly  mobile.    In  such  situations,   resettlement  of  existing
populations and the enforcement  of  set-back lines  for any new developments on
the coast  should be applied.  Where coasts are deemed highly vulnerable, total
ban of new development  is necessary.

     Designs of new buildings and other facilities should take into account the
predicted  and continuing rise in  sea level as  well  as increased heat.   For
instance,  houses should be concerned with increased use of natural ventilation
modes.  Afforestation of coastal  lands would provide  some measure of damping of
wave energy as well as relief from increased heat.

     Other adjustments  would  involve  the protection of  arable  land,  improved
management of water resources, introduction of new agrotechnology to cope with
new realities, controlled land use policies, maintenance of food reserves, and
the introduction of emergency disaster relief measures.

     For protecting arable  lands,  some of  the low-cost, low-technology measures
mentioned above would  be applicable.  Improved water management techniques would
involve the building of dams (after environmental  impact assessment), aqueducts,
reservoirs,  irrigation systems,   and  river diversions  with  the  objective of
husbanding water in times of drought.  The adoption of new agrotechnology should
aim  at  introducing more  salt-  and  heat-tolerant  crops,  developing  adaptive
irrigation systems aimed at reducing salinity stress, and so on.  Although the
region is far  from being self-sufficient  in its food needs at present, there will
be a need to stockpile food and institutionalize  other disaster relief measures
to cope with emergencies that may arise from sudden flooding or drought.

     Other adjustments would  require the setting  up of environmental monitoring
and early warning systems,  providing flood vulnerability and land use maps for
coastal  areas, and perhaps above all, providing public information and education.
This  calls for  extensive  information-gathering,  analysis,   and  utilization.
Public information and education would drive home to the populace the seriousness
of the anticipated impacts from increased atmospheric temperatures and sea level
rise and thus better prepare  them for  the  implementation of certain protective,
preventive, or adaptive measures  that would necessarily have to be put in place.


     Higher atmospheric temperatures and increased sea level rise are realities
that humanity  has  to  cope with  now and  in the future.   Even  if all  suggested
measures to stop the introduction of greenhouse gases were put  in place now, the
world would still  experience  many of the anticipated impacts due  to  "sins of
omission or commission" already committed by man toward global warming.


West Africa

     The application of most of the protective,  preventive, or adaptive measures
suggested  above  will  be  imperative but  it is  important  that  proposals for
adjustments to the expected impacts be embodied in a coordinated and enforceable
regional development  plan.   UNEP's Regional  Seas Programme for  the West and
Central  African   region  affords   a   vantage   platform  for  discussing  and
institutionalizing  such a plan.   It is hoped  that governments  in the region,
while pursuing policy options at  the national level, would now appreciate, even
more than ever before, the distinct advantages for a  regional  approach to the
problems associated with global warming.


     The author acknowledges  the  help of Profs. 0. Ojo,  I. Findlay  and A. Asare,
and Drs. T.  0.  Ajayi,  S. Zabi, I.  Sy-Niang, S.  Ogbuagu,  T. Egunjobi, L. Awosika,
M. Akle, and G. Nai who are  members of the WACAF Task  Team.   Miss S. A.  Fakan
typed the manuscript.


Bruun, P.  1962.  Sea level  rise as  a cause of shoreline erosion.  Am.  Soc.  Civil
Eng., Proc. V.88 Waterways and Harbours Div. Journ. WW1:117-130.

Emery,  K.O.,  E.  Uchupi, J.  Phillips,  C.  Bowin,  and   J. Mascle.   1974.   The
Continental Margin of Western Africa: Angola to Sierra  Leone.  Contribution No.
3481.  Woods Hole, MA:  Woods Hole Oceanographic  Institution.

Ibe, A.C.   1988a.   The  Niger Delta and  the  global rise  in sea  level.   In:
Proceeding of the  SCOPE Workshop on Sea Level  Rise and  Subsiding Coastal Areas,
Bangkok, Thailand, November 7-14, 1988.  Pergamon Press.

Ibe, A.C.   1988b.   Coastline Erosion  in  Nigeria.   Ibadan, Nigeria:   Ibadan
University Press,  217 p.

Ibe, A.C., and R.E.  Quelennec.   1989.   Methodology for assessment and control
of Coastal Erosion  in the West and Central African Region.   UNEP Regional Seas
and Reports and Studies No. 107.  Geneva:  United Nations Environment  Programme,
112 p.

Pilkey, O.H., et  al.  1981.  Old solutions  fail to solve beach  problem. Geotimes

UNEP.   1984.   Environmental  management  problems in resource  utilization and
survey of resources in the West and Central African Region UNEP Regional Reports
and Studies No. 30.  Geneva:   United Nations Environment Programme,  83 p.

                        FOR TOGO AND  BENIN
                             KOLAWOLE S.  ADAM
                     Universite  Nationale du Benin
                              Cotonou, Benin

     The coastline  of West  Africa  in  general,  and  the  Gulf  of Benin  in
particular,  has witnessed sea level variations of great dimensions in the past.
The present  configuration of the coast  is the product of the oscillation of sea
level that took place 20,000 years ago.  Short-term as well as seasonal  oceanic
fluctuations (tides, waves, storm waves) linked to atmospheric disturbances are
sometimes spectacular  on the West African coasts,  but  the greatest dangers are
long-term changes that could result from a change in the world's climate.  Global
warming  is  probably  the  cause of the  rise in  sea  level  that we  have  been
witnessing  since  the beginning of the 20th century.

     Accelerated  sea level rise  -- which  is already  2  cm  per year  along  some
coasts  --  will  bring  about  important natural,  socioeconomic,  and  cultural
disruptions  in the coastal"plain of the  Gulf of Benin.  The coastal  areas are the
most densely populated and contain the economic heart of both Benin and Togo,
including the main towns,  the port and airport infrastructure, and the majority
of the countries'  industries.

     The coast of  the Gulf of Benin is  a  low and even coastal plain stretching
nearly 500 km from the Cape of the Three Headlands (Takoradi Region in Ghana) to
the Delta of Niger (Nigeria).   This  paper focuses on the approximately 175 km
that constitute the coastal zone of Benin and Togo, examining (1) the possible
effects of  future sea  level  rise on the coastal ecosystems such  as  deltas,
estuaries,  lagoons, mangroves, and human  activities of  the coastal plain;   (2)
the reactions of  the  different  research  institutes and decision-makers in the
face of  these  impacts; and  (3)  the present characteristics of the  coastal

     Rising sea level  is  always accompanied by inundation and erosion.  The Gulf
of Benin coast will  be very sensitive and  catastrophes may result if appropriate


West Africa

precautions are not taken in time.   We discuss the effects and damages of three
possible scenarios:

Sea Level Rise of 50 cm

     As  Figure  1 shows,  the shore  could  retreat considerably,  particularly
between Anecho and Grand-Popo.  A retreat of about 100 meters may be foreseen,
which will be  a  big blow to the Cotonou-Lome interstate  road,  which would be
dangerously threatened  and  would have  to  be moved  inland.   Nearly  half the
beaches and coconut-tree plantations would  disappear  in  this region, although
some of the agriculture  would not suffer serious  damage.   We can be certain that
Grand-Popo and Agoue graveyards would be periodically washed by the waves.

     If urbanization is  checked,  particularly in the east of Cotonou, the risks
would be less,  but there is little hope that this will  happen.  The swampy areas
would increase considerably, especially  in  the estuary of the Mono River, which
would bring about a  loss of nearly 25% of the existing  upland, especially in the
city of Cotonou where the situation  is already highly critical.  The ecological
imbalance caused by the  oversalinization of  the coastal lagoons would surely be
disturbed; the degradation of the mangroves which was already persistent will be

     Protective measures would continue to aggravate the problems downstream, but
they can protect  the very sensitive strategic places on the coast.  However, the
protection would be short-lived and would lead  to  other management problems.

Sea Level Rise of 100 cm

     All the damages from the previous scenario would be aggravated.  The retreat
of the shoreline  would provoke the displacement of all  hamlets built on the crest
of recently formed barrier islands.   Two-thirds of the town of Cotonou would be
submerged and  the  town  would be depopulated since there  is  no  possibility of
extension; by contrast,  the  town of Lome could be stretched farther north on the
plateau.  The  towns  of  Grand Popo,  Agoue,  Aneho and  Kpeme  would  be seriously
threatened and may  disappear.  A high salinization of the coastal  plain would
render  life  conditions  more precarious.   Protective measures  would  not  be
feasible, and people would instead think of controlling the migration toward the

Sea Level Rise of 200 cm

     Because their elevations are only 3  m, all  recently formed barrier islands
will come close to complete  submergence;  the portions not inundated will almost
surely erode   (cf.  Figure 2).   Only  a few  small "islets"  of lesser importance
will remain.  All human  settlements of the coastal plain wwould disappear.  Only
the part of the town  of  Lome on the  plateau  would be able to resist destruction.
The Lome-Cotonou-Lagos interstate road would be partly  submerged.  The settlement
patterns in this  part of the world would  have to be reconsidered.  In any case,
if this  rise of  the sea level persisted, people would surely not  wait before
considering relocation toward the plateau and  new  modes of life.


Figure 1.  Areas vulnerable to a 50 to 100 cm rise in sea level.
Figure 2.  Land loss from a 2-meter rise in sea level.

West Africa


     There are two solutions to safeguard the  coastal  zones  of Togo and Benin
along the Gulf of Benin:  (1) coastal defense and the artificial nourishment of
the beaches; and (2)  respect for the littoral dynamics which requires avoiding,
as  much  as possible,  development that sets  up an  unavoidable confrontation
between humanity and the sea.

     The evolution of research  in  the region appears to support a gradual shift
from the former to the  latter  approach.   Still,  most proposals for addressing
erosion are short-term and do not consider sea level  rise.  The overall theme of
most proposals is  a natural  protection of the littoral  zone by using beach rock.
But the characteristics  of the Gulf of Benin coast suggest that the effectiveness
of  this  natural  protection  would  be limited,  particularly  if  sea  level  rise

     In both  Togo  and  Benin,  survey offices  and university Applied  Research
Laboratories are responsible for management of this coast.  The labs are studying
the possibilities of safeguarding nature  according to its evolution  from the
field  and  the  laboratory's research.   The  survey  offices  are studying  the
cheapest methods of protecting certain  elements of the environment by fighting
against some natural  forces.

     Given the prohibitive costs of some solutions and the lack of resources in
these difficult times,  the  majority  favor measures that control  the  littoral
dynamics.   The authority of  the  researchers  is  limited  because  it  is  the
decisionmakers who have the final  word.  Sometimes,  they  neglect the advice of
the nationals  and turn to proposals made by foreign survey offices.  But policies
are changing.   Public opinion  is obliging decisionmakers to enter into dialogue
with researchers,  planners,  and town developers.  Nowadays,  few people perceive
the rise of the sea level as  an  important factor in the management of the coastal
zone.  But over time, the various scientific and policy reports on the subject
will probably be able to convey the importance of such a  phenomenon.


     On the coasts of the Gulf of Benin, the tide is  semidiurnal, with two highs
and two  lows  of nearly equal  amplitudes  that  succeed  each  other  at  regular
intervals.    The  spring  and  neap  tidal   ranges  are  1.6  and  0.6  meters,

     Along the shores of Benin and Togo  is  a coastal  strip whose width increases
from the west (2 km in  Lome) to the east (10 km at the Benin-Nigerian border).
It  is  a  contact zone between  many old and new barrier islands,  lagoons,  and
swamps that separate  the  coastal  features from the  inland slopes  (yellow and
claylike sands).  This body  is  limited in the north by a scarp of the red-clayed
plateau.  There are numerous barrier islands with elevations  of 3 to 5 meters.

   Table 1.  Evolution  of the Coast









1984- 89








           West Africa

                The evolution of the coast has been schematized in Table 1.  The offshore
           barrier islands are mainly occupied by a well-planned planting of coconut trees
           complemented in the east by the planting of eucalyptus and filao.  Mangroves are
           mainly found along the coastal lagoons, with the western boundary schematized by
           an Aneho-Glidji line.

                Since the 16th century, the  littoral of  the  Gulf of Benin,  just like the
           whole of the West African coast, has been the center of many human migrations and
           the magnet for intense agricultural and commercial activities.


                Although the distribution of the population is uneven, the density of the
           rural population  in  the coastal plain of the Gulf of Benin  is  more than 200
           inhabitants per square kilometer.   The urban and demographic dynamism is marked
           by  industrial and  related  activities in  Cotonou  and  Lome.   The  combined
           population of the major  cities (Lome,  Aneho,  Grand-Popo, Ouidah, Cotonou, and
           Seme) is estimated at about 1.5 million inhabitants; the population of the entire
           coastal  plain is  about 2 million,  about  25%  of the  total  population  of both
           countries.  The urban dynamism  of  Cotonou is of concern, as it  is  a town in full
           demographic explosion (600,000 persons) where  the  only open space for expansion
           is on barrier islands stretching east of the town  where erosion is already very

           Economic Activities

                The coastal  region is the economic hub of  both countries, for  it  harbors the
           main  towns,  the  ports, and airports,  and,  above  all,  a number of important
           industries.  The role of  the port activities  in the present economic development
           of those countries is unquestioned (despite the scarcity  of comparative data to
           demonstrate its importance).   Lome and Cotonou ports play an important role in
           the  import  and export trading  of landlocked  countries  of  West  Africa (Mali,
           Burkina Faso, and Niger).  The steady growth  in the port activities, which was
           more than 500% from 1968 to 1978, even recorded a sudden increase between 1977
           and 1980 because of the onset of certain activities  (oil refinery in Lome and the
           role played by Nigerian imports during  the time of the oil boom, when Lagos Port
           was "congested").


                Agriculture  in  this region is  a  function of the climatic  and pedologic
           conditions, which  are not very good.  The  bars are  mainly occupied by well-
           arranged plantations  of  coconut trees.  Near  the  coastal  lagoons,  some grain
           foodcrops are grown (maize, cassava, cowpeas)  as well  as vegetables.



     Just like the Lebou in Senegal, the Akan in Cote d'lvoire and  in Ghana, the
Peda and the Pla peoples from Ghana have moved into the coastal strip of the Gulf
of Benin, practicing a flourishing fishing economy which nurtured  the  big trade
with the people  of the  interior.  It was mainly the lagoons that  attracted the
Peda, even though Lake Nokoue and Porto-Novo lagoon are largely exploited by the
Tofinu.  In general,  fishing  is a  traditional activity  (small day-trip fishing)
that provides freshwater species (tilapia and Crustacea).

     Since  1960,  with  the construction of Lome  and  Cotonou  ports,  offshore
fishing has developed with the  massive arrival  of Ghanaians (Fanti  and  Keta) who
introduced gear boats in this  business that became semi-industrial.   The economic
position of fishing in the region is in an average position (66th)  in the world,
near the Cote d'lvoire and far behind Nigeria (28th), Senegal  (33rd)   and Ghana

     Today,  offshore  fishing  is  the   most  important  activity  practiced  by
fishermen living at the coast; it provides a considerable quantity of fish (about
50 million tons/year  for both countries) to a large part of the population of the
capital cities and the coastal towns.

     Many  of the  fish caught  in the  region  depend  upon  coastal  wetlands.
Accordingly, the  loss of those areas  to rising sea  level  could severely hurt
fishing.  The ability  of the shallow water bodies that replace the wetlands to
support fisheries is  unknown.

Modifications of the Shore

     The demands of the national economy have called  for the construction of two
deepwater ports in Lome and Cotonou.  The protecting jetties of these  ports are
large and they have accelerated the process of coastal erosion already started
by the construction of Akossombo Dam.   More recently, the construction of many
piers for the protection of some strategic zone (Kpeme factory, Aneho town, P.
L. M. Hotel,  Hotel da Silva) and the hydroelectric developments on the Mono River
(Nangbeto Dam)  have  added  to the sedimentary and ecological  inbalance  of the
coastal zone (see Table 1).

Coastal Management

     The general consumption  of space all along the Gulf of Benin  by hotels and
various structures and equipment aiming at the  tourist trade  is presently  a
fundamental concern of planners and developers.  In light of today's disorderly
management,  avoiding  irreversible  choices will require  a new  policy for the
coastal zone. For the past 10 years, a planned development scheme has been under
consideration which,  taking into account the present land uses,  can  be summarized
as follows:

West Africa

         to  limit the  coastwise  boundary of  the  urbanization zones  and main
         to  define the  mode of  stabilization of the coasts; and
         to  plan  the zones for  recreation and tourism exclusively equipped with
         mobile facilities..

     Up to now, no government decree has considered such  ideas; so, for the time
being, they remain purely and simply academic reflections.


     The fragility of  the coasts  in  general  and of  those of West  Africa in
particular  is of great concern.  To try  to  best  preserve this littoral, it is
necessary to understand its dynamics better.  Sea level  rise is an inescapable
parameter to reckon with in any approach to the management of the littoral.  A
systematic inventory of all useful information sources is a foremost task  (e.g.,
topographic maps, general maps,  inventory maps,  aerial  photographs,  satellite
pictures, oceanographic data,  population density  maps,  historical  documents).
Certain approaches such as satellite teledetection are  indispensable tools today
to better understand certain phenomena (e.g.,  waves,  salinity, currents, water
temperatures, biological  processes  of estuaries).  All  of these elements are the
basis for understanding and efficiently managing the coastal  heritage.




The Coastal Climate

     The climate of the  Gulf of Benin is of a beninian type (subequatorial) with
two rainy seasons  (mid-March/July and September/November) and two dry seasons.
The average rainfall is 1,200 mm per year decreasing toward the west (1,400 mm
per year  in  Seme  and 850  mm  per year  in  Lome);  this  decrease is  due  to the
configuration of the coast in  relation to the marine winds.  The temperature is
constantly high (yearly  average is 27C) with the average maximum in March (33C)
and the average minimum  in  August (25C) when temperature can go down to 22.5C.
The months of January, February, and March record high thermal amplitudes (12C).
These variations are reduced during the  rainy season.

     The predominant direction of the wind is southwest with average speeds of
4 to  6  m/s (3 Beaufort).  The  winds from the south-southeast  sector  are not
frequent and they blow in April and May.  Because  of the relatively even relief,
the pattern of winds does not vary much according to seasons.   In dry season, the
wind strength is weak to moderate (2 to  5 m/s)  in the morning.  It is stronger
during the day (5 to 7 m/s) and becomes moderate in the evening and in the night
(4 to 6 m/s).  During the rainy season, a moderate wind blows (4 to 6 m/s) in the
morning which  becomes   stronger  in  the  afternoon  (6  to 8  m/s)   and  remains
constantly moderate to strong  (5 to 8 m/s) in  the evening and at night.  The peak
speeds are reached during the passage of rain  lines (east to west direction) with
average speed of 15 m/s, accompanied by  harsh winds and rainstorms.

Swells and Waves

     Along the Gulf of Benin, one observes a long  swell of a distant origin, the
wavelength of which can  vary between 160  and 220 m.  This  swell unfurls over the
bar at a distance of about 150 to 200 m  from the shore (characteristics at the
Cotonou wharf).  There are also waves due to local winds whose characteristics
are changing but have little importance  for the morphological  phenomena of the
coast.  Their wavelength is about 50  m.   The swell  whose primary  period is 12
seconds (even  though  it can sometimes  vary  between  10  and 16 seconds)  has  a
relatively regular average height between 1.0 and 2.0 m.

     Table 1 gives  the average  amplitude of swell in Cotonou.  Using the averages
observed  in Lome in 1955  and  1961,  it  is  noted  that  swells are stronger in
Cotonou than in  Lome by 28% in 1955  and 11% in 1961.   This  difference  is due,
according to Sitarz (1963), to the protection offered by Cape St.  Paul  (Ghana)
to Lome port area.

     These swells generally travel from southwest  to northeast  (1980).  The most
recent surveys give the  following distribution:


Vest Africa

         SE   -   S                    135 to 180      =  10%
         S   -  SW                   180 to 203      =  36%
         S   -  SSW                  203 to 225      =  54%

     The breaker line in the region of Cotonou occurs at a depth of 3 m, or at
about 150 to 200 m from the shore:  This is the locus of important sedimentary

The Coastal  Geomorphology

     The geomorphological  evolution has mainly resulted from the fluctuations of
the marine  level  during the Quaternary,  and  secondly by  the  local  tectonics
(faults of Togbin, of Godomey  and  Krake determined  by J.  Land  and G. Paradis,
1977).  Since 5,000 years  ago the  series of barrier features have regularized a
coastline that was indented with  deep  rias  during the Flandrian transgressive
maximum.   These  are essentially  sandy bars;  granulometric and  microscopic
analyses confirm the marine origin of these sands.

     One  can   subdivide   this  shore   into   three   sections   with  varying

Lome to Grand-Popo

     A narrow coast  (average width =  1 km and narrows towards  the  east) with
altitudes of between 3  and 5 m.   Three types  of profiles  can be distinguished
according to hydrodynamic parameters:

        Profile with straight crest,  steep  seaward slope, short foreshore (less
         than 3  m), upper  berm  at  1 m,  even surfaced slope:  profile resulting
         from strong  swells.

        Profile of  very strong swells:  profile  with  round  crest,  with basal
         berm on  its  seaward  slope.  The inlandside  of the barrier  is steeply
         sloped  toward the lagoon.

        The  beach profile with  straight or  rounded crest  characterizes  the
         transition between a strong swell and an  average one.

Grand-Popo to Godomev

     The altitudes of the  barriers  in this section also vary between 3 and 5 m,
and they are modified on the inland margin by the  lower course and the mouth of
River Mono,  the  coastal  lagoons, and the swamps.   The width  of the bars is quite
narrow (less than  200 m).  We see  the same types of profiles as in the previous

Godomev to Krake

     The bars break up into a multitude  of successive  parabolic crests which are
rigorously parallel,  of  west-east orientation, and of a maximum altitude of 6 m.



The granulometric (medium and fine  sands) and morphoscopic (blunted and shining
sands) measures are in favor  of  a  marine origin.   These fine sands,  generally
well sorted, have been deposited  under homogeneous hydrodynamic conditions even
though some local disturbances can be noticed.

     Close analysis of sediments  along  the  littoral  of the Gulf of Benin shows
fine to coarse sands (median diameters  between  0.4 and 1 mm) at the foreshore,
up to 4  m;  from 4 m to  16  m elevation,  the sediments are  very  fine  and well
sorted.   Despite the homogeneity  in the distribution of sediments from the west
to the east of the gulf,  there is a strong variation to the east of the mouth of
River Mono; these sediments have  medium diameters from 3 to 6 mm in the depths
of -12 m, and they are composed of coarse sands mixed with gravel.

     The geomorphological  cartography  carried  out  with the  collaboration  of
researchers of both universities (Adam,  1986) has made it  possible to demonstrate
the complexity of the evolution of this coastal strip.  One element is durable
formation,  beachrock,  evidence of  an  old  beach  consolidated by  a  carbonate
cement.   This  formation is made of overlying slabs whose thickness varies between
0.5 and 1.5 m and whose width varies between 25 and 50 m.  Its position in the
littoral  profile  (sometimes  reaching  + 3  m  altitude) and its  mechanical
resistance causes beachrock to be a natural  protection against coastal  erosion.
It presently plays a role of wave-breaker, eliminating the actions of the swell
in the coast of the eastern part  of Lome.  This formation exists all  along the
coast at different altitudes.   Its  role seems to be efficient under the present
hydrological conditions prevailing between  Lome and Kperme,  between Ouidah and
Cotonou, and to the east  of Seme.   Its efficiency is  null  elsewhere.  Today, the
distribution of beachrock is to be considered in any  survey aiming at evaluating
the littoral of the Gulf of Benin.


     Three hydrological  systems present  themselves  from  the  west  to the east:

        The system of Lake Togo:   Lake Togo gathers  the waters from the Zio and
         Haho  Rivers  before  flowing into  the  ocean  through  the lagoon  mouth of
         Aneho.  This mouth has a strange evolution; having been long closed by
         a  spit  of barely 30  meters,  it  discharges  water collected  from brooks
         into  the Mono River through the  latter's  effluent, the Gbaga.  When the
         water rises,  the whole  area  is  flooded  and  since  1987,  with  the
         construction  of  jetties  at Aneho,  an  opening has been made  at Aneho
         which serves as  a permanent mouth for  this  system of  Lake Togo.

        The  estuary of  Mono  is  a  hydrological  complex characterized  by  the
         courses of the Mono and Koufo Rivers and the tidal  flows.  The dynamic
         behavior  of this  sector is linked with  the variations of the tides and
         of the flow of the river.   During flood  time, the flow  is enough to push
         back  the saltwater  zone  beyond  the shoreline.   Inversely, when  the
         freshwater  flow  is at a low level,  the saltwater contact goes  up  to
         Agome-Seva  (40 km).  This part  of the valley (6 m IGN) and Lake Athieme
         are completely under  the influence of  the tide.


West Africa

       The  Delta  of Oueme  is  the most important hydrological  element of this
        area.  It  is characterized by the regime  of the Oueme-So system, which

        is  influenced by the tropical rainfall pattern of the  upper basin of
        River Oueme  and  the  tidal  currents.

     All  these inlets  have  undergone serious changes since  the nouakchottian
transgression that put the  different  barriers  in place.   First of  all,  the
construction of successive spits  has diverted all the inlets toward the east.
Such is the case of the valley of Zio and of Lake Togo,  which used to run into
the sea at the level of Kpeme but today uses the artificial channel, which is the
permanent mouth of Aneho.  The Mono River used to  pour its waters into the ocean
at Grand  Popo;  it currently discharges through the opening at Avlo, which became
a permanent  mouth only a couple of decades ago.  The Oueme River that flowed into
the sea at  Lagos  before the opening  of  Cotonou  channel in  1986, can  only be
explained by this  progressive migration toward the east for 5,000 years.  These
inlets are often  blocked by the construction of different spits, which often
provoke catastrophic  floods  during the  rainy  season.   Such was the  case of
Cotonou in 1985,  which prompted the opening of the channel  in 1986;  even after
this opening, floods were reported in 1907, 1929, 1935,  1942, 1968,  and 1987.

     Those spectacular floods made it possible to map  out  marshy regions which
are more  than 65%  of the  area in the Gulf of Benin.  They are more widespread in
the estuaries of the Mono and Oueme where there are  only few subaerial islands
whose  banks  are  covered with  mangroves.   In  all of the  coastal  plain,  the
depressions between the islands are swamps whose  landscapes look like littoral

                          DR. EUGENE H.  SHANNON
                       Liberian Geological  Survey
                   Ministry of  Lands,  Mines  & Energy
                            Monrovia,  Liberia

     Beach  erosion  affects  all  coastal  countries  of  the world,  including

     The environmental consequences have often been devastating.  In some cases,
whole communities  have  been displaced --or worse,  wiped out.   In  addition to
extensive personal properties, major  losses have  included port  facilities,
building infrastructures, recreational facilities, and agricultural,  industrial,
and residential  land.

     As more and more infrastructures are developed along shorelines,  erosion
seems to  accelerate because of the  nature  of the  type of development.  For
instance, port facilities tend to  promote erosion.   It is, therefore,  essential
to keep  in mind the interaction of developmental activities with natural  factors
so that such development is not threatened at a later  date.  For example, the
construction of  the Free Port  of Monrovia, the Hotel Africa, and the Villas has
accelerated  erosion, causing loss of  beaches  and buildings down  the coast.

     Sea level   rise from the  greenhouse effect would  aggravate all  of  these
problems. Unfortunately the Ministry responsible for assessing erosion  has not
conducted any studies of the implications, of  sea level  rise, and we  were unable
to undertake even a preliminary inventory of the likely consequence --  let alone
the appropriate response strategies.  Nevertheless, the Ministry of Lands, Mines,
and Energy recognizes the increasing  importance of global warming and the need
to participate in the international process. Given these  limitations, this paper
discusses Liberia's current thinking on existing erosion problems, with  a hope
that it will  help researchers trying to understand how our country would  respond
to accelerated sea  level rise.

West Africa

The Importance of Erosion

     Coastal erosion  is  a  dynamic  process  resulting from an imbalance between
sand  accretion  and  erosion by  the sea  or wind.   When  equilibrium  is  not
established between accretion and removal of sand, erosion becomes inevitable.

     Both  manmade and  natural  factors  induce  shifts  in  the  equilibrium of
alongshore transport.  General topographic, geologic, and meteorological features
constitute  natural  process  components,  while  the  construction  of  hydraulic
structures, such as port  facilities, dams, buildings, and beach mining, tends to
induce the artificial component.

     Control  of  coastal  erosion  is  very  important  in the  context  of  the
development and management of coastal environments.  However, choosing the type
of technology appropriate for solving this  problem requires an understanding of
three essential elements:

     t   the basic physical processes of coastal  erosion,  such as wave behavior,
         currents,  and tides;

        human-induced (anthropogenic) changes in  the physical coastal process,
         which  also contribute to erosion;  and

        the structural  and  nonstructural solutions  to  the problem.

While physical  factors  and the  range  of appropriate  technologies may exist,
sometimes for a developing country  the decision  of which  technology to use with
regard to  cost  becomes  very complicated  because  of the relative scarcity of
resources needed for the solution -- e.g., equipment,  skilled manpower, financial

     The development  along  the  coastal  zone has been dramatic  in  the last few
decades.   Construction has included resort settlements, residences, commercial
harbors,  and a  few coastal  defense  structures.  Most  of these  structures were
built  in  response  to  a particular  situation  and with  little  concern  for
environmental  or downcoast impacts.


     The coastal perimeter consists of both landward and seaward  portions of the
shoreline.  Erosion  of  the shoreline  starts when the  removal  of  sediments is
greater than accretion.    Both of these  processes  -- erosion and deposition --
constantly occur  along  the shoreline.   Therefore,  an  assessment  of  shoreline
erosion must consider the difference in the rates of erosion and accretion within
a fixed time span.

     The sources  of  the sand we find  on the shoreline  originate from upland
drainage systems -- e.g., rivers, coastal fastlands,  and offshore outcropping of
landward deposits.  These systems are responsible  in the  long run  for secondary



sources, such as beaches,  sand dunes, and offshore deposits.  Any disturbance of
these source materials, for example by wind  and  water,  which  are the ultimate
agents responsible for accretion and removal  of coastal  material, will lead to

     The natural processes  of erosion are usually impossible  to  resist.   The
natural  shoreline  is  a  result of  the interaction  between  the  processes  of
erosion, accretion, and meteorological and oceanographic conditions. Any changes
in one of these  conditions will result in the transgression or regression of the
shoreline.   Natural erosion is a geological process that seeks to establish an
equilibrium among the natural  forces.  Examples of natural processes of erosion
include the influences of tides, waves, eustatic changes in sea level, storms,
hurricanes, tsunamis, coastal  characteristics, and loss of sediment supply.


     A  significant  amount  of  erosion  is due  to  improperly planned  human
interferences with  natural coastal processes, such as  dam and port construction,
beach sand mining,  drainage alteration, devegetation  and farming,  construction
near the shore  and  beach,  disposal  of solid waste and  landfill  sludge,  inlet
stabilization, and dredging.

     The coast of Liberia is approximately  600 kilometers (350 miles) long.  It
includes deltaic plains,  fan deltas, coastal plains,  and steep slopes produced
by faulting  and intense  erosion.    Part  of the coastline is  characterized by
drowned valleys with bays,  promontories, and  pocket  beaches.   Portions of the
coastline are composed  of sand pits,  barrier beaches,  and lagoonal environments.

     Sands of the  Liberian  coast drift from  Harper  City in the  southeast to
Robertsport City in the northwest.   It has been estimated that 7.2 x  106 cubic
meters are  transported  from  rivers annually, and that  some 20% of this volume is
redeposited on the  coast.  A decrease in supply of sand  is due to a decrease in
the transport of river sediment and  the rate  of  littoral drift,  which results
from the construction of manmade structures on the coast.

     Studies  and  remedies  related   to  coastal  erosion  are  primarily  the
responsibilities of the Ministries of Lands, Mines, and Energy;  Public Works; and
Rural Development.

     Three  organizations  have  conducted  studies  on the  coastal  erosion  of
Liberia: the  Japanese  Agency for  International  Development;  the  Ministry  of
Lands, Mines, and Energy;  and the LAMCO J.V.  Operation Company.


West Africa

Japanese Activities

     In 1978,  the Japanese Agency for International Development conducted studies
for three weeks to  identify the various causes  of  erosion  along the Liberian
coastline.  Their studies took them to Robertsport, Greenville,  Harper, Buchanan,
and Monrovia.  Two  principal  causes of  erosion  were identified by the Agency:
(1) drifting  of river  outlets, and  (2)  changes in  the balance  of littoral
transport caused by blockage of natural  sand drifting, which was the result of
human activities -- e.g., construction  of breakwaters, beach mining,  and possible
reduction of  sand  supply  from the  rivers by the  construction of the St. Paul
River Dam.

LAMCO J.V. Operating Company

     The rate of erosion increased tremendously in Buchanan after erection  of the
breakwaters,  especially  within the port  area.    Although sand  was  naturally
deposited east of those structures, active beach  mining has also been intensive,
thereby accelerating the process of erosion.

     In recognition  of these  threats  to the beaches with  regard  to  coastal
erosion,  the Ministry  of  Lands,  Mines,  and  Energy  recommended that  LAMCO
undertake countermeasures, especially  north  of Buchanan, either by constructing
groins  or  by providing artificial  sand nourishment.   Dr.  Eugene  H.  Shannon
(Director, Liberian Geological Survey) et al.  (1979) reported that two groins,
each reportedly valued at  $35,000 (U.S.  dollars)  were  constructed and proved to
be  rather  effective at the  time.   Boulder dumping was  also instrumental  in
reinforcing the shoreline  against erosion.  After this exercise, the Ministry of
Lands,  Mines,  and  Energy  devised a scheme  --  Environmental  Monitoring  --to
monitor the extent of beach erosion from time to time in Buchanan.

     Whereas the degree of protection  was adequate in  certain  areas, other side
effects  developed,   especially along  Atlantic  Street  in   Buchanan.    While
government, through the Ministry of Lands,  Mines and Energy,  has continuously
recommended that LAMCO establish more  groin systems, progress has been slow.

The Liberian Government

     Realizing the  degradation of  the  country's shorelines  by wave  action,
especially along areas with exorbitant  infrastructures, the Government of Liberia
set up a special  technical committee in  1981,  headed by the  Ministry of Lands,
Mines, and Energy,  to investigate and  find  means of  safeguarding Hotel  Africa,
the adjacent villas, and the beach.  Other Ministries  included Public Works and
Rural  Development.   After some studies, the  committee estimated  the  rate  of
erosion as approximately 10 feet (3 meters)  per  year.

     Dr.  Ntungwa  Maasha,  formerly Head of  the Geology Department  of  the
University of Liberia, conducted a study  between 1980 and 1982  along the Monrovia
coastline between Wamba Town  and Yatono.   Results of  his  study  indicate that 80%
of the coastline of Monrovia consists  of sandy beaches that  erode at a rate of
0.5 to 4 meters per year.   The  only depositional   area  identified was West Point



beach, south of the Free Port of Monrovia.  Natural shorelines were  identified
in the vicinity of lagoons.  Dr. Maasha also reported that the littoral drift  is
everywhere from southeast to northwest, and that the long-shore current velocity
varies between 16 and 31 cm/sec.

     A three-man Swedish team consisting of Hans Hanson, Lennart Jonsson,  and  Bo
Broms conducted a  one-week  study  in 1983  along selected areas of the Liberian
coastline.  Besides substantiating  that harbor construction  and other forms  of
human interferences  have aggravated the erosion problem,  they  gave an  annual
figure of about 50,000-60,000  cubic meters  of  sand  respectively, for  deposition
and erosion south  of the Free Port of Monrovia.  They reported the sediment yield
of the St. Paul River as 1.5 x  106 cubic meters/year.  They  also reported that
the most frequent waves arrive from  south to southwest, and  that their heights
change seasonally from  1.3  m  (highest)  in  June to  0.6 (lowest)  in March.  For
littoral transport, a wave  height of about 1.1 m is said to  be representative.
A semidiurnal tide is also  reported, with a tidal range of about 1-1.5 m.  The
tide induces long-shore  currents with ebb stream directed to the south and  north,
respectively, flood currents being much weaker (5-15 cm/sec, as opposed to 15-45
m/sec for ebb currents).


     Like most  coastal  nations, Liberia is  faced  with serious problems as a
result of changes in the configuration of its shoreline due  to the activity of
the ocean waves.  Erosion is causing shoreline recession in  some cities  -- for
example,  in  Buchanan,  Greenville,  Harper, and  Robertsport.  Most recently,
alarming incidents of beach erosion along some portions of the  Monrovia coastline
have resulted in loss of land and shorefront properties.

     Because of the economic and  environmental  problems associated with beach
erosion, the Government  of  Liberia  --  through the  Liberian Geological  Survey,
Department of Mineral  Exploration and Environmental  Research,  Ministry of Lands,
Mines and  Energy,  the University  of Liberia, other  government  agencies,  and
foreign institutions,  as mentioned in the previous  section  -- has endeavored to
implement beach erosion  studies and recommend possible remedial measures related
to the development of  shorefront properties.  However,  all  of  these studies have
been focused on Monrovia as a result of finance.

OAU Village

     The  beach of  the   OAU Village  area  is  characterized  by  more or less
horizontal layers  of  black  and brown-white,  unconsolidated,  medium- to  fine-
grained  sands.    In  some  areas,  especially  around  Fanti  Town,  diabase  and
melanocratic gneisses  outcrop in the sea and serve as wave barriers.  As a result
of the change in the balance of littoral  transport caused by blockage  of natural
sand drift resulting from human interferences, the  beach of the  OAU Village is
estimated to be receding at the rate of 3  meters a  year.

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New Kru Town Area

     The New Kru Town area is characterized by very fine- to medium-grained sand.
The area is separated from the OAU Village by the  St. Paul River.  At the mouth
of the St.  Paul  River,  the beach is flat and  broad, and  it is composed of poorly
stratified white clayey sand, which is dusty and crumbly when dry.

     The recession rate around the New Kru Town area is  more or less  the same as
around the OAU Village area. The area is affected by the same phenomena.  Away
from  St.  Paul  River,  toward  Point Four,  the beach  face becomes narrower,
gradually developing into a high escarpment  about 5-7 meters higher.

West Point - Mamba Point Area

     The West Point spit/bar,  which lies at the mouth of the Mesurado River, has
characteristics similar to  those  of the  area  around the St.  Paul area, except
that in West Point the flat and broad floodplain of  the Mesurado River has been
destroyed by  manmade structures,  mainly zinc  shacks.   The Mamba Point area,
however, is characterized by massive diabase outcrops with steep cliffs, which
reflect  wave energy,  induce  offshore  sediment  transport,   and prevent  the
formation of  any  beach.   The diabase is well  jointed  horizontally  as well as
vertically.  Boulders of diabase that have been undermined by wave  action can be
seen in the  littoral  zone.  West Point-Mamba  Point  is the only  area that has been
identified as a  depositional area,  especially south of the Free Port of Monrovia.

     The strip of shoreline  from Cape Mesurado to the OAU Village area is within
an embayment.  Wave activity is much more complex  because of wave refraction at
the cape and  at the Free Port breakwaters.   This human interference  has thus
created an imbalance in the  geomorphic system,  and  the adjustments  in morphology
need to be critically  investigated.

Namba Point - Elwa Area

     The beach  area between  Elwa  and Mamba Point  is  mainly  characterized by
coarse-to-medium  to  fine-grained  sand  in alternating  black  and  white layers.
With the exception of the area behind the Executive  Mansion and near King Gray,
where  large  diabase outcrops are  discernible,  the  rest of the  beach  area is
uniform, with sporadic diabase outcrops in the area.

     There is an  unusual  increase in black  sand (heavy minerals) in the Congo
Town area, with band thickness ranging from 1  to  2 feet in  some places.  This
area of increased heavy mineral  occurrences  is  low-lying, swampy, and separated
from the mainland by small  lagoons.

     Neutral  shorelines were  identified  in  the vicinity of lagoons  where sand
accretion and san removal are more or less in equilibrium.



     The methodology employed by the Liberian Geological Survey in the erosion
studies  of  Liberia  includes  beach  profiling,  sediment  sampling,  and  the
observation and measurement of the littoral  parameters in  the  field, as well as
granulometric analyses in the laboratory.  Aerial photographs and maps were also
used to establish stations for studying and future monitoring (Figure 1).

Field Methods

     A ground  survey of the entire  35-km Monrovia coastline between  the OAU
Village area  and ELWA was  conducted between May  and July 1984.   During the
survey, activities were mainly geared toward  a better understanding of prevailing
sedimentary processes and also the dynamics of the Monrovia  littoral environment.
The following paragraphs provide a complete breakdown of field activities.

Beach Profiling

     Permanent features, such as trees, house fences, and electric poles, were
used as reference (bench) marks for profile measurements.  In the  absence of such
features,  temporary  markers  were installed for  easy  location.   Profiles were
measured along lines  perpendicular to the shoreline and extending  to the existing
water line.  Conspicuous  morphological features along the active  beach face were
used as survey points.   Measurements were made  using a surveyor's  level  and a
stadia rod,  and each station  included a  series of substations adequately spaced
along the beach.

Slope Measurement

     The foreshore slope angle was measured directly using  the  clinometer of the
Brunton compass  leveled  on undisturbed  portions  of beach  slope.  Angle values
given represent an average of readings  collected  from  various  places at a given

Wave Measurement

     The wave  periods at  various locations were estimated by  timing the breaking
interval  of incoming  waves.   At each location,  the estimate was  done  in
triplicate and the mean was used as the representative value. These mean values
were then  combined in statistical fashion, and the resulting  average was used as
the representative value  for  Monrovia and its environs.  The  average wave period
was subsequently used to empirically calculate  other  wave parameters,  such as
length, height, and celerity.

Wind Direction

     The direction of wind movement was  measured  using a  flag and a  Brunton
compass.  The  flag was placed on  the  beach,  and the compass  was aligned with it
to  give  the  direction  of wind  approach.   The various  directions  obtained
throughout the study area were combined  statistically  to give an average value.


West Africa
                                                                                JOHNSON VILLE
              EXPL AMATION

            Station Location

                                             KINS  8RAY
Figure  1.  Station location map  (Monrovia  Beach study).



Sediment Sampling

     The width of the beach varies from 9 m to 27 m.  Therefore,  a single  sample
taken at a station would not serve as a  representative sample of a given  station.
For  this  reason, a  triangular pattern was  used in sampling  each station or
substation, with samples taken at  the  three  apexes, as shown in  Figure 2.

     All samples marked A are  those taken on the berm or overwash terrace, while
those marked B and C  were taken at the sea edge and at the midpoint between A and
B, respectively.

     Each  sample was approximately labeled  commensurate with  the station or
substation number.   A geologic description of each sample was noted in the field

Wave Mechanics of Monrovia and Its  Environs

     Waves approach obliquely  to the shoreline in Monrovia and its environs.   The
obliqueness  increases in the  area immediately  north  of Cape  Mesurado,  where
shoreline orientation approaches  parallelism  with the apparent direction of  wave

     Of a total of 40 readings of the direction  of  wind approach,  28 are  toward
the southwest, 4 toward the northwest, and 8 toward the southeast  (Table 1  and
Figure 3).  Values to the southwest are more frequent; they have a range of 77
degrees, a mean of 38.3 degrees, and a standard deviation of 25 degrees.   This
indicates that  at  the beginning of the rainy season  (May-June), the Monrovia
coastline receives  winds  coming predominantly  from  the  southwest (Figure  3).
Considering wind-generated waves  (sea waves), the estimated  average direction of
wave approach is South 38 degrees West.  This bearing compares closely with  wind
records at the Spriggs Payne Airfield Meteorological Station.

     The mean wave period for the Monrovia coastline is about 12.96 seconds.   The
statistical analysis  is shown  in Table 2.   Using empirical  equations (Friedman
and Sanders,  1978),  the deep-water wavelength (L0)  and the deep-water celerity
(C0)  were  calculated as follows:

     L0  =    1.56T2
        =   262.02 m
        =   1.56T
            20.22 m/sec             Where T = wave period.

These values correspond to an  initial breaker depth (H,)  of 13.3 m (L0/20),  and
the associated deep-water weave height  (H0)  is  found to be  10.22  m (0.039  L0).
Considering transformation due to  shallow-water  conditions,  the wave-length  (L,)
and the celerity (C,)  at  initial   breaking are  found  to  be 139.1  m and  11.33
m/sec, respectively.  Wave height  at initial breaking  (H,)  is found to be  10.4
m, and wave break mainly by plunging, with spilling types being observed  in a few
places.   In the opinion of the authors, the landward limit of the breaker  zone
will  be marked by a water depth equal to about one-half the deep-water wave


West Africa
                 BEACH  FACE
                              SEA  EDGE
                                                  BEACH  FACE
                                                          SEA  EDGE
 Figure  2(A).   Sample pattern in plan view.
 Figure 2(B).  Sample pattern  in  profile.

Table 1.
Statistical Analysis of Wind Direction Along the Monrovia  Coastline
(1984 data)
Measured Direction of wind Approach (.Flagging
Set 1
1 8
v) 9

(f 1)
^f,n(- 28
Set 2

(f 2)

^f mn9  8

Set 3



^ j. n? __
Where IN Totol ** of meaeured values

N* 28 t 8 t 4 =40

n. 28/ x 100  70% of It
1 /40

2 * 8 / j^ 1 00 = 2 0% w
n  4y * 100  10% *
Figure 3.   Diagrammatic  illustration  of dominant wind approach  for Monrovia,
based on Table 1.

West Africa

Table 2.  Statistical Treatment  of  Wave  Period  Along the Monrovia Coastline

(f) (x)
1. 00
(7.5 )

                                                           -GROUPING INTERVALS CONSIDERED
1) 4.5
2) 6.5
3) 8.5
4) 10.5
5) 12.5
6) 14.5
7) 16.5
8) 18.5
- 6.5
- 8.5
                                                               Mode  -14.0 sec.

                                                               Median- 13.1 "
                                                               Mean  - 12.96 "
 n = 62; x - 12,96 a - 2.53  sec.
height  (H0/2).   At  this arbitrary  depth  of final  breaking  (h =  5.11  m),  the
characteristic wavelength (Lt)  and celerity  (Cf) are found to  be 90.92 m and 7.08
m/sec, respectively.  The wave height at final  breaking (Hf)  is also found to be
12.57 m.

     The beaches of Monrovia are characterized by medium- to coarse-grained sand,
consisting  of  mostly  quartz,  with  iron  stains  that give  a  brownish-white
appearance.  Heavy minerals (black  sand) occur in minor amounts throughout, with
an apparent increase in the Congo  Town  and  ELWA areas,  as evidenced by locally
high bulk densities.

     Representative  histograms of  the  beach sand are  shown  in Figure  4 with
respect to locality and the dominant size fractions, and a generalized variation
line is shown  in Figure 5.  Local deviations  from this general line were observed
in the vicinity  of rock shorelines where grain  size  is  apparently larger.

                                                             BEACH SAND


                                                             MOTOR ROAD

                                                             RIVER OR CREEK

                                                             SAMPLE LOCATION FOR
                                                                  g UNITS -2-1  0  I  2  3  4

                                                                        4  t  I  1/2 l/ l/ I/IS
                                                                       PHI.MILLI>*TER CONVERSION
Figure  4.  Map showing sediment  size  variation along  the  coast of  Monrovia (OAU-

Hest Africa

                        1st Most frequent interval

                     o   g id  ii     ii     n
Phi 	 Generalized
o ^,-s
1 . 	 -'' \
o o \
i %* 'I
$ Q. i
variation line (m

  o o- o
0 '" 0 - ^ **
8 IH ^ || 3| |^

. .125
- .063
* is I8 1
2 "
Figure 5.   Graphical  illustration of dominant  grain size fractions  along the
Monrovia coastline.
Littoral Drift

     The littoral drift  along the Monrovia coastline is toward  the northwest.
Using the calculated deep-water wave height (H0), the potential longshore energy
flux  (Pis)  and  the  potential  longshore  sediment  transport   rate  (Q)  were
calculated using a representative incidence angle of 78 degrees obtained for the
ELWA-Cape Mesurado shoreline.  According to Sabawa et al. (1981), the calculation
is as follows:

     Pis = 18.3 Ho  5/2(cos a) 1/4sin 2a

         = 1678 joules/sec

         Where a  =  angle of wave of incidence.

              Q = 7.5 x  103 (Pis)

                = 1.26 x  107 m3/yr



     Within the nearshore zone, littoral  transport will  be  affected  by waves of
translation.   The height  of these trans!atory  waves was  evaluated  from the
difference between wave  height at  various  points of breaking and the original
wave height (H0).   Hence, the minimum height of the waves of translation along
the coast of Monrovia  is estimated  as  0.2  m (H,-^), and the maximum height is
estimated  as  2.35  (H,-H0).   However,  a  representative height  (Hr)  of these
translatory waves was  estimated using  the mean  of  H, and  H,  (H.),  and the
calculation is given below:

     Hm = (H, + H,)/2

        = 11.495 m2

        = 11.495  - 10.22

        =  1.275 m

     Therefore, for the littoral  transport,  a wave height of about 1.3 m  is most
probably representative  of Monrovia.   Using this value for H0 in the equation
given previously,  the longshore energy flux is  found to  be 9.68 joules/sec, and
the longshore sediment transport rate is found to be 7.26 x 104  m3/yr.

     The angle of wave incidence for that portion of the study area  immediately
north of Cape Mesurado  is about 15 degrees.  The longshore energy  flux along this
strip is estimated as 17.47 joules/sec,  and the longshore sediment transport rate
is estimated as 1.31 x 105  m3/yr.

     The littoral  drift is therefore greater within the vicinity of the Free Port
breakwaters.  This indicates that waves within this area have a greater capacity
to transport coastal materials along the shore.


     Various methods are  available to fight the  coastal  erosion problem, but
basically they fall under either structural control or nonstructural control.

Nonstructural  Control Methods

     Most nonstructural methods only lessen or regulate the problems caused by
erosion, rather than prevent,  halt, or retard  erosion.   They are grouped into
passive and active methods.

Passive Methods

     The passive methods include:

        Land-Use  Controls:   This means that permission should be granted only
         for structures that have to occupy waterfront sites. All the structures
         associated  with permitted  waterfront should be movable  or, at worst,


Uest Africa
         semipermanent  and  capable of quick, inexpensive  repair.   They should
         always  be designed  to minimize damage.

        Coastal Setback Lines:  This requires that all constructions on coastal
         front should be placed  at  a  safe distance from the shoreline.

Active Methods

        Move Threatened Structures:  Threatened structures must be moved a safe
         distance from the shoreline.  This  may  be less expensive than trying to
         control the erosion that threatens  them.

        Vegetative Methods:   These methods serve to slow the rate of erosion,
         rather  than  stop it.   They include stabilization of sand  dunes,  and
         bluff and bank  slopes with plantings,  as well  as the creation of salt
         marshes  to  absorb  wave  energy.     These  methods are  employed  with
         structural methods.  For example, where a seawall or revetment is used
         to stabilize the base of a cliff, bluff, or  bank,  plantings may be made
         to control erosion  from surface runoff and  wave overtopping.

     Whenever possible and economically practical,  every effort should be made
to correct or modify manmade increases in coastal  erosion before building what
may turn out to be much more costly erosion control  structures.

Structural Methods of Erosion Control

     Shoreline-hardening  structures  make   the  land mass more  resistant  to
erosional forces and protect facilities landward from the  effect of wave action.
They tend to protect only landward infrastructures and have no beneficial effects
on  adjacent  shorelines or  on  beaches seaward  of   them.   Shoreline-hardening
structures include  seawalls, revetments,  and  bulkheads  (see  Appendix  2  for
diagrams and pictures  of these structures).   The characteristic design of these
structures will  depend on the height, length, shape, and degree of differences
in texture permeability of porosity.


     Because  of the  extent  of  beach  erosion  and  its imminent  threat  to
investment, especially along the coastal front,  the Ministry of Public Works has
proposed a temporary solution for reducing the rate  of erosion at the site.  The
technicians at the Ministry have estimated  125  working  days  at a total cost of
$2.4 million (U.S. dollars).  The project includes boulder dumping (with a clay
dam on the villas side facing the  sea) over an area  1,800  feet long and 50 feet
wide.  Engineering consultants estimated that 100,000 cubic yards of boulders and
40,000 cubic yards of clay would be required (see Appendix 1).

     The Ministry of  Rural  Development also  recommended the following tentative
structural measures that are capable of minimizing the erosion problems at Hotel
Africa:  Appendix 2,  a stone revetment ($0.98 million,  U.S.  dollars); Appendix



2, a curved-face wall ($2.7 million, U.S. dollars);  Appendix 2,  bulkheads  ($1.8
million, U.S. dollars);  and Appendix  2,  a  concrete  revetment.

     But these structures are just a first  step for a small part of the Liberian
coast.   At  this  time it  is  difficult  for  us to  contemplate the  nationwide
response to  a  rise in sea level from the greenhouse effect.   Nevertheless,  we
conclude with  the  recommendations that would help us address both the  current
problems and the additional problems  resulting from global  warming.

     1.  During the dredging of the port by  the National Port Authority, all  sand
         removed from the port should be deposited on the beach near  the Hotel
         Africa for nourishment of the shoreline.

     2.  The  National  Port  Authority  should  be  included  on  the   technical
         committee  for future  study of beach  erosion.

     3.  Funds  should be appropriated to the Technical Committee  for  logistics
         that should  be used to monitor the rate of erosion.   This  would  provide
         data for potential consultants.  Also, a soil conservation and pollution
         control  division should be developed and empowered to undertake long-
         range  measures  for adequate monitoring.

     4.  A  Beach Erosion  Control  Commission should be  created.

     5.  Specific beaches should be designated  for sand  mining.


Fayia, A.K.,  J.B. Massah, F.T. Morlu and B.O.  Weeks,  B.O.  1987.  A Survey of the
Monrovia Beaches.  Monrovia:  Liberian Geological Survey.

Friedman, G.M., and J.E.  Sanders.  1978.  Principles of Sedimentology.   New York:
John Wiley and Sons,  Inc..

Hanson, H., L.  Johnson and B. Broms.  1984.  Beach Erosion in Liberia:  Causes and
Remedial Measures.   Lund, Sweden:  University of Lund.

Japan International Cooperation Agency.  1978.   Report on the Beach Erosion  in
the Republic of Liberia.  Tokyo:  Japan  International Cooperation Agency.

Maasha, N.   1982.   Erosion of the Monrovia Beaches.  Monrovia:  University  of
Liberia, Department of Research.

GDL.   1981.  Government of Liberia.  Report  on "Seminar of Beach  Erosion at Hotel
Africa" OAU Village, Virginia, Liberia:  Government of Liberia, Lands, Mines &
Energy, Public Works & Rural Development, Technical Committee.

Shulze, W.  1971.  Notes on settlement  research in Liberia.  In:  Rural Africana,
No. 15, Liberia: An  Evaluation  of Rural  Research.  East Lansing, MI:  Michigan


Uest Africa

State University.

U.N.D.P.  1972.  United Nations Development Program.  Heavy Mineral Occurrence
Between Monrovia and  Marshall.   Technical  report No. 5.   Monrovia:   Liberian
Geological Survey.

White, R.W.  1972.  Stratigraph and Structure of Basins on  the Coast of Liberia.
Liberian  Geological   Survey  Special  Paper No.  1.    Monrovia:   Ministry of
Information Press.


                                  APPENDIX 1

                          ESTIMATE FROM PUBLIC WORKS
                             (Temporary Solution)

Subject:    To prevent the coastal erosion at the OAU Village by the sea.

     In order to start the work on temporary solution,  an access  road is needed.

1.   Mobilization for access road.

     A.  Access  road  12'  wide  6" thickness  laterite  surface length  = 1,800'
         laterite  =  1,000 C.Y.


         1.4 dump  trucks
         2.1 grader
         3.1 front end loader

         Fuel  consumption:

         4  x 25  gallon per day/trucks      =  100 gallons
         40 gallons  per day/grader         =   40 gallons
         35 gallons  per day/front end
           loader                          =   35 gallons
                                             175 gallons/day

         For 7 working days, all  equipment  =  1,250 gallons.   1250 gallons of
         fuel  for  the  access road, and  100 gallons of gasoline.

         Total cost  for fuel consumption @$1.88 x  1,250   =  $2,350.00
         Total cost  for gasoline  consumption  @$2.09  x 100 =  $  209.00

Temporary Solution;

     Although this solution  is  costly,  it  will delay the rate of erosion at the
site.  Also,  the sand hauling  from the beach around the area should be stopped
by the authorities.

     The attached drawing gives a physical  picture of what is needed at the site
in question and the following  are the descriptions:

1.   Rolder Rock --  with  clay dam on the Village  side and facing  the sea will be
     the Rolder with  the  length of about  1,800'  and 50'  wide  at the  top about
     100,000 cubic yards  (cu. yd.) of Rolder will  be  needed and about 40,000 cu.
     yd. Clay will be needed.


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     1 Engineer               9  $40.00/day     =  $ 40.00
     1 Superintendent         @  $30.00/day     =  $ 30.00
     20 Truck Drivers         @  $10.00/day     =  $200.00
     20 Laborers              9  $ 7.70/day     =  $154.00
     10 Operators             @  $12.50/day     =  $125.00

                                    Sub-total   =  $650.00/day

     Equipment:                     Fuel Consumption/Day

     20 - 12 cu. yd.
       dump trucks            =             550/day
      2 Trexcavators          =             100/day
      1 Dozer D/C             =              50/day
      1 Front end loader      =              35/day
      1 Mobile crane          =              50/day
      2 Pick-ups              =              20/day (gas)
      1 Man-haul truck        =              15/day
      1 Compressor*           =             830/day
      2 Tankers*

* Plus 20% contingency fuel for emergency equipment of the total consumption.

     Minimum haulage/day:

     4 Trips/day  =  12 x 4 = 48 cu. yd.
     40 cu. yd. Truck/day
     Total volume of rock needed  =  120,000 cu. yd.
       for 20 Trucks = 48 x 20 = 960
        No. =  120.000         =     1.000       =  125 days
                 960                  8


     $650.00 x 125 days                   =           $   78,000.00
     $15/cu. yd. x 12,000
       (cost of B. Rock)                  =           $    1,800.00
     Cost of fuel  100 x 125 x $1.88      =           $  235,000.00
     Plus 25% of fuel cost for:
       Lubricant and fast moving parts    =           $   60,000.00
     Gasoline 2.09 x 250                  =           $    5.225.00

                                    Grand Total       $2,178,225.00
     Plus 10% contingency                             $  217.822.50
                                    Total             $2,396,047.50

     It should be noted that this  solution will  only delay the rate of erosion,
until a permanent solution is to be found.



Permanent Solution:

     There should be a comprehensive study by the Engineering Division to find
the causes of the erosion and the factors influencing it.  The following facts
have to be known:

     a)  Direction of wind
     b)  Frequency of waves
     c)  Direction of waves
     d)  Height of tide
     e)  Topography of the area
     f)  Soil test
                                                Submitted by:  Emmanuel Oseni

West Africa
                                  APPENDIX 2

                                STONE  REVETMENT

  (above 400 Iba)






                                      Grand Total

$ 419,112.50

$  702,012.50
$   84,241.50

$  979.307.44
                               CURVED FACE WALL

Concrete Work
Form Work

Pile Work

Back Filing
Front Filing

1955. cu.yd.
6286.67 cu.yd.
12% of concrete
15% of concrete
8941.04 cu.yd.
1257.33 cu.yd.


                           Plus 15% contingency:

                                    Grand Total:
$   30,315.68





                              BULKHEAD ESTIMATES


50,293.33 cu.yd.

                                      Grand Total



                                  Stone  Revetment
                                              RIPRAP (lOOOIbs to 6000lb  Averaging 4000lbi)
                                                      Chinked Witil  One Man Stone
                                                                      NATURAL BEACH  LINE
                                    One Man  Stone
                                    20lbs  to 150 Ibs
                                 Concrete Revetment
     These are lighter construction which primarily functions as  shore or beach
protection against  erosion from wave, tide,  or current  actions.
                                        SLAI '/if' &tJteLlD
                                             ft -
                                     SECTION  THROUGH SLAB
                                         UNDER  JOINT

      Vest Africa
                                 Curved Face  Wall  (Seawall)
           This  structure is used  for moderately severe  wave action where the water
      level is over the structural  base,  permitting the  full waves to  hit the wall.
      This structure  could also be used where  poor  foundations exist.
                                  Bulkheads  (Breakwaters)
           The primary  function  of bulkheads  is  to retain  fill  and  secondarily  to
      resist wave action.

                                     RIPRAP  I IDOOIk-OOO*)AB1
                                          4000w CM*** MM OM
     (photographs reproduced by permission of the Koppers Co.,  Inc.,  Pittsburgh,  PA

                       L.F.  AWOSIKA and  A.C.  IBE
      Nigerian Institute  for Oceanography and Marine Research
                              Lagos,  Nigeria


                               M.A. UDO-AKA
             Federal  Ministry of Science and Technology
                      Kofo Abayomi,  Lagos, Nigeria

     Widespread erosion, flooding,  and  subsidence are already devastating vast
areas of the Nigerian coastline causing  severe  ecological problems that have
compelled the federal government to set up a special  relief fund to mitigate the
impact.   A rise in sea level of approximately 1 m would aggravate the existing
ecological   problems  through  accelerated  coastal  erosion,   more persistent
flooding, loss of ecologically significant wetlands, increased salinization of
rivers and groundwater aquifers, and greater influx of diverse  pollutants. Other
socioeconomic impacts include uprooting  human settlements, disrupting oil  and gas
production,  dislodging  port and navigational  structures,  upsetting  the rich
fishery, forcing businesses and  industries to relocate,  wiping out the fledgling
coast based-tourism, and generally  increasing the level of misery. The  several
engineering  counter-measures being  presently proposed for coping with sea level
rise are too expensive for a developing country like Nigeria with huge external
debts.  Responding to sea level  rise should consist largely of  keeping some steps
ahead of the projected rise by slowly "disengaging" from the coast where possible
and establishing and enforcing set-back lines in areas of new development. Where
this  is  not possible,  as in heavily  built up  areas,  emphasis  should be on
developing and implementing low-cost, low-technology, but nonetheless effective


     Along  the coastal  zone, probably  the main  consequence  of an increase in
global temperatures is an  accelerated rise in global sea level. This will be due
to the melting  of alpine and polar glaciers and the thermal  expansion of the
ocean surface.


West Africa

     Estimates of the  projected  rise in sea level differ,  sometimes markedly
(e.g., from 0.45 to 3.65 m, according to various estimates), but the following
assumptions were  accepted  at  the UNEP/ICSU/WMO  International Conference  in
Villach, 9-15 October  1985:  increased  temperature of 1.5-4.5C and sea level
rise of 20-140 cm before the end of the 21st century, with the understanding that
these estimates may be revised on the basis of new scientific evidence.

     This paper examines the potential  impact of climate change on the coastal
and marine environment in Nigeria and suggests certain suitable policy options
and response measures that may mitigate the negative consequences of the impact.


     The Nigerian coastal zone extends for a distance of about 800 km between the
western  and eastern borders of  the  country with the Republics of  Benin  and
Cameroun, respectively. It lies generally between 410' and 620'N latitudes and
245' and 835'E longitudes adjacent to the Gulf of Guinea.

     The coastal zone  is mounted  on a voluminous, though localized, sedimentary
protrusion into the Gulf of Guinea ocean  basin comprising a 12-km-thick pile of
Cretaceous and Tertiary sediments, close  to the juncture of two of the boundary
realms of  the Guinea  basin  (Allen,  1964).   The  origin  and evolution  of  the
Nigerian coastal zone  are  closely linked with the Mesozoic  (Upper  Jurasic  to
Lower Cretaceous)  opening of the  Atlantic Ocean  and  by different,  more recent
phases associated  with the  structural  deformation  of  the  East African  Rift

     The coast is bounded laterally to the north by an extensive river floodplain
(area, 8400 square  kilometers), which slopes southward from about 20 m above sea
level in the Onitsha gap (Figure  1).   This narrow zone is  mounted on the Benue
Valley and  contains the  main  channel  of the  Niger  River  before  and  after
bifurcation.   This plain  broadens  southward  with  a decrease  in  slope  and
subsequent increase in  the density of tributaries of the major drainage channels
and down to the coast.

     To the  south is the Continental  Shelf characterized by more or less uniform
gentle slopes broken at specific  points  by the  recognizable submarine canyons
(Avon, Mahin,  and  Calabar Canyons).

     The Nigerian coastal zone is composed of  four distinct units with different
surficial configurations (Figure  2).  A 200-km-long barrier lagoon coast in the
western part is  followed by 75  km of transgressive mud coast, which tapers into
the dominating 450-km-long  and beach-ridge-barrier-island-rimmed  Niger Delta;
farther to the east is an 85-km  Strand coast where mangrove fronts the  sea in the
extreme eastern corner.

     A common  feature of these geomorphic zones  is their low-lying nature.  Most
areas along these zones are less than 3 m in elevation.  The beach ridges on the
barrier islands that rim much of the coastline constitute  the highest grounds


                                                                 Awosika, et al.
rrrr\ MARINE
     n n iii
Figure 1.  Sketch map showing the main physiographic features of the coastal and
adjacent land  areas  (after Short and Stauble, 1967).
            BARRIER- LAGOON
Figure 2.   Map of  coastal  Nigeria  showing main geomorphic  units  (after  Ibe,

Vest Africa

with elevation of 2-3 m.  In the transgressive mud coast,  elevations of less than
1 m are common.

     An important feature of the  Nigerian coastal zone is that it  is part of an
actively subsiding geosyncline.   A sequence of dead coralline banks in shallow
waters off the Nigerian coast indicates stages in subsidence or rise in sea level
during the past 4,000 years (Allen and Wells,  1962).  More specifically, Burke
(1972) has proposed that all the  subsidence  (approximately 80 m in about 15,000
years  in  the  northwestern flank of the Niger  Delta)  can be  accounted  for by
eustatic sea  level rise  and isostatic  adjustment to water  load.   The Nigerian
coastal geosyncline is subsiding not only because  it was  formed  in an area of
subsidence but also because of the continued dewatering and compaction  of its
sediments that were deposited rapidly.   The present rates of subsidence are being
studied by  the authors.   The only  reliable figures available to date  reveal
subsidence rates  of more than 2.5  cm/yr at the site of a tank farm along the
deltaic coast, after correcting  for  loading effects caused by the  oil  in the
tanks  (Render Awani, personal communication, 1987).

Socioeconomic Setting

Settlement and Population

     The Nigerian Coastal zone comprises all of the Lagos,  Rivers, Cross River
and Akwa-Ibom states and the large southern  sections of the Ogun,  Ondo, Bendel,
and Imo states (Nigeria consists of 21 states).

     Recent population  projections  indicate  that  up  to  30  percent  of  the
estimated 100 million people in Nigeria live in  the  coastal zone with population
densities of  more  than 400  persons per square  kilometer in  urban centers like
Lagos, Warri,  Port Harcourt, and Calabar (Nigeria in maps,  1982).   Most of these
urban  centers are also port and  industrial  cities, which  accounts  for their
teaming  populations.    Lagos alone  is  thought to  harbour  about 8  million
inhabitants.  Most of those  urban centers are literarily  bursting  at their seams
with the continued rural-urban drift of the population.

     Apart from the large urban centers, several  important historical settlements
like  Badagry,  Forcados,  Brass,  Abonema, Opobo,  and Duke Town,  with  enduring
monuments of early European  contacts and trade, are located on or near the coast.
Populations reaching  150 persons per  square kilometer  are typical  of these
settlements.   Oil  exploration and exploitation  activities  in the coastal zone
have given rise to sprawling coastal settlements at Escravos, Brass, Bonny, and
Ibeno-Eket, and several  fishing  and trading  settlements, smaller  in size but no
less  significant  in  socioeconomic  terms,  dot the  coastal  zone.    Some  of the
fishing settlements now house fishing terminals with a large work force.


     Apart from a fledgling inland port at Onitsha, all other ports and harbors
in Nigeria  are located  naturally in the coastal  zone.   These ports  at Lagos
(Apapa and Tin Can), Warri,  Port Harcourt, Calabar,  Sapele, Bonny,  Burutu, Onne,


                                                               Awosika, et a7.

and Koko constitute the economic lifeline of the country supporting a hitherto
flourishing import-export trade.  Many canals, creeks, and rivers  in the coastal
zone, particularly in the Niger Delta, provide sometimes the only communication
links between coastal  towns  and  settlements  on  the one hand and between these
towns  and  settlements  and the  hinterlands  on  the other  hand.   This  water
transportation system  is  vital to  the country's economy in terms of passenger
traffic and goods haulage.

     Of the four functional international airports, only Aminu Kano International
Airport, located at Kano  to  the  north,  is  outside  the coastal  zone;  the other
three airports are at Lagos (Ikeja), Port-Harcourt,  and Calabar.  These airports
constitute a rapid link with the outside world and account for heavy movements
of persons, goods, and services to  and from Nigeria.  Many other local airports
and helipads in the coastal zone provide easy links to these large airports.

     The terminals of many road and rail systems in the country are located in
the coastal zone.  Besides very  important cross-country roads, transport networks
criss-cross the coastal  zone; in some cases, these are the only links between the
western and eastern regions of the country.


     The coastal  zone proximal  to the sea is  not fit for agriculture because of
the high salinization of soils and aquifers.   Beyond the present  limits of direct
marine influence are vast agricultural lands  afforded by the floodplains of the
Niger Delta and its numerous distributaries.  The major staples of Nigeria (such
as yams, cassava,  plantains, and  rice)  flourish on these  lands,  earning the
coastal zone the nickname  "food basket of southern Nigeria";  most of the produce
has found a favorable export market in West and Central  Africa.  A planned World
Bank-assisted swamp rice cultivation  project  will further boost food production
from the coastal zone.

     The coastal  zone fias been found to be a highly suitable area for mariculture
and  aquaculture techniques  to  enhance natural  fish  production.    Although
production from captive breeding  currently only modestly contributes to overall
fish production  from the  coastal  zone,  projections conservatively  place the
productive potential  from future  fish farming at a significant 175, 150-525,000
tons annually (Talabi and Ajayi, 1984).


     Nigeria has well over 2,000  industrial establishments, about 85 percent of
which are concentrated  in  the coastal zone.   The  coastal cities of Lagos, Warri,
and Port-Harcourt are centers of heavy industry;  products and activities include
iron and steel, automobile assembly, textiles, Pharmaceuticals, cement, soaps and
detergents, paints, refined petroleum products,  electronics, tires,  plastics,
brewing, beverages and  tobacco,  and wool and wood  products.  About  75 percent
Nigeria's manufacturing industries  are located in Lagos and  its environs.  Warri
and Port-Harcourt have two of the country's three petroleum refineries and two


Hest Africa

of its three petrochemical industries.  Warri hosts one of Nigeria's two iron and
steel industries.

     In both economic terms  and  physical layout, the oil industry dominates the
coastal  zone   (Figure  3).    Oil  production  and  export handling  facilities,
including structures associated  with the ongoing liquefied natural gas project,
dot the coastal  zone  with constellations  at  Escravos,  Forcados,  Warri, Brass,
Bonny, and Ibeno-Eket.

     Elsewhere along the coast, local and small-scale industries like wood works,
ceramics, weaving and, boat building flourish around coastal settlements.

Natural Resources

     The  Nigerian  coastal   zone   has  abundant  natural  resources  of  great
socioeconomic importance. These resources include forests and wildlife, a vast
fishery, minerals (including oil and gas), and surface and ground water.

Forests and Wildlife

     The natural vegetation  along  the Nigerian coastal  zone consists mainly of
strand vegetation consisting of Halophyllons, coastal thickets, and forest in the
area immediately adjacent to  the beaches.  Mangroves grow in  the lower Niger and
the northwestern flank of the Niger Delta.  The mangrove forests alone cover more
than 9,000 square kilometers.  The  mangrove swamps serve as spawning  and breeding
grounds for most of the finfish and shellfish resources in the  coastal zone.
Swamp and riparian forests are found along  the western region, in the upper Niger
Delta, and also fringing the banks of the  Niger up to Onitsha.  Forest reserves
exist on barrier-bar islands between the Benin and Forcados  River estuaries and
east of the Cross River estuary; these reserves form the raw materials for the
timber and  plywood  industries based in Sapele and Calabar  as well  as for the
paper and pulp industries in Iwopin and  Iku-Iboku.  Other natural forest products
within the coastal zone include  thriving wildlife (locally,  "bush meat"), which
boosts the protein availability  ,  as well as palm oil, fuel wood, and south palm
wine and its derivatives.  Apart from helping to meet the protein needs of the
country,  the  forest  is the  home  of  biologically diverse fauna  and flora,
including  medicinal  herbs,  that  provide  a  source of  scientific  interest and
tourist fascination.

Fisheries Resources

     Nigeria's coastal zone  is blessed with lagoons, creeks, estuaries and, of
course, the shallow inshore ocean, which constitute a major source of the fish
and fisheries products sought by artisanal fishermen.

     Before the advent of the oil  industry in the late 1950's the coastal zone
served as a base for much of the country's artisanal fisheries.  Myriad fishing
settlements established on  protected, better drained land or on stilts  in river
estuaries  and  beaches  were,  and are still, the dominant feature  of the well-
watered coastal  zone.  The artisanal fishermen and women who harvest fish,


                                                                Awosika,  et al.
 Figure  3.   The  lowland muddy  coast of  the Niger  Delta with  oil  handling
 facilities  in  the  background.

 shrimps,  and molluscs  in the fresh, brackish, and  immediate marine waters with
 set nets, traps, and other passive gear, use crafts ranging from paddled dugouts
 to motorized large canoes.  Ajayi and Talabi (1984), based on earlier surveys by
 Tobor et  al. (1977)  and  others, have  estimated the annual yield of the coastal
 and brackish water artisanal fisheries to be between  128,000 and 170,000 metric
 tons.  The  coastal zone  remains the base for this artisanal fishery.

     Bonga  (Ethmalosa fimbriatah sardines  (Sardine!la madarensis = Sardinella
 eba =  Sardinella cameronensisK  and  shad  (Ilisha  africana)  are the principal
 pelagic and semi pelagic  components of coastal artisanal fishery.  The demersal
 component of this fishery targets croackers (Pseudotolithus elonaatus. P. tvous.
 and P. senegal_eniis), catfish (Aurius  spp.),  sole  (Cvnoqlossus  spp.), shinynose
 (Polvdactvlus Quadrifilis). grunters (Pomadasvs  spp.)  snappers  (Lut.ianus spp.),
 and groupers  (Eoineohelus  spp.).   Large  tarpons (Meqaloos  atlanticaK  bill
 fishes, sharks,  and rays  are  also  caught.  Shellfish  harvested  by artisanal
 fishermen include white shrimps (Nematopalaemon  hastatus = Palaeinon hastatus).
 brackish  prawn  (Macrobrachium  machrobrachionK   river  prawn  (Macrabrachium
 vollenhovenii). and juvenile pink shrimp  (Penaeus notialis =Penaeus duorariumK
 The mangrove oyster, Crassostrea  gasar. and other molluscs, e.g., Pachyacllion,
 are delicacies in high demand.

     Artisanal  fishery  revolving  around the  above-listed resources not  only
 contributes to the nation's march toward self-sufficiency in its protein needs
 but also  provides,  particularly in  the  case of  shrimps and  oysters  (annual
 production  approximately 48,000  tons, exportable resources with  high  foreign
 exchange earning potential.  For example,  one metric ton of prawns fetches 12,000
U.S. dollars.  The mangrove swamps serve as the breeding and nursery grounds for


Uest Africa

most of the  finfish  and  shellfish  resources  that  are  the targets of artisanal

     The potential  of industural fishery within inshore waters  is  also very high
(Talabi and Ajayi, 1984; Tobor et al., 1977).


     Nigeria's coastal zone  is richly blessed with  a variety of minerals.  Large
deposits  of  crude  oil  have  been  discovered both   on land   and  offshore,
particularly in the Niger Delta.  Nigeria is the sixth  largest  producer of crude
petroleum oil in the world and the second largest produces in Africa.  Nigeria's
production capacity reached  2.3 million barrels per day in the late seventies but
declined to 1.3 million barrels per day as a result  of present OPEC restrictions.
Despite this decline, petroleum still accounts for more than  90 percent of the
country's exports and foreign exchange earnings.

     Natural  gas has  also been found in the  Niger Delta  in commercial quantities
either alone or in association with crude oil.  At present, about much of the gas
is  flared  as  there  are no large gas utilization projects  in the  country.
Projected investments  in the planned  liquefied  Natural  Gas  (LNG) project will
further increase the importance of petroleum to the national  economy.

     Other  mineral   resources   such   as   limestone   and  valuable   mineral
concentrations  have  been reported along the  sandy beaches of Nigeria;  these
provide raw materials for some coastal industries  (Ibe, 1982;  Ibe and Awosika,
1986).   Coal  and  lignite  occur in  the eastern  sector  of the  coastal  zone,
particularly east of the northern tip of the Cross River estuary.

Surface and Groundwater

     Some decades ago,  based on folklore and meager records at  the University of
Agriculture and Water Resources, surface water (rivers, creeks, etc.)  supplied
the freshwater needs of the coastal zone apart from the director impact of the
sea.  But all  that  has changed, and groundwater  is now  one of Nigeria's most
important natural resources, especially in  the coastal  areas.   The coastal zone
is heavily dependent  on  groundwater  because  of  the increasing salinization of
waters of the lagoons, creeks,  rivers,  and  estuaries.  The water table is often
less than 9 m near the coast, and varies from 15 m to 39.6 m farther  inland.  The
groundwater potential of this zone is  very high (with a yield several  hundred
thousand gallons per hour),  due to generally high  permeabilities, considerable
thicknesses of the aquifers,  and high  recharge potentials attributable to heavy

Present Erosion and Flood Situation

     Analyses of historical  hydrographic charts  and aerial photographs, as well
as data from  ongoing research  by the  Nigerian  Institute for  Oceanography and
Marine Research, reveal widespread erosion and  flooding along the entire national


                                                               Auoslka, et al.

     Present typical rates  established  at  erosion monitoring stations include
more than 18 m at Ugborodo/Escravos,  20 m at Forcados, 16-19 m at  Brass, and 10-
14 m  at  the Imo River entrance  (Ibe and  Antia, 1983 a, b;  Ibe, 1984a,  b, c,
1985a, b, 1986,  1987a, b, c; Ibe et  al., 1985a, b, c; Ibe and Awani, 1986; Ibe
et al.,  1986a, b; Ibe and Awosika, 1986; Ibe and Murday (In Press); Oguara and
Ibe (in press); Stein et al., 1986; Ibe,  1988a,  b).   Some of these rates are so
erratic  and out of  proportion  with historical rates  that sea  level  rise is
thought to be a part of the  problem (Ibe, 1988). An acceleration  of  the rise in
sea level would  further exacerbate the situation.

Increase in Beach Erosion Rates

     Although the amount of  sea level rise totals a few millimeters per year and
may seem small,  it  plays a  big  role in explaining erosion processes affecting
most of the low-lying coastline in the world, particularly in Nigeria.  Though
rising sea level  does not cause beach erosion per se, other more important causes
are waves, winds, longshore currents, tidal currents, low relief, shelf width,
subsidence, sediment characteristics, offshore topography, and human impact.  The
seriousness of sea level rise with respect to increased erosion and flooding can
be deduced from the data of Bruun  (1977), which  showed that a sea level rise of
0.3 m (1 foot) would cause a shoreline recession of more than 35 m (100 feet).
This may  even translate  to  higher values on  low-lying areas typical  of the
Nigerian coastal zone.

     A rise in sea level  of approximately 1  m,  which here will be accentuated by
the phenomenon of subsidence, would aggravate the existing ecological problem
of coastal erosion, resulting in loss  of wetland  and creating  a  threat to all
installations on or near the coastline.


     A rise in sea level will result in flooding  of the low-lying beaches.  This
will automatically  cause flooding  in the  adjacent  coastal areas.    This  is
expected to  become  even more threatening whenever  storm surges  coincide with
spring tides.

     Many of  these  barrier  islands  defend the  rich low-lying  coastal  lands
against  storms;  they  enclose and  protect  the rich  low-lying  resources  of
estuaries, marshes,  and mangroves,  all which are highly vulnerable to flooding
resulting from sea level rise.

     Many of the barrier island, e.g., Victoria Island, Ikoyi  Island, are heavily
developed and urbanized, with most  state capitals and  settlements situated near
the coast.  Flooding of these urban  area will result in destruction of properties
and loss of income and lives.  Many  industries  and oil-handling facilities built
near the coastline, particularly in  the Niger Delta,  will  also be  affected by


 Vest Africa

      With  rising  sea  level of approximately 1 m, the potential for flooding and
 erosion of certain key transportation arteries on barrier islands and others near
 the coast  will increase.  This will lead to a  degeneration  or  interruption of
 emergency  and other social  services.   With  higher sea  levels, existing fishing
 facilities,  such  as jetties, and storage centers built  on the  coastal  fringes
 only a couple of feet above the mean high tide line will be subjected to more
 frequent tidal and storm inundation.   The growing coast based-tourism will  be
 heavily affected  as a result of both  increased  rates of erosion  and  persistent
 flooding (Figure  4).
Figure 4.   Tourist and recreational scene on a  beach  on Victoria Island with
hotels in the background.

     The  effects  of  sea level  rise will  increase  as  a  result  of  ongoing

     The Nigerian  coastal  geosyncline, particularly the Niger Delta, is sinking
not only because of tectonic subsidence but also because of continued dewatering
and compaction of sediments that were rapidly deposited.

     The authors are studying the present rates of subsidence. The only reliable
figures available  to data reveal subsidence rates of more than 2.5 cm/year at the
site of  a tank farm along the  delta coast,  after correcting  for  the  loading
effects of the oil in the tanks (Render Awani,  personal  communications, 1987).

     Human intervention  in the coastal zone (e.g., fluid extraction) has tended
to accelerate the  subsidence problem.  Subsidence associated with withdrawal of
fluids results in  the reduction of fluid pressure in  the  reservoir or aquifer,


                                                               Auoslka, et a7.

thus leading directly to an increase in "effective stress" (or "grain to grain
stress") in the system.  Compaction results, and basin subsides.

Saltwater Intrusion and Higher Water Tables

     The depth to  water-table  in the coastal zone is often very shallow, and the
groundwater  itself  is  subject  to pollution  and  saline contamination  from
seawater.  Sweet water in the  area is,  however,  contained  in the deeper aquifer,
which probably is in hydraulic continuity with the coastal plain sands.

     Many towns and cities situated on the coastal lowlands obtain their water
supplies  from  the   enormous  groundwater  resources  of   this  hydrogeological
province.  Some municipal wells in Port Harcourt yield as  much as 90,000 gallons
per hour. A global sea level rise is expected to raise the water table along the
coast and result  in increased salinity of the groundwater.


     The Nigerian coastal  zone  is  endowed with  an extensive  and productive
mangrove ecosystem, particularly in the Niger Delta.

     Vast and fertile river floodplains have made the delta and other parts of
the coastal zone  the food  basket of southern Nigeria.   Rising  sea level  will
increase the salinity of the water and  soil.  Such  plants  that are not tolerant
to this increased  salinity will die.  Scenes of dying vegetation are now common
along the Mahin mud beach where saline waters have flooded  the adjacent low-lying
coastal areas.

     This has resulted in the complete decimation of the once-flourishing rain
and mangrove forests  (Figure  5).  The  lumber  industry in Spele  is expected to
suffer from the deforestation resulting from increased salinity attributable to
global sea level  rise.

Transportation and Communication

     Owing  to  the booming  economic  activities,  an extensive network  of roads
(about 4,000 km in  Bendel  State,  2,500 km in Rivers  State, and  the new 65-km
Lagos to Epe dual  highway built on the Lekki  barrier island) has been developed,
while extensive creeks,  channels,  rivers, and estuaries  provide  an excellent
water communication and transportation network.  Increasing sea level will result
in flooding of these transportation and communications networks.

     The state  government canals linking the numerous settlements along the Mahin
mud beach are close to being overtaken by the ocean (Figure 6).   This could be
disastrous  to tertiary institutions,  hundreds of secondary schools, commercial
houses, hospitals, hotels, and other institutions in which billions  of naira have
been invested.

Uest Africa
Figure 5.  Trees dying as a result of saltwater intrusion.

Ocean Dynamics

     It has been suggested  that  sea level rise will cause a continued deepening
of the  Continental  Shelf beyond  the  depth of closure  and will result  in an
increase of effective wave height due to the reduction in bottom friction as a
result of greater depth.

     It is hence to be expected that  the present  ocean  dynamics (wave height,
period, length, breaker angle, longshore current direction and magnitude, etc.)
shaping  the  coastal  zone  will  change.    A  change or  modification  of  ocean
dynamics, particularly the nearshore dynamics, will affect the sedimentary fluxes
and hence  sedimentary budget.   This  controls the  coastline  evolution through
erosion, accretion, or stability.   These modifications will vary from place to
place,  depending on  whether  the changing dynamics  will  result  in  erosion,
accretion, or  stabilization.   These  impacts  could be further  exacerbated if
storms become more frequent, or winds and currents change.


     The possible measures that can be  taken to mitigate the impacts  of  sea level
rise on  the  Nigerian  coastal  zone can be  classified  according  to  whether the
measure will  attempt to halt the  approach of the sea, i.e.,  "no retreat"; whether
the measure will allow the sea to rise while avoiding the impacts,  i.e.,

                                                               Awosika,  et  al.
Figure 6.  The Niger Delta is already experiencing flooding  problems which will
only be made worse by sea level rise.

("retreat"); or whether  the  measure  will  be an attempt to cope with sea level
rise ("adaptation").

"No Retreat" Measures

     "No retreat" measures include construction of the following:

     1.    Levees, seawalls and revetments, which basically protect the shoreline
           from waves and floods;  and

     2.    Construction of groins and breakwaters to act as a wave  barrier; this
           results  in a  zone of reduced wave  energy,  and  also  helps  to trap

     Generally the "no retreat" measures are very  expensive  for a developing
country like Nigeria with huge  external  debts.   Examples from other countries
where these "no retreat"  measures have been  attempted have shown that they have
not worked effectively and, in some cases, have exercabated the erosion and flood
problem.  Again, these "no retreat"  measures  are not  capable of abating other
impacts of  sea level  rise such as higher water  tables and  saline groundwater

"Retreat" Measures

     "Retreat"  measures  are  generally soft regulatory and policy measures that
generally do not require large  and immediate  expenditure.  These measures are
also flexible and can be  easily changed in response  to  new sea level rise data.


Vest Africa

However implementation of such of measures results in the loss of land.  Retreat
measures include the following:

     1.    Set  back line:   A set back line is  a  predetermined  limit along the
           coast seaward to which no settlements or facilities should be located.
           Ibe et al. (1984) suggested a set back line of 20 times the determined
           rate of  erosion.

     2.    Beach nourishment program:  This method is a  popular approach used to
           protect  coastal  property  and  to   maintain  recreational  beaches.
           However  the  success of  beach  nourishment  programs depend  on correct
           implementation procedures, i.e., choosing the right grain size, burrow
           pit, etc.  The many beach  nourishment programs  implemented at the Bar
           beach during 1974-75, 1981,  and 1985-86  have  not very successfully
           checked  erosion and  flooding.  This  was partly  due to  incorrect
           implementation  procedures.

     3.    Controlled urbanization and capital  facilities:  The coastal zone of
           Nigeria  has witnessed sporadic urbanization in the 20 years due to the
           oil boom of the seventies.  Efforts should now be made to control this
           urbanization within  the  coastal  zone.   Construction  of  capital
           facilities  such as roads, buildings,  sewers,  etc., should  be kept
           beyond the reach of projected  sea level rise.

     4.    Public awareness program:  Measures  to increase  public awareness of
           the  potential  impacts of  sea  level  rise should be pursued.   Private
           developers  should be enlightened  on the  foundation  and  structural
           codes required  for buildings in such unstable zones  along the coast.
           Illegal  mining  of  beach sand  should  also  be  discouraged.   These san
           miners   should  be  made  aware  of the  danger  they  create  by  their

     5.    Increase in  flood plan elevation:  Efforts should be made to increase
           the  elevations of the  floodplain  or  beach  ridges  around  the many
           barrier  islands.  This would help to  reduce the potential of flooding
           of the adjacent lowland, but preliminary studies show that this is an
           expensive option.

     6.    Afforestation:   Limiting  deforestation and  using reforestation and
           afforestation  to  slow or  stop the  rise in atmospheric concentration
           of carbon dioxide was first proposed during the 1970's.  Today it is
           accepted as  one of the effective  ways of slowing down  erosion and
           denudation of  the land.  Efforts to  afforest the coastal  zone should
           be stepped up,  while  deforestion should be discouraged.

     7.    Studies; Since rising  sea  level affects  all coastal  areas, studies
           must be  initiated with the aim of identifying area that will be very
           sensitive to impacts  of sea level  rise.   These  studies  should also
           include  collecting data on water level,  rates of erosion, subsidence,
           groundwater, ocean dynamics, and other facets of coastal  management.


                                                               Awosika, et al.

           Such studies  must  be  viewed  by government  and  other sponsoring
           agencies as  essential  and not as  an  academic exercise.


     Nigeria does not presently have a well-articulated, concrete and enforceable
coastal zone management policy.  The lagoon  city project, which was intended to
create prime real  estate on  the foreshore of the Lagos lagoon but  instead led to
enormous ecological damage,  took  advantage  of  this lack of a  coherent policy.
An urgent need exists for national policies with adequate legal provisions for
coastwide,  coordinated,  and effective management  and  control  of the Nigerian
coastal zone.

Allen,  J.R.L.    1964.   The  Nigerian continental  margin:  bottom sediments,
submarine morphology, and geological evolution.  Marine Geology 1:  289-332.

Allen,  J.R.L.    1965a.   Late  Quaternary  Niger delta,  and  adjacent  areas:
Sedimentary environments and lithofacies.  A.A.P.G. Bull 49:  547-600.

Allen, J.R.L.,  and Wells, J.W.  1962.  Holocene coral banks and subsidence in the
Niger Delta.  J. Geol. 70:  381-397.

Ajayi T.O., and Talabi, S.O.  1984.  The potentials and strategies for optimum
utilization of the fisheries resources of Nigeria.  NIOMR Tech. Paper No.  18.

Atlas of the Federal Republic of Nigeria.  First Edition 1978.  Lagos.

Bruun,  P.   1977.   Practical solution  to a beach  erosion  problem.   Coastal
Engineering 1:   3-_16.

Burke,  K.   1972.   Longshore drift,  submarine  canyons and  submarine  fans  in
development of Niger Delta.  AAPG Bull. 56:  175-1983.

Ibe, A.C.   1984a.   Defending Victoria Island against  sea  incursion.   Special
Report, Lagos,  Nigeria:  Federal  Ministry of Education, Science and Technology,
7 p.

Ibe, A.C.  1984b.   Protecting Victoria Island against sea incursion.  A position
paper submitted to the Ad Hoc Committee on the Victoria Island Erosion Problem;
August 1984. 5p.

Ibe, A.C.   1984c.   A rational strategy  for defending  Victoria Island against
oceanic surges.   In:   Proc.  Conference on  the  Bar Beach Surge.  Federation  of
Building and Civil Engineering Contractors of Nigeria Ltd.

West Africa

Ibe, A.C.   1985a.   Nearshore Dynamics and Coastal  Erosion  in  Nigeria.  Paper
presented at the UNESCO Expert Workshop on WACAF/3 Project; Dakar, Senegal; March
11-19, 1985.

Ibe, A.C.  1985b.  Harbor development related erosion at Victoria Island, Lagos.
First  International  Conference  on Geomorphology,  University of Manchester,
England;  September  15-21,   1985.    In:     International  Geomorphology  1986.
Gardiner, V., ed.  pp.165-181.

Ibe, A.C.   1986.   Port  development related  erosion at Escravos,  Bendel State,
Nigeria.  In:  Proc. Man's Impact on the Coastal Environment Barcelona, Spain,
6-13  September  1986.   In:    Thallasa,  Revista De  Ciencions Del  Mar Special
edition.  Villas, F., ed.

Ibe,  A.C.    1987a.   Marine  erosion  on  a transgressive  Mud Beach  in Western
Nigeria.    In:   Proc.  Intern.  Symposium on  Geomorphology  and  Environmental
Management,  Alahabad;  India, Jan.  1-20 eds.   S.  Sighn  and R. C.  Tiwari  (in

Ibe, A.C.   1987b.   Collective response to erosion  hazards  along  the Nigerian
Coastline.   In:   Proc. Coastal Zone, 1987.  Seattle, Washington:  pp. 741-754.

Ibe, A.C.   1987c.  Human Impact on the coastal erosion problem in the west and
central  Africa   (WACAF)  region.    In:    Proc.  International  Se  Conference,
University of Mauritius, Reduit, Mauritius,  7-12 September 1987 (in press).

Ibe, A.C.,  and E.E. Antia.   1983a.  Preliminary study of the impact of erosion
along the  Nigerian  coastline.   In:   Proc.  First  International  Conference on
Flooding, Desertification and Erosion in Africa.  Port Harcourt,  Nigeria:  Rivers
State University of Science  and Technology,  May 2-6, 1983.

Ibe, A.C.,  and  E.E.  Antia.   1983b.   Preliminary assessment of the impact of
erosion along the Nigerian shoreline.  NIOMR Tech. Paper No. 17p.

Ibe, A.C., and P.E. Awani.   1986.  Erosion management strategies for the Mahin
Mud Beach, Ondo State.  In:  Proc.  National Seminar on Flooding and  Erosion along
the Nigerian Coastline.  University of Lagos, May 1986.

Ibe, A.C., and L.F.  Awosika.   1986.  Sedimentology  of the barrier bar complexes
in Nigeria.  NIOMR Tech. Paper No. 26.

Ibe, A.C., L.F. Awosika,  and  E.E. Antia.  1984.  Progress  Report No.  2.  Coastal
Erosion Research Projects.   NIOMR Special  Publications;  106p.

Ibe, A.C.,  L.F.  Awosika, A.E.  Ihenyen,  C.E.  Ibe,  and  A.I. Tiamiyu.   1985a.
Coastal erosion  at Awoye and  Molume, Ondo State, Nigeria.   A  report for Gulf Oil
Company (Nigeria) Ltd. 123p.

                                                               Awosika, et al.

Ibe, A.C., L.F. Awosika, A.E.  Ihenyen,  C.E.  Ibe, A.I. Tiamiyu, E.G. Okonya, and
T. Orekoya.   1985b.  A  study  of currents and scouring effects at the proposed
Davy Banks  'A'  Location in OML 14.  A  report  for Shell  Petroleum Development
Company of Nigeria Ltd. 56p.

Ibe, A.C., L.F.  Awosika, C.E. Ibe, A.I. Tiamiyu, P.O. Egberongbe,  and S. Orupabo.
1986.   The  erosion problem  at  Victoria  Island  (1900  to  Present)  and  its
solutions.   In:   Proc. National  Seminar on  Flooding  and Erosion  along  the
Nigerian and similar coastlines.  University of Lagos, May 1986.

Ibe, A.C., A.E.  Ihenyen,  and  C.E. Ibe.   1985c.   A hydrographic Survey of the
Proposed Benin Estuary Location OML 43.   A report for Shell Petroleum Development
company of Nigeria Ltd. 25p.

Ibe, A.C., and M. Murday.  1986.  Aerial Photostudy of recent migration of the
Lagos shoreline.  NIOMR Techn. Paper (in press).

Stein,  D., G. Echwebber,  and A.C.  Ibe.   1986.   Investigation  on the Bar Beach
erosion and  a  proposal  on the maintenance of  the  coast.   National  Seminar on
Flooding  and Erosion along the  Nigerian and  related  coastlines.   May 1986,
University of Lagos.

Oguara, T.M.,  and  A.C.  Ibe.   Decision  Analysis for the selection  of erosion
control measures.  NIOMR Tech. Paper (in press).

Nigeria in Maps, 1982.    Barbour,  K.M.,  Oguntoyinbo, J.S., Onyemelukwe, J.O.C.,
and Nwafor, J.C., eds.

Tobor,  J.G., M.O. Okpanefe, J.O.  Oladoye, A.L.  Ekwemalor, and 0. Oladip.  1977.
Fisheries Statistical Survey of Nigeria.  Report 1975-1976 NIOMR, Lagos.


                    SEA  LEVEL RISE ON  SENEGAL
                        PROFESSOR  ISABELLE NIANG
            Departement  de Geologie,  Faculte des  Sciences
                      Universite Cheikh Anta  Diop
                           Dakar-Fann,  Senegal

     The predicted rise  in  sea  level  of 1 m  from greenhouse-induced  global
warming will greatly impact the country of Senegal.  The coastline of Senegal  is
made up of three large estuaries  (Senegal, Saloum,  and  Casamance Rivers), about
400 km of sandy coastline,  and approximately 70 km of rocky cliffs.   The low-
lying estuarine areas will  be prone to inundation, and the sandy coasts will most
likely experience  increased  erosion if sea level  rises as predicted.  The Cap
Vert peninsula, where the majority of the population and economic activity are
concentrated,  will  be greatly affected.   Furthermore,  Senegal relies  upon the
coast  for  the income  generated  from  agriculture, fisheries,   industry, and
tourism. Coastal  towns  and cities,  like Dakar, Saint-Louis, Rufisque, Mbour, and
Joal, will  be  required  to retreat and/or  stabilize  their waterfronts.


     Senegal would  be very vulnerable to a rise  in  sea  level, because low-lying
beaches and  estuaries  account   for  approximately  90% of  its  700-km  coast.
Increased  coastal erosion would be particularly severe  in areas that are already
eroding, such  as   Saint-Louis,   Rufisque,  and  Joal,   and  homes  would  almost
certainly  be destroyed.   Coastal wetlands,  including tidal  flats, mangroves, and
tannes would be flooded, upsetting  fish and wildlife.   Saltwater intrusion into
both groundwater and agricultural lands would increase.   Sand spits would  breach
more often,  and roads and other infrastructure would be lost.

     Because two-thirds  of the nation's population and 90% of its industry is  in
the coastal  zone,   the  nation cannot afford to ignore  this issue, nor  should
coastal cities and  towns.   The authorities are aware of the importance  of the
coastal zone, but not about the possible acceleration in  sea level  rise.  It will
be necessary to coordinate efforts among authorities, scientists, educators, and
industry leaders,   who  should all  consider the  national  well-being  to  be  of
highest priority.   An action plan is required that would include:


West Africa
     1.   Scientific  monitoring of the  coastal  zone (e.g.  beaches,  estuaries,
         mangrove, qroundwater evolution).  No tide data have been recorded since
         1964.  A network of tide gauges should be established.  Swell monitoring
         and  regular  morphological  and  sedimentological  profiles  should  be

     2.   Education of the entire nation about sea level  rise  and its consequences
         through  a  ma.ior  public  information campaign.    This  is  especially
         critical  in  a nation  of  diverse ethnic  groups who  have  long histories
         of living and working  in ancestral grounds.  For example,  at Rufisque,
         the Lebou fishermen refuse to leave even when their  homes are inundated,
         because these are  ancestral grounds.  In other areas, sand miners need
         to learn  the consequences of  their  removing sand from eroding coastal
         areas, but perhaps more important, they  need to learn other occupations
         that  would  provide  an acceptable  livelihood for them  and  would  be
         harmless  to  the  environment.

     3.   Revision or creation ofstrong and consistent  national policies for use
         of the coastal  zone.   This  would  enhance uses of the coastal  zone and
         would  avoid  future problems of inappropriate  siting  of  industries  or

     4.   Creation  of response strategies to  a  rise in sea level.   Developing
         countries such as Senegal find it  very difficult, if not impossible,  to
         invest in  hard coastal protection works, or  even  those  such  as beach
         renourishment.   Other options  will  have to be developed  for inclusion
         in the national  policy.

     5.   Programs to cope with potential relocation  of  communities, and possible
         retraining  of people  for  new skills  or  occupations.    For  example,
         artisanal  fisheries  or even certain agricultural  activities  might  be
         changed to  mariculture or  aquiculture.   Strong  tribal or ethnic ties
         that exist in some traditional  communal  villages  on the coast will have
         to be considered in any  relocation and  retraining  activities.

     6.   Programs  to  develop  and encourage  new  industries,  or  agricultural
         activities to replace others displaced by the effects  of sea level rise.
         For  example, in  the  Casamance River valley  perhaps some  peanut  and
         millet growing  might  be  replaced  by more  rice growing,  which already
         exists.  Saltworks at Kaolack  on the  Saloum River have the potential  to

     In  the absence of detailed studies, it is impossible to  be  any more specific
about the effects  and  responses   to  a   rise   in  sea level.    Nevertheless,
considerable knowledge about the  coast  of Senegal has  accumulated.  To give the
reader an idea of  the environments at risk, the  following sections describe the
nature of the coastal environment,  the impacts of current changes in sea level
and climate, and the  socioeconomic  resources of the coastal  zone.  Geological
details  about the coast  are found in the  appendix.




     The three main types of coastlines in Senegal (Figure 1) are rocky coasts
(about 70  km  long),  sandy coasts (about 400  km  long),  and mangrove estuaries
(about 250 km).

Rocky Coasts

     These coasts  are  located  along the Dakar and Ndiass  horsts.   Generally,
their base is covered by blocks, cobbles, and pebbles, which protect them from
wave attack.  There are often small bay beaches between adjacent rocky capes.

Sandy Coast

The North Coast or "Grande Cote" (Saint-Louis to Yoff)

     Here, the  straight  sandy beaches  are  linked with three  Quaternary dune
systems:   (1) the  continental  "red  dunes," which  are about 20  m high; (2) the
yellow dunes,  which form a 250- to 4,500-m-wide field that is often 20-30 m high;
and (3) the littoral  white dunes, which range from a  few to 100 m wide and vary
between a  few to 25 m  high  and are  still  accumulating windblown sand from the
beach.   The  interdunes    (known as "niayes")  are periodically  inundated  by
precipitation and groundwater,  and play an important role in the coastal ecology.
Although they are 3 to 10 m above the sea level, they would be affected by any
rise in sea level due to the backwater effect.

     The beaches are  relatively narrow (between 40  m at Yoff  and  110  m  at
Camberene).   Sail  (1982)  suggests  that they erode during the dry  season and
accumulate during the wet season.  The Bruun rule suggests that with a rise in
sea level, the reaccumulation would be less owing to the need for the offshore
profile to rise with  sea level.  Given  the Bruun rule-of-thumb that a one meter
rise in sea level causes one to two hundred meters of  beach  erosion, it is clear
that even a relatively small  rise in sea level could completely eliminate these

The South Coast or "Petite Cote" (Hann to D.iiffere)

     Unlike the  North Coast, the  South Coast is characterized  by rocky capes and
the absence of  dunes  (Demoulin,  1967).  Because the  beaches are lined  with a
sandy barrier, however, we consider these areas to be part of the sandy coasts
(Figure 2). These barriers are often adjacent to shallow lagoons  (wadi).  During
the rainy  season, these lagoons  and wadi have much higher water levels,  which
sometimes  causes  a barrier  to  break;  this  can  release  substantial  organic
material into nearby coastal waters.

     The beaches are very narrow  (30 to  40 m).  Beach rocks  stick out of the sand
at the beaches at Rufisque,  Bargny-Sienndou,  and along the  "Pointe de Sangomar"
sand spit.

     Because the beaches are very narrow, a rise  in sea level  could have an even
greater impact here than along  the North Coast.  In cases where rocky capes lie


 West Africa

                  *_j Rocky coot

                  Tvl Sondy coatt

                  ^5 Mongrov* stuary
                          gut oiseouE
                             Cap S Wring
Figure  1.  Main  coastal  types  of  Senegal.


             3 Meter Contour

             5 Meter Contour
Figure  2.  Map of Senegal showing 3-  and 5-meter contours.


Hest Africa

behind the beach, there would be little opportunity for the ecosystem to shift

Mangrove Estuaries

     These estuaries correspond to the three most  important rivers: the Senegal,
Saloum, and Casamance.  All of these estuaries are characterized by tidal flats,
mangroves, marshes,  and  tannes.   Moving inland from  the tidal  channel,  one
observes  first tidal flats, then mangrove marshes  with Rhizophora racemosa (5
to 12 m high) replaced by R.  harisonnii  and R. mangle in  the Saloum estuary, then
Avicennia africana  (1  to 3  m high).   From south to north,  owing  to climatic
conditions, we  notice  a  reduction  of the  mangrove  population density  and  a
diminution of the species number (six in Casamance, four in Saloum, and two in
Senegal).   The  bare tanne  is  limited by  the  annual  tide level,  whereas  the
vegetated tanne is also found above  this  tide level  but can tolerate inundation
by freshwater.

     These estuaries are  also characterized  by manmade shell deposits resulting
from the  trade  of Anadara senilis and the  Rhizophora  oysters  (Gryphea gasar)
since  the  Neolithic times.   They are  present  in the three  estuaries  but  are
particularly pronounced in the Saloum (Diop, 1986).

     Studies on the  mangrove population  along the  Saloum  (UNESCO,  1985)  have
shown that from the mouth to the  upstream part of the estuary, there has been a
height reduction of Rhizophora,  diminution of the area occupied by Rhizophora,
reduction  of  the  population density,  and augmentation  of dead  Rhizophora.
Finally, the mangrove disappears upstream of Foundiougne.  This regression of the
mangrove environment will be related to the drought,  to the human activities (use
of trees for cooking, small-scale exploitation of salt),  and to natural diseases.


Consequences of the Drought

     First of  all,  there  is  a renewal of  eolian (wind-blown) migration of dunes
due to recent  droughts.  Along the Grande Cote, white dunes are migrating toward
the continent (2  m/year  to  7.1  m/year), the exception  being the  "Gandiolais"
(south of St-Louis), where the white dunes migrate seaward (11.5 m/year between
1954 and  1980).   This  phenomenon determines  a  progressive  filling  up  of  the
interdunes (niayes). The migration speed  of the yellow dunes varies between 4.80
m/year in the  Cayar-Tanma lake sector  to  1.3-3.8 m/year at Vele and Pikine.   If
global warming worsens drought conditions, we may see an  acceleration in the rate
of dune migration.

     The lack  of precipitations  also induces a salinization  of  the rivers,  the
groundwaters,  and soils due to the weak or absent freshwater input.  Saltwater
intrusion has  led to a decline in the mangroves  (in Casamance, 70 to 80% of the
mangrove has disappeared  since  1969  (Diop,  1986; Marius et  al.,  1986)).   The
reduction of the mangrove population is accelerated by human activities such as
the use of trees for cooking,  construction of dams, the rice culture (responsible



for  25% of  the destruction  in  Casamance  between  1967 and  1982),  and  the
exploitation  of salt  (Paradis,  1986).    Therefore,  tannes are  replacing  the
mangrove swamps (Marius et al., 1986).  For example, between 1973 and  1979, in
the Casamance  estuary,  Sail  (1982) noted that  tannes  increased 107 km2 while
mangroves declined by 87 km2.

     Other consequences of the drought are  the acidification and oxidation of the
soils, well studied in the Casamance estuary  (Boivin et al., 1986;  Marius et al.,
1986).  The acido-sulfated soils are characterized by a  low pH (<4.5), formation
of jarosite  (iron  sulfate),  and salt precipitation  with  appearance of gypsum
unknown in Casamance before 1972.

     Last,  there is a tendency  toward  salt contamination of the groundwater due
to the lowering of the groundwater table  (Boivin et al., 1986).

     All of these problems could be made substantially worse if global  warming
leads to a  drier climate in coastal  Senegal.  Destruction of mangroves would have
a particularly severe impact on fishing.   The threat  to water supplies would be
particularly   important  for   communities   already   struggling   with  salt

Coastal Erosion

Cliff erosion

     The speed of a cliff's retreat depends on its type.   The Cap  de  Naze cliffs
are retreating slowly (5.8 cm/year) at the base  owing to accumulation of blocks
and pebbles, but five  times as  rapidly  at their summits.   The plunging cliffs
(Cap des  Biches,  Fann) are eroding  more  rapidly, particularly  those  made of
sedimentary rocks (32.9 cm/year for the  Cap  des  Biches and 29.3 cm/year  for the
Fann cliffs).

Erosion Along the Sandy Coasts

     Several  parts  of the Senegalese coasts are eroding rapidly  (DHV,  1979; PNUE,
1985): St-Louis (1.25 to 1.30 m/year), Rufisque (about 1.30 m/year),  and Joal in
particular.  The impacts are important  because  all  of  these  areas are  densely
inhabited.   Consequently,  many  coastal  defense  structures  have  been built,
including  seawalls  at  St-Louis,  Rufisque,  and Joal,  and groins  at Rufisque
(Murday, 1986).

     The causes of  coastal erosion  are still unclear. According to Masse (1968)
and DHV (1979), the erosion  between Mbao and Bargny is induced by a predominant
onshore-offshore sand transport especially during  storms,  part of the sands not
being  recovered by  the beaches.   This  result is  consistent  with the  slow
continuous rate of sea level rise (a few millimeters per year,  Elouard  et al.,
1967).  In addition,  human activities  such as the hardening of the coastline by
human construction and especially the extensive sand mining along the Cap Vert
coast (from Cayar to  Bargny) are contributing to the problem.  Below  Bargny,  the
littoral drift also contributes to the problem.  If sea level  rise accelerates,


West Africa

there Is little doubt that erosion would Increase proportionately throughout much
of the coastal zone.

     The many sand  spits  are even more vulnerable, even  with  current trends.
From 1850 to 1980, the  "Langue de Barbaric" has seen 24 breaks,  which forced the
authorities to stabilize  the sand  spit.   Since then,  the  breaks have occurred
only south  of St-Louis.   With  an accelerated  rise in sea  level,  additional
protective measures will be necessary.


     About the two thirds  of the nation's population (about 6.8  million in 1987)
is concentrated along the littoral zone.  The population density is between 10
and 20 persons/km2  along the North Coast, 20-50 persons/km2  in  the South Coast
and Casamance, and  more than 1,800 persons/km2  in the Cap Vert peninsula.  Most
of the  big  cities   and  towns are located along  the littoral  zone:   St-Louis
(88,404 inhabitants in 1976), Dakar (about 500,000), Pikine (1  million), Mbour
(37,896), Joal (15,665), Kaolack (135,473),  and Ziguinchor (69,757).  Directly
or indirectly, a rise in sea level would affect all of these inhabitants.

     The most important maritime fishing centers are,  from north to south, St-
Louis, Cayar, Dakar, Mbour,  and Joal.  Owing  to the  seasonal migration of fauna,
in relation to upwellings, the fishermen migrate from north during the dry season
to south during  the  wet season.  Estuaries are important centers for nonmaritime
fishing.  The total  fish production was approximately 157,000 tons in 1987 with
a predominance of maritime  and  industrial fishing.   Part  of the production is
distributed on the great markets, another part is smoked and/or dried, and a part
is exported.  Global warming could upset these fisheries both through the loss
of wetlands that support estuarine fishing and as a result of changes in ocean
currents, which could affect maritime fisheries.

     The main farm  crops  along the  coast are  peanuts (total production of 946.4
thousand tons in 1987) and  millet  (total  production of  801.2 thousand tons in
1987); the rice culture  (total  production of 135.8 thousand tons in 1987) has
traditionally has been confined to the Casamance estuary, but now is also present
in the Senegal and Saloum estuaries (EPEEC,  1983).   Along the North Coast, the
niayes are used for market gardening, which  is also practiced  in the different

     Since 1950, the Senegal  estuary has been subject to management of irrigated
perimeters; this development program is now  enhanced by the Diama and Manantali
Dams.  These projects will permit the irrigation of  250,000 hectares  (Michel and
Sail, 1984).  Both  sea level rise  and  changes in precipitation  could impair the
functioning of these new systems.

     Tourism is extensive  on the South Coast  (Saly, Mbour, Joal)  and in Casamance
(Cap Skiring, Kabrousse),  where  it contributes 31 billion CFA francs  per year in
hard currency.




     The configuration and the evolution of the coastline in Senegal have been
controlled  by  three main factors:   climate,  geology, and  hydrodynamics.   We
discuss each in turn.


     Senegal's climate is characterized by the alternation of two seasons:

       The dry  season:   cold,  lasting 6 or 8 months during which the N to NW
        maritime  trade winds are dominant  all  along  the  coastline, with some
        incursions  of the NE continental  trade  wind  or "harmattan."

       The wet  or rainy season:  hot,  during  which the  precipitation occurs
        (80% of the precipitation between July  and September with a maximum in
        August).  The wind  regime is  dominated  by SW monsoon winds.

     The main characteristic of this climate  is the great interannual variability
of the precipitation.  The recent drought has been in  effect  since 1968 (Olivry,


     The lithology  and  tectonics  are responsible for the great morphological
subdivisions of the coastline (Sail,  1982).  The entire  Senegalese coastline
belongs to the Meso-Cenozoic Senegalo-Mauritanian passive margin  basin (Bellion,
1987) (Figure A-l).


     The Cap Vert  peninsula  is subdivided by N-S to NNE-SSW faults in two horsts
(Dakar and Ndiass  horsts)  separated by the Rufisque graben  (Elouard,  1980).  The
two horsts constitute the higher parts of the  coastline (105 m).  From Kayar to
Mbour three main fault directions (NNE, NW,  and NE)  have  been identified (Dia,
1980; Bell ion,  1987; Lompo,  1987),  and these faults  appear to have been active
since the  last Pleistocene (Dia, 1980).  Furthermore,  two subsidence  centers are
located in  the Senegal  "delta"  zone  to the north and in  the Saloum-Casamance
regions to  the south.   But  recent studies  (Faure et al.,  1980) have  shown a
lithospheric rigidity of more importance than predicted.


     It is a basic volcanism (Dia, 1980, 1982;  Bellion, 1987), subdivided in two

       The Tertiary volcanism (35.5  to 5.3 MA) is fissural (Dia, 1982).  In the
        Cape Verde peninsula, this volcanism determines the  "eruptive system of
        Dakar" (Dia,  1980);


Vest  Africa
                                        LHH  iflaiiH^TC-ijj
                 JBJTertiory and Ouorernary
                     Littoral dunes
                 ^21 Fluvio deltaic deposits
                     "Continental Terminal"
                 Ur^-^l Nummulite limestones
                     Lower Eocene
                I'  i '] Paleocene
 Figure  A-1.   Geology of Senegal


        The  Quaternary volcanism (2 MA to 500,000  ago)  is represented in the
         extreme  west  of  the  Cap  Vert  peninsula  by  the  Mamelles  volcano,
         secondary  eruptive bodies  (Mermoz), and also by about five or six lava
         beds  and interstratified tuffs  (Dia,  1980,  1982;  Lo,  1988).


     The tidal range  is only about one meter on the ocean coast, and less  in most
estuaries.  The NW  swells  are dominant and associated with  SW  swells only during
the rainy season (Figure A-2).  On the North Coast, the NW swell determines a NE-
SW littoral drift  (Pinson-Mouillot,  1980).   Then,  the  NW swell  is diffracted
three  times   around  the  Cap Vert  peninsula  (Riffault,   1980),  determining  a
divergence in the Hann bay and  an E-W current  between Rufisque and Hann  (Masse,
1968).  From Rufisque, the swell obliquity  increases, generating a  NW-SE littoral
drift with speeds  between 0.8 m/s at  Bargny  and 1 m/s at the  Somone estuary
(Demoulin, 1967).

     Estimates  of   volume  of  sand   transport  by  the   littoral  drift  vary
(PNUE/UNESCO/ONU-DAESI, 1985),  but  all  indicate  that the sand  transport  is much
more important along the North Coast than along the South Coast.


     Three main types of  coastlines  are encountered in  Senegal  (see Figure 1)
(Sail, 1982):   rocky  coasts (about 70 km long), sandy coasts (about 400 km long),
and the mangrove estuaries (about 250 km).

The Rocky Coasts

     About 70 km long,  they are located along  the Dakar and Ndiass horsts.  The
cliffs consist of the following:

        Volcanic rocks along  the  Cap  Vert  peninsula.   The  Tertiary eruptive
         system of  Dakar gives rise  to  the  ankaratrite cliffs of Goree (40  m
         high) and Cap Manuel (35-40 m) and to  the basanite cliffs of Madeleines
         Island and Fann.  The Quaternary eruptive  system of Mamelles gives rise
         to the dolerite cliffs located between Yoff and  Fann  (10  to 12 m high);

        Paleocene and Eocene marly limestones  for  the cliffs of Popenguine, Cap
         des Biches  (13 m  high),"anse" Bernard and Madeleines;

        Maastrichtian sandstones and shales  for the  cliffs of  the Ndiass horst:
         Cap Rouge  (47 m),  Toubab Diallao  (12m), and Cap de Naze  (about  60 m);

        "Continental   terminal"  sandstones   capped  by  lateritic   crust  in

     These cliffs can  be  plunging  cliffs (Cap  Manuel)  when they are  made  of
volcanic rocks, or have a straight to convex face when they consist of


Uest Africa
                     Littorol drift
                 l:'.-.;:'':iv.'-j Sedimentation
 Figure A-2.   Hydrodynamics of Senegal.


sedimentary rocks (Cap de Naze) (Sail,  1982).   Generally,  their  base  is covered
by blocks, cobbles, and pebbles protecting them from wave  attack.  The abrasion
platforms are very rare (Cap des Biches,  Cap Manuel, Fann-Almadies). Between two
rocky capes, there are often small bay  beaches.

The Sandy Coasts

     The North Coast or "Grande Cote" (Saint-Louis to Yoffl

     Here, the  straight  sandy beaches  are  linked with three  Quaternary dune
systems present above the Eocene shaley limestones (see Figure 1 and Figure A-l).
From the land to the sea, we can distinguish:

        The  continental  dunes or Ogolian red  dunes (20,000-12,000  years ago)
         with  first NE-SW flattened  longitudinal dunes (about 10 m high) built
         during  the arid Ogolian (18,000 years ago),  followed by  NNW-SSE to WNW-
         ESE  dunes of  about  20 m high  that are the result of Ogolian dunes
         reworking during a short arid phase (8,000 to 6,800 years ago) (Michel,

        The  semi-fixated yellow dunes  built  during an arid phase   (Tafolian,
         4,000-1,800 years ago) form  a 250- to 4,500-m-broad dune  field. They are
         made of NNW-SSE parabolic dunes, barkhans (Pinson-Mouillot, 1980). Often
         very  high  (up  to 20-30 m),   they  are ended  by an  abrupt upthrow front
         (30-45  steep,  more  than  30 m high)  above the niayes or the red dunes
         (Pezeril  et  al.,  1986);

        The  littoral  dunes or  white dunes form a  band from a  few  meters to
         hundred meters broad.  They are parallel to  the  coast, the typical form
         being  the  NNW  parabolic dunes.   The  heights vary between a few meters
         to 25 m maximum.  They began to form during  the  Subactual and are still
         supplied  by  the  beach  sands.

     The main  characteristic of this littoral  zone are the  interdunes' so-called
niayes, temporarily inundated  by precipitation and  groundwater.   Three to ten
meters above sea level, these niayes are of three different types  (Michel, 1969;
Pezeril et al., 1986);  they can originate from old hydrographic networks or be
true  interdunes.  These  niayes are  characterized  by  a  relictual  subguinean
vegetation with the oil palmtree (Elaeis guineensis)  bordering them (Fall, 1986;
Lezine, 1986).

     The beaches  are relatively narrow (between 40  m  at  Yoff and  110  m at
Camberere). The average  slopes  are  less than 8.  The characteristic forms of
these beaches are  beach cusps, with ridges and runnels (Diaw,  1981; Sail, 1982).
Sail (1982) proposed a model  of the beach cycle, swell controlled with erosion
during the dry season and accumulation during the wet season and determining a
seasonal balance between the foreshore and the shore face.

West Africa

     The South Coast or "Petite Cote" (Hann to D.iiffere)

     Unlike the North Coast, the South Coast littoral zone is characterized by
rocky capes and the  absence  of  dunes (Demoulin,  1967).   The beaches are lined
with a sandy barrier, however (see Figure 1 and Figure A-l).

     The sandy  barrier can  lean  on  a  shallow  lagoon or  wadi  or  on  a rocky
bedrock. Arid during the dry season,  these lagoons and wadi are filled up during
the rainy season,  sometimes inducing  a barrier break with little detrital input
to the coast (Masse, 1968).

     Very  often,   we  can  observe   behind  the  lagoon  the  Anadara  senilis
Nouakchottian terrace.   This terrace,  located between  -1-2.5 and +3  m,  is the
result of the  last  important Holocene transgression, the so-called Nouakchottian
(max; at 5,500 years ago).  This terrace is present at Mbao, Bargny  (Demoulin,
1967), between Mbour and Nianing (Elouard et al., 1967), and at Mbodiene (Elouard
et al., 1967; Debenay and Bel lion, 1983).

     The sandy barrier(s)., 100 to  150 m wide and less  than  5 m high, can present
several aspects (Demoulin., 1967).  The fixated barrier (the most common type) is
covered by  Opuntia tuna  and limited  seawards  by a mi croc! iff.    In the Mbour
sector (Elouard et al., 1977), there is a barrier of several generations, with
the first one  very  rich  in heavy minerals (ilmenite, zircon, and rutile).  After
this barrier, there  are successive and more recent barriers up to the beach.
     The beaches  are  narrow  (30 to  40 m)  with  average  slopes  of 3  to 4
(Demoulin,  1967), the shore face being more steep (5 to 15).  The beach cusps
are well developed on  this  coast (Demoulin,  1967)  and sometimes  consist of
pebbles.  The beach sands on this coast are very often titaniferous  (amorphous
ilmenite),  the more important  concentrations  being  found at Rufisque  (33,360 to
92,580 ppm) and Tine Dine island near Joal  (131,000 ppm)  (Dumon,  1981).

     One feature of this coast is the presence of Holocene to Pleistocene "beach
rocks" (Demoulin and Masse, 1969) outcropping  on the beaches  at Rufisque, Bargny-
Sienndou, and  along the "Pointe de Sangomar" sand  spit.   The  first carbon-14
dating made on shells have given an age  of 32,500 +2150 years ago (Demoulin and
Masse, 1969), which corresponds  to the so-called  Inchirian.  New petrographical
and geochemical studies (Giresse et al.,  1988; Diouf,  1989) have questioned the
previous dating.

Mangrove Estuaries

     Representing about 150 km of coastline,  these estuaries correspond to the
three  most  important  rivers,  from   North  to  South:    Senegal,   Saloum,  and

     General  Characteristics

     In all the estuaries, the  common geomorphological  units  have been formed
during the last Quaternary (Sail, 1982; Diop, 1986).



        Tidal  channels.  They are sinuous except in the Senegal estuary.  These
         channels  present a well-developed hierarchy.   The depths are not very
         important except in the  main channels:   8-10  m in the Senegal, 6 m in
         the  Saloum,  and 8-9 m in the Casamance.  These channels present sandy
         or clay channel bars, very developed and unstable in the mouth channels.
         From north to south,  the channel  sediment  granulometry diminishes.

        Tidal  flats-mangrove marshes-"tannes."   From the tidal channel, we can
         observe in the intertidal zone, first tidal  flats then mangrove marshes
         with Rhizophora  racemosa  (5 to 12 m high) replaced  by R. harisonnii and
         R.  mangle in  the  Saloum estuary, then  Avicennia  africana (1  to  3 m
         high).    The sediments  are  finer in  the   inner  estuary than  on  its
         maritime  part.  From  south  to north, due  to  climatic  conditions,  we
         notice a  reduction  of the mangrove population density and a diminution
         of the species number (six  in Casamance,  four in  Saloum,  and two in
         Senegal).   The bare tanne presents salt efflorescences and is limited
         by the very  high tide level.   The herbaceous tanne  is developed beyond
         the  tide  levels but can be inundated by freshwater.  It is colonized by
         an halophyte vegetation.

        Sandy barriers:   with  "kjokkenmoddinger"  and some  "lunettes,"  they
         constitute the rare permanent  emerged units (+2 to  +4 m high) in these
         estuaries.  They are, therefore, favored  sites for habitat and fresh
         groundwater.  Well  developed  in the Senegal  estuary,  they surround small
         lagoonal  lows.   They are also  present along the maritime parts of the
         Saloum and Casamance  estuaries but less developed.  The different sand
         spits  bordering  the main  rivers  belong   to  this unit:   "Langue  de
         Barbarie," "Pointe  de Sangomar,"  and "Presqu'ile  aux  Oiseaux."  These
         sand spits,  built  since  3,000 years ago,  are  N-S  oriented  due to the
         littoral  drift.

        "Kjokkenmoddinger"  (manmade  shell deposits):   These  are  due  to  the
         completion and trade  of Anadara  senilis  and the  Rhizophora  oysters
         (Grvphea  gasar)  since the Neolithic.  They are accumulations sometimes
         of huge  size marked by the presence of  Adansonia  diqitata.   They are
         present  in the three estuaries but are  particularly  developed in the
         Saloum (Diop,  1986).

     The Senegal  Estuary

     The estuary is a triangle. First flowing E-W with numerous meanderings, the
Senegal River changes direction from Keur Macene, flowing NE-SW  then N-S from St-
Louis,  bordered  by  the  25-km-long  "Langue  de Barbarie"  sand  spit.   Before
reaching St-Louis, it receives a  number of tributaries (Gorom, Lampsar), which
are ancient  deltaic  channels.   From  Bogue, the Senegal river  bed  is  situated
below the sea level (-5 m up to St-Louis).

     The Senegal  estuary presents normal  fluctuations  with  two  seasons (Sail,


West Africa

       A  high-water  season  (July  to  November)  during  which  there  is  a
        fluviatile  regime.   The flood is characterized by an high interannual
        variability in relation to the precipitation irregularity.  For example,
        at Dagana,  the annual  module varies between 890 m3/s during wet years
        and 490 m3/s during dry years.  Studies by Kane  (1985) and Gac and Kane
        (1986) on suspended matter  in the "delta"  zone showed that the values
        are higher  than  200 mg/L until the beginning of the flood, then reach
        maximum  values  of  686.4 mg/L  (1981) and  415.8 mg/L  (1982).   From
        November, these values diminish to reach mean concentrations of 10 mg/L
        during  the  low water  period.   The inundated  areas  fluctuate between
        100,000 and 500,000 hectares, depending on  the  flood  quality.

       A low-water season  (December to June)  during which the saltwater enters
        the low estuary.  The mechanism of the salt  intrusion  has been described
        by Gac et al.  (1986a,b).  The salt front was found around Richard Toll
        (170  km from  the mouth) during wet periods  and reached  Dagana (217 km
        from  the mouth)  during  dry  periods.

     The Saloum Estuary

     It opens  into the Atlantic Ocean through three distributaries:  the Saloum,
the Diomboss,  and the Bandiala separating  three groups of islands  (Gandoul to the
North, Betanti and Fathila to the South).  The three distributaries are connected
by a dense network  of  small  and shallow  tidal channels, the so-called bolons.
The Saloum is bordered by a 20-km-long sand spit,  the "Pointe de Sangomar."  A
mangrove swamp stretches all over the estuary. The main characteristics of the
Saloum estuary are the following:

       Hydrodynamic and hydrological regime:  several studies conducted between
        1981  and  1984  (EPEEC,  1983,  1984;  UNESCO,  1985) have proposed for the
        Saloum and  Diomboss a reverse estuarine model (Barusseau et al., 1985,
        1986)  due to the weak  or absent  freshwater inflow  (water discharges
        lower than  0.7  m3/s  (Diop,  1986)).   The  characterized model  of  the
        regime is as follows:   the flood phase lasts longer than the ebb, with
        current velocities  generally higher  during  the flood than on the ebb;
        and the Saloum distributaries receive more  water than flows back into
        the sea (about  66%); the estuarine salinity is always higher than  the
        seawater, even after the wet season.  It increases from the mouth (35%
        in the wet  season,  55% in the dry season)  to  the upstream end of  the
        estuary (respectively,  42 and 88%  in  Kaolack).

       The Saloum estuary is characterized by the  presence of relatively coarse
        sediments,  and,  even  if  the fine fraction  is important, it  is silt
        dominated.   The  percentage  of  carbonates  is  low  (<5%)  due to  the
        mechanical  and chemical  destruction  (low pH) of the  shells.

       Studies on the mangrove population along the Saloum (UNESCO, 1985) have
        shown that from the mouth to  the upstream part of the  estuary, there has
        been  a height reduction of Rhizophora. diminution of the area occupied
        by  Rhizophora,  of  the  population density  and augmentation  of dead



         Rhizophora.   Finally, the mangrove disappears upstream of Foundiougne.
         This  regression of  the mangrove environment will  be related  to the
         drought, to the human activities (use of trees for cooking, small-scale
         exploitation  of salt),  and  to  natural diseases.

        The great  development of  "kjokkenmoddinger."

     The Casamance Estuary

     It  is, in  fact,  a ria dominated  by  the "Continental  terminal" sandstone
plateau  (30-40 m high) often capped by a lateritic crust (Pages et a!., 1987).
During  the  last 240  km,  the slope of the  Casamance  is null.   Downstream of
Ziguinchor, the Casamance River  receives  the  Diouloulou tributary and there are
numerous small tidal channels interconnected ("bolons").  The mangrove marshes
are well developed with Rhizophora racemosa and Avicennia nitida. followed by the
tannes.  There are two types of sandy barriers (TECASEN, 1979). The recent ones,
like the "Presqu'ile aux Oiseaux"  which is a  sand spit, are N-S oriented in the
direction of  the actual  littoral  drift;  the  old ones  (since about 4,000 years
ago) are oriented NNW-SSE (change of direction of the littoral drift since 4,000
years ago) or NE-SW south of the Casamance mouth  (built by the SW swells).

     The water discharges  are relatively low.    During wet  years  (1962, 1967,
1969, 1975),  the annual module  was  of  6.4 m3/s with a maximum of 32 m3/s.   But
now, with the drought,  the  annual  module is  of 1.7 m3/s  with a  maximum of 6.8
m3/s (Pages et al.,  1987).   Before  1970,  the  Casamance  River  had  a normal
estuarine function, but now it is  a  reverse estuary  like the Saloum (Debenay et
al., 1987; Pages et al., 1987).  Actually, the salinity increases upstream with
values higher than 100% upstream of Sedhiou located  200 km from the mouth (max;
of 170%  in June 1986) (Pages and Debenay, 1987).


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reversal   in   tropical   estuaries,   geomorphological   and   sedimentological
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evolution  des  sediments  fluviomarins  au Senegal.    In:   Symp  INQUA/ASEQUA,
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petrochimi-ques et geotechniques des granulats basaltiques  de la presqu'ile du
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Diaw, A.T.  1981.  Etude morpho-sedimentologique de 1'estran sur la cote nord du
Senegal.  Bull. IFAN, Dakar, (A),  43:1-2,  69-78.

Diop, E.H.S. 1986.  Estuaires holocenes  tropicaux.  Etude de geographic physique
comparee des "Rivieres du Sud":  du Saloum  (Senegal) a la Mellacoree (Republique
de Guinee).  Thesis, Strasbourg, 2 volumes,  522 p.


Diop, E.S., and Sail, M.  1986.  Estuaires et mangroves en Afrique de 1'Quest:
evolution  et  changements  du  Quaternaire  recent  a  1'Actuel.    In  Symp.
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Diouf, M.B.  1989.  Sedimentologie, mineralogie et geochimie des gres carbonates
quaternaires du littoral senegalo-mauritanien.  Thesis, Perpignan, 237 p.

Dumon, J.C.  1981.  Comportement du titane dans les phenomenes d'alteration et
de sedimentation sous differents climats:  Esquisse d'un cycle biogeochimique.
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Elouard, P.  1980.  Geomorphologie structurale, lithologique et climatique de la
presqu'ile du Cap Vert (Senegal).  Notes Afr., IFAN, Dakar,  167:1-68.

Elouard, P.,  Faure,  H.,  and Hebrard, L.   1967.   Quaternaire de  la  region de
Mbour.  Sixth Cong. Panafr. Prehist. Et. Quatern., Dakar, p.  31-33.

Elouard, P., Faure, H., and Hebrard, L.   1977.  Variations du niveau de la mer
au cours des 15,000 dernieres annees autour de la  presqu'ile du Cap Vert. Dakar,
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E.P.E.E.C.   1983.   Atelier d'etude des mangroves au Sud  de 1'estuaire du Saloum:
Diomboss-Bandiala  (Senegal).  UNESCO/ROSTA, Dakar, 219 p.

E.P.E.E.C.   1984.   Etude des mangroves et estuaires du Senegal: Salom et Somone.
UNESCO/ROSTA, Dakar,  88 p.

Fall,  M.    1986.   Environnements  sedimentaires   quaternaires  et  actuels  des
tourbieres des niayes de la Grande Cote  du Senegal.  Thesis,  Dakar, 130 p.

Faure, H.,  Fontes,  J.C., Hebrard, L., Monteillet,  J., and  Pirazzoli, P.A.  1980.
Geoidal change and  shore-level tilt along Holocene estuaries: Senegal river area,
West Africa.  Science 210:421-423.

Gac, J.Y.,  Kane, A.,  and Monteillet, J.   1982.   Migrations de 1'embouchure du
fleuve Senegal depuis 1850.  Paris: Cahiers Orstom, Ser.  Geol.  12(l):73-75.

Gac, J.Y.,  Cam, M.,  and Saos,  J.L.  1986a.   L'invasion marine  dans la  basse
valleedu fleuve Senegal. I.Periode 1903-1980.  Rev. Hydrobiol. trop. 19(1):3-17.

Gac, J.Y.,  Carn, M.,  and Saos,  J.L.  1986b.   L'invasion marine  dans la  basse
vallee du fleuve Senegal.  I.Periode 1980-1983: proposition d'un nouveau modele
d'intrusion  continentale   des   eaux  oceaniques.     Rev.   Hydrobiol.   trop.

Gac, J.Y.,  and Kane, A.  1986.  Le Fleuve Senegal:  I. Bilan hydrologique et flux
continentaux  de  matieres   particulaires  a  1'embouchure.     Sciences  Geol.


Vest Africa

Giresse, P., Oiouf,  M.,  and Barusseau, J.P.  1988.  Lithological, mineralogical
and  geochemical  observations  of  Senegalo-Mauritanian  Quaternary  shoreline
deposits: possible chronological revisions.  Paleogeogr. Palaeoclim. Palaeoecol.

Kane, A.  1985.  Le bassin du fleuve Senegal a 1'embouchure. Flux continentaux
dissous et  particulaires.  Invasion  marine dans la vallee du  fleuve.   Thesis,
Nancy I, 205 p.

Lezine,  A.-M.   1986.  Environnement et paleoenvironnement des niayes depuis 12
000 B.P.  In Symp.INQUA/ASEQUA, Changements globaux en Afrique durant le
Quaternaire:  Passe-Present-Futur.   Paris: Orstom, p. 261-263.

Lo,  P.G.    1988.    Le volcanisme  quaternaire  de Dakar  (Senegal  occidental):
particularites   petrographiques,   caracteres    geochimiques.    Implications
petrogenetiques.  Thesis, Nancy I,  143 p.

Lompo, M.  1987. Methodes et etude de la  fracturation et des filons. Exemple de
la region du Cap Vert (Senegal).  Mem. DEA,  Dakar, 58 p.

Marius, C., Lucas, J., and Kalck, Y.   1986.  Evolution du golfe de Casamance au
Quaternaire recent et changements de la vegetation et des  sols de mangroves lies
a la secheresse actuelle.   In  Symp.INQUA/ASEQUA, Changements globaux en Afrique
durant le Quaternaire:   Passe-Present-Futur.  Paris: Orstom, p. 293-295.

Masse, J.P.   1968.   Contribution a  1'etude des sediments  actuels  du plateau
continental de  la region  de Dakar  (Republique du Senegal).   Rapp.  Lab. Geol.
23:81 p.

Michel,  P.    1969.    Les bassins  des  fleuves  Senegal  et  Gambie.  Etude
geomorphologique.  Thesis, Strasbourg, 1169 p.

Michel, P., and Sail, M.   1984.  Dynamique des  paysages  et amenagement de la
vallee alluviale du Senegal.  Paris: Mem. Orstom, No. 106, p. 89-109.

Murday, M.  1986.  Beach  erosion in West Africa.  Res.  Plan. Inst. ed., Columbia,
101 p.

Olivry, J.C.    1983.  Le point en  1982  sur  1'evolution  de la  secheresse en
Senegambie et aux iles du  Cap  Vert. Examen  de quelques series de longue duree
(debits et precipitations).  Paris:  Cahiers Orstom,  Ser.Hydrol. 20(l):47-69.

Pages, J., and Debenay,  J.P.  1987.  Evolution  saisonniere de la salinite de la
Casamance.  Description   et essai  de  modelisation.    Rev.  Hydrobiol.  trop.

Pages, J., Debenay,  J.P.,  and Lebrusq, J.Y.  1987.  L'environnement estuarien de
la Casamance.   Rev. Hydrobiol. trop. 20(3-4):191-202.


Paradis, G.  1986.  Role de I'homme dans les changements du paysage tropical: les
mangroves ouest africaines.  In Symp.INQUA/ASEQUA, Changements globaux en Afrique
durant le Quaternaire: Passe-Present-Futur.  Paris: Orstom, p. 357-362.

Pelissier, P.   1983.  Atlas du Senegal.  Paris: Jeune Afrique, 72 p.

Pezeril, G., Chateauneuf, J.J., and Diop, C.E.W.  1986.  La tourbe des niayes au
Senegal: genese et  gitologie.  In Symp.  INQUA/ASEQUA,  Changements  globaux en
Afrique durant le Quaternaire. Passe-Present-Futur.  Paris: Orstom, p. 385-392.

Pinson-Mouillot,  J.    1980.    Les  environnements sedimentaires  actuels  et
quaternaires du plateau  continental  senegalais (Nord de  la  presqu'ile du Cap
Vert).  Thesis, Bordeaux I, No. 1554, 106 p.

PNUE/UNESCO/ONU-DAESI.   1985.  Erosion  cotiere en Afrique  de 1'Quest  et du
Centre.  Rapp Et. Mers regionales Geneve, 67, 248 p.

Riffault, A.  1980.  Les environnements sedimentaires actuels  et quaternaires du
plateau continental  senegalais (Sud  de  la  presqu'ile du Cap Vert).   Thesis,
Bordeaux I, No. 1561, 145 p.

Sail, M.   1982.  Dynamique  et morphogenese actuelles  au Senegal  Occidental.
Thesis, Strasbourg,  604 p.

Sy,  A.    1982.   Etude  geomorphologique des  fleches  sableuses  du  littoral
senegalais:  Langue  de Barbaric (Nord  Senegal),  Pointe de Sangomar (Saloum),
Presqu'ile aux Oiseaux (Casamance).  Trav. Et.  Rech.,  Dakar,  103 p.

Sy-Niang I.  Littoral ore deposits in Senegal.   In International Conference on
Geosciences in Development.  Nottingham,  England:  in preparation.

TECASEN.   1979.   Teledetection de quelques  geosystemes littoraux  senegalais.
Depart. Geogr. Dakar, E.N.S.J.F. Montrouge,  Rapp.l, 83 p.

UNESCO.   1985.   L'estuaire  et la mangrove  du  Sine Saloum.   Proceedings  of a
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1983.  Rap. UNESCO Sciences de la Mer, No. 32,  139 p.


                         PHILIBERT  KOFFI  KOFFI
                              NASSERA  KABA
                              SOKO G.  ZABI
              Oceanographic Research Center  of Abidjan
                          Abidjan, Ivory Coast

      Since  1985,  scientists  in  the Oceanographic Research  Center  of  Abidjan
(Cote d'lvoire)  have  been studying erosion.   Although the southwest shoreline
(Tabou-Sassandra) is stable, the southeast (Fresco-Vridi-Port-Bouet-Ghana) border
is very unstable and is eroding at the  rate of 1 to 2 m/year.  Although  part of
that erosion  results  from the  Vridi Canal and the Bottomless  Pit  Canyon, the
Fresco-Vridi  area appears to be eroding as a natural consequence of current sea
level trends.

     The potential  implications of an accelerated rise  for  Cote d'lvoire are
similar to those for  other nations in West Africa.  Erosion would accelerate
threatening some  structures.   Perhaps  more important are the implications for
the lagoonal  systems.   If the outer barriers should break up  due to erosion and
inundation, these lagoons might become  exposed to the open ocean; even where the
barriers remain  intact, rising water levels could  drown the  intertidal  wetland
areas.   In either event, subsistence fishing  in  the lagoons would be seriously

      This paper briefly describes the  environmental  conditions  along Cote
d'lvoire and  the  administrative structure for dealing with coastal  management

      Cote  d'lvoire is located in  West Africa on the Gulf of Guinea  (Atlantic
Ocean), between latitudes 4  and 11 North;  its  surface area is 322,463  square
kilometers.   Its 500-km coastline is fringed with 350 km of lagoons,  which are
separated from the sea by a narrow offshore bar and  a narrow continental  shelf.


West Africa

Of the nation's 10 million people, about 3 million live along the coast (about
2 million in and around Abidjan).

      The climate is warm and humid  in the south and tropical dry in the north,
which results in two major types of vegetation:  guinean  (dense forests and pre-
forest savannahs)  and  Sudanese  (savannahs).   The economy of Cote  d'lvoire is
essentially based on agriculture:  traditional agriculture using slash and burn
techniques,  and  industrial  plantations  using very  extended land  areas.   The
industrial growth rate for the last three decades has  been  about 7% from 1960
to 1984.


      Lagoons are found along 60 percent  of the coast and cover about 1200 square
km.  There are three main lagoons (Grand-Lahou, Ebrie, and Aby Lagoon) connected
with the  sea and each other  by  natural  or artificial  channels.   Grand-Lahou
lagoon, which covers  190 square km, is the smallest and shallowest (average depth
of 3 m).  The Bandama River, which  drains the largest  watershed of Cote d'lvoire,
flows into it.   Ebrie Lagoon, in the middle,  covers  566 square km and is on an
average, 4.8 km deep.  It is  connected to the sea by the Vridi Canal and Grand-
Bassam Channel.  Aby Lagoon,  near the Ghana border,  covers 424 square km.

      Lagoonal  seasons are determined by riverflow and  rainfall.  The dry season
(January to April)  is characterized by marine  influence  (maximum temperature and
salinity).   During the rainy  season  (May to  August),  heavy  rains swell  forest
rivers.  The flood  season (from  September to December)  corresponds to maximum
inputs by  "Sudanese"  rivers  (Comoe  and  Bandama) causing  lagoon  salinities to
approach zero.

     A change in climate-could affect these lagoons in many ways.  The inundation
of intertidal vegetation  would remove important habitats for  fisheries.  Erosion
and flooding would  increasingly threaten establishments along the shore.  Rising
seas and  decreased  precipitation would  increase the salinity of the lagoons,
perhaps leading to increased predation in some  cases.

The Open Coast

      There  are two  types of  landscapes  in the coastal  region:   (1) cliffs of
the southwest (from the Liberian  border  to Fresco) are characterized by a step-
like  profile where  a narrow quaternary  coastline and  the contact of  the
precambrian  plinth  alternate.   These plateau-coasts,  cut as abrupt or gently
sloping cliffs, are elevated more than 20 m above sea  level  (more than 65 m in
the  San  Pedro  sector);  and  (2)   sandy  low  coasts  (from  Fresco  to  the  Ghana
border),  which  have flat landscapes  where  the  quaternary  shoreline  is more
developed (maximal width 4,500 m) and continuous.   Low plateaus  of the nearby
inland areas are generally less  than  12 m above  sea level.   The  land adjacent
to the sandy shorelines is usually 2-6 meters above sea  level  -- even lower near

                                                                 Koffl, et al.

      There are two major  marine  seasons:   a major warm season (from February
to May) during which water temperatures vary  from  27 to  28C; and a major cold
season (from July to October) during which the upwelling is more distinct, water
temperatures are less than 23C, and the salinity is near 35%.  Beside these two
distinct seasons, there is a short warm season (November to December) with the
disappearance of the upwelling, and a short  cold  season (December to January)
with a coastal upwelling and water temperature varying from 24 to 25C.

     If sea  level  rises one meter, the Bruun  rule implies  that sandy beaches
could erode 100-200  meters,  which would threaten some  establishments along the
coast.  In addition, upwelling and other aspects of the marine climate have an
important  impact on  fisheries.    If climate  change  alters  the  seasonal  or
geographical extent of upwelling, fishing would probably be affected.


Administrative and Institutional Efforts

      Environmental protection is a national concern.  Among the institutional
establishments dealing with this subject are the Oceanographic Research Center,
the Tropical Ecology  Institute, the National Agency of Meteorology, the National
Committee for fighting  bush  fires,  and  nongovernmental organizations like the
Green Cross.   Cote d'lvoire has also signed several international conventions
in environmental  protection.   Actions against environmental degradation include
the monitoring of coastal erosion.

      Shoreline evolution  and coastal erosion  have been studied since 1985 at
18 stations from Tabou to Assinie.  The initial results  are as follows:  (1) the
southwest shore (Tabou-Sassandra) is stable because of  its geology and steplike
formation; and (2) the sandy low coast at the southeast (Fresco-Vridi-Port-Bouet-
Ghana border) is very  unstable and  is eroding  at  1 to  2 m/year.   This area in
turn can be divided into an area with natural erosion (Fresco-Vridi) and an area
where erosion is  linked both to the presence of the Vridi canal and the proximity
of the "Bottomless Pit" canyon (Vridi-Port-Bouet).

      The aim of this  erosion study is to establish  a coastline sensitivity map.
This map will include the geology and coastal  shapes, erosion and sedimentation
rate of the coastline, coastal drift, the  topography of the  coast,  and inter-
tidal zones.  This study will help in managing (1)  passive measures of coastal
protection; (2)  the exploitation of quarries (sand and others); and (3) refining
a  sedimentation model  built  to  predict   erosion  and  the  effectiveness  of
protection options for the Abidjan area.

     With  respect to the  fight  against  deforestation,  Cote  d'lvoire  has
established a permanent national  forest domain  in the thick forest and savannah
zones  (decree  no. 78-231  of 3/15/78), which includes  a  total  of  5,921,558
hectares divided into 205 forests and parks.  A program of reforestation favoring
rapid-growing species of trees  is being instituted,  which will help slow global
warming by providing a natural  sink for carbon dioxide.


West Africa

Ma.ior Constraints to Environmental Protection

      An obstacle to protecting and managing the environment is the antagonism
between environmental and developmental forces, which must be reduced to achieve
the benefit of an effective equilibrium between the two.

      The search for this precarious equilibrium is sometimes difficult because
of  the  ingrained  habits  of  people,  which  are often detrimental  to  the
environment, and because of financial  constraints.


      The Ministry of Defense and the Ministry of Scientific  Research coordinate
national activities  related  to research and monitoring  of  meteorological  and
oceanographic   surface   conditions   among  all   regional   institutions  with
responsibilities for studying climatic variability and its local impact. We need
to establish public education projects to promote an understanding of changing
climate and  rising seas, to assess its  potential impacts  on  society,  and to
encourage  regional  scientific  centers  related to  environmental  research to
establish studies to identify the vulnerability of particular  geographical areas.

                     SEA  LEVEL RISE FOR  GHANA
                                J.  F.  ABBAN
                            Hydrology Division
             Architecture and Engineering  Services Corp.
                               Accra, Ghana

     This paper identifies coastal areas in Ghana subject to erosion and some of
the causes of erosion,  such as  artificial  structures along the coast or river
barriers.   The  socioeconomic aspects of  sea erosion are  also  highlighted,
including the displacement of people with subsequent destruction  of economic
activities,  and the threat to tourist activities.  Some of the studies conducted
to evaluate shoreline recession  are  discussed, as are attempts that  have been
made to  arrest or to contain sea erosion.   Finally, this paper addresses  sea
level rise and ways  to  assess it with data that could be obtained in  Ghana.


     The Ghanaian coastline stretches roughly 550 km from Half Assini in the west
to Aflao in the east. A substantial  number  of dwellings, commercial  activities,
and industries,  as well as fishing and tourism,  are found within 300 m of the
ocean coast.  Coastal areas can be grouped into three basic economic categories:

     1.   Commercial   and  industrial  areas,  such  as Accra, Tema, Sekondi,  and

     2.   Fishing  areas,  such as Tema, Keta, and Winneba;  and

     3.   Tourist  areas,  such as Batianor,  Ada,  Labadi, Biniwa, Elmina, Winneba,
         and Busia.

     Coastal erosion  is experienced  in  varying degrees; the adverse effects  on
developments  along the  coastal zones cannot be overemphasized.   The  immediate
result of shoreline  retreat  is  the  loss  of  land,  which in almost  all  cases
results   in loss of  properties  and  displacement  of people.    Erosion  greatly
affects  the social and economic activities of coastal  dwellers and users.   Lack
of economic  activities  means lack of jobs or forced change of vocation,  with a


Uest Africa

subsequent loss of revenue  to the government.  New fishing areas must be sought,
and tourist sites are threatened.  A  typical example is Keta, where portions of
the/population had to seek shelter elsewhere because properties had been engulfed
by the sea.  The Labadi pleasure beach, until  coastal  protection measures were
carried out,  lost its  tourist  business to other areas.    Bortianor,  another
tourist spot, is being seriously threatened by coastal erosion.


     Most  of the coastal areas  in Ghana  are low-lying and  sandy,  interspersed
with beach rocks  and  rock outcrops.    In some  areas experiencing  active beach
erosion (see  Figures  1  and 2,  which show shoreline changes  for Keta and Ada,
respectively), shoreline changes have been monitored;  these areas include Axim,
Dixcove, Nkontompo,  Labadi, Ada,  and Keta.   Records  for periods  indicated in
Table 1 have been  kept for Keta, Ada, Labadi,  and Nkontompo.
                   Table  1.   Periods  of  Shoreline Monitoring



Soil logging
Beach profile monitoring
Soil logging
Beach profile monitoring
Soil logging
Beach profile monitoring
Geological data
Beach profile monitoring
     Studies conducted on these  areas  indicate the following  major causes of

     1.   Creation of artificial barriers across some rivers  (e.g., the Volta and
         Densu),  which reduce or otherwise interfere with the sediment load to
         the coast;

     2.   Creation of  artificial  harbors  (e.g.,  the Takoradi  and  Tema Ports),
         where breakwaters and  jetties  interrupt littoral transport  of sand and
         other sediments;

     3.   The mining  of sand  along the coastline,  which removes supply material
         from the coastal zone so  that natural shoreline stability is diminished;

               ATLANTIC OCEAN
Figure 1.  Successive flooding and erosion through the years at Keta.
Figure 2.  Successive flooding and erosion through the years at Ada.

West Africa

     4.   Natural,  constant coastal  processes  (e.g.,  subsidence,  seasonal  and
         interannual  wave  climate  variability, and tectonic movement).


     The Ghanaian wetland ecosystem  has  not been exhaustively  studied  in  the
environmental context,  but a few studies have been conducted through the graduate
school at the University of Cape Coast.  The Environmental Protection Agency of
Ghana is generally responsible for the policies developed  to protect the wetland

     Two types of marsh-ecosystems are found in  the West  African region:

     1.   Wet-humid areas dominated by grasses and marshy shrubs  (found near small
         estuaries and  lagoons); and

     2.   Mangrove-type  vegetation  dominated  by almost  all types of hydrophilic
         angiosperms  (with monocots of  oil  palm  in  plantations  near  large

     Human habitation  is  common  in the  areas  described  above, since  these
ecosystems are  also  dominated  by  fauna  that form the economic basis  of  the
region.    Fishing  is  the  predominant activity in  Ghana and the  west  coast of
Africa.    Most of the  wetlands  on the Ghanaian  coast  are natural,  and  human
habitation and industry have  not yet  taken their toll.  Mangroves generally are
not cut, except  in cases where land has to be cleared for farming purposes, e.g.,
rice farming. This is  all the more reason why  specific  policies and research
leading to protection of such areas should be initiated now.


     Coastal  river estuaries are subjected to saltwater intrusion. Low riverflow
allows seawater to intrude farther upstream.  This tends to seriously affect the
drinking water supply in areas such as Ada and Keta,  where the local  residents
rely on  groundwater  as a source of  drinking  water.    In some  cases,  the high
salinity of the groundwater has made the water unsuitable for drinking.


     Flooding along  the  coastal  areas  occurs in Accra,  Botianor,   and  Keta.
Floods in Accra  are mainly due to improper planning or to the inadequate drainage
system.    Efforts  to  desilt and improve  the hydraulics of the  primary  drains
(stormwater   channels),   coupled   with   various  maintenance   schemes,   have
significantly reduced flooding in Accra.

     Flooding in Botianor  Is due mainly to releases from the Weija  Reservoir (one
of the impounding waters providing Accra with a  water supply)  during the rainy


                                                                         Abb an

seasons.  This could be controlled by  proper regulation of the Weija Reservoir,
channeling  the  river downstream  from the dam,  and  construction of  a proper
outfall to the sea.

     Since the early  1960's,  three floods in Keta have  been  caused by excess
water discharged into the Keta Lagoon  from the Todzie and Belikpa Rivers during
exceptionally wet seasons.  The creeks connecting the Keta Lagoon to the River
Volta estuary are blocked and, therefore, the excess water is impounded in the
lagoon instead of being discharged into the sea.


     About 13.5 million people were estimated to live in Ghana in 1987, with a
large percentage residing in the coastal zone where most of the major cities are
located.  Population density in the coastal urban areas exceeds 550 people per
square  kilometer,   10  times   the  density  of  inland  areas.    The  last  three
population censuses indicate that the Keta area (including Kedzi and Vodza) is
being  rapidly depopulated, the  result  of severe erosion  coupled with  non-
availability of land.


     Ghanaian coastal  area inhabitants are primarily fishermen, except for those
directly in commercial centers such as Labadi, a suburb of Accra  (the capital of
Ghana), Tema,  and  Sekondi.   Although Keta used  to  be  a bustling  commercial
center, these activities have dwindled to nothing because of severe waterfront

     Some of  the tourist  beaches  along  the  Ghanaian  coastal  zone  are  Ada,
Chemuna,  Labadi,  Botianor, Biriwa,  Elmina,  Winneba, and  Busia.    Erosion  of
varying degrees has been recorded in these areas.


     The most important  crop  in Ghana is  cocoa,  which  accounts for  about  60
percent of the nation's exports.  Although  the cocoa-growing area is not located
in the coastal zone,  shipments  must pass through the coastal ports.   Production
of corn and  other grains  is  substantial  and  is  increasing.   Data  for  1969
indicate that production of corn and rice totaled 305,000  and 61,000 metric tons,
respectively; fishing produced  162,800 metric tons.   In 1969,  salt production
totaled 1,700 metric tons in the coastal  lagoon  area.

     Although fishing is the mainstay of  the coastal  people,  some  inhabitants
move inland to practice arable  farming during the off-season.  Some of the local


Vest Africa

farms along the fringes of the Keta Lagoon primarily cultivate shallots, rice,
sugarcane, okra, pepper,  and maize.  These farming  activities are disrupted each
time the Keta Lagoon is flooded.


     No  consistent rules  seem to limit coastal  land development.   In the past,
coconut trees planted along the coast indicated  the off-limit zones for building
structures.  However, the zones vary from place to place; in some beach areas,
structures are very close to the coastline.

     In  areas  of active sea erosion, such as Keta,  Vodza,  Kedzi, and Labadi, the
coconut plantations have  been claimed  by  the sea; thus, development, previously
behind the plantations are now close to the sea.


     Four  major ports  are  located along the shores  of Ghana:   Tema,  Elmina,
Sekondi,  and  Takoradi.   Sekondi  is  a naval port,  and Tema  and  Takoradi  are
commercial ports.  Tema has  a  fishing  port attached,  and Elmina  is purely for
fishing.  All  four harbors  are  manmade, and their breakwaters protrude into the
sea.  Elmina harbor has two basins:  the inner basin is  in the Benya Lagoon, and
the outer basin is at the mouth of the  lagoon where the lagoon water discharges
into the sea.

     Apart from Tema  harbor,  where erosion  is occurring on the western side of
the breakwater structure,  erosion is occurring  on the leeward  (eastern) side of
the harbors.

     Takoradi  and Tema  have tidal gauges.  The  Takoradi  and  Tema harbors were
opened in 1928 and 1962, respectively.  The tidal gauge  installations are as old
as the ports.   Hydrological gauging stations are also  located in the Keta Lagoon
and on the Volta estuary at Ada.  Hydrological  gauges were established at Keta
and Ada in August 1963  and  September 1963,  respectively.  The mean range of the
semidiurnal tide along the Ghanaian coast is a  nearly uniform 1.0 meters.


     A one-meter  sea level  rise would  have  a   serious  negative  socioeconomic
impact on the  country, causing  storm  flooding,  beach  and coastal  erosion,  and
loss of wetlands.

Storm Flooding

     A one-meter rise in sea  level would create a higher mean water  level  in
coastal  lagoons and estuaries.   This,  combined with high riverflow due to heavy
rainfall,  would exacerbate the  flooding  that presently occurs.   Such  flooding


                                                                         Abb an

would cause additional  loss  of property and would very likely require relocating
whole communities and  industries.

     As indicated previously, Accra and Keta  are  but two examples of areas of
constant  flooding.   Although Accra and  Botianor floods are  attributed  to an
inadequate  drainage   system  and  improper  regulation  of  Weija  Reservoir,
respectively, these areas, like many coastal towns, have drainage outlets subject
to tidal  influence of  the sea.  Flooding affects industries through inundation
of  warehouses,  which  results  in  damage  to  equipment,  raw materials,  and
manufactured goods.  Some residential  areas near natural drainage channels are
constantly flooded during the wet season.

     The traditional reaction of local people  is  to  move out  until  the floods
subside  and  then  to  move  back  again.    Some people,  however,  tend  to  find
permanent accommodations elsewhere.

     The government antiflooding  program, especially  in Accra and other coastal
areas, focuses on improving  the drainage  system in these  areas.  The government
is also discouraging development of lowland areas.

     The projected sea  level  rise would allow water pushed by coastal storms to
surge farther ashore with devastating effects.

Beach and Coastal Erosion

     The projected  one-meter  rise  in sea  level  would exacerbate the  erosion
already seen along the low-lying sandy coast  of Ghana.   Loss  of these coastal
lands would  have a far-reaching  socioeconomic impact on the  nation.   Coastal
tourist enterprises would be at risk; commercial and industrial  sites would need
major protection or relocation. Agriculture in the near-shore zone might suffer,
requiring inhabitants  either to move or to change crops to remain productive.

Loss of Wetlands

     The rate of  natural growth and  migration might not be able  to keep pace with
the rate of wetland submersion caused by rapid sea level rise.  Consequently,
valuable wetlands could be lost.   A more gradual rise might permit wetlands to
survive and  migrate.   Wetland migration could  occur only in  areas  having no
barriers  to  lateral displacement.   Agricultural lands,  sharply rising  land
contours, dams, or other barriers would interfere with migration.


     Sea level rise would certainly influence the development of new settlements
and the use of beaches  as recreational grounds.  Existing laws would have to be
enforced or modified,  especially regarding restrictions  on  development of the
coastal zone.   Decisions would have to be made concerning whether or  not to
resettle people affected by sea level  rise.


West Africa

Response to Sea Level Rise

     The country will have to reassess its planning with regard to development
along the coastal area once the sea  level  rise impacts have been identified and

     Historical   records  of  the  tidal   and  hydrological  stations  mentioned
previously, together with  studies conducted so  far at Keta  and Ada and aerial
photographs, could form the basis for the study of the sea level rise.
     Although dozens  of culturally different tribes  live in Ghana, the people are
well integrated into a whole national fabric.   The Ghanaian educational system
is one of the best in the West Africa region,  with a literacy rate that stands
at roughly 30 percent.  The government is striving to rehabilitate and strengthen
the national economy; therefore, many issues have more immediate concern than sea
level rise.  Educating and informing everyone at  all  levels of government and
industry,  as  well as  the general  public, of  the need  to plan  and prepare
responses to rising  sea level will be a formidable task.

     Preparations also will  be formidable.  These will  encompass  the entire
spectrum of the nation's business:  enhancing education, enacting legislation,
establishing  government  agency  responsibility  for  oversight  or  regulation,
monitoring industry and private sector activity in the coastal zone, carrying out
scientific monitoring programs,  and conducting research to assess impacts of sea
level rise.  Such research must address geomorphological impacts and must also
provide  important information  upon which  to   base  appropriate responses  to
socioeconomic impacts.  Cultural impacts must be considered as well.

Property Ownership

     In Ghana, land is entrusted to the government  (local  authorities)  or to the
"stool" (kings or chiefs  as custodians).   Land for  development can therefore be
leased to interested parties by these agencies.

     The government could only  advise people to  move as the sea  level  begins to
rise and areas are threatened.   Experience in Keta  and elsewhere has shown that
people are not very willing to vacate their houses,  let  alone resettle elsewhere,
when being threatened by  the sea.  In most  cases, people move out or migrate only
when their  houses have  been destroyed by the sea.  There have been  instances
where people have built more than one house that has been engulfed by the sea.


     Ghana has  protected  its coast since the  1920's.


     Steel  sheet pike bulkhead was tried  in Keta  in the sixties.   The average
depth of the pile was 10 m.  Even though this form of sea defense wall was



expected to  last  at least 40 years,  it started to fail  within  6 years after
construction and has now collapsed completely.

Stone Revetment

     Stone  revetment in the form of armor rocks has been successfully tried at
Sekondi.  About a  kilometer  of  road  lined with houses has been saved from sea

     Another successful form of stone  revetment is the gabion revetment.  Tourist
spots such as Labadi and  Elmina  have been protected since 1981.  A gabion armor
rock revetment is currently being put in place at  kilometer  22 along the Accra-
Tema beach road to prevent that section of the road from being engulfed by the


     Wooden  groins were tried in  Keta  several times between the 1920's and 1960's
without much  success.   Pilot gabion  groins  constructed along the  James  Town
Beach, Accra, about 5 years ago  appear to  be very promising,  and they are being
monitored for eventual adoption along some sandy beaches.

Sea Outfalls

     A rubble mound outfall structure constructed  in the sixties  at James Town
to help with the runoff from stormwater and sewage  had no adverse effect on the
coastal morphological changes in the vicinity.


     Land subsidence has not been investigated  much  in Ghana,  but there is reason
to suspect that  subsidence  might be contributing to the severe erosion occurring
at Keta.


                                  0.  OJO
                        Department of Geography
                           University of Lagos
                              Lagos,  Nigeria

     This   paper  begins  by examining  what  is  presently  known  about  the
characteristics of climate and climate variations in the West and Central African
(WACAF)  regions  and  then  looks  at   the  socioeconomic  and   sociocultural
implications of the environmental  impacts of climate change and sea  level rise.
Also discussed are strategies  that could be used to reduce or eliminate the
vulnerability of  human   settlements and  environmental  systems,  as well  as
socioeconomic and sociocultural  systems, to the adverse consequences of climate
change and sea level rise.


     Since the beginning  of time, the world's  climate  has fluctuated.  In the
West and Central African region,  for instance,  there has been a great variation
in  rainfall,  which  in turn has  affected  environmental  processes  and  human
activities in the region.  The impact on geological processes has influenced and
indeed severely  disrupted local,  regional,  and even global  socioeconomic and
sociocultural systems  (for example,  natural  resources planning and management,
food production and agriculture, water resources and energy  systems, forestry,
marine resources development,  transportation, and tourism).

     There is mounting  scientific  evidence  that  human activity  is  partly
responsible for changing the earth's global and regional climates.  Although it
is difficult to distinguish between ecological changes due to human activities
and those  caused  by natural processes,  there is no  doubt that the differences
in climate between various parts of the earth  has  in  large measure determined
the types  of activities  people  pursue  for both  recreational  and productive

     This  paper examines  the impact of  climate change  on  the West and Central
African regions, with  particular focus on the sociocultural implications of the
greenhouse warming and the rise  in sea level.


Nest Africa


     Future climate changes are likely to have a significant impact on the marine
environment  and  the  adjacent coastal  areas.   The  coastal  areas of  West and
Central Africa extend from the coast of Mauritania in West Africa to the coast
of Angola.   Most of the region  is  in the tropics and  spans  the low latitude
areas between approximately 30  N and 30 S.

     Annual precipitation varies from less than 200  mm  in the north and south
to over 2,000 mm  in  the  western  equatorial regions,  most  of the area receives
between 200 and  1,000 mm of rainfall  per year.  Of  this total,  75% or more of
the precipitation  falls during the  rainy  season,  which  lasts  between 6 and 12
months in the central part:; of the West and Central  African region, and less than
4 months  in  the  extreme north and  south.   The rainy season  is  linked to the
migratory pattern of the intertropical convergence (ITC),  sometimes called the
intertropical  discontinuity  (ITD),  which  is  associated  with  the  apparent
migratory patterns of the sun (incorporating a time lag of about a  month or two).

     The climate in the WACAF region  is also  influenced by factors  other than
the ITC, such as atmosphere and oceanic circulation, and land and sea breezes.
However, little is known about their relative influence.


     Climate change is defined here  as the change in the mean values of climate
variables.  Climate variability is defined as the  differences between monthly,
seasonal,  and  annual  values of  climate  parameters  and their  average values.
Clearly, it is possible  for climate  to  change  without  becoming more variable,
and  it  is  possible  to  become  more  variable without  the average  condition
changing.  Any impact analysis must examine both the long-term climate changes
and the short-term climate  variabilities.   These  must  be examined  over three
natural time  scales:  (1) the short-term  periods,  which  range  between daily,
weekly, monthly,  seasonal,  or  annual  periods;  (2) the medium-term scales, which
cover a  decade or so;  and (3)  the long-term scales,  which  span  decades  or
centuries  (although  in the case  of nuclear waste sites the  assessments span tens
of thousands of years.)

     The impacts created by short-  and medium-term  climate problems have made
the governments and people  of  the West and Central  African regions aware of the
need to examine their own causative role and to fashion appropriate responses.
Droughts and floods in particular have caused so much  damage that world attention
has  been  drawn   to  the  socioeconomic  consequences  in   the  WACAF  regions,
particularly over the past three decades.  Indeed, there  is  a growing realization
that society is vulnerable.

Ecological and Physical  Impacts

     The average global  rise in temperature is expected to  be in the range of
1.5C  to 4.5C, while sea level rise is expected to be between about 20 and 140
cm.  Based on these expectations, it is assumed that both evaporation and
precipitation will increase by about 2 to 3% for each degree of global warming.



Thus, it is reasonable to expect that both precipitation and evaporation would
increase, possibly between 5 and 20% in the humid, tropical areas of the WACAF
regions,  which  are  already  too  hot  and  too  wet.   The  increase  in  both
precipitation and temperature could have significant environmental  impacts.  The
increase in average rainfall may be  accompanied largely by an increase in the
amount of rain per hour during severe storms and shifts  in geographical patterns
of precipitation  and  cloudiness.   However, since  the  increase in temperature
could increase evaporation and  potential  evapotranspiration,  there would be a
tendency toward more  droughts  in  many,  if not  most, of these humid,  tropical
areas.   With the  increase  in ocean  temperatures,  tropical  storms  (e.g.,
hurricanes and thunderstorms)  are likely  to  extend into  areas of the region
where they have  been  less common.   Where  tropical  storms  already occur,  more
intense winds and rainfall might be expected.

     The savanna  and semi arid areas of the WACAF region  would probably have less
rain, which -- coupled with  temperature  increases  -- would  reduce soil moisture
availability  (WMO/TD,  1988).  Less soil  moisture, in turn, would diminish food
production and  availability, the  availability of  water  and fuel,  and  human

     The rise  in  sea  level   that would  accompany global climate  change  would
result in submergence  and  inundation of the coastal lowland areas.  It would also
lead to increased salinity of the estuarine areas and increase the size of the
coastal  region.

     The ecological and physical implications  of climate change include effects
on geological, geomorphological,  and hydrological  processes,  ocean  dynamics,
droughts and desertification, and floods and erosion.  Decreased precipitation
would  lessen  the  water  supply  and hydroelectric power generation,  while
decreasing the risk  of  floods.    Increased  variability  could  increase  the
probability of both floods and droughts.

     Forest ecology and the  ecosystems  would  also  be  affected.   For example,
changes in ecological  conditions might be  less favorable to the existing biota.
Ecosystems would respond by gradually invading the neighboring areas where the
climate is more favorable.

Impacts on Agriculture and Livestock Production and Management

     Agriculture  and livestock  production  are  the  center of life for almost all
the peoples in the region.  The climate  and soil characteristics determine how
the land is used for agriculture and livestock  production, including which crops
are grown.

     The impact of climate change and sea  level rise on agricultural production
would no doubt be  significant, as  would the  socioeconomic  and sociocultural
consequences.   For example,  decreased  rainfall  would reduce  the production
potential  of  the  crops  presently grown in  the  various ecological  zones,
increasing hunger in the region and reducing the incomes of farmers and others
whose occupation depend on farming.  In  the extreme, unemployment, starvation,
and death could also result.   There might also be increased migration to urban


West Africa

centers for alterantive employment; and livestock farmers may migrate to other
areas in search of water for their cattle.

     Livestock  zones  are  also clearly  determined  by climate,  particularly
rainfall.  The cattle zone is essentially determined by  distribution of the tse-
tse fly, which  so far has made  it  virtually  impossible to keep zebu cattle in
the southern reaches of West Africa.  Furthermore,  these southern reaches have
been unable to  develop  mixed farming even though  their  heavily leached soils
could greatly benefit from animal manure.  The north  is the main cattle area in
the region primarily because its climate is  not hospitable to the tse-tse.

     Decreased rainfall  and drought would affect livestock production in other
ways.   The  productivity of existing grassland  areas,  important for livestock
production, would be reduced.  On the other hand, new grazing lands would emerge,
possibly shifting livestock production toward the coast.  As  with reduced crop
production, income would  decline,  leading to greater  financial  stress,  which
could threaten  economic survival.   There  would  also  be significant  impacts on
labor,  employment, and population distribution.

     Along the  coasts,  where sea  level  rise may  lead to submergence  of the
lowland coastal areas (e.g., along  the coasts of Senegal  and Gambia),  much of
the land currently used  for agricultural  and  livestock practices would be lost.
As a result, there would  be  mass migration out  of  that area, substantial loss
of income and great financial  stress, and unemployment.  Large-scale resettlement
would cause additional problems.  In a  few cases, farmers may be  forced to change
their practices.  Because most of the coastal  environment would be characterized
by  water surfaces  and  their   associated  ecological  systems,  converting  to
aquaculture may be a viable response (see  Everett, Volume  1,  Environmental

Impacts on Water Resources and Water Resources Management

     Agriculture,  industry,  and domestic  activities depend on water resources.
Unfortunately,  a large proportion of the population in  the WACAF regions lacks
access to adequate freshwater supplies, especially  because of population growth
and rising standards of living which increase water demands.

      The  changes  in   the  magnitude  and timing   of  water resources  would
necessitate changes in management strategies toward  greater conservation efforts
in order to balance water supply and demand.   In addition, because most of the
water resources along the coast would become polluted by intrusion of saltwater,
water resources management would place greater emphasis on desalinization.

     In general,  the WACAF regions have  five  types of water  supply systems.
The first category includes  areas that depend mainly upon precipitation; unless
storage  is  available,  these systems  are only  useful  during the wet  season,
usually  six months  of  the year or  less.   The  second  category  includes water
supply  systems  based on river  flows that do not store significant  amounts of
water for use during periods of deficiency.

     The third  category of water supply  systems  is located  in  coastal  areas
where  precipitation  occurs  during  most  months  of the year.   The  impact of



decreased regional precipitation on  this region may be less than elsewhere since
there  would  be  a  general  tendency  for  coastal  areas  to  receive  more
precipitation.  However,  sea level rise may cause floods and saltwater intrusion,
which could contaminate water supplies.  This would hurt agriculture and might
even disrupt settlements, with all the consequences  discussed in the conference
report section on social and cultural implications.

     The fourth category of water supply  systems  consist of manmade reservoir
systems, which  can  reduce  the effect of intra- and interannual  variations in
precipitation and runoff.  With reservoirs, water is released when  it is required
for agriculture and other purposes.   Examples  include  such  manmade lakes as the
Kainji and  Akosombo dams.   If  climate  becomes  drier, it  may  be  necessary to
curtail releases of water to maintain needed storage capacity for later release.
Water  shortages  in   these   reservoirs   could   have  considerable  financial
implications and lead to hunger, famine, and death.

     The fifth  category  of  water resource systems  consists of those  based on
groundwater resources.  In this case, decreased precipitation would lead lower
water tables and  thus  increase  the   difficulty  in obtaining water even if the
total amount of water in the aquifer is still  sufficient.

Impacts on Other Sectors

     Although the impacts on agriculture and  water  resources are  likely to be
the most  important,  other  sectors would also be  affected, including  fishing,
energy resources, transportation, manufacturing,  and construction.

   Upwelling fisheries predominate off the southwest coast  of the WACAF region.
Increased global  temperatures  would warm the normally cold upwelling waters,
making them unsuitable for the fisheries and causing a reduction in and possible
collapse of ocean upwelling fishing activities.   Tropical warm water fisheries
would  be hurt  since  a rise   in  temperature would  cause  a  change  in  the
characteristics of the ocean waters  and consequently in the habitat of the fish
currently found in the area.  Any significant reduction in the catch would upset
both the economy and culture of the coastal  zone.   In addition, wetland loss and
increased salinity would reduce estuarine fishing.

     Energy supply and demand would  also be affected.  For example, Critchfield
(1966) notes that the construction of power lines must always take into account
a great number of climate effects on the equipment.  Strong gusty winds can down
poles and snap  lines, or cause  trees  and other debris to fall  onto the lines.
An increase  in  the  number  of thunderstorms would bring  more lightning, which
causes at least temporary power  failure if it strikes a power line.  Temperature
fluctuations can also affect the operation of  switches, transformers, and other
equipment.   In warmer weather,  lines  tend to  expand and  sag; thus they become
susceptible to more damage from strong winds.

     Climate change  could  also have  significant  impacts on solar energy  and
wind, two sources of energy that still  remain  untapped  in the WACAF region.
Submergence  of  the  coastal  areas   would  make  the  onshore  development  and
exploration of petroleum more difficult  and more  expensive.


West Africa

     However, of more immediate concern are the possible impacts on the supply
and demand of hydroelectric power  and  fuelwood,  which  is the most widely used
source of energy in the WACAF  region.   For example, reduced precipitation would
adversely affect the supply of hydroelectric power, which is very sensitive to
riverflows.   There might also be  problems  related to the  seasonal  aspect of
riverflows,  as well  as  to the unreliability of rainfall as  a  source of water
supply  in many  parts  of the  WACAF  regions.    Reduced hydroelectric  power
production would impose economic hardships.

     The impacts  on the supply of fuelwood could also be important.  For example,
with  a decrease   in  precipitation,  some  sources of  the  fuelwood would  be
eliminated.   Also, more  frequent  thunderstorms  and  erosion could  cause more
damage to the forests.   With  a  rising  sea,  the increased landward penetration
of  storms  would hurt  all but  a few  (salt-tolerant)  tree  species,  and thus
decrease the area  of  forests.   If  climate  change  leads people  to migrate to a
particular area,  the increases demand for fuelwood in  some areas would aggravate
all the environmental problems commonly associated with deforestation.

     There could also be important  impacts on energy demand.  For example, with
increased temperatures,  particularly at night, there would  be  less demand for
space  heat  in the WACAF  regions and,  consequently,  less energy consumption.
However,  if  temperatures were higher  during the  day,  there would  be greater
demand for energy  to cool buildings.


     The above discussion shows that the impacts of climate change and sea level
rise are likely  to  be  considerable.  The question  arises:  what are the possible
solutions for reducing  or,  if possible, eliminating  the adverse consequences.
In  general,  there  are two categories  of  strategies:  (1) avert  or  reduce the
magnitude of climate change and  (2) mitigate the  consequences.

     The following measures could  be used to avert or  reduce the magnitude of
climate change:

        Reduce demand for fossil fuels;
        Adopt technical  solutions  to collect or control  carbon dioxide;  and

        Increase biomass production, which includes the reforestation of denuded

     Strategies  to  reduce demand for fossil fuels involve the  use of conservation
measures  and alternative  sources  of  energy.   This  measure  is  particularly
important for developing  areas such as the  WACAF  regions because the relative
contribution of these areas to the atmospheric  gases  has been increasing since
1950.  Reducing energy  demand will  reduce  burning of fossil  fuels.   Technical
solutions,  which  include  the  use  of  mechanisms   to  control  atmospheric
concentrations of  carbon  dioxide,  are  linked to  world, regional,  and national
energy policies,  forest management, and personal  and  societal values.   Such
solutions  include  measures  to  control the production  and use  of coal  and
petroleum and measures to control emissions from power plants or those occurring



at  the point of  combustion.   The  adoption  of such  measures,  however, could
require complete  sociocultural change.

     Increasing biomass production through afforestation will provide a  natural
sink  that will absorb carbon dioxide.   Cooper,  for example,  noted  that an
increase  of  only  1% in the plant life  on earth,  especially forests,  would be
sufficient to absorb  one  year's  release of carbon dioxide at the present rate
(Kellogg  and Schware,  1982).   In tropical areas  in  general,  and  in the WACAF
regions in particular, there is a great need to reduce the  rate of deforestation
and  to reforest  deforested areas.   However,  it is  important to  note that
reforestation  implies  ecological  changes,  which in turn  may have   climate
consequences.   Marchetti  (1979)  has  pointed  out that a  change in vegetation
patterns  could  offset  the intended  cooling by absorbing  more solar radiation,
thus warming the  earth.

     Strategies for mitigating the consequences of climate change include those
that would help to  increase human  resilience  to the  effects.  Such strategies
include protecting arable soil,  improving water resources management, applying
agrotechnology,  improving land-use policies,  maintaining  food reserves,  and
adopting  disaster response measures.

     In the  WACAF regions, there  has been a  tremendous  loss  of  arable soil
through soil  erosion  and salinization  in recent years,   and this  trend would
probably  persist  with  climate  change  and sea  level rise.   Largely responsible
for this  loss are poor agricultural management practices  such  as  overgrazing.
Improving water resources management,  for example,  through effective management
of dams,  aqueducts, reservoirs,  irrigation systems, and diverted rivers, would
ensure  adequate  and reliable water supply  in  the event  of drought and water

     Another effective measure  would be to develop agrotechnologies  such  as more
efficient irrigation systems,  saltwater crops,  and new forms of nitrogen-fixing
plants.   Improved coastal land-use policies would also be important and should
be considered in  sociocultural planning for mitigating the consequences of sea
level rise.

     Maintenance of food reserves and adoption of provisions  for disaster relief
now being  promoted by international  organizations to help the  countries adversely
affected  by  the   recent  climate  variations,  also   could   help  to  mitigate
sociocultural impacts.   The WACAF regions, like  any  other  part of the world,
require a reliable  food supply;  since any variation  or change  in  climate and
consequent sea level rise could adversely affect food  production in the  region,
it would  be prudent to develop adequate food reserves.

     Other strategies  for  mitigating the effects of climate change and sea level
rise involve  access to information and  technology,  which  can  lead  to better
decisionmaking  regarding  how  best  to  respond to  potential climate  change.
Examples  of  such  strategies include  the use  of  environmental  monitoring and
warning systems, the collection and use of improved data, public  information and
education, and the transfer of technology.

Vest Africa


     Climate change and sea level rise would have considerable Implications on
human cultural systems.  We need to  plan  and  Implement the measures necessary
to either avert or mitigate the consequences.  It is  important to note, however,
that usually the  sufferer of the consequences sees the causes and effects of the
problem  as wholly local,  and  thus thinks  only of local solutions.  However, to
effectively plan and implement solutions to  the  problems that could result from
climate  changes,   it  is important  for local  people  to  base their  response
decisions on a larger world view.

     We  need  to   ensure that  solutions are carried  out  on world,  regional,
national, and local scales.  For the WACAF region, in  particular, it is important
that cooperation,  collaboration, and coordinated efforts occur at the regional
and local levels as well as at the national  and international  levels.  To this
end, national  governments must  be ready  to do  their  part  as  appropriate, for
example, by  ensuring  that  their national  observing  and  communication  systems
function  efficiently,   and  doing  more to  protect   the  coastal  environment.
Scientists, planners, and  policymakers must promote  research,  provide improved
access   to   data   and  information  necessary  for   effective   planning  and
implementation, prudently  use  data and information, and support effective public
participation  in  planning and implementation of measures  to  avert or mitigate
the consequences of climate change and sea level rise.


Critchfield, H.J.  1966.  General Climatology.   Englewood Cliffs,  NJ:  Prentice

Flohn, H.   1979.   A scenario of possible future climates  --  natural  and man-
made.   In:   Proceedings of World  Climate Conference.  WMO No.  537.   Geneva:
World Meterorological Organization, pp. 243-268.

Kellogg, W.W., and R.  Schware.   1982.  Climate and  Society:   Consequences of
Increasing Atmospheric Carbon Dioxide.  Boulder, CO:  Westview Press.

Marchetti, C.   1977.   On  geoengineering  and the  C02  problem.   Climate Change

Maunder, W.J.  1970.  The Value of Weather.   London:  Meuthen.

Ramanathan,  V.    1980.  Climatic effects of  anthropogenic trace gases.   In:
Interactional  of  Energy and Climatic.   W.  Bach,  J.  Bankrath  and J. Williams,
eds.  Dordrecht,  Netherlands:  Reidel.

Rotty, R.M.  1979.  Energy demand and global climate  change.  In:  Man's Impact
on  Climate.   W.   Bach,  J.  Pankrath,  and  W.W.  Kellogg, eds.   Developments in
Atmospheric Science 10.  Amsterdam:  Elsevier, pp. 269-283.

WMO.  1979.   World Meteorological  Organization.   Proceedings  of World Climate
Conference.  WMO,  No. 537.  Geneva: World Meteorological Organization.



WCP.  1986.  Report of the International Conference on the Assessment of the Role
of  Carbon Dioxide  and  Other  Greenhouse  Gases  on  Climatic  Variations  and
Associated Impacts.   WMO, No. 661.  Geneva; World Meteorological  Organization.




                                G.  SESTINI
                   Applied Earth  Science Consultant
                           Via Delia Robbia 24
                         50132 Florence,  Italy

     Global climate change is likely to have two major types of negative impacts
on the Mediterranean  region:  (1) changes of precipitation and soil moisture,
which  will   affect  water  resources,  riverflows,   irrigation  systems,  and
agriculture;  and  (2) sea level  rise, which will exacerbate  coastal erosion and
flooding with repercussions  on tourism,  settlements, communications, and ports.
To minimize the adverse  impacts  of  climate  change, analyses  of these impacts
should be incorporated into the planning  of new projects and  activities along
the coast.

     In  most Mediterranean countries, the  use of the coastal zone has increased,
especially  for  agriculture and  tourism.    Unfortunately,   development  has
progressed  in  a   haphazard way,  with  little  planning  or  consideration  of
environmental  impacts.   This present state  of  environmental  degradation will
exacerbate  sea  level rise impacts.

     The large  amount of capital  investment along the  coasts  suggests that
protective measures will be desired,  even though  they may not be feasible in many
cases; thus, the cost of protection will greatly escalate and difficult political
decisions will have to be made concerning  when,  where,  and how the coast should
be protected.

     In  the meantime,  preparation  is imperative through increased awareness,
analysis, regional  planning efforts, and  regulation in the face of unhindered
development based  on short-term profitability.


     The impact of  climate change on soils,  hydrology, vegetation,  and  on two
Mediterranean deltaic regions  was first  evaluated at the European Workshop on
Interrelated Bioclimatic  and Land Use Changes, in the Netherlands, October 1987



(Imeson et al., 1987; Sestini, 1989).  The consequences of temperature and sea
level  rise  for the coastal  areas  were further examined  in 1988  by  a United
Nations Environment Programme (UNEP)  task  team of experts in Split, Yugoslavia,
which  attempted  to forecast changes  of  climate,  sea  level,  hydrology,  ocean
circulation, marine  ecosystems,  and vegetation (Sestini  et al.,  1989,  for a
review), as well  as  socioeconomic  changes (Baric and  Gasparovic,  1989).   Six
case  studies   have evaluated  impacts on major  deltaic  areas   (Georgas  and
Perissoratis,  1989; Corre,  1989;  Marino, 1989; Sestini, 1989a,b; Hollis, 1989).

     The conclusions with regard to  climate variables were that doubled C02 would
result in a temperature increase of 1.5 to 3.5C;  evaporation increases of 15-
20%;  a possible  northward  shift of  the  areas  of  cyclonic activity, with a
probability  of   a  precipitation  decrease  in  the   southern   half  of  the
Mediterranean; and magnification  of interannual variability, with more frequent
occurrence of extreme conditions (e.g., heat waves,  droughts) (Wigley, 1989).

     Soils would  be affected  in  their physiochemical  structures,  particularly
where  rainfall  is <500 mm/year, with greater salinization and  reduction  in
organic matter.  Soil erosion would increase.  Higher temperatures would cause
a northward and upward shift of vegetation zones, changes in forest composition,
and greater incidence  of  forest  fires; desertification would  increase in the
marginal areas of  limited rainfall.   Agriculture might be  affected by changed
water supplies, decreased soil fertility, and especially by the greater incidence
of  extreme  events.   Lagoons  and   salt  marsh ecosystems  might  change   as  a
consequence  of  greater  temperature  and  salinity  fluctuations,  with  water
stratification phenomena becoming more frequent.

     A discussion at  the September  1987 UNEP Conference in Norwich, England,  on
the type and magnitude of  changes  in sea level  produced an estimate that sea
level will rise 14-22 cm by  2030,  25-40 cm by 2050,  and  perhaps  up to 1  meter
by the end of the  21st century (Raper et al.,  1990).  Nevertheless, the behavior
of some of the  causal variables (e.g., oceanic thermal expansion and the melting
of polar ice) are more uncertain than these estimates would lead one to believe.

     The Mediterranean study also emphasized  that  (at least in some countries)
the pressure on the environment from  rapid population growth would far outweigh
the impact of climate change (Baric and Gasparovic,  1989).

     Two principal effects of climate change stand  out for their far-reaching
consequences and require urgent attention from both scientists and policy makers:

     1.  Coastal  instability  due  to sea level rise,  and its attendant negative
         consequences  for  lowlands  and wetlands,  maritime  cities,  and harbors
         (e.g., for lagoonal fishing,  reclaimed land agriculture, beach tourism,
         industries, and communications);  and

     2.  Precipitation  and  soil  changes   and  their  consequences  for  slope
         stability, for surface and  subsurface waters, and stream and irrigation
         systems  (e.g., for the management of hydropower,  irrigation, drinking



         and  industrial  water supplies, inland navigation,  and waste disposal
         systems,  especially  in  a  situation of growing water pollution).


     The complex,  interrelated nature of the physical-biological  systems and the
present and future population and economic patterns of the coasts and alluvial
plains  (Figure 1) makes assessing the  impacts of climate change and sea level
rise difficult.

     The physical  impact of sea level rise on  low-lying coasts can be predicted,
even  modeled  quantitatively,   on  the  basis  of  the  present  parameters  of
morphology, hydrodynamics, sediment budgets, land subsidence,  and the effects
of artificial  structures.  Likewise,  the impacts of altered rainfall distribution
on surface  and groundwater can be  modeled,  and  the effects of increased air
temperatures and  changed  soil-water parameters on biosystems  can be estimated
at least  qualitatively.   What  is more difficult  to  quantify,  however,  is the
impact  of these  physical  and  biological  changes on the future socioeconomic
framework of the threatened coastal  zones.

     Future organization of these regions (Figure 2) depends  on an evaluation of
the present and future state of the environment;  on the  side  effects of large
construction  projects  with  a  life  of  decades;  on  the  necessity  to  protect
unmovable assets such as historical cities, harbors, and industrial centers; and
also on the possibility of abandoning threatened areas and/or the redeployment
of land uses.

     Evaluation of economic  impacts must consider  not only the present function
and value of land uses in the  context  of  local needs and of the importance of
the lowland  concerned to  its   hinterland  and  farther,  but also  future  land
functions and values.  The primary needs are  determined by the present level of
population and its trends of growth or decline,  by the wider  economic role of
the region, and by external market  forces.   Some economic activities and  land
uses cannot  be projected  into  the  future because they  are  interrelated  with
"external" --  economic, social,  and political  -- factors and therefore can evolve
independently of local conditions (Figure 2).  For instance, the future relevance
of local  industries,  agriculture,  and ports  will  largely depend  on worldwide
commodity prices and trade trends such as  those  related  to  mineral  and energy
raw materials  (with  their effects  on heavy and  chemical  industries)  and to
cereals  and  industrial crops;  and  on the  demand  for  consumer  goods  in  a
competitive,  exchange-oriented  international  society.

    The role of ports may  change in response to altered trends of maritime trade
(e.g.,  the Suez Canal after a decline of petroleum transport), and local markets
for consumer goods and  services  could vary  in relation to stagnating or reduced
urban growth resulting from shortages and pollution of surface and ground waters.

                        I  HIGHER TEMPERATURES I
                             SURFACE WATERS
                            AQUIFERS RECHARGE
                        POPULATION, SETTLEMENTS
                       SOCIO-ECONOMIC WELLBEIN6


                                                                          SEA LEVEL RISE
                                                                        LONG TERM PLANNING

                                                                          SYSTEMS TRENDS

                                                                                OF FUTURE IMPACTS
                                                                                             LAND   RESOURCES USES
                                                                                             ECONOMIC REQUIREMENTS
                                                                                          PROJECTED POPULATION PRESSURE
                                                                                                          PRESENT STATE

                                                                                                             OF THE

                                                                                                           UNMOVABLE ASSETS
                                                                                                           AND INVESTMENTS
                                                                                                           NEW APPROACHES
 Figure  1.
Some of the  variables affecting the assessment
of the  impacts of future climatic changes.
Figure  2.   The  interrelated  nature of
             physical and biological systems.



     Much of the 46,000-km-long Mediterranean coastline rises quickly from the
sea.   There are many  alluvial  and coastal  plains, but  each  is fairly small.
Nevertheless, they have been important since ancient times as communication
pathways  for  the interior.   Deltas have  been  generally  advancing in the past
centuries (despite a 1- to 2-mm sea level rise and local geological subsidence),
and until early  in this century (or a few decades ago in some countries), they
were in a fairly natural  state with extensive lagoons and marshes.

     Today, all  coastal plains  are intensively used for agriculture, often on
lands  reclaimed from  wetlands,  with  active fishing  and  aquaculture  in the
lagoons.   Industrial  centers  and harbors have  been established in some areas
(e.g., Ravenna and Porto Marghera,  Venice, Italy; Fos de  Mer by  the Rhone Delta
in France; and Abuqir-El Taba by Alexandria,  Damietta,  and  Port  Said  in Egypt).
Considerable portions of the Mediterranean coastlines have  become more and more
intensively exploited  for beach recreation  at  the  edges of  coastal  plains or
between cliffed shores. In fact, in the northern Mediterranean,  practically all
beaches are  presently used  (utilization  ranges from  as  low as  25% of total
coastline in  Yugoslavia to  as  high as 75% in  north Italy  and eastern Spain).
Tourism development has involved construction  of hotels, apartments, pleasure
boat harbors, and related  permanent infrastructures  and services.  Some resorts
have become very urbanized  (high rises),  and old towns  have  expanded with an
increase in resident year-round population.   Undoubtedly, all these activities
and settlements would  be  the first to be threatened by a rising sea level.

     Coastal settlements,  from  villages  to cities, are numerous.  However, with
a few notable exceptions  (e.g., Venice, Siracusa), most major cities have only
small  portions at sea level with exposed seaside boulevards  and some residential
quarters at an elevation of 1 meter or less (e.g., Barcelona, Nice, Marseilles,
Genoa, Naples, Ancona, Algiers, Pyreus, Alexandria).

     The effects of sea level rise must be considered  in conjunction with the
degree of exposure to storm waves and surges that aggravate  coastal erosion with
seaward removal  of  sand, direct  attack,  or  overtopping  (with  flooding)  of
seawalls and dikes.   The  degree of exposure to wave energy varies with coastal
orientation in relation to waves  (Figure 3).   Storms with  high waves (2-6 m) are
generated in the western  Mediterranean  (and  to a lesser  extent in the central
basin) causing wave  paths  to the northwest, west, and northeast  (in the west and
in the Adriatic  Sea),  and to the southeast in  the eastern  Mediterranean.   The
cold and violent winds  that blow in  winter from the north and northeast (mistral,
bora,  etc.) generate waves that  attack  the Algerian-Tunisian,  Sardinian,  west
Adriatic,  central Aegean,  and Nile  Delta coasts.  All other lowlands and cities
are more sheltered  (e.g., Albania,  Turkey, northern Greece)  and suffer from a
smaller degree of storm wave impact.

     Low sandy coasts  still  in  a fairly natural  state would  probably retreat
gradually in response  to  beach  profile  readjustment (Bruun and Schwarz,  1985)
with some periodic flooding.  The  breakup of barrier  islands  and breaching of
beach/dune ridges would occur where exposure to storm  waves  is accompanied by


Figure 3.  Main deltaic-alluvial  lowlands  of  the  Mediterranean  region (arrows
indicate the predominant directions of winter storm waves).
natural (in some cases also manmade) subsidence or where the coastal sand budget
is low or negative.   Undoubtedly, well developed, thick ribbons of coastal sand
can survive sea level rise, as indicated by the relic dune and beach ridges on
the Continental Shelf of the Adriatic Sea and Nile  Delta.

     Wetlands can move landward and grow upward if the rate of  sea level rise is
low.  However, the persistence of brackish lagoons  and marshes would depend on
the integrity of the barrier islands, while their ability to move landward is,
in fact, generally impeded by dikes, roads, and other structures.

     Many stretches of the  Mediterranean  coasts are, however, no  longer in a
natural state.  Many  shores are retreating because dams have sharply reduced (or
eliminated) the  ability  of  rivers  to supply sand to  the  coast  (Figure 4), or
because people are mining the sand  in river beds.  In addition, dunes have been
flattened to make room for  beach resorts.   The natural  beach  fluctuations and
coast-parallel sand movements are impaired  by fixed defense structures, as well
as  by  the jetties that  protect  the  entrances  of  estuaries,  lagoon  outlets,
canals, and ports.

     The most heavily fortified lowland coasts are in  the  west  Gulf of Lions, on
the Tyrrhenian and Adriatic side of northcentral Italy,  and in parts of Greece



and northern Tunisia.  The  other lowland coasts  (e.g.,  Turkey, Albania)  have
fewer coastal protection structures; continued shore erosion in conjunction with
increased use of the  coast will gradually motivate other  coastal  areas to begin
employing these devices as well, as in the Nile Delta.  From a local  perspective,
these measures are  justified to stabilize harbor accesses and  to protect beach
investments; but when one considers the  impacts that protecting one area can have
on other areas, the wisdom of these measures  is  not  as obvious.   All  too often,
people fail  to sufficiently   consider the future effects of  hard structures on
sediment-starved  coasts (e.g., the dikes  built at  the  retreating Rosetta  and
Damietta headlands  in the Nile  Delta will eventually weaken  the lagoon barriers
to the east).

     A 25- to 30-cm sea level rise would not flood most Mediterranean lowlands,
but  it would  worsen the  present situation of  beach,  delta,  and  lagoonal
instability.  Water levels  in   lagoons, estuaries, and canals would  be higher,
especially in areas  already  facing land subsidence (e.g., the Adriatic coast).
There would  be increased  salinity in  the lagoons,  more extended  salt wedges in
rivers, and  further salinization  of reclaimed lands.  All protective  structures
(breakwaters, seawalls, dikes)  would  have to be raised periodically,  and beach
nourishment  schemes  would  have  to be  intensified.   The cost  of beach and urban
seaside protection  will  threaten the economic viability  of some beach resorts
and small towns.
  Cities <1 m elevation,* surrounded by water
   Cities mostly >2 m, with parts <1 m (iniharboura)
   (fein SLR impact on port/shoreline infrastructures
Figure 4.  Mediterranean cities that would be most threatened by sea level rise
in association with  storm surges.   Also shown are the  main river systems that
are dammed.



     A further rise of 30-100 centimeters would have catastrophic effects, unless
measures of  artificial  protection measures are  implemented  in  advance (e.g.,
raising and stabilizing dunes, erecting more seawalls, and blocking
canals/estuaries  and  lagoonal entrances with  sluice systems).   Recreational
beaches would continue to  exist  (along coastal  plains  if not  along cliffed
coasts), but existing seaside resorts  and exposed cities would suffer extensive
damage.  Higher water  levels  in the northern  Adriatic lagoons would cause the
gradual decline of several historical and commercial centers; these impacts could
be further  exacerbated by other human activities such as withdrawing groundwater.

     The socioeconomic impact of  sea  level  rise  on coastal  lowlands will  vary
because the degree of land use and development varies  -- both in absolute terms
and  in  comparison with nationwide averages  (e.g., the Ebro  and  south Turkey
Deltas are  relatively undeveloped as compared with the Nile  Delta, which contains
45% of Egypt's population).  Few people live below  the 1-m contour, even in the
generally overcrowded Nile Delta.  Populations are usually concentrated on ground
more than 2 m above sea level, especially on the  raised present or past alluvial
channels.  But there  are exceptions, including Venice, and new recreational and
port/industrial centers.  Moreover, land use will become more intensive because
of population growth  (probably 550 million by 2025,  as compared with 350 million
in the Mediterranean countries today), and increased tourism (213 million a year
in 1984, perhaps doubling by 2025) (UNEP, 1987).  Recent urbanization on coasts
has been and will continue to be  focused on all  available flat ground near the

     In the southeastern Mediterranean countries, populations will grow faster
and coastal areas will  continue to provide  focal points for development, mainly
in  the  vicinity  of cities.    In  North Africa,  the  nature and extent  of the
economic consequence of  sea level rise will depend on the  degree and type of
coastal development during  the next 2-3 decades.   In Egypt,  for instance, the
economic consequences will depend  on the uses made of the coastal lagoons (i.e.,
land reclamation, fishing, or freshwater storage).

     In conclusion, the most serious negative consequences  for coastal  (in some
cases national) economies would be the physical  impacts on (1) tourist beaches
and infrastructure; (2)  pleasure marinas; (3) coastal  protection structures; (4)
towns and cities  by the sea,  seaside boulevards, and residential areas subject
to washovers; (5) ports and industrial  installations,  especially those built on
lowlands and  in  lagoonal  areas; (6) roads,  railways,  airports by the sea; (7)
lagoonal fishing; and (8) reclaimed lands and relative irrigation systems.


     Responses to rising  sea level would  vary  from  (1)  extensive artificial
protection, to (2) altered land use (e.g.,  less urbanized tourist beach centers,
the return of some agricultural reclaimed lands back to their lagoonal state),
to  (3)  abandonment.    Because the Mediterranean  coast  is diverse,  no single
solution is likely.



     Nevertheless, the intensity of development and the economic value of coastal
activities  suggest  that  abandonment will be  confined  to isolated localities;
however, in many places, public and private investments might gradually become
economically unviable as increased physical  damages make maintenance too costly
(e.g., polders,  infrastructures,  tourist harbors, power  stations by the sea).
The Mediterranean coast  already  has a high degree of  coastal  defense in many
areas;  the  large  number  of unmovable features  (cities,  ports,  valuable
agriculture, etc.) would make abandonment expensive.   But the escalating costs
of protection would  impose major burdens on state and local governmental budgets,
perhaps  taking  up  a  large percentage  of the  income  generated  by  coastal

     The maintenance of beach recreation facilities requires a more practical and
rational approach than that  of today.   Is  the vision  of  total  protection held
by local  residents,  private investors, and politicians practical in the long run,
given the natural processes  involved?  The present state of degradation caused
by  the  very activities  to  be protected suggest  that  it  is  not.  It  may be
unrealistic to continue  occupying a retreating sandy  shoreline by maintaining
the existing defense structures.   A more rational  approach would be to establish
setback  lines  and zoning,  with less urbanized settlements,  and  to  adopt more
"open-space" tourism, wherever feasible,  based on the model of the Camargue in
the Rhone Delta  (Corre,  1989).

     With a  few  notable exceptions of good regional  planning (e.g.,  Gulf of
Lion), coastal  exploitation has been a local or private investment  venture (often
with political backing), whereas  the  ownership and responsibility for coastal
use usually  are  with the state,  which has  to pay for protection and  for the
damages caused by natural hazards.

     In the face  of  rising  costs of protection, it may be necessary for nations
to  adopt  the  approach  that  coastal  investments,  if  carried   out  with  no
consideration for environmental impact, must be accepted as  "high  risk," and the
consequences are to be borne by the investors themselves.  (See papers in this
volume for  a discussion of  this  principle.  The  concept  is  parallel  with the
spreading attitude and burgeoning legislation that industrial-urban-agricultural
polluters must pay for degrading and redressing the environment.)

     Given the  continued  uncertainty about the  timing and magnitudes of sea level
rise,  determining which policies  ought to be implemented now is difficult.  A
low level of awareness persists on the  part  of the public and authorities alike
concerning the consequences of climate  change  and the seriousness  of -- and the
need to address -- the present state of coastal degradation.

     It would also seem to be reasonable that countries where the coastal zone
is still  mostly undeveloped should look at the consequences of failing to conduct
impact assessments,  which  can be seen  in  most  nations  with  heavily  managed

     Response strategies  will depend on the degree of local  impact, physical and
financial,  according  to  present   and projected land  and  water resource  uses.



Impacts have, by and large,  yet to  be evaluated because data bases are, In many
cases, limited or nonexistent.

     Strategies imply long-term planning based on interdisciplinary approaches.
Policy decisions based on these strategies  will  require  political  insight and
the will  to  carry out and  implement them;  that  is, they will  require a high
degree of centralized decision  --  in the  rather  tight  timeframe of just a few
decades.  Even the first stage, that of deciding upon and implementing a phase
of rational  studies  (i.e.,  to  create institutes  and/or to coordinate existing
ones  for  environmental  impact assessment and planning),  is no  light  task in
countries where  responsibility for environmental  matters is  dispersed among
different ministries,  local authorities,  universities, and  national  research


Baric, A. and F. Gasparovic.  1989.  "Implications of climatic changes for the
socio-economic activities in the Mediterranean coastal zone." UNEP/OCA, Nairobi,
Rept. WG 2/12.

Brunn, P. and  M.L.  Schwartz.   1985.   "Analytical  prediction  of beach profile
change in response to a  sea level  rise."   Zeitschr. fur  Geomorphologi, Suppl.
Bd. 57: 33-55.

Corre, J.J.   1989.   "Implications  of climatic changes for  the Gulf of Lion."
UNEP, Nairobi, Rept. WG 2/4E.

Georgas, D. and C. Perissoratis.  1989.  "Implications of climatic changes for
the inner Thermaikos Gulf."  UNEP/OCA,  Nairobi,  Rept. WG  2/9.

Hollis, G.E.   1989.   "Implications  of  climatic changes for the Garaet Ichkeul
and Lac Bizerte."  UNEP/OCA, Nairobi,  Rept. WG 2/a.

Imeson, A., H. Dumont, and  S.  Sekliziotis.   1987.   "Impact analysis of climatic
change in the Mediterranean  region." European Workshop on Interrelated Biocli-
matic Changes, Norwijkerhout Oct. 1987, v.F.

Marino, M.G.   1989.   "Implications of climatic  changes on the Ebro delta, Spain.
UNEP/OCA, Nairobi, Rept. WG 2/3.

Raper, S.C.B., R.A. Warrick, and T.M.L. Wigley.   1990.   Global Sea Level Rise.
In:   Milliman, D.J.  (ed.)   Rising Sea  Levels  and  Subsiding  Coastal  Areas.:
SCOPE, Bangkok, Nov. 1988 Seminar (in preparation).

Sestini, G.  1989a.  "The implications  of  climatic  changes for  the Po delta and
Venice lagoon."  UNEP/OCA,  Nairobi, Rept. WG 2/11.

Sestini, G.  19895.  "The implications  of climatic change for the Nile delta."
UNEP/OCA, Nairobi, Rept. WG 2/14.



Sestini, G.,  L.  Jeftic,  and J.D. Milliman.  1989.   "Implications of expected
climatic changes in the Mediterranean region: An overview."  UNEP Regional Seas
Reports and Studies, No. 103, UNEP, Nairobi.
Sestini, G.  1990.  The impact of climatic change on two deltaic lowlands of the
Eastern Mediterranean.   In:  Jelgersma  S.  (ed.)  Sea Level  Rise  and European
Coastal Lowlands. Basil Blackwell (in press).

UNEP,  1988.   The  Blue  Plan,  Futures of the  Mediterranean Basin.   Executive
Summary and Suggestions for Action.  Sophia Antipolis, France.

Wigley, T.M.L.  1989.  Future climate of the Mediterranean Basin with particular
emphasis on changes in precipitation.  UNEP/OCA, Nairobi,  Rept.  G WG/2/6.


                                ANTE  BARIC
               Institute  of Oceanography and  Fisheries
                            Split,  Yugoslavia

     This paper  examines  the  possible  impacts  of climate  change    on  the
Mediterranean coastal areas,  focusing special attention  on human settlements and
major economic  sectors  (agriculture,  tourism, fisheries,  and aquaculture).

     Society's  activities depend closely on the existing climate.  One can assume
that the impact on activities and institutions will be primarily local,  with
possible important common characteristics for small  and large areas or regions.
However, the assessment of local impacts is outside the scope  of this paper owing
to our lack  of  knowledge on the particular circumstances  facing  other regions.

     Climate change will have a limited impact on the distribution and dynamics
of coastal populations.  The natural  population growth  will  not  be affected by
climate changes and will continue  to follow the present general  trends -- i.e.,
little natural  population growth in  the northern Mediterranean countries,  with
high growth rates for nations along the southern and eastern coasts.  The  current
rate of migration toward the coast will probably not change, although it could
accelerate   in  the  south  owing  to  the  natural  spreading of the  deserts.
Approximately  5 percent of  the population  living  in coastal  zones will  be
indirectly affected by the impacts of climate changes and sea level rise; about
one percent  reside in areas that would  be inundated by  a  rise in sea level.

     An inherent quality of most institutions is a certain inertness in response
to phenomena that are not expected for decades.  However,  because these  changes
could begin  to  occur as soon  as the next decade, the governments  and the public
should begin preparing for them today.

     The nations of the world should incorporate the mitigation of climate change
into national  development  and environmental  management.  This  calls  for (1)
alerting the public  (avoiding unnecessary  alarm)  and  all   administrative  and
economic institutions involved  in the decision-making process about the possible



effects of the climate changes;  (2)  studying  the  local  conditions under which
these changes will  occur;  (3)  incorporating the implications of climate changes
into the integrated planning process for global  development and development of
individual economic activities;  (4)  undertaking   appropriate  cost-benefit and
environmental impact analyses  within  land-use, environmental, and town planning
and management;  and (5) promoting and developing new technologies for mitigating
the impacts of climate change.

     Responding to climate change will require considerable funds, which should
be anticipated in national, regional, and local  plans.


     It is no exaggeration to say that climate largely  determines the basis of
all  human  activities.     Directly   and  indirectly,  climate  affects  soils,
vegetation, water resources, storminess,  and most other environmental conditions,
which in turn help to determine our productive pursuits and the very institutions
by which society organizes itself.

     Thus a change  in climate  would  affect the social  and  economic structures
of the entire world in ways that we  cannot yet predict.  Would the changes be
sudden or gradual?   Should we view the worldwide  impact  as simply the sum of all
local  impacts,  or  must   the  socioeconomic  impacts  -- like   the  geophysical
processes -- be  viewed  in a global  context?  Both  approaches  yield important
insights,  although  predicting  regional  and local  impacts is  impossible unless
someone has become truly familiar with a particular area.

     Reducing  the   impacts  of  climate  change  in the  next  century  will  be
expensive.  New investments will be required for coastal defense and supplying
sufficient water to agricultural  areas, or for relocating people should such
engineering projects be too  costly.   The need for new  investments may affect
developing nations  in the eastern and southern Mediterranean region particularly
severely.   New  strategies will be necessary for  development,  technology, and
environmental protection.

     The changes brought about by the greenhouse  effect are chronic, while the
sociopolitical  and economic institutions react  only to existing and impending
emergencies.  Because the complex network of  institutions  need 20 to  50 years
to adapt,  the planning should already be under way.   In this paper, we attempt
to evaluate  the  adaptability of the  socioeconomic  activities to  a  change in


     Although the  coastal zones  of  the  Mediterranean countries represent only
17% of the total area  of  the countries (Blue Plan, 1988), they  are a primary
focus in assessments of climate changes, given the risk of a rise in sea level.

     The 46,000 kilometer  Mediterranean coast is very ragged and indented.  More
than half of it  is  rocky, while  the  rest  is  considered  to  be  sedimentary (see
Table 1).   About 75% of the coastline belongs to four  countries:


                             Table 1.   Selected Data for the Mediterranean Coastal  Zones
coastal zones
  (sq. km)
  in coastal
zones (1,000's)
  of coastal
in urban areas
  of coast
Length of coastal
 shoreline (km)
total     islands








Greece, Yugoslavia, Italy, and Turkey.  The islands in three of these countries
account  for  roughly  40%  of  the  Mediterranean  coast:   Greece,  7,700  km;
Yugoslavia, 4,024 km;  and Italy, 3,766 km (Blue Plan,  1987).

     Approximately 133 million  people live in  coastal  zones,  representing 37%
of the total  population of the Mediterranean countries.   About 87 million people
live in the coastal cities.  The gross national product in the region ranges from
about $700 to $10,000  (U.S.)  per capita (Blue Plan, 1988).  The distribution of
gross  domestic  product  varies  among  the countries (Table  2).    For  example,
agriculture's contribution ranges from 2% in Libya up to 20% in Syria and Egypt;
industry's contribution ranges from 24% in Libya up to 69% in  Syria.



     Agricultural production  in the  Mediterranean countries is generally oriented
toward  food,  although  a  few  countries  also  produce tobacco  and  cotton.
Cultivated land  is less than 50% of the  total  area of  each country;  in north
African countries, it  is  always less than 10%.  In recent times Mediterranean
agricultural regions have generally remained unchanged,  although  in  Italy and
France the total cultivated land has declined  (Blue  Plan,  1988).

     In the  northern Mediterranean countries and Turkey, most  agriculture is
removed from the coast,  although the high fertility of coastal  soils  makes the
coastal zone  highly  productive.   By  contrast,  in   the eastern  and  southern
Mediterranean countries,  production  is concentrated  in the coastal zone.   In
Egypt, agriculture is found  both in  the  Nile Delta and  inland  along  the Nile

     The expected  climate  changes  in  the Mediterranean  region  (Wigley,  1988)
could have very far-reaching consequences on  agriculture.  Sea level  rise will
inundate some areas and lead to salinization of others.   Other factors could also
be  important,   such  as  higher temperatures   and changes  in  the amount  and
distribution of precipitation.

     Lengthening of the summer dry period may affect  the existence of crops or
plantations, the  incomes  of farmers, and  the  commercial values  of  products.
Rising temperatures will change  growth cycles,  harvest  times, and the quality
of produce;  for example,  as spring comes earlier in  northern  Europe,  the need
for early  fruits  and  vegetables produced in  the Mediterranean  will  decrease.
Warmer  temperatures  will   also have  indirect  effects,  such  as  increased
evaporation, lower moisture levels  of the soil, and increased  erosion.

     Most  plants  require  the greatest amounts  of  water during the  spring or
summer, which is the period  of least precipitation in  the Mediterranean.   The
absence of showers in late  spring or early  summer  may significantly  reduce
productivity or  necessitate  increased  irrigation.   At  the  same  time,  warmer
temperatures will increase water requirements for plants. Wherever possible,


                              Table  2.   Distribution of Gross Domestic Product  (%)
1976 1980
1976 1980
1976 1980

  Source:  World  Bank,  World  Development Reports.




it will  be  necessary  to use closed systems of water distribution  and ways of
supplying water, which  will minimize evaporation;  it may  also be necessary to
reuse wastewaters.

     Temperature rise may also significantly affect the development of various
parasites and insects, which may directly affect agricultural productivity and

     The investments required  for coastal defense, dams, and irrigation systems
will make agricultural  production much more expensive, which  could  have far-
reaching socioeconomic consequences.  The rich northern Mediterranean countries
should be able to solve these  problems.  But the poorer countries in the south,
which even today have  problems with supplying their inhabitants with food, will
have more difficulty coping.


     The Mediterranean is by far  the strongest tourist region in the world.  For
over 30% of the  tourists  that  vacation  outside  their own  country,  their final
destination is one or more of the Mediterranean countries.  In 1984,  about 100
million people visited  the  Mediterranean,1 of these, 45 million  were domestic
tourists.  Although France,  Spain, and  Italy are the most popular destinations,
tourism is an important part of the coastal economy throughout the region.

     Mediterranean tourism is primarily oriented toward swimming and sunbathing -
- activities that directly use the seashore.2  Therefore,  the immediate coast,
its slope, climate,3 and the quality of land and  sea are  of prime importance.
Most tourist facilities, such as hotels, camps,  and youth  hostels,  are located
within 200-300 m of the coast.   Facilities  farther from the  shore  are found
mainly in the developed and luxurious tourist areas.

     Tourism will suffer from  climate change.  Beaches that lie  below cliffs and
other rocky inclines would be  first to disappear.  There would also be problems
with beaches where  infrastructure is  within a few meters of the  high water mark.
It may be necessary to relocate city streets and promenades (e.g., Nice, Cannes)
     1   This number  is  probably too low,  since  most of the countries  do not
accurately register their domestic tourists (Blue Plan,  1988).

     2  Mediterranean tourism fluctuates seasonally.   Depending on location, the
number of visitors from June to  September  is from 50% to 80% greater than other
periods of the year.

     3  Mediterranean tourism fluctuates seasonally.   Depending on location, the
number of visitors from  June to September is from  50% to 80% greater than during
other periods of the year.



or highways and railway lines (the coastal  stretch between Nice and Cannes, and
parts of the Italian and Yugoslav coasts).

     Even if sea level rises moderately and does not threaten tourist facilities,
the  loss  of beaches  would disappear  or  require substantial  investments for
reconstruction.   Moreover,  saltwater  intrusion  due  to sea  level   rise and
increased evaporation from higher temperatures would diminish the availability
of water needed for tourism and wastewater drainage.  Islands may experience even
greater damages than the coast of the mainland.

     A special  type of  tourism,  nautical  tourism,  has stimulated the building
of a  large  number of marinas, sport  harbors,  and berths.   They  will  be much
harder hit than the large freight harbors.

     Global warming may lengthen the tourist season in the  northern Mediterranean
by creating more  favorable weather.   However,  the rise in  air temperature and
sea level may  enhance  the attractiveness  of the  continental  lakes  and  of the
coastal tourist areas  of other  seas  (e.g.,  Baltic,  North Sea),  thus negating the
need for many northern Europeans to travel south for their vacations.

     Any attempts to  relieve  the  impacts  of climate changes on  tourism will
encounter great organizational and financial  difficulties.   The industry has a
great number of hotels, restaurants,  shops,  and tour operators,  each of which
respond to their own  sets  of incentives.  Moreover, mitigating the consequences
would  require  high  public   investments  in   roads,   utilities,  and  other


     Foods harvested  from  the sea have historically provided an important staple
in the  diets of  the  inhabitants of  the  Mediterranean,  especially  the small
islands.   With the  development  of food   preservation  techniques  and  faster
transport, the consumption of  fresh seafoods  has spread inland.

     About 4 million tons  of seafood are produced in the Mediterranean countries
every year.  The  needs  of individual Mediterranean  countries  for seafood are
basically  satisfied   through   national  fishing.    The  annual  catch  on  the
Mediterranean is approximately 1 million tons.

     Although the  total  catch has remained  constant for about the last 10 years,
there have been  significant changes in the species composition  of the catch (Blue
Plan, 1988).  This  change has resulted from  the overexplcitation of some species,
the demands of  the market,  and the development of specific  new  techniques  in
fishing.  Looking at  individual countries, we find major differences:  In more
developed northern countries, there has been a significant decrease  in the number
of average-quality fish (sardines, mackerel) caught and an increase  in the number
of high-quality fish  (mullet,  perch,  dorade).   In the less developed countries,
there has been no real  change  in the catch of poorer quality  fish.


     According to some assessments, the present level of fishing is close to the
sustainable catch, endangering  the  existing fish stock.   In  some  regions the
catch may  not be threatening species  survival,  while in  other areas certain
species are clearly overfished.   The consequences at first  are reduced catches,
but eventually the species can disappear (e.g., mackerel in the Adriatic Sea).
Because  sustainable  yields  themselves will  change,  better   assessments  and
regulation to ensure  an optimal catch without overexplcitation  will be even more
important in the face of climate change.

     It  is  likely  that  the expected  climate  changes will   break  existing
ecological balances  and  chains,  and new ones will  be  formed  on significantly
different levels.  The Mediterranean region  is typical of this problem, because
it contains species that  are  heterogeneous in every  individual area, the result
of the vastly different biotypes. Generally speaking, the weak primary production
limits fish stocks.  Cyclonal activity directly affects the dynamics of water-
mass movements, especially in shallower coastal regions.

     A general decrease of precipitation is  predicted  for  the entire year and
for the  summer period.4 The resulting increase in the salinity  of the sea, along
with sea level rise, could affect the inflow of nutrients from river runoff or
from "upwelling"  of deep-sea waters.  The changes in the physical characteristics
also could affect the oxygen  solubility in the sea.   The  changes  in the physical
characteristics could speed up the physiological processes  of marine organisms.
They also could accelerate the mineralization of organic matter.

     The rise in  the sea  temperature in the shallow coastal waters could create
subtropical or even tropical  conditions, which would probably stimulate a greater
immigration of numerous plant and animal species  from  the  Red Sea  through the
Suez Canal  into  the Mediterranean  region.    Some plant  and  animal  species
indigenous to the Red  Sea have already naturalized in the eastern Mediterranean,
but in the future they will  spread  westward.   In contrast, the boreal species
will be endangered or may even disappear.

     These changes could bring  about major  alterations  in  the qualitative and
quantitative  composition  of   the  Mediterranean   marine  flora  and  fauna.
Economically  important populations of marine organisms  will  also be affected.
Climate change also may cause subsequent changes in the migratory habits of fish
species that constitute the largest part of the  annual catch.   Likewise, a shift
in the distribution of niches of some other economically important species may
require  significant  modification of  existing  fishing  techniques.    This  may
include new devices and equipment for detecting  fish,  larger  boats capable of
fishing  in  farther  and deeper waters,  and  new fishing equipment.   All  these
changes will  require  significant financial  expenditures that may depress further
development of fishing in the economically weaker countries.
     4  However,  in  some regions of the Mediterranean, precipitation and/or the
inflow of freshwater may  increase.   Nonuniform changes  in precipitation could
cause  very  complex  alterations  in  the  physical  characteristics  of  the
Mediterranean Sea, especially the shallow coastal areas.




     Some countries have  tried  to  satisfy  the demand for high-quality fish by
artificial fish production, although it still accounts for a small fraction of
total fish consumption.   In 1987, approximately 26,500 tons of high-quality fish
were produced; by  1992, this number is estimated to reach 44,000  tons (Blue Plan,
1988).  About 90% of the  present aquatic farming  in the Mediterranean occurs in
lagoons.   Other  techniques,  for  example  raising  fish in  tanks,   are  being
introduced in some countries.

     The Mediterranean coast provides great conditions for further development
of  aquaculture.   However, uncontrolled development  often endangers  the areas
suitable for aquaculture.  If aquaculture is to be notably increased, measures
for the protection of suitable habitats must be taken immediately.  Within the
framework of the  program prepared  by  the Priority  Action  Programme  of the
Mediterranean  Action  Plan   in  cooperation  with  the  Food  and  Agricultural
Organization, ecological  criteria  for  the  rational  development and  protection
of aquaculture in  the Mediterranean coastal  regions are being developed, so that
the Mediterranean  countries can in time legislate the proper protective measures.

     Since marine  aquaculture is mainly located  in  the coastal zones, climate
changes and their direct  consequences (sea  temperature rise, salinity rise, sea
level rise)  will  greatly affect its development.  Keeping mind  the  fact that
marine culture in the Mediterranean comes from lagoons whose average depths are
only 50 cm,  sea level rise may make the lagoons completely unfit for production.
New lagoons will  need to be created or existing ones greatly modified.

     A rise  in both the  salinity  and the temperature of the Mediterranean Sea
will  result  in   a decrease  of  oxygen  solubility  and  an  increase in  the
decomposition of organic matter.  This may  enhance the oxygen depletion and may
even create  anoxic conditions.   On  the  other hand, warmer  temperatures will
accelerate the growth of marine organisms  in the colder periods  of  the year,
shortening the production cycle.

     The changes  in climate conditions may alter the effects of pollutants on
certain organisms.  For example,  the  expected  temperature rise may create major
changes in the bioaccumulation of certain pollutants,  which may negative impacts
on some commercially important  species.  Regulations on the  acceptable levels
of water pollution in fish ponds may need to be amended, and some aquacultural
activities may need to be relocated (see Titus,  Problem Identification, Volume
1, for additional  discussion of impacts of  sea level  rise on fish ponds.)

Community Infrastructure

     The discussion here  on human settlements  is restricted to freshwater supply
and wastewater collection, treatment, and disposal.   Although little  technical
data are available on  community  infrastructure in the Mediterranean  region, we
can anticipate the general impacts of climate  change.  However, the impacts will
vary by locality.



     When discussing infrastructure along the Mediterranean, we must distinguish
between the northern, eastern, and southern areas, and between urban and rural
units.   Infrastructure  is  generally  most numerous in the cities  of the more-
developed  northern  countries.   While  all  northern  cities  have  systems  of
waterworks, most areas  in  the south  do  not and some do not  even  have running

     Until recently, most  sewage systems in the  Mediterranean  released their
wastes directly to the  sea by the shortest  possible route.   A large number of
small systems released  wastes  immediately  under or just at  the  surface of the
sea.  It was difficult to control  these releases, and consequently coastal waters
became polluted.

     Recently the  philosophy and practice  of  wastewater  management  has been
changing.  The general belief now is that wastewater should be collected, treated
to  an  acceptable  degree of  contamination,  and then  released through  a long
pipeline far into the sea.,   This method  of wastewater disposal also allows for
the reuse of wastewater --  a  point of great  importance to areas with inadequate
water sources.   Israel  has not released any wastewater  into the sea for the last
several years; after proper treatment it  is reused, mainly for irrigating crops.

     The  expected  climate   changes  will   have   affect  existing  community
infrastructures  and require  new  infrastructures.   Basically,  the  reduction of
available water  will exacerbate present-day problems in many areas.  It will be
necessary to supply some cities and settlements with water from far-away sources,
since the local  sources will  have a lessened capacity and  poorer quality.

     Due to the  temperature rise, the rate of growth  of various microorganisms
in  some  water  sources  will   increase,   thus  increasing  possible  waterborne
environmental health risks.  Eutrophication may be intensified in  some sources
and rivers.  All this will  require the construction of equipment and facilities
for  freshwater  purification,  which will  significantly  increase the  price of
freshwater -- the price may even double.

     Sea level  rise  may endanger the sewage systems  in some  coastal  cities,
particularly those whose sewage  systems  also serve as  cisterns.   Drainage may
also be more difficult.   After rainstorms, wastewater may flood the lower parts
of these cities. Both this situation and the shortage of water will require the
construction of completely new  sewage  systems and facilities  for  wastewater
treatment and possibly reuse.


     The current migration toward the coast will continue in the future, but with
less intensity than urbani2:ation. This latter process will be especially intense
in the southern and eastern  parts of the Mediterranean, where today 40-50% of
the population  lives in the  urban  areas.  According to the  Blue  Plan (1988),
this figure is expected to reach 70-80%  by the year 2025.



     Changing climate will have a limited impact on the population in the coastal
zone, especially in  the  initial years  of accelerated sea level  rise, assuming
that coastal  defense measures  are  taken.   The  natural population  growth is
primarily  affected  by other  factors,  such as the  growth  of the  standard of
living, the  growth  of the economic  vitality,  the level of  medical  care,  and
cultural and  religious  customs.   Nevertheless,  migration to  the coast  may be
accelerated in the south if global warming increases desertification.

     Urbanization probably will be slower than predicted by the Blue Plan (1988).
Reduced water supplies, poorer water quality,  the need for more purified drinking
water,   transport of water  from  distant  sources,   plus  a  greater  level  of
wastewater treatment and recycling will require greater expenditures for urban
infrastructure.  The  resulting rise  in  the cost  of  urban living will slow the
migration toward cities.  The temperature rise will make living in crowded cities
less pleasant during the summer.   The hot  exhausts of air-conditioning systems,
which probably will  be  increasingly used, also add  to  the  warming  in  cities.
A reduction of their use would occur only with a drastic rise  in energy prices,
which may be necessary to limit fossil-fuel emissions.

     Our  preliminary calculations  suggest that  at  least  5% of the  coastal
population -- some 6,700,000  inhabitants -- would  be  affected  by the impacts of
sea  level  rise.   Some  of  these people  would  be  directly threatened  with
inundation, but probably not  more  than 10-20% of the  total number affected.  The
repercussions will include the need to remove structures and construct  new one
for the eventual relocation of the inhabitants.

     Inertia  is  inherent  to  economic,  social,  and political  institutions,
particularly for  phenomena  that will not manifest themselves  in the near future.
But because recent information indicates that these changes could happen as early
the next decade,  the public and the governments  should start preparing for them
now.  Our recommendations are as follows:

     1. Information should  be disseminated to the public as well  as to all levels
        of economic and political decision-making entities  about the possible
        consequences of gradual changes  in the climate and the need for measures
        to mitigate the impact.  This should be a national action,  not be left
        to the local authorities or to coastal zones.

     2. Local inventories should be made of the coastal  zones,  and data should
        be  collected  on the  expected  local  impacts  of sea  level  rise  and
        temperature  rise  on  water,   soil,   precipitation,   and   individual
        socioeconomic activities.

     3. A  strategy  should  be  developed that  can react  to changing  climate
        conditions,  keeping  in mind the  accumulative  nature of these changes.
        Calculating expenditures  for a given change or given time horizon ignores
        any additional  changes in subsequent years.


                   CREATED  BY  SEA  LEVEL  RISE
     A.  SBAVAGLIA (Chairman Magistrate  delle Acque in  Venice,
                   Italian Ministry of Public  Works)
           C. CLINI (Chairman  Expert Committee  for R &  Dr
                   Italian  Ministry of Environment)
    F.  DE SIERVO (Technical Director, Consorzio  Venezia Nuova)
      G.  FERRO  (Deputy  General  Director,  D'Appolonia S.p.A.)
                              Via Siena,  20
                          16146  Genova,  Italy

     This paper discusses the social,  cultural, and other impacts of increased
flooding in Venice.  It briefly describes Venice's  physical, ecological, social,
economic,  and cultural framework and the  characteristics and  evolution  of
flooding phenomena.  It then analyzes the short-term impacts of the increased
floodings and discusses the  response of the city (and the country) at the social,
technical, and political levels.  The paper next describes the special projects
being undertaken to prevent floodings, with particular emphasis on the mobile
gates at the lagoon entrances (whose construction  will  soon be started), on the
impact of this project, and on  the reactions of the  city.  Finally,  the paper
attempts to interpret the Venice experience,  identifying  the features that can
be considered as representative of generally expected impacts and the reactions
to sea level rise in seafront cities.

    Although it is necessary  "to consider with great caution casual connections
(to the  earth's climate evolution) often proposed" (Puppi  and Speranza,  1988),
a large number of  studies indicate that there  is credible evidence for  an
accelerated rise of sea level in the next century.

    The current trend  is characterized by an increase of  about 10 centimeters
per century (Gormitz et al.,  1982).  With respect to this  trend, all scenarios
forecast by different researchers indicate a significant increase.  Most of the
studies  forecast a rise in global  sea level  of between 25 and 75 centimeters  by
the year 2050 and  between 50 and 225 centimeters by the year 2100 (Titus,  1986).


     The many consequences expected In coastal areas  as  a  result of sea level
rise can be classified into  three categories:  shoreline retreat, flooding, and
salt intrusion (Titus, 1986).  These consequences would affect urban and rural
areas differently,  but in  both  cases they  would have  significant economic,
social,  and cultural impacts.  All  of these have been extensively investigated
by many  authors  in recent years.   Previous  assessments  have been  based  on a
priori estimates of the impacts, since experience on this  topic has not yet been
acquired.  However,  few cases exist worldwide that can provide a valuable insight
into the  phenomenon.   Among them,  Venice represents  an  extremely significant

     Since the beginning of  this century, the relative mean sea level in Venice
has risen by about 25 centimeters, and the mean number of floodings of the city
has  increased from  less  than  10  to more than  40 per  year.    Catastrophic
floodings, having a return period of 800 years at the beginning of the century,
presently  have  a return  period  of  200 years;  that is,  a  25-centimeter  rise
quadrupled the  risk of serious flooding.   For  these reasons,  the  problem of
protecting the city from the sea has taken an increasingly urgent priority, and
in such  a way Venice represents the likely economic, social,  and cultural impacts
that sea  level rise would have on an urban environment.

     This  paper  illustrates the Venice  experience  in  order  to  provide  some
indication for future, possibly more generalized situations.  It first briefly
describes  Venice and its  environment  and provides  a  short history of sea level
rise.  It then analyzes the  perception of the problem, discusses the short- and
long-term  reactions,  and  presents  the  course of  action that  officials  have
selected.  Finally,  it illustrates  future  perspectives and critically reviews
the  Venice experience,  outlining   the  most  prominent aspects  likely to  be
experienced by coastal communities in general as sea level  rises.


     The  Venice  lagoon is  the most important remnant of  a series  of lagoon
formations that,  thousands  of  years ago, occupied  all  the  northern  bow of the
Adriatic.  It is made  up of a basin of 550 square kilometers,  and is connected
to the sea by three openings at Lido,  Malamocco, and Chioggia (Figure 1).   The
basin has  an oblong and arched shape and extends about 50 kilometers along the
Adriatic coast, varying from 4 to 15 kilometers in width, with an average depth
of about  1.5 meters.

     One portion of the lagoon  (420  square kilometers) is permanently submerged
by  water  (shallows);  another is  permanently  above the  water  (islands  and
urbanized  areas).  Of  the remainder, one part (the "barene") is submerged only
by normal tides, while another part  (the  "velme")  is  generally submerged and is
above water only  during very low tides.  At  the  edge of the lagoon, 90 square
kilometers of water are reserved for fish farming.  Figure 2 illustrates various
parts of  the Venice lagoon.

                                                             Sbavaglia, et  a7.
Figure 1.  Map of the Venice lagoon.
     The evolution of the Venice lagoon has been reconstructed on the basis of
geological studies.  About 10,000 years ago, the sea level  began  to rise and the
coastline migrated north from the lower Adriatic.  When  it reached approximately
the present location (about 6,000 years ago),  an intense and prolonged alluvial
phase took place.   Sediment  flowed  into  the  sea and was distributed along the
coast by the wave  motion  and the sea currents,  forming the littoral line that
delimited the primitive Venice lagoon (albeit  with  a  smaller extension than the
present one).

     Among the factors  affecting the  lagoon's morphology  during the ages, the
activity of the lagoon's tributaries was dominant.   They kept the water brackish
(rather than  salty), but  they also  threatened  to  make  the  entire  lagoon  a
marshland and eventually to fill it completely.

     The lagoon is an extraordinary environment  to be conserved  and protected,
with a  balance  between  the natural beauty of the place and the needs  of the
communities living  there.   Several hydraulic works  have been  carried  out  to
preserve it,  particularly the diversion of major tributaries into the sea, the
location  of  the  sea  entrances,   and the  dredging  of channels   for  inland


Figure 2 (A).  Historic Venice.

Figure 2  (B and  C).   Aerial  view  of a  fish  farm  in  the Lagoon of  Venice.
Conditions  in  the lagoon  are particularly  favorable  for this  type of  fish
farming.   This had led to the construction of numerous  dykes  which isolate the
farms that are now part of the Venetian landscape.

 Figure  2  (D).   Aerial view of a low-tide  inlet  of  the  Lagoon of Venice.  The
 strips  of land that emerge at low tide are a distinctive  feature  of the lagoon
 They  have  a very important hydraulic  and  ecological  role;  they can attenuate
 currents and wave motion, and so  help to control two of the causes of the city's
     The Venice lagoon is characterized by  networks of deep natural channels to
the mainland, which  branch  out  of the three openings.   Other manmade channels
have been operated over the centuries to improve navigation within the lagoon,
and two  large channels  have  been  created  in recent  times to house shipping to
the industrial Port of Marghera: the Vittorio-Emanuele Channel (1926) from the
Lido opening, and the San  Leonardo Channel  (1968)  from  the Malamocco opening
Tides propagate primarily along these natural and manmade channels.

     To allow ships  of increasing  tonnage to enter the lagoon  (for military and
commercial reasons),  as  well as to avoid the frequent malaria caused by stagnant
water,  the Venetians  carried out, between the 16th and 19th centuries, a complex
series of works  to redirect the  course of rivers  such as the Brenta, Piave, and
Sile,  so that they came out into  open sea rather than within the lagoon.  In this
way, the  flow of  freshwater into the  lagoon   was reduced, and  the  rivers no
longer carried sediments into the lagoon, which in the long run  would have caused
the basin to silt  up.


                                                             Sbavaglia, et a7.

     Other internal defense measures were  undertaken against the major external
threat  represented by the sea.   In the 18th century,  the  "Murazzi," massive
seawalls performing their function even today, were built to protect the shores
from flooding by high tides.  Between the 19th and 20th centuries, breakwaters
were also built to prevent the silting up  of the three openings to the sea.  As
a result, the tidal flow between the sea and the lagoon was increased along with
the speed of the tides  in the internal channels,  leading to noticeable changes
in  the  physical characteristics  of the lagoon.   These changes  were further
emphasized by the  two large shipping channels opened during this century.  For
the Venetian lagoon, therefore, the problem has always been one of maintaining
the equilibrium between the natural and human environments.

     The presence  of  human  settlements in the lagoon has made  the ecological
balance even more complicated, and so the  search for an equilibrium between the
various  needs  of  the  environment  is becoming increasingly  difficult.   The
movement of the sea is essential to the renewal of the lagoon's waters, removing
human, industrial,  and agricultural waste, but stronger tides must be controlled
to  avoid both  flooding  of inhabited areas and erosion  of the  "barene," which
would silt up the  channels.


     From the hydraulic  point of view, the complex system of the Venice lagoon
can be  subdivided  into  (1) the basin  of Lido, or  the  northern  lagoon; (2) the
basin of Malamocco, or  the central  lagoon; and (3) the basin  of  Chioggia,  or
the southern lagoon.  Each of these  three  basins  is connected  to  the northern
Adriatic by inlets, known as port openings.  The three port openings have a total
cross-sectional area of approximately 18,000 square meters,  and for each tidal
cycle about 330 million cubic meters are exchanged.

     Approximately  430  square  kilometers of  the lagoon  are  open   to  tidal
expansion,  which flows into the lagoon through the  three  openings along the 800-
kilometer network  of channels.  These channels wind across  shallow waters and
"velme" (areas  of the lagoon usually covered with water), islands, and "barene,"
and their depth and width gradually decrease as they reach upland to the extreme
borders of  the  lagoon.   Excluding  fish farms, 75 percent of the area subject to
tidal expansion is between 0 and 2 meters  deep,  whereas  only 5 percent exceeds
5 meters, as is the case of the deepest channels.

     In this natural environment,  with largely urbanized areas,  the phenomenon
of exceptionally high tides is taking place with  an  increasing  frequency,  thus
becoming a  real threat to Venice and  its lagoon.  High tides are often determined
by  the  coincidence of  various  factors:   the normal  astronomical  tide,  the
scirocco wind that drives waters  of the Adriatic  to the north, the  sea level
fluctuations due to different  atmospheric  pressures at each end of the Adriatic
(seiche), rain on  the catchment  basin drained by the lagoon, and  finally the
seasonal variations in the level  of the Mediterranean  Sea.


     The frequency and severity of tidal  floods increased in this century as a
result of sea level  rise due to the melting of world's glaciers, and as a result
of land subsidence due to natural  settling  and the drawing of water from artesian

     Land subsidence, which is also caused by  natural  factors,  played  a major
role  in  the  origin  and  evolution of the lagoon, and has  become  a determining
factor  affecting  the city  and lagoon environment  after human  intervention.
Anthropogenic subsidence initially started with  the  heavy groundwater  pumping
used mainly for industrial  purposes.  Intense pumping of groundwater resources,
which is the main cause of  Venice's sinking, mainly  occurred  between 1950 and
1970.  Since the progressive reduction in  artesian water consumption started in
1970, the piezometric levels have moved back to  their  original  values,  and by
1978 the natural aquifer pressure had  been reestablished.

     Aquifer depletion and  subsidence  ran parallel  courses between 1950 and
1969-70.  Both reached their peak values  in 1969, when  subsidence was reported
to be 12 centimeters in the  industrial zone and 10 centimeters in Venice.  With
the reduction in consumption and further natural recovery of aquifers after 1970,
the land survey of  1973 showed subsidence  to be  slowing.  A small  rebound (of
the order of 2 centimeters) in  the historical center was  measured during the 1975

     However, human-induced subsidence was not  the  only factor  causing  more
tidal  floods  in  the  lagoon:   natural  subsidence and  global  sea level  rise
(eustacy) also contribute  to the diminishing land surface level of the city with
respect to the sea level,  thus increasing the impacts of high tides (Carbognin
et al., 1984).

     Leveling measures from before and  after  groundwater exploitation -- i.e.,
between 1908 and  1980 --  suggest that the present  natural subsidence is about
half a millimeter  per year.   This annual  average  rate is appreciably lower than
the average rate of about 1.3  millimeters per year estimated with reference to
the last millennium.

     Eustacy has affected the water level  of the  lagoon  due to  its connection
to the Adriatic Sea.  From the beginning of this century,  the sea level has been
rising 1.27 millimeters per year.

     These three  factors  (human-induced  subsidence,  natural subsidence,  and
global sea level rise) and their effects on the Venetian  environment are depicted
in Figure 3.  The  period  1908-80  includes  the different stages of land sinking.
The aforementioned anthropogenic subsidence lowered  the  land  an  average of 10
centimeters, netting out any rebound.

     In conclusion,  these  three factors   have  lowered  the surface level  with
respect to sea level by about  22  centimeters from the beginning of the century.
Today the mean elevation of the land surface of the city  is  about 110 centimeters
above mean sea level, while 80 years ago  it was  nearly 130  centimeters.  This
loss of 22 centimeters has caused Venice  to flood more  frequently.


                                                             SbavagTia,  et  al.

               Natural Trend  Period  Influenced by Hun an  Activity
Figure 3.  Eustacy and subsidence trend.
     Parallel to the rise of relative mean  sea  level,  high  tides  have  increased
as well.  Figure 4 shows  the  increase of the annual mean level  of high  tides  (as
well as of low tides) from 1920 to 1980.   In  Figure 5,  the  number of high  tides
for height  classes (for each  10  years  from  1955  to  1985)  is presented.    The
increasing  number  of  exceptionally  high  tides  is  clearly  indicated.    For
instance, between 1931 and  1945,  eight  exceptionally  high  tides took place,
reaching or exceeding  1.10 meters above the average sea level; whereas  between
1971  and 1985,   with  the  increased subsidence  due  to  human   interventions
subsequently interrupted, forty-nine high tides were recorded.

     As Figure 6 shows, Venice is  extremely vulnerable  to sea-induced  flooding.
When water  levels are  70 centimeters above zero  (relative to the Punta  del la
Salute hydrometer),  St.  Mark's cathedral  is  flooded;  at 80 centimeters,  water
pools appear in St. Mark's square;  at 90 centimeters, the square cannot  be walked
through  any more  and  begins  flooding  the lowest streets ("calli");  at  140
centimeters, more than  60 percent of the  city  is flooded.  In the period 1920-50,
the tidal level  exceeded the  "critical  threshold"  level  of 80 centimeters 15
times a year.  This threshold has been exceeded, on the average,  25 times a year
in the period 1950-60,  and 50 times a year since 1960.   Exceptionally high  tides
(e.g., greater than 140 centimeters) have become more frequent as  well.  Looking
back to history, during the preceding seven centuries the Republic of Venice  was


                1920     1930     1940     1960     1960     1970     1980
Figure 4.  Annual  average  high (a), mean  (m),  and low  (b)  tides.
     a) HIOH TIDES
                                                                   b)  LOU TIDES
 Figure 5.   Number of high tides for  height classes.

                                                             Sbavaglia, et al.

subjected  to  fewer  exceptionally  high  tides (51)  than in the 52 years between
1914  and  1966,  when it experienced 53.  Figure 7 illustrates the area flooded
by tides of 1 to  1.9 meters.


     Venice has always  been  a sea-town, organized and subordinated to the lagoon
environment.  Its economy was based mostly on shipping.   Water was an essential
factor of  life.   It simultaneously meant refuge,  safety, nourishment, income,
and prospects for development.   As an example,  until  1300 there were no streets
in Venice: its  channels  were the  only  transportation system, and the boat was
the only transportation  facility in town.

     Though Venetians became allied with the lagoon water to  build their "living
environment" on the archipelago, practically in every age calamities have been
reported periodically  affecting the town.  An exceptionally catastrophic event
occurred on November 4, 1966,  at the time of a  big flooding  of the Padana Plain
by the  Po  River and of  the city of Florence  by  the Arno  River:  a  tide 194
centimeters above average sea level was recorded.  More than 4,000 ground-floor
apartments were inundated,  and  more  than  13,000 people  lost their homes.   The
tide devastated shops  and storerooms, caused an electric blackout, and cut off
gas supplies and telephone  connections.

     Although the  problem of rising sea level was already studied and discussed
by a few specialists in the fifties and early sixties (e.g., Miozzi,  1960), at
that time the problem was basically ignored by  public opinion and the political
groups.  The  main  issues  at  the beginning of the sixties were the  industrial and
urban development of the city and the surrounding area.

     The situation suddenly  changed after the catastrophic 1966 event.  The high
tides ("acque alte") immediately became the central problem of the  public debate.
The impact was enormous, not only in Italy but worldwide,  and  committees to "Save
Venice" grew up all over the world.  The  event, defined  by  an  author as being
"cruelly beneficial" (Miozzi, 1968), also gave a substantial  impetus to the work
of the interministerial committee "Per lo Studio dei Provedimenti a Difensa della
Citta di Venezia," set up in 1963 and practically inactive until  then.

     The high tides continued  in  the years after 1966  (basically  at  the  same
level  as during the  years immediately prior), and the press gave them extensive
attention.  In 1970, a public body was set up to predict high tides.

     Meanwhile,  the program for protection proceeded slowly. The  slowness  of
the interministerial committee  that was  supposed  to coordinate  the operations
exasperated the citizens.   The  Venetians protested  and  organized  symbolic
demonstrations of disapproval  of the city's administrators.

     In 1971,  seven  proposals for a special  law  for Venice were presented within
eight  months.    Finally, after endless  discussions and  a large  number  of
amendments, on April 16, 1973,   the Special  Law (Law 171/73) was  approved.   It


                                                              Sbavaglia,  et al.
Figure 6.   Flooding  in Venice (continued):   (C)  Venice  during the exeptional
flood tide of 1966, (D) damage to buildings produced by the combined action of
high tides and wave motion.


A f /
                                                                  s'Sv "'"-
 Figure 7.   The shaded areas show the portion of Venice flooded by tides of (A)
 1 m,  (B) 1.1 m, (C) 1.2 m,  and (D) 1.9 m.   Assuming  no change in storm frequency,
 these areas will be underwater 50 times a year for  rises  in sea level of 20, 30,
 40,  and 110 cm,  respectively.






established  that  the  national  government  should  take  care  of  the  physical
safeguarding of the lagoon and urban  areas;  the regional government would be in
charge  of  planning  activities;  and  the  city  government would manage  the
restoration of the historical center.  The planned response measures have four
objectives:  the  physical  safeguard  of  the  lagoon,  decontamination,  the
restoration of monumental  and  smaller  buildings,  and  the economic development
of the Venetian area.  The law also  provided  financial  support of 300 billion
lire (about 3 billion  U.S.  dollars).   At  that  time, many people believed that
most of the problems were  over.   However,  the  long  path toward the protection
of Venice from high tides was just beginning.


     Since the Venice program started in 1973,  the people became more and more
accustomed to the  periodic: flooding of  the city, intensifying public commitment
to a solution.

     To carry out the  1973 Special  Law, an international  bid  was issued (Law
404/75) to solicit proposals for implementing  the Special Law.   Five groups of
well-recognized companies  submitted  their proposals,  but  none  was considered
adequate (March 1978).  Then the Ministry of Public Works was authorized to buy
the  projects  submitted  (Law  56/80).   The Ministry  commissioned a  group  of
internationally recognized experts to  draw  up  a plan  of action to protect the
city from  high  tides.   The plan  was based mainly on the  idea of temporarily
closing off the lagoon at the three openings,  using barriers that were in part
fixed,  in part mobile.   These would normally be left open and  closed only when

     The project drawn up  by  the  experts  was  approved  in  1982  by the Supreme
Council of Public  Works,  which established  that the work should aim, above all,
to achieve these primary objectives:

        the reduction  of  flood  tides in the lagoon;

        the  guarantee  that a sufficient renewal  of the  lagoon  water  would be
        maintained to  prevent  a worsening  of the water  pollution;

        the maintenance of the  three openings  at Lido, Malamocco, and Chioggia
        as  viable port entrances, limiting closures to  a minimum.

     To carry out  intensive studies  of the  area,  test possible solutions,  and
then plan and carry out a complex  series of measures that should meet the needs
of both the environment and the tourist, commercial,  and industrial activities
that are now part  of it,  the Italian  Government has entrusted the Venezia Nuova

     The project drawn up  by  the  experts  in 1981 suggested, as  a solution to
the  problem,  the  installation  of mobile  gates  set   in  fixed  barriers.   The


                                                             Sbavaglia, et al.

barriers made it possible to reduce the effects of excessively high tides, but
they also permanently reduced the exchange-flow between the sea and lagoon.

     The "Venice  Project"  has as  its  primary objective the  conservation and
development  of  the  city of  Venice,  and  of its  lagoon,  which  is a  unique
ecosystem.   This obviously requires controlling the high tides.  The difficulty
arises from the impossibility of closing off the  lagoon  from  the  sea for long
periods of time.  The tides have a fundamental role in maintaining the life of
the lagoon  environment.   Even a simple reduction  in the exchange-flow could have
consequences that should not be underestimated (see Park, Volume 1).

     The series  of  operations  to  safeguard Venice  was  given  its  clearest
definition in Law 798 of November 29,  1984.

     In 1982,  the  Magistrate alle Acque charged the Consortium with the task of
carrying out  studies  and producing mathematical  models of the  lagoon.   These
studies were to focus on reestablishing the hydrogeological equilibrium of the
lagoon;  arresting  and  reversing  the  process  of  decay  within  the  lagoon  by
eliminating its  causes;  reducing the level of  the tides in  the lagoon; defending,
with  specific  local  measures, the  islets  that make  up  the city  center; and
safeguarding the  urban  areas of the lagoon  from  flooding by means  of mobile
gates at the three openings to regulate the tides.  The work of the Consortium
actually started in 1986.

     To finance  this  first  stage of operations, the law set aside 234.5 billion
lire (almost 2 billion U.S.  dollars).  The funding  for the following studies was
to be guaranteed by the  budgets from the fiscal year  1987  onward.   An updated
estimate of the cost of the work is 3,300 billion  lire.

     To protect Venice and  its  lagoon  from sea level rise,  the  only possible
solution is the control  of tidal  flow at the port openings.  In compliance with
Law 798, the  solution that has been found most suited to the conditions and needs
of the  lagoon  environment consists of a  system of mobile structures  for the
regulation of tidal flow.

     The project envisions the use of specially designed gates,  respecting the
typical  conditions of  the  lagoon system  from the  viewpoints  of both  the
environment  and  socioeconomic development.   For each port  opening, a  set  of
rectangular flap gates will be installed;  these will be hinged to a foundation
structure made of cellular-reinforced concrete caissons.
     Each gate --  i.e.,  each module --  is 20 meters wide (Figure 8).   In their
"off" position, the gates are flooded and lie  horizontally  in  a recess  in  the
foundation structure.  If necessary, by expelling part of the water they contain,
the gates are lifted to their operating position (at an  angle of 45 degrees with
the horizontal) to stop the tidal  flow.  The gates have no  intermediate piers
to hold them in their  operating position  and, therefore, oscillate freely under



Figure 8.   (A)  Schematic  illustration of the mobile gates  and  (B)  gate being
towed past San Marco.


                                                             Sbavaglia, et a7.

the  action  of  the  waves,  which are transmitted,  practically unaltered, to the
lagoon.   The compliance of  the  gates with the waves  drastically reduces the
forces  transmitted  to  the  foundation  structures,   thus  simplifying  their
construction and reducing costs as compared with more traditional solutions.

     In normal  conditions, when the gates are open, the port openings are free
from any structure.   Therefore,  there are no  obstacles  to either  water flow or
navigation.   There  will  be  no  aerial  superstructures,  either  temporary  or
permanent,  since these  would alter the landscape  and could  hinder the transit
of ships.

     Although  strongly  requested  after  the  1966  event,  the project  for the
temporary closing  of the  lagoon  has encountered  increasing  public opposition.
A  strong environmental  concern  grew,  fed  by  the tremendous   environmental
degradation of the lagoon.   Fear  was  expressed that the closing of the lagoon
could reduce the water exchange and further worsen the environmental problems.
In view  of  the rise  of  the  "green movement,"  increasing attention was devoted
to those concerns, and  a  number  of additional  detailed studies were performed
by the Venezia  Nuova  Consortium  to investigate these problems.  However, a final
approval of the project is still pending.

     In  the  same  period, the  interministerial  committee,  set  up by  the Law
798/84, recognized the  pollution  of the lagoon as  a major problem and started
a restoration plan.   The  guidelines for the  restoration plan  were approved by
the Committee in October 1989.

     Updated estimates indicate that the total  financing needed for safeguarding
and  restoring  Venice and the  lagoon  will  most  likely reach  some billions  of

     During this century,  Venice  has  experienced a significant increase in both
the frequency and the magnitude of periodic  floodings.  This is due to a number
of different simultaneously occurring causes (particularly mean sea level rise
in the Adriatic Sea and land  subsidence due  to uncontrolled exploitation of the
water table).  The experience of  Venice has  many similarities with the expected
effects of  the  sea level  rise on  other  seafront  cities,  at least  in  a  first

     However, although the Venice situation  represents a very  interesting case
study, some of its peculiarities  must be carefully considered:

        its physical characteristics  -- i.e., the presence  of the lagoon between
        the  sea  and  the inland environments;

        its  sociocultural  implications,  since  the  sea-town  of Venice  always
        tried to manage the  lagoon environment  not  only by integrating itself
        with  the element  "water" but also  by developing  its organization  "on
        the  sea";  and



         its  political  and  economical  peculiarities,  being  a  "unique"  town
         worldwide  and having  available  large financial resources.

     Some interesting conclusions can be drawn  from the Venice case study:

         sea  level  rise  (although of limited  extent)  represents  a  critical
         problem  for  the town;
         the problems were recognized  for a long time by  the scientific community
         and were outlined to  the public administration, but interventions were
         started  only following a catastrophic event;

         the definition and implementation of remedial measures required a very
         long  period  of  planning  and  study,  and  after 20 years real work still
         has to start;

         some  years after  the catastrophic event,  Venetians  started to accept
         the floodings as  an unavoidable phenomenon  in  its particular  habitat;

         as time passed, other issues  started  to be  considered essential for the
         remedial measures (environmental conservation,  city development, etc.),
         slowing  down the  initial rate in the development and implementation of
         the remedial measures; and

         remedial measures need very large financial resources, that in general
         can be collected  only from the  national government.

     From a  more  general  point of  view,  the  Venice case  can  provide  some
guidelines on the following:

         the need to  focus in  advance public  attention  on both the primary and
         secondary  effects of  the sea  level rise phenomenon;

         the   need    to  consider   the  environmental,   urban   planning,   and
         socioeconomic impacts of the safeguard  projects  from their inception;

         the need to  clearly  evaluate the  project's financial  requirements and
         to assign  priorities.

     In particular,  we  believe  that   it  is  not  generally possible to rigidly
maintain the  "ante quo"  situation.    Rather, when  a sea level  rise effect is
forecast, it  is  necessary to develop  a new environmental  strategy,  (1)  with
adequate human,  urban planning,  and aesthetic characteristics;  (2) with limited
social and cultural impacts; and (3) that is achievable with available financial

Carbognin, L.,  P.  Gatto and F. Marabini.   1984.  The City of the Lagoon of Venice
- A Guidebook on the Environment and Land Subsidence.  Venice.


                                                             Sbavaglia, et a7.

Gormitz, V., S. Labedeff and J. Hansen.   1982.   Global  sea level  trend in the
past century.   Science 215:1611-1614.

Miozzi, E.   1960.   La Conservazione e la Difesa  dell'Edilizia  di  Venezia, il
Minacciato  suo  Sprofondamento   ed  i  Mezzi  per Salvarla.   Proceedings of the
Conference for "La Conservazione e Difesa della Laguna e della Citta di Venezia".

Miozzi, E.  1968.   Venezia  nei  Secoli,  Vol.  Ill:  La Laguna.   Venice:  Libeccio

Puppi, G.,  and A. Speranza.  1988.   The physical  problem of global  climate on
Earth.  Alma Mater Studiorum 1:1-14.

Titus, J.G., ed.  1988.  Greenhouse Effect, Sea  Level Rise and Coastal Wetlands.
Washington, DC:  U.S. Environmental Protection  Agency.

Titus,  J.G.   1986.    Greenhouse  effect,  sea  level  rise,  and coastal  zone
management.  Coastal  Zone Management Journal 14:3.


                           DR. HAMPIK MAROUKIAN
                         Department  of Geography
                           University of Athens
                              Athens, Greece

     Many parts of coastal Greece will be seriously affected by a  rising  sea
level.  If drastic measures are not taken soon by state and local governments,
it will  be much more  difficult and more costly to face this problem  later.

     Consider the  delta of the Sperkhios River.   If sea level rises  2 meters in
the next century,  this deltaic  plain  could  lose  about  40  square  kilometers of
land.  A rising sea  level would  also  cause  serious problems to  coastal  urban
areas, industries, settlements,  harbor facilities,  tourist complexes,  coastal
communication networks, airports,  and other infrastructure.  The areas that will
probably be  most  threatened are the big  harbors  of the country:    Pireas,
Thessaloniki, Patra,  Volos,  Iraklio,  Alexandroupoli, etc.   Many  airports like
Kerkyra,  Alexandroupoli,   and Thessaloniki  are  almost at  sea  level  and will
certainly  be  threatened.    Coastal   highways   in  northern   Peloponnessos,
Thessaloniki  plain, Sperkhios delta, Porto Lagos, etc., will have problems  too
(Figure 1).

     The  incursion of the sea will  create another very serious problem to  the
coastal  environment,  that of erosion.  This process  will  most certainly affect
densely populated  coastal  zones  on  low  to intermediate  slopes.   In recent
decades,  more than one million cottages have been constructed on or near  the
coastal  zone.  Many  of  these  already face  erosion  problems, since they were
constructed without  prior knowledge of  the  conditions that prevailed in  the
environment.    Thus,   a  sea level  rise of  just a  few  decimeters  would   be
destructive to all these  structures.  Unfortunately, nothing has  yet  been done
to put some limitations on coastal construction.

     Correspondingly,  similar  problems  are expected  to  occur  in  coastal
cultivated areas  like  the  deltaic  plain   of  the   Sperkhios,  the  plain   of
Thessaloniki, the  Argolis plain, Akheloos plain, and the Louros-Arakhthos plain.
It is believed that parts of the  extensive drainage  and irrigation networks of
these areas  will  be   rendered useless.   The groundwater  table  will  also   be
affected by rising seas.   The underground saltwater wedge in the water table will
certainly shift inland, affecting cultivated land.




    0    50   100  150 Km
Figure 1.  Map of  Greece.


     Finally, coastal wetlands will be covered  by  the  rising sea level and an
important natural resource of the environment of Greece will cease to exist.  The
lagoons of Messologi, Amvrakikos, and Porto Lagos, which are important fishing
grounds, will become shallow  bays or gulfs.  The extensive saltworks  of Messologi
and other areas of Greece will have to move farther inland.

     Despite these  problems,  the  prospect  of sea level  rise does  not seem to
concern officials from government or private organizations in Greece.   In recent
meetings with high  ranking officials  of  the Ministry of Environment,  Physical
Planning and Public  Works  (the main  agency responsible for the management and
protection of the Greek Coasts),  they  agreed that they would eventually need to
take measures to  confront  the problem, but they felt that there is no urgency
today.   They generally encouraged me  to  assess  in  more detail   the likely
consequences of global warming and sea level  rise,  and  to come back and suggest
to  them  options  that  could be   rationally   implemented today,  given  the

     This initial response made me  realize  that  the most  fundamental barrier to
responding to sea level rise in Greece will probably be similar to the barrier
that has confronted the world in  general  since Svante Arhenius warned us of the
greenhouse effect in  1896: the information gap  between researchers and policy
makers.  This gap  is more than a failure to communicate often enough: between our
respective fields of scientific and policy expertise lies a  conceptual "no man's
land" into which both scientists and policy makers are reluctant to tread.

     As I left the meeting, my initial reaction was that the policymakers seem
to unrealistically expect me  to have all  the answers on  a "silver platter."  But
on the other hand, perhaps I  was  unrealistic to  expect that  if I presented them
with scientific  information on an environmental risk, they would  be  able to give
me  the  response  options  on  a  silver platter.   Scientists feel  comfortable
describing observable facts,  but  are hesitant to speculate  about future impacts
of new phenomena, and are even less  qualified to recommend  policy actions.  Yet
by the same  token, policy makers that feel comfortable making decisions when all
the options have been laid out feel  less  qualifiedand often lack the time--to
develop planning and structural responses  that have not been  thoroughly assessed.
To properly  respond  to sea level rise,   scientists  and  policymakers must work
together to answer questions  that are interdisciplinary in the broadest sense of
the word.

     But the necessary  collaborative  effort has not  yet gotten under  way in
Greece, so it is not possible to  provide  a  detailed examination of the impacts
and responses to  sea level  rise.   The remainder of this  paper  describes the
environment and  the resources at  risk.

Climate and Tides

     The coastal climate of Greece can be  characterized  as  Mediterranean with
warm  to hot dry  summers and moist  cool  winters.   Storms  are  not a  common
phenomenon in Greece.  Storm winds usually  blow  from  the northern  or southern



quadrants.  Those from the east  or west are rare and of short duration, no more
than one or two days.

     The tidal range  around  Greece,  as  in all of the Mediterranean  Basin,  is
small.  The greatest tidal range is observed at the Strait of Evripos where the
northern and southern Evvoikos Gulfs join.  The maximum tidal range  is  1.20 m in
the northern port of Khalkis and the mean is 0.42 m.

     Although the  Greek  region  has  numerous  earthquakes,  tsunamis  are  rare.
Nevertheless, it is very  likely  that the great  explosion of the volcano of Thera
(Santorini) around 3,400 years ago was followed by a  catastrophic tsunami that
reached all the shores of eastern Mediterranean Sea.  According to Galanopoulos
(1960), from 1801 to 1958 there  occurred  170 earthquakes with a range fron I to
VIII on the Mercalli-Sieberg scale,  but only 6 tsunamis  were destructive.

     The low tidal  range  and absence of frequent storms implies that it has been
safe to build one to  two meters above sea  level.  As Titus (this volume, Problem
Identification)  points out,  this situation potentially  makes low areas more
vulnerable to inundation  than areas with  frequent storms or large tidal ranges.

Types of Coasts

     Fortunately, Greece  does not have  a particularly flat coast, except for
deltas.   About  31%  of  the  coasts  are  rocky with  slopes  greater  than 50%,
generally  along  the  northern portion of  the western coasts  of  Greece,  the
northeastern coasts of the Gulf of Corinth, the western coasts of the Aegean, and
some parts  of Khalkidiki (Figure 2).  Another  25% of the  coasts  have  slopes
between 10% and 50%;  these shores are  often easily erodible,  e.g., the southern
Korinthiakos Gulf.

     Despite the predominance of steep coasts,  about 45% of the coast has slopes
less than 10%.  These include the deltaic plains of Arakhthos-Louros,  Akheloos,
Pinios (Peloponnessos), Sperkhios, Pinios  (Thessalia),  Aliakmon-Axios,  Evros, and
the  fan  delta of Nestos;  the barrier beaches of  northwestern  Peloponnessos,
Akheloos-Messologi, Amvrakikos,  and Nestos; the lagoons of Messologi, Amvrakikos,
and Vistonida; and all the pocket beaches, accretion beaches,  and coastal plains.
Figure 3 shows a number of low-lying areas in  Greece.

     The sediment size of most of the depositional features is in the sand range,
but in many parts the presence of pebbles  and  stones is not uncommon.   Although
the presence of sand  dunes is not rare in  many  parts of Greece, they are located
along the coast  without  extending inland  because  of  the  short duration  of the
high intensity winds.

     A final feature typical  of  warm seas is the presence of beachrocks.   They
all seem to  be  eroding today and are  found  mostly  in the central and southern
part of the country,  usually  in  sandy  beaches.  Most of them date from the Late
Holocene age and are  located a couple of meters above or below present sea level.

                                                     Gently sloping coasts

                                                     Intermediate coasts

                                                     Steeply sloping coasts

                                                   o Major ports
Figure  2.   Distribution of slopes along the  coasts  of mainland Greece.
     There  are five  major deltaic  plains  (Evros,  Axios-Aliakmon,  Sperkhios,
Akheloos, and  Louros-Arakhthos) and  four regions with barrier beaches, barrier
islands, and spits (Amvrakikos, Akheloos-Messologi, northwestern Peloponnessos,
and Nestos).  There are also numerous pocket beaches, accretion beaches,  and fan
deltas  (the largest at Nestos).


     The Ramsar Agreement, concluded in Iran in 1971, called for each country to
delineate the wetlands that were environmentally significant.  For Greece these
are the following:


>    B
                                                                       ,r.    e road is gone

 Figure  3  (D-F).   Low-lying areas of Greece,

(D)  Saltworks  in Zakynthos island, western
(E)  Astakos, west-central Greece.  Barrier
(F)  Amvrakikos Gulf,  western Greece.
     Barrier  beach  with lagoon on the


The Evros Delta Wetland

     The River Evros  is one of the largest rivers of the Balkan peninsula and is
characterized by high discharge and sediment transport rates, particularly during
the winter and spring months.  There are four lagoons  and at least three barrier
islands  of limited  size.   Until  1950, human  interference  in  the  natural
environment was minimal.  Since then, various artificial drainage systems control
to a large degree the flow of the river.

The Vistonida-Porto Lagos Wetland

     Lake Vistonida is located  in central Thrace and is the extension of the bay
of Porto  Lagos.   It has  an area  of  4500 hectares (11,120 acres) and  forms a
shallow lagoon  with  an  average depth of 2.0-2.5  meters  and a maximum  of 3.5
meters.  The average height of Vistonida  is 0.10 meter. The deterioration of the
surrounding  lowlands  has  led  to  their increased  erosion  and  sedimentation
deposition in the lake,  which  has  resulted in a rise of the lake bottom by 0.40
meter from 1976 to 1982.

The Nestos Delta Wetland

     The Nestos River is the natural  boundary between  Macedonia and Thrace.  Its
source is in Bulgaria and  its length in Greece is 130  km.  The main wetland area
comprises the main channel, the bank zones, and  the coastal zone of lagoons (Nea
Karvali-Nestos mouth - Cape Baloustra).  The general area of the coastal zone (a
length of about 45 km and width of 1.5-3 km together with  the Nestos Delta)  is
characterized by  a great  variety  of biotopes with various plant  colonies and
zones of  vegetation.   The present  cultivation of the  land  has  worsened the
conditions in the Nestos wetland.

The A1iakmon-Loudias-Axios Delta Wetland

     This region  covers  the lower  deltaic  plain  of three rivers  (Aliakmon,
Loudias, and Axios)  and has an area of about  200  square kilometers.  The largest
part  has  been apportioned to  the local peasants.   The  coastal  parts  of the
deltaic plain  are drained today for cultivation purposes.  This process, together
with water and soil  pollution,  has turned this wetland into a very unstable and
endangered environment.

The Messologi  Lagoon Wetland

     This wetland  is  found in the  middle of western Greece next to the Akheloos
Delta.  It is composed  of three lagoons  (Aetoliko, Messologi,  and  Klisova) and
has a total area  of  25,800 hectares  (63,752 acres).  The natural biotope has
deteriorated in the last twenty years  owing to the draining  of some areas and the
conversion of others to  salt-works.

The Armvrrakikos Wetland

     Found in  northwestern Greece, the wetland  forms  a closed  sea  with a total
shoreline length of 256 km and a maximum  depth of 60 m. The Louros and Arakhthos



Rivers flow into the gulf where the Logarou, Tsoukalio, Rodia,  and Mazoma Lagoons
are located as well  as the Bay of Koprani.  The wetland  is burdened by human and
industrial effluents as well as agricultural and cattle by-products.

The Lake Koukhi Wetland

     This wetland is located in northwestern Peloponnessos facing the  Ionian Sea.
It connects to the sea through a very narrow inlet having a width of only 8 m.
The deepest part of the  lake  is 40 cm and  the  mean  is  30  cm.   Its area varies
seasonally from 710  hectares (1,754 acres) to 850 hectares  (2,100  acres).  It is
one of the largest lagoons in Peloponnessos.  It is rapidly deteriorating, mainly
as a result of human activities (agriculture,  hunting,  and pollution).

     Because of the  low  tidal  ranges  in Greece, these wetlands are barely above
sea level and hence would be mostly lost with a one-meter rise in sea level.



     A large part of the Greek population has lived near the coast since ancient
times.  Many  ancient city-states flourished along the  Greek  coast and  in many
cases  their  very  existence  depended   on  their  coastal   colonies  in  the
Mediterranean Basin.  The population  of ancient Athens, for example, could have
been a few hundred thousand people.  In Roman and Byzantine times and the ensuing
period of Turkish occupation between the fifteenth and nineteenth centuries, life
deteriorated and inhabitation in coastal  areas decreased considerably.   In the
early nineteenth century, Athens was  just a village  of 5-6,000 people.   Today,
greater Athens has about 3.5 million  inhabitants.

     Table 1 gives a general picture of the proportion of inhabitants on or near
the coast of  mainland Greece.   This  number is 52%  of  the  total  population of
7,083,000 living in the above-mentioned departments.  If we  consider the seasonal
migration of the Greek population  toward the  coasts in  summer,  then  this
percentage  could easily reach the 65% mark.   Furthermore,  if we  include  the
millions of tourists who visit Greece during the  summer months, then it is safe
to say that  for a considerable time  of  the year, about three  quarters  of the
population live along the coasts.

Harbors, Ports, and Other Coastal  Structures

      Various  types  of  artificial structures  are  found  along the coasts  of
Greece. They may be  classified into three main groups:

      1.    harbor and other ship-related structures,
      2.    coastal  defense structures,  and
      3.    water intake/outfall structures.


Table 1.    Number of  Inhabitants  Who  Lived  On or Near the  Coast of Mainland
            Greece (by department in 1981)
Population (x 1,000)
TOTAL (includes rounding)
     Greece  has  a  total  of  444  commercial  harbors  of  various  sizes  and
importance,  of  which 284  have sea defense  structures  (these numbers  do  not
include small harbors for local ferries).  The first group of structures is by
far the most important.    It  includes,  among other types,  such  structures as
moles, breakwaters,  bulkheads, jetties, and trestles.  Moles and breakwaters have
either vertical  or sloping faces.  The most commonly used materials are quarry
stones and concrete.  In  many cases, especially in the smaller harbors, jetties
serve several purposes  including those served by  moles and quays.   The most
common type  of quay walls  are gravity walls of concrete  blocks.   Jetties  are
usually formed with a surrounding bulkhead and backfilling.

     Coastal  defense measures usually consist of revetments, groins, and, more
recently,  artificial nourishment.  Coastal  revetments and groins are built almost
exclusively with quarry and concrete blocks.


     In Table 2,  the most important harbor installations are shown together with
passenger and cargo movement.

     Pireas shows the greatest domestic movement of passengers and cargo, most
of it being car-ferries (ferry boats).  Pireas together with Rafina serve to a
great extent the Aegean islands.  The high cargo movement of Thessaloniki  is due
to the transport  of goods  to neighboring countries (Yugoslavia and Bulgaria).
The increased cargo movementin Volos is due to the transport of goods from Europe
to the Middle East (Syria).  The high number of passengers arriving in Patra and
Igoumenitsa is due to  the  increased  arrivals  of tourists from Italy with car-
ferries during the summer months.

Land Use

     A large proportion of  the  Greek  coast with  steep slopes and cliffs has not
been developed.   The  remainder is composed of  deltaic plains,  narrow coastal
plains, and pocket beaches.  In many cases, these coastal zones were developed
in a very disorderly fashion before the state could intervene.  As a result of
this  anarchic development,  construction  in  the  coastal  zone  has,   in  many
instances, upset the equilibrium that exists in the coastal  environment.

     In several  coastal  lowland  areas,  particularly in  the  Messologi  region,
there are extensive salt works.   In  other parts of Greece,  like the plains of
Thessaloniki, Sperkhios, Amvrakikos, Evros, and southern Peloponnessos, there are
large areas with rice fields.  In the Argolida-Messinia-Lakonia area,  northern
Peloponnessos, Volos,  and Crete, there is extensive  cultivation of fruit-bearing
trees and horticulture. Olive  trees  are found everywhere in     Greece, but the
main producing  areas  are  in Amfissa-Itea, western  and southern Peloponnessos
(Kalamata), and Crete.

      The often thoughtless exploitation of water resources in  coastal areas with
water pumps and wells  has led to  a serious drop  of underground water tables and
simultaneous  advance   of  saltwater.    This  has  led  to the  degradation  of
underground waters which,  in turn,   has  affected  the  quality and  quantity of
agriculture in  the coastal  zone.   This problem will only be exacerbated with
rising sea level and more frequent droughts resulting from global  warming.


      Aquaculture is a very important activity in Greece.  The indented coastline
and its great  length  complement  aquaculture development.  Important  areas of
coastal fisheries are the lagoons  of Messologi, Amvrakikos gulf, and Porto Lagos.
Fishing boats are usually of small displacement and the production is  intended
for domestic consumption (Table 3).   Exports are minimal.

      In recent years, a great effort  has been directed to the reorganization and
modernization  of fisheries  in the  various  lagoons of Greece  to make  them
profitable, in both quality and quantity.


Table 2.  Number of Arriving Boats, Passenger and Cargo Movement in Selected
          Harbors of Greece (1986)
Iraki io
Khania (Souda)
(IO3 tons)
(IO3 tons)
          Table 3.  Fishing Vessels and Fish Caught in Greece (1986)
Coastal Fisheries
Number of fishing
Fish caught (tons)
     Fishing could be vulnerable to sea level rise both because the fishing ports
and other activities are located in low areas, and because the loss of wetlands
would reduce fish populations.

Coastal Development

     Human intervention  in  the deltaic plains, the lagoons, and the wetlands is
not very extensive.  Shore alignment and protection structures are found in some
lagoons  like those  of  Amvrakikos,  Messologi,  and  Porto Lagos  (Vistonida).



Important shore protection  structures  (against  erosion)  are found only in the
area of Messologi and the deltaic plain of Thessaloniki.

     The state has spent very little on  the  development  and protection of the
coastal environment.   Beside harbor works in various locations of Greece and the
construction  of  some coastal roads,  state assistance that  addresses coastal
problems is of only local significance.

     Private investment in the coastal  region,  however, is at high levels.  In
the last decades,  thousands of summer cottages have  been constructed in many
parts of the  Greek coasts.   This rapid settlement development is frequently
accomplished  without  any  planning and  is many  times  done illegally.   Another
important development along the Greek shores is the construction  of big vacation
complexes with hotels and all kinds of sports and recreational facilities.

     Finally,  a variety of industrial  complexes, like oil refineries,  aluminum
smelters, steel works, shipyards, and dockyards, are located in coastal zones.
All of these  activities will  be  vulnerable to  a rise  in  sea level unless some
remedial actions are taken.

     The first attempt at a comprehensive solution  to  the  question of coastal
management and  protection  was made with  Law 2344/1940.    There  followed many
amendments and  additions,  mostly relating to  land  use and management  of the
coastal zone.

     Following the increasing  interest in  the protection  of the environment in
recent decades, a national  coastal  management program was started in 1980.  The
implementation of this program was entrusted to the Ministry  of Physical Planning
and Environment.  The primary aims were as follows:

     1.   To prepare  a  uniform and  complete  program  for  the  development and
         management  of the  coastal  zone; and

     2.   To study the following:

            Settlement patterns and deterioration of the coastal zones;
            The frequent irreversible destruction of the natural ecosystems and
            The reduction of productive agricultural land;
            The   exhaustion   of  marine  resources  due   to   pollution  and
            overexploitation; and
            The  inaccessibility of  the beach due to continuous land ownership
            along the beach.

     Unfortunately,  this  program never had the financial resources necessary to
carry  out  its  original  mandate.    Recent administrations  have shown  little
interest in spending additional  money on  the  project,  and  there has not been a
large outcry  from the public to revive this initiative.  Nevertheless, the wave



of concern for the environment sweeping across Europe is beginning to be felt in
Greece, and the protection of our coastal heritage is an obvious priority.

     Clearly,  any new  national  research, planning,  or management efforts  to
protect the coastal1 environment  should  estimate the likely impacts of sea level
rise; calculate the  costs of alternative response  strategies  such as retreat and
holding back the sea;  and  compare  costs  for alternative policy implementation
dates between today  and 2020, particularly in the  case of land-use restrictions.
Such an assessment will require  a technical panel  including coastal  geologists,
engineers, planners, economists, and public works officials.

     In the narrow sense, we can afford  to ignore  accelerated sea level rise for
a while, because the consequences are a few decades away, and a culture that has
survived as long as  ours is hardly likely to perish at the hands of a changing
climate.  But, by the same  token, since we know that there will be a Greece for
centuries to come,  is it proper to ignore the adverse impacts that  our actions
today  may  bequeath to  future  generations?    Compared  with  the  potential
environmental, cultural, and economic losses that  could result from a rise in sea
level, the cost of developing a national  response strategy would be small.

                            AND TSUNAMIS IN GREECE

     The general  characteristic of the geographical  distribution of mean monthly
temperatures is a decrease with higher latitudes.  July and August are exceptions
because  they  present great  temperature  homogeneity.   Generally,  the western
coasts of Greece are a little warmer than the eastern coasts during the winter
months.  The opposite  is true during the summer  months.   Both the temperature
difference and the summer duration increase  with  higher latitudes.  The eastern
coasts experience a more continental climate.

     The  precipitation  system   that  prevails   all  over  Greece  is  of  the
Mediterranean  type  and  is  characterized by  winter precipitation  and  summer
drought (Table A-l).  During the warm period  of the year, rainfall increases from
south to north  because of the increasing continental ity of the climate.  The mean
annual precipitation is 706.8 mm.

        Table A-l.  Mean Monthly Precipitation in Greece (mm)

           Month        Amount              Month   Amount
     The maximum 24-hour period precipitation occurs  during  autumn and winter
months and rarely during the remaining months of the year,  e.g., Lefkas 248.0 mm
in November,  and Rodos  320  mm in January.   The  largest  number of   days  of
precipitation are observed during the month of January.

     The greatest snowfall  occurs  in January and February, followed by December
and March. The mean number of days with snow increases  with increasing latitude,
distance from the sea, and from west to east.

     When a low-pressure storm arrives from the west,  the weather over Greece
becomes cloudy with a tendency  toward  rain  and storms  over the Aegean Sea while
wind intensity abates.   Finally, storms from the south  occur when  a low pressure
from the west passes over the Balkan Peninsula,  north  of the Aegean Sea.



     In general,  the  most  prevalent winds blow from the northern quadrant.  The
highest wind speeds occur  in the open seas,  mostly in  the central Aegean Sea, in
the Ionian sea,  and between Crete and Peloponnessos.   In the summer, the Etesian
winds blow from the north.

     The direction, intensity,  and duration of the winds,  along with the fetch
length, determines the height of waves.  The general circulation of winds in the
Greek seas depends on the distribution of the atmospheric pressure,  which is
affected to a great  extent by  the  local  influences of the distribution of the
seas and the uneven setting of the mountain masses.

     In winter,  we have northerly winds,  which are the result of high-pressure
cells covering the Balkans and northern Russia. These winds become very intense
if a storm occurs over Greece when cyclonic depressions move over or move north
of the Greek seas.  This results in very intense  southerly winds.

     In summer, the prevailing winds over the Greek seas are northerlies, called
Etesian.  They are  seasonally very constant,  being  northernly and northeasternly
in  the  Aegean and northwesternly in  the  Ionian and  western  Greece.   Their
dominance is  interrupted  in fall when  southerly winds start  becoming  more and
more frequent, thus keeping coastal temperatures high  long  after summer is over.

     The temperature  of the  surface  of the  Greek  seas presents  a normal  annual
fluctuation with a minimum in February and a maximum in August  (Figure A-l).  The
annual temperature range  of the  surface water  fluctuates  between  9.8C in the
south Aegean Sea and  11.5C in the north Aegean Sea.   The warmest seas of Greece
are found in the north Aegean and the Ionian Seas all year round.

     According to observations by the Hydrographic Service of Greece, the highest
mean annual sea  surface temperature  is located around Rodos (19.7C)  and the
lowest near Alexandroupolis (15.5C).


     The currents  in  Greece are of three types:

        Local  currents,
        Tidal  currents,  and
        General currents of the open sea.

     Local currents are directly dependent on the configuration of coasts, depth,
the bottom relief, and the direction and intensity of winds.

     The main  tidal currents occur at the Strait of Evripos, the Corinth Canal,
the Strait of Lefkas,  at  the  entrance of Amvrakikos  gulf, and  at Rio-Antirio

Figure A-l.   Mean monthly sea surface temperatures (C)  of the Greek seas,


     The open sea currents generally follow an  east-west direction.  The current
originating from the Black Sea determines the motion of the north Aegean currents
giving a general east-west direction  and a north-south direction in the western
Aegean.  The Black Sea current,  as  it comes out of the Dardanelles, has a speed
of up to 2.5 knots and is directed to the south.

     In the central  Aegean,  there  is  an anticlockwise motion,  while  in  the
southern Aegean there  is  a clockwise movement around the island of Crete.  Along
the east Aegean,  there is a south to  north  current.   In the  Ionian  sea,  the
general motion  of the currents is from south to north except near Kerkyra (Corfu)
and Lefkas, where the current near the coast runs from north to south.

     Most stations use automatic tide gauges,  and the remainder use tide poles
(Table A-2).
                      Table A-2.  Tide Stations  in Greece
Iraki ion*
Sal amis
Pi reefs*

Souda (Khania)*
Styl i s
Khalkis (north)*
Khalkis (south)*

Note:   Stations  with  a cross use  automatic  tide gauges; all others  use tide
poles.  Stations 4 and 11 have been discontinued.  Source:   Zoi-Morou (1981).
     During  their installation,  the leveling of the stations  is  linked to the
national geodetic system of the  country by the Greek Army Geographical Service.
It is possible to divide the Greek seas into three large areas (Table A-3).

     1.   The north  Aegean Sea  with  tidal  ranges  between  0.11  and  0.25 m;
     2.   The south  Aegean Sea  with  tidal  ranges  between  0.05  and  0.08 m;  and
     3.   The Ionian Sea with tidal  ranges between  0.05 and  0.18 m.

     Tsunamis  in Greece  are rare.   Their zones of  origin coincide  with  the
seismogenic zones of  the  external  island arc of the Greek microplate (Ionian



islands, Crete, Rodos)  as well as with the internal volcanic arc (Corinth-Megara,
Aegina, Milos, Santorini, Nisyros, Kos).

     Along these zones there occur numerous  earthquakes  which  every few years
reach an intensity of *6 on the Richter scale.  Owing to the highly  irregular sea
bottom  terrain,   there is  a possibility  of submarine  landslides  which  can
sometimes produce tsunamis.

     The tsunamis have not  been systematically  studied  in  Greece.   The first
study  was  done   in  1956  by seismologist  Galanopoulos  when   a  tsunami-like
phenomenon occurred  in the southeastern Cyclades, following a great earthquake
on July 9,  1956  (36.9N,  26 E,  H = 03:11:38, M  = 7.5).   The tsunami owed its
genesis to a submarine  landslide on the steep slopes  of the southeastern shores

Table A-3.  Maximum,  Mean, and Minimum Tidal Ranges (in Meters) at Tide Stations
            in the Ionian and Aegean Seas
Maximum Range     Mean Range
              Minimum Range
Ionian Sea



South Aegean
Khania (Souda)

North Aegean
Source:  Zoi-Morou (1981).
of Amorgos Island (36.8N, 26.2E).  The  seismic  sea  wave  caused sea level  to
fall up to 3 meters and rise 2.5 meters.  The wave train affected  almost all the
harbors of the south Aegean.   Galanopoulos  prepared a map  with  the sources  of
known tsunamis which  proved to  be destructive in historical  times (Figure A-2).

      A second tsunami was generated by an  earth  slump,  set  in  motion without
shock,  in  the area  of Aegion  in  northwestern  Peloponnessos  when  a  massive


slumping, estimated to have a mass of 57,000 cubic meters,  subsided 5-44 meters
below the sea  level  and the coastline  in  some  parts receded up  to  500 meters
inland (Comninakis et  al.,  1964).   Even though there was  no  earthquake at the
moment, the  slump  occurred (7 February  1963),  it was preceded by  seven local
earthquakes west of Aegion on 2  February 1963.
             Earthquakes accompanied
Figure A-2.  Sources of tsunamis that have affected the coasts of Greece from 479
B.C. to A.D. 1956.

Comninakis, P., N. Delibasis, and A. Galanopoulos.   1964.  A tsumami  generated
by an earth  slump set in motion without  shock.   Annales Geologiques  des pays
Helleniques 16:  93-110  (in Greek).


Dagre, D., and Lambrou, D.  1981.   Study  of the legislation about "aegialos" and
"paralia."  Athens:  Technical Chamber of Commerce, (in Greek).

Galanopoulos, A.G.   1957.    The  Seismic sea wave  of  July 9,  1956.   Praktika
Akadimias Athinon 32:  90-101 (in Greek).

Galanopoulos, A.G.    1960.   Tsunamis observed  on the  coasts of  Greece from
Antiquity to present time.   Annali di Geofisica, 13 (3-4):  369-386.

Hydrographic Service.  PILOT (Ploigos),  Athens (in Greek).
      Volume A.   Western coasts of Greece 1971,  with announcements in 1983 and
      Volume B.   Southern coasts of Greece 1976.
      Volume C.   Northeastern coasts  of  Greece 1947, with announcements in 1983
                 and 1987.
      Volume D.   Northern and eastern coasts of Greece, 1987.

Kamkhis, M.   1981.  The development and protection of the coastal zone in Greece.
Proceedings of the Conference on the Development (Growth) of Greece, Athens, III.
pp. 152-156.

Kotini-Zabaka.   1983.   Contribution  to  the Study of the  Climate  of Greece by
month.  Doctoral dissertation. Thessaloniki, Greece: University of Thessaloniki
(in Greek).

Maroukian, H. 1989.   Sea level in the past,  present and  future.  Proceedings of
the First Panhellenic Geographical Conference, 2, 1987, Athens.

Ministry of the  Environment, Physical Planning,  and Public Works.   Program for
the delineation  of wetlands of the RAMSAR agreement.   1986.   Athens:  Ministry
of the Environment, Physical Planning,  and Public Works (in Greek).

        i.  Evros delta
       ii.  Lake Mitrikou
      iii.  Lake Vistonida-Porto Lagos
       iv.  Axios-Loudias-Aliakmon delta
        v.  Nestos delta
       vi.  Kotyhi lagoon
      vii.  Messologi lagoon
    viii.   Amvrakikos gulf

Moutzouris,  C.,  and Maroukian, H.  1988.   Greece.   In: Artificial Structures and
Shorelines.   H.J. Walker ed.  New York:   Academic Publishers, pp.  207-215.

National Statistical  Service of Greece.   1982.   Actual population  of Greece
according to the April  5, 1981 census, Athens:  National Statistical Service of
Greece (in Greek and French).

Zoi-Morou, A.  1981.   Tide  data of Greek harbors.  Oceanographic  Study no. 13,
Athens:  Hydrographic Service (in Greek).



                           PROF. DR.  OGUZ  EROL
              Institute of  Marine Sciences  and Geography
                     University  of Istanbul,  Turkey

     The low coastal  belt of Turkey is occupied by intensive agricultural  land
use, and most of the cities, towns, and villages are found  along  the  lowland
coasts.  But most of the population  is settled on the high cliff sections of the
coast.   The ports are principally established at a point where the stretches of
sedimentary coastline meet the relatively higher bedrock ground.  Some parts of
the  harbor  cities  and  industrial establishments have  extended  onto the  low
coastal plains, especially during recent years.  Because they are not wide areas,
these parts may be subject to disruption as sea level rises.  Artificial  coastal
protection is not present along this  low coastline because  there  is  mainly no
need for it at present.

     The common  assumption  in Turkey that  sea level is  constant  is not  shared
by the  scientists, and  for good reason.   The  Turkish  shores have fluctuated
several times during  the Holocene,  and  sea level  has  been  rising  at  least  for
the  past  4,000 years.    But  because  the rising sea  has  been  balanced by
sedimentation and tectonic uplift,  for most  practical  purposes  it  has  been
reasonable to assume that sea level is constant.  But if global warming  is likely
to cause a 50- to 100-cm rise in the next century, the time is now to  recognize
this issue in the coastal  decisionmaking  process.   In Turkey,  some government
offices are  responsible  for  planning  and  construction  of harbors  and other
coastal  establishments.    Some  municipalities  of coastal  cities  are  also
responsible for managing low coastal plains, but none of them is yet dealing  with
a future sea level  rise.   Will  it take  a dramatic  event to  draw  the  attention
of policymakers,  or can  they respond to scientific information?


     When  one asks "What will happen on the Turkish coastline if  the  sea level
rises?", the  answer at  first seems  simple:   not much,  because the  Anatolian
Peninsula is a tectonically uprising block,  and, except  in  the deltaic  areas,
there  are  no extensive  lowland areas  around  it.   But  if sea  level  rise
accelerates, the hidden  dangers will emerge. Because tides and storms are small,



many coastal establishments and settlements have been built within 2 meters of
sea level and  will  eventually be inundated unless dikes are  built.   But many
fishing villages,  such as Meset Limani illustrated in  Figure 1, could not afford
dikes, and an inland migration would not be feasible if traditional activities
were to continue.

     In the  past,  the main  causes  of shoreline  changes  have been  sea level
fluctuations due  to  tectonic  uplift and  subsidence,  alluviation,  and human
activities (Erol,  1983, 1988).  The most important recent changes have been in
deltas (Erol, 1983;  Bird, 1985), which in some cases have advanced 40 kilometers
seaward  (Erol,  1976).  Because  of  changes in river courses,  Ephesus,  Priene
Miletus,  Kaunos,    and  many  other   ancient   harbors   have  been  abandoned.
Nevertheless, tectonic uplift -- often associated with earthquakes'--^has also
been important in some cases.  For example,  the city of Seleukeia Pieria'in Hatay
was completely abandoned after Byzantine times  (Erol,  1963; Pirazzoli  et al.,

     No one  has assessed  the impacts of  a 50-  to  200-cm  rise  in  sea  level.
Nevertheless, a number of expectations seem  reasonable.  First, in  the high rocky
cliff coasts, the  rising sea level will not  cause great  changes or shifts of the
coastline,  but  the rate of cliff recession  will accelerate, increasing  the
frequency and extent of landslides and destroying portions of many coastal roads.
Second, along low,  eroding,  soil cliffs,  there may not be immediate changes, but
erosion  will eventually  result.   Because  these areas  are already  densely
populated narrow terrace strips, displacement of destroyed coastal establishments
will  become  a  serious problem,  and  protecting  them  from  the sea  will  cause
erosion elsewhere.   Finally,  along deltaic coasts that are advancing seaward
today, rising sea  level will reverse the  shoreline change, and coasts will begin
to retreat.   The geomorphological result  of  this will be a thick alluviation that
may bury relatively new deltaic soils and perhaps interrupt agricultural activity
on the deltaic plain  as much as droughts do today.

     Many coastal establishments would be displaced as a result of these changes.
In  the high rock  cliff  areas,  the increased  activity  will   influence  the
settlement points,  roads, etc.   Since the  places at  the  top of the cliffs are
already  scarce,  rebuilding  settlements  elsewhere  will  be  difficult  if  not
impossible.     In   the narrow  strip  of low  soil-cliff   terrace  areas,  the
displacement of ruined coastal establishments, especially tourist places, will
be several times more expensive.   In  the low deltaic areas, which are already
overcrowded,  displacing  the  populations  may   be   politically  impossible,
necessitating expensive coastal  protection.  Even where it  is feasible, it will
encroach upon important agricultural  areas,  which is already happening  due to
population growth.  In Turkey, the art of life may have to change.

     Many cultural  sites would also be at risk.  Besides the modern settlements,
most of the  ancient harbors  and  cities would  be  covered  by seawater.   Because
of sedimentation,  they would be  buried,  and access to these  ruins would be much
more difficult.   Some of  them would be destroyed  by increased wave activity.
Because of their great number, moving the ruins would  be practically impossible,
and in any event,  it would change their  character.


                                                                          fro 7
Figure 1.  A typical Turkish fishing town.  While towns like this clearly lack
the resources to hold back the sea, retreat is not a viable option either.

     In Turkey,  the State  general  directorates  and  offices  responsible for
planning and constructing airports and  harbors are connected to the Ministry of
Construction and Settlements.   In  addition  to these General  Directorates, the
State  Planning Department  and  some municipalities of the  coastal  cities have
interests in the low coastal belt of Turkey.

     None of these agencies is dealing yet with the issues and problems that will
accompany future sea level rise.  When asked about the problem, they generally
minimize  its  significance.    Even  coastal  engineers,  who would seem  more
predisposed  to  incorporate  technical  information,   are  designing  coastal
establishments without regard for future changes.

     In the  Turkish  law for coastal protection,  sea  level is accepted  as  an
"unchanging" boundary between  the  land and sea.  Even  without the greenhouse
effect, we know that such a definition is technically inaccurate, but in the past
it has not  mattered as  other processes offset  rising  sea level.   But  in the
future, keeping  this  definition in  our  coastal  policy will yield irrational
results, as the United States and other countries with higher current rates of
relative sea level  rise have already seen (Titus et al., 1985).

     The remainder of this paper summarizes the  natural  environment of Turkey
and human activities along its coasts.




Climate and Waves

     Turkey lies between the middle latitudes and the Mediterranean macroclimatic
zones and has a transitional  character.  The climate of the Black Sea is mainly
under the influence of northerly winds that usually blow as gales.   Because of
the long fetch of the Black  Sea  and  the absence of  intervening islands, large
waves strike  the  shore;  hence high  coastal cliffs and shingle beaches at the
mouths of short mountain rivers are eroding.  Details of wave heights and water
temperatures are in Appendix 1.

Coastal  Geomorphology

     The  coast of  Turkey  has  developed  under the  influence  of   (1)  the
geomorphology  of  the  mainland  --  that  is of the Anatolian Peninsula  and
especially of the  North Anatolian and Taurus folded mountain chains and  the belt
of faulted  central  plateaus; and (2) the  submarine  relief of  the  sea basins
surrounding the peninsula.   The  coastline  of Turkey may  be  divided  into three
main groups:  (1) retreating cliffed coastlines on rocky  and soil material (5,752
km),  (2) advancing sandy depositional soil  (1,546 km), and  (3) advancing, partly
swampy deltaic soils (1,035 km).

High Rocky Cliff Coastlines

     High rocky  cliffs  are  found mainly  on  the north  and   south  Anatolian
coastlines, which  run parallel  to  the folded  mountain  chains.   There  are,
however, some shorter stretches of similar  coastline on the faultline coasts of
the Aegean and Marmara Seas.   This type of high rocky  cliff rises  sometimes a
hundred meters above the  sea.  These cliffs are  interrupted by river mouths with
limited shingle beaches  on  the north and  south Anatolian coastlines.   On the
Aegean coastline,  on the other hand,  the rocky cliff coasts of fault mountains
are relatively short and are interrupted by several  deltas.

     Generally, the  high  rocky cliff  coasts are  slowly eroding.  At the foot of
the cliffs, the coastal  platform is  usually very narrow or absent.   Therefore,
building highways  along  the coastline is extremely difficult, and the roads are
located on  the top  of the cliffs if possible.   Because  of the humid  climate
during all seasons of the year, landslides are common on  the Black Sea coastal
strip.  However, because of the minor drop in sea level  following  the Climatic
Optimum of the middle Holocene,  narrow sandy beaches have developed at the foot
of these cliffs.  In  the  event of a future sea  level rise, these  narrow sandy
beaches will  be covered  by  water again,  exposing cliffs  to waves,  which will
accelerate their erosion.

The Low Soil Cliff Coastlines

     Low (2-meter  elevation)  and  medium-high (10- to 20-meter elevation) cliffs
composed of soft sediment are  found  at the base of many  Pleistocene terraces.
For the most part, the coastal belt  is a  narrow strip  between  the  sea  and the


                                                                          Fro 7

mountains.  Because these coastal  belts have been  ideal for settlement, tourist
and industrial establishments, and road construction, they are densely populated.
Although this  narrow strip has a few meters of relief, the increasing exposure
to waves will cause erosion,  and shorefront establishments will  be ruined at an
increasing rate.

The Low Unconsolidated Coastlines

     These low stretches  are  found  especially  on  the deltaic coastlines. They
include wide sandy beaches, beach rock, lagoons, tidal flats,  and coastal dunes.
Because  rivers  are  supplying  large   amounts  of  sediment,  these shores  are
advancing into the sea today.  Accelerated sea level rise,  however, would reverse
this process.

     Especially on the north  and  south Anatolian  coastline,  the small deltaic
unconsolidated coastlines consist mainly of gravel  and shingle beaches.   This
is  the result  of the  influence  of  the strong  waves and  coastal  currents.
Although  there  are  no barrier  islands  in  Turkey,  some  coastal spits  have
developed at the mouths of rivers  and  bays;  some have  formed  along the foots of
cliffed coasts.   These low areas  are very vulnerable to both inundation and
erosion due to sea level rise.

Coastal Dunes, Wetlands, and Lagoons

     Turkey has well-developed coastal dunes, especially along the western Black
Sea coast and in  the deltas of the Aegean and Mediterranean Seas.  These natural
barriers to storms would  provide  some defense  against the  consequences of sea
level  rise,  at least  in the  short  run.   Elsewhere,  beach  rock has  developed
along numerous low soil cliffs.

     Wetlands are mostly confined  to relatively narrow areas  in the Kizilirmak,
Yesilirmak, Seyhan, and Ceyhan Deltas and in other  low coastal reaches along the
Aegean Sea, most  of which are associated with lagoons.  There  are no coral reefs,
mangroves, or  saltmarshes in Turkey.

     Lagoons are found mainly behind the coastal  spits of the deltaic areas of
Turkey.  There are, however,  lagoons in some inlets with high-  and low-cliffed
coasts, too.  The lagoons  of  the Turkish  coastline are used partly as salt pans
and  fish  ponds.    The former  lagoons of  Kucukcekmece and  Buyukcekmece  have
recently been converted to water reservoirs for the city of Istanbul.

     Genuine tidal estuaries  are  not  found in Turkey, although some ria-type
inlets are present.  The ancient harbor of Istanbul, which  is called  Halic,  is
an example of this type of ria.


     Recent sea level  changes  have played a very  important  role in the coastal
geomorphology of Turkey.   The  influence of young tectonic subsidence and uplift



phenomena are observed at several points of the coastline.  Alluviation, deltaic
subsidence, and climate changes  must be added to this group.   These kinds of
coastal processes are controlling the prograding and retrograding stretches of
the coastline.

     Finding some unchanging coastline  stretch  in Turkey  is  really difficult.
Generally, the upper  Pleistocene  (Tyrrhenian)  terraces with  their fossils are
less than about 250,000 years old, and they are found at  elevations between 10
and 80  meters  in  different coastal  places.   Some coastal terraces  and their
fossils at about 6 to 10 meters must belong to the last interglacial  period --
that is, about 100,000 years ago.  Moreover, on the recent coastline of Turkey,
except  prograding  deltaic  coastline stretches,  there  are traces  of elevated
former sea levels  of 200 cm (about 6,000-8,000 years ago), 100 cm (about 2,000-
2,500 years ago), and  50 cm (about 1,400 years ago) (Kayan et al., 1983; Laborel,
1989; Pirazzoli et al., 1989).   If  we  reconstruct these  former traces,  we may
determine  what  will   happen  in  the  future.   These  kinds  of studies must be
extended for all the Turkish coastline.


     Most of Turkey's  population  of 50 million  is  well  out of danger  from a
rising sea.  Of the 399 cities and  towns in Turkey, more than half the population
lives less than  100 meters above sea level.  Unfortunately, the lack of vertical
resolution on topographic maps makes  it  impossible  to estimate  the  portion of
the population that lives within a few meters of sea level.


     During ancient times, there were several harbors and cities on the coastline
of Turkey, generally at the point where the main trade ways of the country ended,
usually on a deltaic  plain  next to a low soil-cliff  (Erol,  1976,  1983, 1989;
Akurgal,  1970).   The presence of lagoons facilitated  the establishment  of
primitive landing places that were  later  converted  to harbors.   Many of these
harbors and cities had to be  abandoned because  deltaic alluviation,  sea level
changes,  earthquakes,  and tectonic uplift shifted  the  shorelines  (c.f. Erol,
1963, 1983; Kraft et al., 1977, 1980a,b,  1982; Kayan, 1981,  1987).

     In modern  times,  the ports  have expanded  and situated on much  broader
grounds.  In addition to the historical ports, several smaller fishing harbors
and shelters with breakwaters have  been  built.   According to  Erol  (1988), the
total number of the artificial structures of Turkey is as follows:

            Large commercial  harbors             12
            Small harbors                       115
            Shelters with breakwaters             9
            Abandoned ancient harbors            44
            Major coastal protection works        6


                                                                          Fro 7

     In the  building  of all  these coastal  establishments,  unfortunately,  sea
level and other environmental conditions are assumed to be constant.   In reality,
even some of the new harbors  have been  destroyed or covered by sediments, often
within a period less than 10 years. Warning  the policy makers in Turkey has been
extremely difficult.   In some  cases,  sea  level  rise  may help to  offset  the
sedimentation processes that  have forced port abandonments. However, this would
be merely a  fortuitous coincidence.

Other Land Uses

     The coastal zone has Turkey's most fertile agricultural  lands and a mild,
humid climate.  In recent times, coastal tourism and yachting have experienced
explosive growth.   The tourist establishments were first built on  the narrow
beach strip, but now they are backing up to the country's most valuable inland
agricultural fields.  The land has also been expanded  toward the sea with walls,
embankments, quays, etc.  But as noted  previously, the coastal lowland strip of
Turkey is narrow at the base of  inland mountains.   A rise in sea level would
force the nation  either to give up agricultural  lands  to facilitate landward
resettlements or to spend large  amounts of money on erecting coastal defenses.


     Fishing has been  an attractive livelihood  for the people who have lived on
the Turkish Mediterranean coastline since historic and even prehistoric times.
For example, in 1923,  there were about  30  fish  ponds on the Anatolian coastline
with a yearly production of 9,000 tons of fish products.  However, in the area
of the Marmara  Sea and Straits,  the local character of fishing developed somewhat
differently.  This is  because fish from the Black Sea migrate toward the Marmara
and Aegean  Seas during the autumn and winter months, as  the  Black  Sea waters
become cooler.  In the  early years, the migrating  fish  were  staying partly in
the Marmara Sea during the winter season.  But in recent years, because of water
pollution and other hostile conditions, they prefer to continue their migration
to the north Aegean Sea.  Those  fish return to the Black Sea during spring and
summer seasons.   So fishermen  are following the  fish and are  catching them,
especially in the Anatolian coastal waters of the Black Sea, at the entrance of
the  Bosphorus,  and   in  the  Marmara   and  north  Aegean  Seas.    Under  these
circumstances, fish production has increased yearly from 79,000 tons (1952) to
532,000  tons (1985).    The percentage  of  this production  is distributed  as
             Black Sea                          80
             Marmara Sea and Straits            12
             Aegean Sea                          5
             Mediterranean Sea                   3

     Climate change could affect the fisheries  in many  ways.   Although Turkey
does not have extensive wetlands, many of the  fish  caught  there spend part of
their  lifetimes  in the marshes  found elsewhere.   Warmer  temperatures  could
encourage some of the fish that migrate out  of the Black Sea during the winter
to remain there longer.  On  the  other  hand,  warmer  temperatures might amplify



pollution  problems.    The  unknown   impact  of  global  warming  on  seasonal
precipitation, river flow patterns, and currents also could be important.


     An evaluation  of  the  implications for Turkey  leads one to  realize that
worldwide, sea level rise would be a  serious problem.   Turkey would appear to
be one of the countries least vulnerable; yet even here, the consequences could
be severe.

     Clearly, policy makers need to take sea level  rise into account.  Even in
the short run, doing so would help  to ensure that new development is consistent
with current  environmental  changes.    In  the long  run,  it is  important both
because our  valuable coastal strip is  very  narrow  and because it  would help
introduce policy makers to the other consequences of  the greenhouse effect, such
as  hotter summers  and  more droughts,  which   in  Turkey  could  be far  more

                                                                          fro 7


     The climate conditions that control  the recent phenomena are determined by
the main physiographic features.  The country lies between the middle latitude
and Mediterranean  macroclimatic zones  and has a  transitional  character.   The
Middle European and Mediterranean climates alternatively dominate in the Black
Sea region, whereas only the Mediterranean climate dominates  south of the Taurus
Mountains  and in the Aegean Sea region.   The  climate  of the Marmara region is
transitional between the Black Sea and Mediterranean types.  In  the central part
of the  Anatolian  Peninsula, which  is  between the North  Anatolian  and Taurus
Mountains, a continental plateau type of Mediterranean climate is characteristic.
The types  of coastal regions found in Turkey are shown in Figure A-l.

Black Sea

     The climate of the Black  Sea coast  of Turkey  is mainly under the influence
of northerly winds  (air masses)  that usually blow as gales  called Karayel (black
winds) in  Turkish.   Because of the long fetch (i.e.,  distance over which waves
can form)  in the  Black Sea  and  the  absence of islands along this  somewhat
straight coastline, the wave energy is considerable.  Thus, rapidly retrograding
high coastal cliffs and shingle beaches  at the north of  the short mountain rivers
are predominant  along this  coastline.  The sandy  beaches  and their related dunes
are also developed under the influence of these  strong northerly winds.

     The heavy rainstorms  and  strong northerly winds  that dominate  the winter
climate  (temperature 0 to  7C) of the Turkish Black  Sea  coasts yield  to mild
winds during the summer.  Except for some rare winds in the eastern part of the
coastline, the influence of the southerly winds  is extremely rare in the Black
Sea coastal strip of Turkey.  Therefore, the summers  are  also  mild (19 to 23C),
cloudy, and rainy in this area.  The temperature  of the seawater is cool (15 to
16C), and the surface of the Black Sea is mainly rough.

Marmara Region

     The North Anatolian Mountain chain  usually prevents the penetration of the
marine climate  influences  inlandthat  is  toward the main  plateau  of  Central
Anatolia, especially in the middle and eastern parts  of the country.  But in the
west,  toward the Marmara Region, the climatic influence  of the northerly winds
and air masses can  easily  penetrate to  the  south during  the winter  and summer
seasons. But usually these  northerly weather conditions alternate with southerly
conditions.   In  Istanbul,  for  example,  the southerly gales  alternating  with
northerly winds  have an important effect.  The Maramara  Region with  cold (1 to
6C)  rainy winters  and cool (22 to 23C), windy  summers  is a transitional  area
between  the Black  Sea  and  the Mediterranean  environments.   These  climate
characteristics  as  well as  sea currents  in the straits are also controlling the
physical properties of the water masses in the Marmara Sea.

                                                           Mountain ridges
                                                           Deltaic  areas
Figure A-l.  Types of coastal  regions of Turkey: (1) Black Sea type; (2) Maramara
type; (3) Aegean type; and (4) Mediterranean type.

Aegean Sea

     The climate  in the Aegean Sea is a transitional blend of the climate between
the Black Sea and the Mediterranean Sea.   But  there  the Mediterranean climate
dominates mainly during the  summer, whereas  the  Black Sea conditions dominate
during the winter in the Marmara region.   However,  because of the northerly cool
to warm (26  to 28C) summer winds in the  Aegean  Sea, the  summers are cooler than
the eastern Mediterranean area,  and this  climate  characteristic  also controls
the summer seawater temperatures (16 to  19C) of the  Aegean Sea.

     Along  the   Mediterranean   coast  of  Turkey,  the  Mediterranean  climate
dominates.   Warm  (24  to 29C),  dry,   and  calm  weather conditions  are  very
conducive to the development of  biogenetic coastal forms as well  as dunes and
beach rock.  The  rainy, cool to warm (9 to 11C) winters  and wave activity cause
the formation of wide, sandy beaches.   The excessive  summer evaporation causes
cementation  in the beach sands or calcite concentrations in the coastal to inland
soils.  Investigations have shown that similar conditions were prevalent in this
part of the  coastline  during  the Holocene  and even during the upper Pleistocene
(Erol, 1983; Kayan et al., 1983; Laborel, 1989).

                                                                          fro 7

Marine Hydrology

Water Masses

     The Black Sea in the north and the eastern Mediterranean in the south are
Turkey's two main sources of water masses.   The  water masses originating from
the Mediterranean Sea are principally  warm  (21.54C  on  the  surface) with high
salinity (39.15 parts per thousand),  and the water masses in the Black Sea are
cool (8 to 15C on the surface)  with  low salinity  (18.36%).   In the area of the
Marmara Sea and Straits, there are transitional  conditions between the Black Sea
and Mediterranean masses.  Indeed, the warm and  saline Mediterranean water flows
on the  surface along the Anatolian  coast  toward  the north  in  the  Aegean Sea
(Figure 3)  and meets the  cool  and  less  saline  Black  Sea  water.    There the
lighter, less saline Black Sea  water  flows on the surface toward the south, and
relatively heavy saline Mediterranean water flows under it toward the north into
the Dardanelles Strait.   These  layered  surface  and deep-water masses also occur
in the Marmara Sea and Bosphorus Strait.

     The mean surface temperature in  the Marmara Sea is 15 to  17C.o  The surface
temperature of  the  seawater  is  8  to  9C in January  and  24  to  26C  in August.
The salinity of  the  surface  waters  is  23.47%,  and that  of  the  deep waters  is

     The characteristics of deep seawaters are also  influenced  by  the surface
conditions.  In the eastern Mediterranean,  there are four layers of water masses
(Yuce,  1987):    (1)  surface  waters  of Atlantic  origin  (temperature  21.54C,
salinity 39.15%);  (2)  intermediate  eastern Mediterranean waters  (temperature
15.5C, salinity 39.15%); (3) deep water (temperature 12.6C, salinity 38.4%);
and (4) Bottom water.

     In the Black Sea, there are three layers of water masses:  (1) surface water
in the upper 200 m (temperature 8 to 15C,  salinity  18%);  (2) transitional water
layer; and (3) deep water (temperature 9C,  salinity 22.5%).

     The surface temperatures drop below the freezing point, especially in the
north and  western coasts  of the  Black Sea, and  ice masses may penetrate through
the Bosphorus to the northern Marmara Sea  (Erinc,  1985).


     The characteristics of  the currents  in the  straits and Marmara  Sea are
principally influenced by the salinity and temperature differences  between the
Black and  Mediterranean Seas.  The water volume  brought by rivers into the Black
Sea Basin  is great,  and because of this,  the surface level of the  Black Sea  is
50 cm  higher than that of the  Marmara Sea.   This  is another reason  for the
currents in the straits.

     The winds are a significant  influence  on  the currents  in  the  Bosphorus.
Normally,  the  surface  current  in  the  Bosphorus  is  from north to south.   Its
velocity is directly under the control  of  the dominant northerly winds, and  it



may reach up to 9-10  km/h.  But it may decrease  or completely disappear when the
southern winds blow persistently for a few days,  especially during the southerly
gales.  In this case, the warm and saline Mediterranean deep water may rise to
the surface.  This kind of unusual sudden change causes mass mortality of fish
that live in the upper, less-saline,  cool waters and also of fish that live in
the deeper, saline, and warm water layers.

     Because of the strong underwater currents,  the bottom of the Bosphorus is
partly bare of fine sediments or is covered in some places by larger particles
of sands and even shells.  The water exchange between the Black and Mediterranean
Seas has been studied by several authors  since the 19th century (e.g., Makarov,
1885; Wharton, 1886;  Ullyott  and  Ilgaz, 1946; Pektas, 1953; Yuce, 1985, 1987b).
The influence of the currents in the area  of the straits and Marmara Sea has also
been discussed by Stanley and Blanpied (1980).  According to these authors, the
sea  level  changes duringi the  late   Holocene  was  the  most important  factor
controlling the currents  in this area.

     In the Marmara Sea,  the surface  currents  are  directed  from the Bosphorus
toward the Dardanelles  Strait with a  maximum speed  of  2.5 km/h,  and a minimum
speed  of  750 m/h  (Figure A-2).    In the Dardanelles  Strait,  similar  to the
Bosphorus, the Black  Sea water flows on the surface  from north to south, and the
Mediterranean water flows as an undercurrent toward the north.   Because of the
strong mixing on the  boundary of these two counter-currents, the salinity of the
surface water increases rapidly here.  It is 18% in  the  north  Marmara Sea, it
becomes 25% in the Dardanelles,  and 37.52% in the north Aegean Sea.  There, the
surface temperature is at  a maximum of 24.11C in August and a minimum of 13.33C
in March.  Toward  the  southern Aegean Sea,  the  surface waters  coming from the
Black Sea gradually disappear.

Dissolved Oxygen

     The amount of  the dissolved oxygen, especially  in the surface water masses,
plays an important role in the  biologic properties of the sea.  The boundary of
this dissolved oxygen surface layer is 150-300 meters in the Black Sea.  Below
this level  is  an  anaerobic (due to high  levels of  H2S) water  body,  as in the
Marmara Sea.  This  deep  layer is not found in the Aegean and Mediterranean Seas.

Wave Conditions

     The wave conditions on the surface of the seas surrounding Turkey is under
the control of wind direction and  its velocity  and  the fetch distances.   But,
since  satisfactory studies on  fetch  are  missing,  only the  conditions  of wave
heights and directions will be explained  here.

     In the  Black Sea, northerly and northwesterly winds are dominant especially
in winter months.   Because the  fetch  distance is great in this direction, waves
are high and they  strongly erode the foot  of high cliffs on the coastline of the
North Anatolian Mountain chain.  The  strong southwesterly winds in the Marmara
Sea blow  sometimes as gales and  they alternate with northern  winds.   In the
Aegean and Mediterranean Seas, the southwesterly winds influence the coastline
during  the  winter, whereas  the  moderate northerly  winds prevail  during the
summer, especially in the Aegean Sea.


                                                                          fro 7
Figure A-2.  Surface currents in the seas surrounding Turkey.
     The height of the waves and related wind directions are as follows:
     Black Sea
     Marmara Sea
     Aegean Sea

 N 3-4
 N 1
SW 3-4
SW 1-2
SW 3-4
SW 3-4

Up to 13 m in winter

Up to 4-6 m in winter

Up to 8-9 m in winter
     The tides and  other  sea level fluctuations  are  small  along  the  Turkish
coastline.   The daily periods of the tides are as follows:


     Black Sea           maximum  10 cm
     Bosphorus           maximum 2.5 cm
     Marmara Sea         maximum 2.5 cm
     Aegean Sea          maximum  30 cm
     Mediterranean Sea   maximum  30 cm
     Izmir Gulf          maximum  50 cm
     Iskenderun Gulf     maximum  50 cm

     The pattern of  storm  surges  (compared to mean sea  level)  are as follows
(Aykulu, 1952):
     Marmara Sea
     Aegean Sea
     Black Sea
maximum 101 cm
maximum 122 cm in Izmir
maximum  65 cm in Eregli
     According  to  historical  records  in  Turkey  and surrounding  countries,
tsunamis and  other  rapid  sea level changes were  frequently  observed (Soysal,
1985).  The waves may not  be very  high,  but they are destructive.  Some of them
may be only storm surges, but the  others must  be  tsunamis.   This kind of wave
was especially destructive at the Izmit Gulf and at the estuary of Istanbul-
Halic Harbor in  the Marmara Sea,  at the Izmir Gulf and Islands  in  the Aegean Sea,
and at the Fethiye Gulf in the Mediterranean Sea.


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                            YURII D.  SHUISKY
                          Geography  Department
                        Odessa State University
                        Ukraine,  270000 U.S.S.R.

     The Union of Soviet Socialist Republics has a larger mainland coastline than
any other nation. However, concerns about global warming have not focused on sea
level rise  as much  as  on  other  implications of global warming.  This relative
emphasis  is reasonable when one realizes  that most of the Pacific, Arctic, and
Baltic coasts are  sparsely developed and  that much  of  this  coastal  area is
currently   experiencing uplift.   Aside  from  Leningrad, the  most  important
exception is probably the  Ukrainian Black Sea coast.  Unlike most other parts of
the U.S.S.R., this is a warm coast with a  low barrier appropriate for tourism and
substantial fishing that  depends on natural systems  that are sensitive to sea

     Because no research has been done on the subject, we are  unable to present
any quantitative estimates of the impacts  of accelerated sea level rise,  and the
lack of policy  assessments makes  it impossible  for us to  discuss  response
strategies.  With those limitations, this paper briefly describes the activities
along the Ukrainian Black  Sea coast that  seem vulnerable to a 50- to 200-cm rise
in sea level, characterizes the coastal  environment, and summarizes  existing
research on sea  level trends and related  coastal processes.  We  hope that this
paper helps to encourage officials in the  Ukrainian Republic to begin considering
the implications of global warming  and sea  level rise.


     The Black Sea coast of the Ukranian Republic is heavily developed and is one
of  the  most  populated coasts  in the  U.S.S.R.    Fortunately,  most   of  the
development  is  concentrated  on  the  highlands.    Nevertheless,  some  coastal
barriers and low terraces  with elevations between  1 and 5 meters  are completely
occupied with buildings, including port facilities, sanatoriums,  holiday homes,
and camping establishments.  The barriers  along the Sukhoy and Adjalyk Lagoons,


for example,  have considerable port facilities.  All  of these economic resources
would be at risk from a 50- to 200-cm rise in sea level.

     The Sasyk Lagoon near the mouth of the Danube has  been transformed into a
freshwater basin, with river water used for  irrigation.  To prevent seawater from
encroaching during heavy storms,  a 12-kilometer-long, 4-kilometer-high dike was
built;  however,  sea  level rise  could  threaten  the  dike unless  additional
protection is constructed.

     Along the Sasyk (near Eupatoria)  and Dniester Lagoon, the coastal barriers
have railroads and  highways.  For almost 40  years,  the  retreating  shores have
created difficulties for these critical  transportation links, especially on the
Dniester barrier.  As a result,  the Dniester barrier has been protected with a
5,000-foot-long  concrete  structure  and rip-rap.  On  some  parts of  the Sasyk
barrier  the  highway has  been  rebuilt  somewhat  inland.   On  the Tiligul  and
Kujalnik barriers,  the  highway  is about 200  meters inland on a dike  with an
elevation of about 5 meters.

     Because the  coastal  barriers are only 1 to 5 meters  above sea level, future
sea level rise threatens  the aquaculture in the lagoons  behind them.  To prevent
problems in the Usunlar, Burnas, and a few other barriers,  the dunes have been
artificially elevated.   Because  the  Shagany,  Alibey, Budaki,  Tiligul,  Usunlar
limans are  important  for fish  breeding, stabilizing barriers in front of the
lagoons is important.

     The natural  conditions of the Black Sea coast encourage erosion and cliff
retreat; average  annual cliff erosion rates  range from 0.1 to 4.5 meters per year
(Shuisky and  Schwartz,  1988).   More  than  half of  all   the  coastal  protection
structures attempt to retain artificial  beaches, mainly groins and breakwaters.
Seawalls are  less  widespread,  and there are very few rip-rap structures.   An
accelerated  rise in  sea  level   would clearly  diminish the effectiveness  of
existing structures, and probably necessitate increased artificial replenishments
of beaches, as has already occurred in other countries.

     The largest  portion  of the shoreline protected from  landslides is along the
Crimea coast, where 50 kilometers (almost 15%  of the coast) -- mainly from Sarych
Cape to Alushta -- is protected  by short concrete groins with artificial gravel
beaches between them.  On the western Crimea coast,  5 kilometers are protected
near Eupatoria, Saky, and Nikolayevka.  Around Skadovsk the shore is protected
by a one-kilometer-long seawall  and  an artificial  beach, and there is a seawall
of about 2  kilometers (concrete and rip-rap groins with an artificial sand beach)
near Port Zhelezny.  All of these structures will  have  to be fortified.

     In a number  of cases, artificial beaches have been used.   The  District of
Ochakov, Koblevo, and along Odessa Bay each have about 2  kilometers of protected
shore (solid concrete and stabilized slopes).   In  the City of Odessa, the shore
is strengthened for 12 kilometers from Langeron Cape to Bolshoy Fountain Cape.
Coastal  protection  structures were  built near  Illichevsk  and on the Dniester
barrier.  All  of  these artificial beaches would require additional fortification
as sea level rise accelerates.



     Neither the U.S.S.R.  nor the Ukraine has a single organization to deal with
research on and exploitation of the natural  and  cultural resources of the Black
Sea  coastal  zone  as  a whole.   Instead,  several  regional  organizations  are
responsible for  part  of the problem, for example, the  Ukrainian Institute of
Communal  Building  (Odessa) in  the  Ukraine,  the Sea  Coast  Protecting Concern
(Krasnodar) and the Sea Hydrotechnical Construction Institute (Sochi) in Russia,
and the Sea Coast Protecting Concern  (Tbilisi) in Georgia.   Some  aid is rendered
by other  organizations,  such as the Sea Institute  in  Odessa,  the  Geological
Station in Yalta, and the  Hydrological  Station in Vilkovo.  Scientific research
is carried  out by  laboratories  and  scientific  groups  in  the  Universities of
Odessa, Rostov, Kuban, Moscow, and Kiev.

      No  administrative  or economic  organization  on the  Black Sea  coast is
concerned with solving the sea level rise problem.  The lack of concern  is caused
by a number of factors, including the following: (1)  the lack of reliable data
about the disastrous effects of the rise on the natural  and cultural  resources
of the Ukranian coast; (2) the relatively low rate of  the rise of the Black Sea;
(3) the economic  system  of the Ukraine, which  does  not encourage  research on
possible future disastrous consequences of the sea level rise;  and (4) the low
prestige  of the  scientists,  whose  opinion  is  usually ignored by state  and
economic institutions.


     The average  air  temperature at the coast  varies  from 9C  in  the Odessa
region to 16C in  the Yalta region.  The mean temperature during the warm season,
which lasts from  April to  October,  is  22-24C.   Maximum temperatures occur in
August when some days reach 30-35C, the absolute maximum being 40C.

     The winter is fairly mild; in January, the average air temperature is
-2.5C  in Odessa  and  about 6.5C in the Yalta  region.   The temperature often
falls below -10C, but rarely  below  -20C.   The absolute minimum is -28C.  A
severe winter happens  once  in 14-15 years, and a warm winter occurs once in 12-13

     Rain and  fog  prevail during the cold half of the year,  and snow falls every
year.   The  precipitation  reaches 300-400  mm  per year  in  the  Odessa  region,
200-300 mm in  the Tarkhankut and Kerch peninsulas, and 500-600 mm  in the southern
coast of the Crimea.

     The Black Sea water  is warm; in the open sea its temperature  is never lower
than 6C, reaching 19C  to 26C in July and August and  up  to  28C  in  shallow
bays.   In the winter,  the  temperature  falls to 2-3C at  the shore;  in narrow
areas along the  shores between the  Danube  delta  and  the Crimea, sea  ice can
appear, on the average, every 3-5 years.  The sea freezes annually only at the
Danube  and Dnieper outfalls,  and in small   bays  (Egorlyk,  Tendra,  Djarylgach,
Perekop, and in the Kerch Strait).




     It  is  known  (Shuisky,   1982)  that  the northern  Black  Sea coasts  are
characterized as classical liman coasts.   Sediments  in  the limans and lagoons
contain  chemical  elements and  organic  salts  that  can be  used  for  medical
treatment.  Deposits of medicinal mud were found in the limans of Burnas, Budaki,
Hadjibey, Mojnacki, Saky, and especially the Kujalnik liman.   Those medicinal
sediments have  led to  the  establishment  of numerous medical  and sanatorium

     The districts  of  the Danube delta, Shagany, Burnas,  Kujalnik, Saky limans,
Yalta, Theodosia, Kerch,  and Skadovsk towns  are the sites  of  mineral water baths.
Their contents are varied including carbonates,  hydrocarbonates, potassium and
sodium, sodium and  magnesium, and chalybeate waters.   These  deposits, too, serve
as the basis for many medical institutions.

     The Black Sea coast within the Ukraine  borders  also contains deposits of
certain nonmetallic minerals,  such as building stone,  sand,  gravel, pebbles, and
sedimentary ores.   The largest deposits are located near the Danube delta, near
Odessa  city,  Sevastopol  and  Theodosia  towns (building  stone and  raw cement
materials),  on the  shores of the Jebrijan cove and  Dnieper,  and  the Sasyk limans
(sand and shells).

     Among  the  natural   resources  of  the  Black  Sea  coast,   the  recreational
resources are the most important.  Warm water  and a long warm season are the main
factors that make  the  Black  Sea a popular tourism and  recreational  area.   In
addition, coastal sediments contain important  deposits used for medical purposes.

      Sand  and pebble sediment exploitation  (removal) is forbidden within the
coastal zone.  The nearshore  zone  is  the traditional  location for the fishery
industry.   It is  most  intensive in  the Danube,  Dniester, Dnieper outfalls,
Karkinit  and Kalamit  Bays,   and  Kerok  Strait.    The  biggest   seaports  are
Illichevsk,  Sevastopol,  and  Kerch.   Fish-breeding  farms  are  situated  on the
shores of the Sasyk,  Shagany, Budaki,  and Tiligul  limans.

     There  are many nature  reserves on  the  Ukranian Black Sea coast.   Their
purpose is to save the gene banks and  protect flora and  fauna.  The largest of
them, the Danube reservation,  is situated in the Danube outfall. It is oriented
to ornithology and  botany, as well as research on freshwater fish.   In addition,
there are important bird reservations in  Chernomorsky  (in Egorlyk and Tendra
Bays) and Lebiashiy (on  Lebiazhiy isles), and the  Kalanchak Isles  in Djarylgach
Bay were declared reserve areas.  The Martian Cape  reserve on the southern coast
of the  Crimea Seas has  a botanic orientation.   The  Kara-Dag  reserve protects
volcanic landscapes and  relief shapes, and also the  precious  and semiprecious
mineral and rock deposits.



     There is a general awareness that the Black Sea has been rising for at least
the past 200 years.  This phenomenon was discovered by instrumented
measurements at many locations  in the U.S.S.R. and in other countries (Bulgaria,
Romania, Turkey) on the Black Sea.

     Although the measurements  of the sea level changes began in Odessa in 1803,
the first gauging rods turned out to be unreliable, and the data from  1870 are
now  the  earliest  used.    In   that  year,  controlled gauging   stations  were
established in Odessa, Ochakov, Sevastopol, and Poti,  which are now sources of
precise data about the changing level.   During 1916-23, measurements were begun
in other places, generally in seaports.  The data from those observations have
been  analyzed   by  many   researchers   (Blagovolin  and   Pobedonostzv,  1973;
Pobedonostzv, 1972).

     The direct observations with gauging staffs indicate  a  relative rise of sea
level.  On the  Black Sea coast it consists of the two constituent phenomena:  (1)
the  eustatic  rise  and  (2)  tectonic  sinking  of the  littoral   areas.    The
correlation  of the eustatic and  tectonic  factors can differ,  however,  among
various parts of the Black  Sea.  The level can rise, but also the littoral areas
can rise, sink, or  be stable, and the rates of these phenomena can be equal  or
unequal.  It has been determined that there are 16 combinations of eustatic (E)
and tectonic (T) factors (Shuisky, 1978).

 1.  +T>-E                 -  very  strong,  relative sinking,  never rises
 2.  +T<-E                 -  strong,  relative sinking, never rises
 3.  +T4>+E                 -  weak,  relative sinking,  usually does not  rise
 4.  +T<+E                 -  weak,  relative sinking
 5.  -T>-E                 -  very  weak,  relative  sinking
 6.  -T<-E                 -  weak,  relative sinking
 7.  -T>+E                 -  moderate,  relative  sinking
 8.  -T<+E                 -  strong,  never turns  into  sinking
 9.  +T=+E                 -  the level  state  is  relatively  stable
10.  -T=-E                 -  the level  state  is  relatively  stable
11.  +T=-E                 -  strong,  relative sinking
12.  -T=+E                 -  strong,  relative rising
13.  Stable  T with +E      -  rising
14.  Stable  T with -E      -  sinking
15.  Stable  E with +T      -  relative  sinking
16.  Stable  E with -T      -  relative  rising

     This pattern of the T and  E  correlation should  serve  as a  basis for the
coastal   zone  dynamics analysis.   (For  the  most  part,  the  coastal   zone  is
indifferent  to the causes of both stability and changing with various rates.  It
is the stability, rising, or sinking at various  rates that  is  important.   The
actual rates of positive and negative long-term changes  in different physical and
geographic conditions of a sea  coast  are of particular significance.)


     There is a lack of practical information in  connection with sea level rise.
Although scientific research  on the process  is  under way,  there  is  still  no
interest on the part of industrial, economic, and  financial organizations despite
the important natural  and cultural resources on lowlands (Stepanov and Andreev,
1981).   The  most  serious reports of the researchers  on the  natural  processes
connected with the sea level changes were published in collections such as "Sea
Level  Fluctuations"  (Kaplin et  al.,  1982a)  and "The Sea  and Oceanic  Level
Fluctuations" (Kaplin et al.,  1982b).

     The analysis  of the modern data on Black Sea level  change within the Ukraine
led to the conclusion that there is a relative rise at 26  stations and sinking
at only  one  (Kherson,  situated in the Dnieper outfall).  The  relative rising
rates vary considerably from place to place  -- from +5.10 to -1.50 mm/year (Table
1), with an average of 1.40 mm/year.  The higher rates prevail between the Danube
Delta  and  Dophinovka  Lagoon and in the  Dnieper outfall.   The  information  on
modern relative changes referred to here were verified  by other geomorphological
and geological research methods (Melnik and Mitin, 1982;  Ivanov and Shmuratko,


     The influence of multicentennial sea level change  on coastal development in
different seas has been studied quite extensively.  Much research was carried out
to define the curve of sea level  rise in the Holocene period using stratigraphic,
radiocarbon,  oxygen, palynologic, and archeologic methods.  These studies led to
the  construction  of Black  Sea coast maps  and   the distribution  maps  of  the
abrasive and  accumulative relief shapes for the  last  50,000  years.   In Odessa
University, the climate-stratigraphic method is  being  worked out,  based on the
astronomic climate theory of M.  Milankovich.  Transferring a radiation curve into
a climate  (or eustatic) curve, we use the sea level  as an  integral index.

     As far as the annual  and centennial changes  (algebraic sum of E and T) and
their  influence  on coasts,  the  study  of  this  question  in  the  U.S.S.R.  is
inadequate at present.

     The methods for calculating the nearshore  bottom abrasion rates have almost
been completed.  These methods  also  take into  account  the T and E correlations.
Finally, we  will  be able  to quantitatively  estimate  the  impact  on  the shore
processes of the sea level change rates and figures.

     But it is already obvious  that a more rigorous analysis of such a phenomenon
-- its nature and its impacts  on coastal systems -- is extremely urgent.  Such
an analysis should address sea  wave activity and the eustatic factor interaction.
It is  also necessary to  carefully check the benchmark tidal  gauges,  and their
steadiness, where especially high relative  rising rates are  noticed.   We know
(Klige,  1981) that  about 14.3% of the general world  ocean  shoreline  has been
rising at more than 2 mm/year.


Table 1.  Average Relative Fluctuations of the  Black  Sea  Level Along the Shores
         of the Ukraine (mm/year)
Rates of sea level

Coastal points
1. Sulina (Romania)
2. Primorskoje
3. Lebedevka
4. Bugaz
5. Illichevsk
6. Odessa
7. Yuzhnij
8. Ochakov
9. Nikolayev
10. Stanislav
11. Kasperovka
12. Kherson
13. Gerojskoye
14. Tendra Spit
15. Lazurnoye
16. Skadovsk
17. Khorly
18. Chernomorskoye
19. Tarkhankut
20. Yevpatoriya
21. Sevastopol
22. Balaklava
23. Yalta
24. Alushta
25. Sudak
26. Feodosiya
27. Kerch
a + = Sea level is rising.
b - = Sea level is sinking.

Average Precision


     By drawing analogies from  storage  lakes  and from the Caspian  Sea in the
U.S.S.R., we can propose the following steps to respond to intensive sea level
rise expected as a result of the greenhouse effect:

       A survey of both the most and the  least  valuable  natural  and cultural
        resources  states, and of their locations along the Ukranian coast,  is
        needed.   An assessment of the morphology and  coastal  dynamics is also
        important.   The  results  should be used to identify the places requiring
        protection  from the  seawater  invasion  --   in the first  phase, second
        phase,  third  phase,  etc.   The  financial  and  material  resources  to
        accomplish  the necessary measures must  also  be identified.



       Some of the cultural resources can be relocated to secure areas.  Others
        can be dismantled  because  their  work is complete.  The  remainder may
        need protection from the advancing sea when the level  rises.   Various
        combinations  of these approaches  are possible.

       The protection of the most valuable  natural and cultural  resources on
        the lowlands  can  be realized by  using  protective seawalls or dikes,
        following the example of the Netherlands,  Belgium, Great  Britain, and
        China.   The lowland in the  State of New Jersey (U.S.)  is also protected
        and we have taken such experience into account here in the Ukraine --
        not, however,  as  protection  from  the  eustatic  level  rise,  but  as
        protection from heavy storms.

       Elevation of  artificial  sandy dunes  can be used where  the appropriate
        conditions exist,  especially  in  the areas of  active  wave  and eolian
        accumulation  of sandy sediments.  Dune formation should precede the sea
        level  rise.

       The long-term  effect  on  the coastal zone  of  artificial  placement of
        sediments usually  promotes the increase  of  beaches and  accumulative
        forms.    In  the  Holocene  period  of  the  Black Sea  shelf,  during the
        periods of coastal  zone  sediment  activation, the areas  of accumulative
        forms increased, and  in the  periods of sediment deficit,  these  areas
        decreased, down to  an  entire washout.  In the modern stage of the Black
        Sea  coast development,  most  of the  barriers  and  spits  developed
        following a sea level  rise, especially where the sediment reserves are
        sufficient.   Accordingly,  we cannot  rule out the  possibility  that the
        coastal  zone   is  artificially  saturated  with  sediments that will  also
        promote the rise of the  accumulation forms after the  accelerated sea
        level  rise in the following decades.

       Since the Black Sea coastal zone structure  is very complicated, there is
        no  single step  that  will  resolve   the  sea  level  rise  problem.   A
        combination of measures  is  necessary.

     It is unclear whether the disastrous sea level  rise is something certain and
unavoidable.  But in  the  last year, the idea  of such a rise caused a tide of new
research,  which  widely discussed  various  causes  of the  world ocean  level's
changing nature,  including the influence  of  the  anthropogenic  factor.

     Hoffert and Flannery (1985)  came to  the conclusion that  the nonstationary
impact of C02 on  the climate  (in the time scale of 10-100 years) is conditioned
by  simultaneous  influence  of  several   external   factors   (outer-atmosphere
insolation, volcanic  aerosols,  concentration of C02  and  the other greenhouse
gases, and also by internal  changeability of  the climatic system (first of all,
the internal oceanic  dynamics).

     In the U.S.S.R.,  many scientists  have also  come to such  conclusions.   For
instance, on the basis  of the analysis of the  latest comprehensive observations,
results, and climate  numerical modeling, Kondratiev (1986,  1987) concluded that
existing information  is insufficient for elucidation of global climate trends and



the complicated changeability and causal  conditionality of climate. The tendency
to  ascribe  observed  climate temperature to  C02 influence  encounters  has been
rejected  by some  for a  number  of  reasons,  including the  character  of the
atmosphere and ocean  interaction.

     Long-term observations  of the abrasion and accumulative shore dynamics cause
me to make other correlations with the latest Black Sea level relative changes.
The connections are not significant.  The causes are still unknown,  the nature
of such interaction is not clear,  and the complex analysis of the results has not
yet been carried out.  But  still, the results received are sufficient to offer
a  series  of theoretical  theses,  which  can  explain  the  causes  of  the modern
seashore retreat.

     Although the  Ukraine has  no policy to address  sea level  rise, long-term
research on the winds, waves,  currents, and  changing level  is  continuing.  In
this case,  it is  important to carry out  the  synchronic observations  of the
cliffs, beaches, barriers, spits, and changing longshore drifts.   We have already
received such data, but  laboratory work  and theoretical analysis, which will be
completed in 1990,  are also  required to  demonstrate the connections between the
sea level  changes and  the changing storm  strength, and the changing sea level and
cliff abrasion rates.  We will look at the shoreline accumulative  forms, retreat
rates, drift distribution, and the interrelationships between the destructive and
accumulating processes.


     Before we can  sensibly specify or implement policies to protect the Ukranian
coast from  rising  sea level,  we  must understand the implications.   To do so,
scientists will  need the enthusiastic encouragement of policy officials, who have
much of the information necessary for meaningful  assessments.

     Scientists will also have to  cooperate better with policy officials and with
each other. The issue is clearly interdisciplinary, which  means that the issues
that professionals in one field  prefer  to  study may  not address the questions
that people from other fields  are  -- or at least should be --  asking.   In the
case of sea level rise, policy makers need coastal scientists  to determine which
land would be inundated  or eroded,  or which would experience  increased flooding
or salinization, and  to  assess  the ecological implications; they need engineers
to  estimate  the  cost  of  protecting  all  the  coastal   areas,  as  well  as
recommendations for  incorporating sea  level  rise into  current infrastructure
planning;  and they need economists  to estimate the costs  of protection versus
allowing the  sea to  advance.   In turn,  the researchers need policy makers to
provide continual guidance on the type of information most useful for decision


Blagovolin, N.S., and S.V. Pobedonostsev.   1973.   Recent vertical movements of
the shores of the Black and  Azov  seas.   Geomorphology 3:46-55  (in Russian).



Hoffert,.  M.I.,  and B.P.  Flannery.    1985.   Model  projections of  the time-
dependent response in increasing carbon dioxide.  In:  Potential Climatic  Effects
of  Increasing  Carbon   Dioxide.    MacCracken,  M.C.,  and  P.M.  Luther,  eds.
Washington, DC:  U.S. Department of Energy, p. 149-190.

Ivanov, G.I.,  and V.I. Shmuratko.  1982.  Oceanic levels during the Pleistocene.
In: Sea Level  Fluctuations.  Moscow:  Moscow State University Publishing House,
p. 60-75 (in Russian).

Kaplin, P., R. Klige, and  A.  Chepalyga,  eds.   1982a.  Sea Level Fluctuations.
Moscow:  Moscow State University Publishing House, 310 p. (in Russian).

Kaplin, P., R.  Klige,  and A. Chepalyga,  eds.   1982b.   Sea  and Oceanic Level
Fluctuations for  15,000 Years.   Moscow:   Nauka Publishing House,  230  p.   (in

Klige, R.K.   1980.   The Ocean  Level  During  Geological Time.   Moscow:   Nauka
Publishing House, 145 p. (in Russian).

Klige, R.K.  1981.  Estimations of Contemporary Seashores Vertical  Changing in
Connection with Ocean's  Level/Coastal  Zone of  the Sea.  Moscow:  Nauka Publishing
House, p. 11-17 (in Russian).

Kondratiev, K.Y.   1986.   Natural  and anthropogenous changing of climate.  Heral
of Acad. Sci.  U.S.S.R.   10:30-39 (in Russian).

Kondratiev, K.Y.   1987.   Carbonic acid gas and climate: Data of observation  and
numerical modelling.  New All-Union Geogr.Soc. 119(2):97-105 (in Russian).

Melnik, V.I.,  and L.I.   Mitin,  eds.   1982.   Geology of  the  Ukrainian  Shelf:
Environment, History,  and Methods of Investigations.    Kiev,  Naukova Dumka
Publishing House, 175 p. (in Russian).

Pobedonostsev, S.V.   1972.   Contemporary vertical   changing of  the seashores
around the European  part of the U.S.S.R.  Oceanology 12(4):460-469 (in Russian).

Shuisky, Y.D.   1978.  Types of Coasts of the Earth  Globe.   Odessa:  Odessa State
University Publishing House, 75 p. (in Russian).

Shuisky, Y.D.   1982.  Limans and liman's coasts.  In:  Encyclopedia of Beaches
and Coastal Environment. Schwartz, M.L., ed.  Stroudsburg:  Hutchinson Ross Co.,
p. 516-518.

Shuisky, Y.D.,  and M.L.  Schwartz.  1988.   Human impact and  rates of shore retreat
along the Black Sea coasts.  Journal  of Coastal  Research  4(1):405-416.

Stepanov,  V.N.,  and V.N.  Andreev.    1981.   The  Black  Sea --  Resources   and
Problems.  Leningrad:  Hydrol.-Meteorol.  Publishing House, 157  p.  (in Russian).

                      CONSEQUENCES  IN  TUNISIA
                            DR. AMEUR OUESLATI
                          University  of Tunisia
                              Tunis, Tunisia

     The consequences of  sea  level  rise are already  evident  on  the 1300-km
Tunisian coast  (Oueslati et al.,  1987).  Almost the entire landscape of beaches,
rocky low  coasts,  salt  marshes  -- and  particularly  cliffs  -- is retreating
(Oueslati,  1989).  In many cities, erosion is threatening hotels,  dwellings, salt
pans, industrial establishments, and the public infrastructure; the nation's
archeological  heritage  is  also at risk.  The few sections  of  the coast not yet
suffering erosion are generally in undeveloped areas  at the mouths of rivers and
the bottom  of some  bays.

     The vulnerability of the Tunisian coast has been  particularly evident  in the
aftermath of storms.  For example,  a January 1981  storm in the Gulf of Tunis
caused  severe damage and  completely  removed  beaches  along many stretches  of
coast, especially the suburbs of  the capital.  With a  stable sea level,  the waves
could have  rebuilt these beaches  after the storm. But the Bruun  Rule shows that
when sea level  rises, offshore portions  of the beach system must gradually rise
as well, implying that much of the sediment deposited  offshore during storms will
remain there.  The experience in Tunisia  after the 1981 storm has  been consistent
with this theory.

     Water  tables are also  rising, with  a resulting salinization of  low-lying
areas, particularly in subsiding  areas such as those along the Gulfs  of  Tunis and
Gabes (Oueslati, 1989).   Rising  seas have also transformed many occupied (in
ancient times)  areas  into wetlands, and may soon do  the same  to  the cultivated
areas of antiquity  (Oueslati, 1989; Paskoff and  Oueslati,  in  press).

     In  response to  these  problems,  coastal  defense  structures are  becoming
increasingly common on  the  Tunisian  coast.   Seawalls are most common, with
dimensions  scaled to the size and value of the buildings being  protected.  Along
the Gulf of Tunis  and at Mahdia, the  structures are very large.  On the other
hand, many  human activities  are increasing the vulnerability  of  the  coast:
extraction  of beach  sand for construction and the loss of marine vegetation as
a result of pollution  directly  weaken  the  coast.   Dams  for  managing  water



resources  and  jetties  at harbor  entrances diminish  the  natural  supply  of
sediment, which might otherwise offset some of the erosion  (particularly in cases
where the littoral  drift  is mostly in one direction,  such  as  Bizerte and Ghar el
Mebah, where beaches downdrift of the jetties are eroding rapidly).

     The next two sections briefly summarize the likely impacts of an accelerated
rise in sea level  on the  Tunisian coast  and  the  possible responses.   Although
Tunisians have not  studied in detail  the implications of sea  level rise for each
particular  coast,   the  reader  can  better  understand  our vulnerability  by
considering the  environmental  conditions  of the coast  in  more detail;  this
information is provided by the final sections of this paper.


     About half of  Tunisia's  population and most of  its major cities are on the
coast (Figure 1).  The many ports range from industrial-sized  harbors to those
servicing small fishing or pleasure  villages.  Most of the nation's  industrial
and tourist establishments,  and all  of its salt production facilities, are very
close to  the shore.   The remainder  of the coastal  lowlands are  cultivated --
mostly for cereals, although fruits  and  vegetables  are also profitable  in the
Medjerda  River Delta  and around urban areas where  they  can be  sold  to local
residents.  All of these activities  are at risk.

     A rise in sea level  of 50 to 200 centimeters would almost undoubtedly result
in a great retreat  of the entire coast, the extension of salinized  areas, and the
disappearance of some  natural systems.  Along the  Gulf of  Tunis, important parts
of the Medjeida delta (Figure 1) and the Milian plain would be inundated; most
lagoons either would disappear or would be shifted substantially landward; and
Tunis and its suburbs would be seriously threatened.  Along the Gulf of Gabes,
coastal systems could probably shift landward.  New wetland  ecosystems may form
on the  alluvial  plains  where the current ecosystems are inundated.   Figure 2
illustrates the Kerkna archipelago,  where the outer  parts of Sfax and Gabes may
be seriously damaged -- perhaps even more than Tunis, given current  subsidence
trends.  Sea level  rise at sfax is estimated to be 5.7 mm/yr, a rate almost four
times higher than the worldwide average (Pirazzoli,  1986).

     In the central part  of  Hammamet  Gulf, the most important  impact would be
saltwater intrusion into  cultivated  alluvial plains.   Meanwhile, the wetlands
behind the foredunes may  be  converted into  open-water  lagoons.   Cities  in the
northern and southern  parts of this gulf may be  severely damaged, especially the
large tourist complexes of Hammamet and Sousse Monastir. Along the eastern coast
of the Cap Bon  peninsula and  at Dimass, the  lagoons seem likely to be completely
lost, because  rocky high ground  (a consolidated Tyrrhenian  bar)  immediately
inland would preclude  a landward migration.  Similarly,  in the Sahel, the narrow
alluvial plain would be squeezed between an advancing shore and the  rocky high

     Rising sea level also threatens  fishing, a major occupation  and an important
Tunisian tradition. The  two  largest fisheries are located at the  inlets of the


Figure 1.   Cultural  and  economic features (urban population, hotels, and ports)
[Legend:   a  = towns wholly or  partly installed on unconsolidated  lowlands  -
1,000s of  inhabitants; b = zone occupied by  important  tourist  area;  c = hotel
capacity - 1,000s of beds;  d = ports; e = fishing ports;  f = marina]

Figure 2.  Kerkna archipelago -- possible consequences  of  50,  100,  and 200 cm
rise in sea level (hatched areas would be invaded by sea water).


                                                                      Dues 1 ati

 Ichkeul and Bhiret el Biban Lagoons, which would be drastically altered by sea
 level rise.  Along the Gulf of Gabes (particularly Jerba and Kerkna  Islands)
 fishing is still conducted by the traditional  method of using palm fronds stuck
 into tidal flats to trap  fish  brought in by tidal currents;  along other parts of
 the gulf, many  families  feed  or  support themselves by gathering cockles in the
 tidal  flats.     But sea  level  rise would  inundate most of the  tidal  flats.
 Breeding facilities for  fish  (Monastir), oysters (Lagoon of Bizerte) and other
 shellfish would also be  at risk.

     Finally, we could expect  the erosion and loss of a major portion  of the many
 archeological sites that  are  among  the most important constituents of Tunisian

     Like other nations discussed in this report, Tunisia could respond to sea
level rise either by holding back the sea or by retreating landward.  Most of the
structural approaches described  by  Pope (Adaptive Options,  Volume 1) would be
appropriate  for some  part of  the  coast, and  in  many cases,  the necessary
structures would  not have to  be erected for  several  decades.   By contrast,
although shores will retreat and settlements will be relocated in many (if not
most)  parts  of the  coast,  the  anticipatory  strategies  presented  by  Titus
(Adaptive  Options,  Volume 1)  would be  difficult to implement,  because  they
presuppose that (1)  officials are willing to modify current activities to protect
against  crises  not  likely  to  occur  for  several  decades,  and   (2)  that
environmental protection is sometimes important enough to prohibit construction.
Neither of these assumptions yet applies to coastal management in Tunisia.

     The  inhabitants  of  the   coast   are  somewhat  aware  that  erosion  and
salinization threaten  their  fields  and dwellings, but  they  generally are not
aware that rising  sea level  is  causing the  problem.   Similarly,  it would be
obvious to mudflat  fishermen that if sea level  rise inundated the flats, their
livelihood would  be threatened.   Because their  ancestors have  pursued  this
traditional occupation for centuries,  the fact that  the crisis would confront
their grandchildren (instead  of them) would  not substantially  reduce  their
concern.  But no one has informed them about this problem.

     Currently, only two state agencies are  even  concerned about current beach
erosion problems.   Although they have  tried  solutions,  the projects have  been
arbitrary, scattered, and poorly  studied.  They  have been mostly ineffective and
in some cases have made the problems worse.  Managers almost never consider the
relationship between sea level  rise and current problems.   There is a complete
lack of  legislation and policies  to  protect the coastal environment.   When
coastal  areas  are  developed,  no one  is considering  the argument  by Everett
(Environmental   Implications,  Volume 1)  that in  the long  run,  a  hectare  of
mudflats might  feed  more  people than a hectare of  agricultural  land, and that we
should therefore set development back farther from the  shore.




     The most important and extensive active cliffs  are  characteristic of the
northern coasts (characterized by relatively deep water  and exposed to strong
northern and  northwestern  swell)  of the country where they generally average
15-30 m in height.   In rare contrast, such  as  at the extremity of the Cap Bon
peninsula, they are higher than 50 m.

     For the most part, these cliffs  consist of sandstone and clay and rarely are
composed of rocks,  limestone,  or  marls.  Rocky cliffs  (eolianites  and marine
quaternary limestones) that alternate with fluvial layers often show remarkable
differential  erosion rates.  However, such cliffs are usually only a few meters
high (5-10 m).

     Along the entire  northern coast, the cliffs are retreating, sometimes quite
rapidly, under the  attack of north and northwesterly swells.  Measurements taken
during 1982-87 on cliffs 7 to 15 m high, formed in  the Numidian flysch, showed
them retreating  at rates  varying from 1.5 to 8 m/yr.  Because of the very humid
atmosphere and  steep coastal  slopes, landslides  are frequent  wherever clays
dominate.   Landslides along  the  northern coasts  are also  threatening human
dwellings.  Fortunately,  this area is not yet densely occupied.

     There are fewer eroding cliffs  on  the eastern  coasts.   For the most part,
they are  a few meters  (2-5  m)  high and are  formed in  Pleistocene materials
(especially alluvium,  eolianite,  and marine limestone).    The  only important
cliffs there  are along the Gulf of  Gabes and its surroundings, where they are
formed in gypsum-rich clays covered by a  strong calcrete (attributed to the lower
Quaternary) or a gypsum crest (late Pleistocene).  These latter cliffs, generally
averaging  7 to  15  m in height,  are  sometimes prone  to high rates of erosion,
despite the small waves.  There is severe erosion of the important archeological
sites that are visible in the upper  part of the cliffs (e.g., on western coast
of the Kerkna archipelago and at Nadhour between  Sfax and Gabes Town).

Unconsolidated Low Coasts

     Unconsolidated low coasts are extensive in Tunisia and  are found primarily
at the inland  margin of wide gulfs (Tunis, Hammamet,  Gabes) and bays (Tabarka and
Bizerte).   They are  especially  developed and predominant along the eastern
portion of the  coastal  landscape.   They generally consist  of  alluvial plains
formed by fine material dating back  to the late Quaternary, mainly the Holocene
and the historic times.  The seaward margin of these lowlands is characterized
by sandy beaches,  small  cliffs,  or salt marshes.   These are found in the Gulf
of Gabes and  its surroundings where  tides are high  and may reach 2 m at spring

     Careful   observations  reveal  significant  regional  differences  in these
lowlands because of physical  conditions, human  activities,  and the orientation
of the coast.  This section describes several  distinctions:



       A narrow alluvial  plain situated at the inland portion  of a bay bordered
        bv sizable  cliffs and  intersected bv  small  but  active  wadis.   The
        shoreline is characterized bv a large sandy beach favoring the formation
        of extensive dunefields and  important human settlements inland.

     This is the case of the  Tabarka and Zwaraa coasts, which are situated near
the Algerian border.  The plain, averaging 4  m  in height,  is  made of sand and
clay sometimes  containing more or less well-rounded pebbles.   It  covers about
5 km2 and is  partly occupied  by the Tabarka agglomeration.

     This area boasts one of the best sandy beaches of the country.   Extending
over 10 km, this beach stretches to 50-70 m  in width, especially around the mouth
of wadis.  It benefits from two important sources  of sediments:  (1)  wadis that
cross in their higher courses steep slopes formed in the Numidian flysch, and (2)
rocky active cliffs situated  at the borders of Tabanka Bay.  Well exposed to the
ambient winds,  this beach formed  an important  source of sand to be blown inland
to create an extensive and thick dunefield (Ouchtata field)  that is today largely
stabilized by  a planted  forest.   The system must have  been  repeated  in the
geologic past,  because recent dunes cover Pleistocene eolianite.  The assemblage
of forms is  crossed by active wadis that in  turn  supply the  shoreline with sand.

       A narrow, largely alleviated plain,  occupying  the inner margin of a bay
        and  devoid of active wadis.   The shoreline is also characterized  by a
        sandy beach favoring  the  formation  of large dunes.

     In Bizerte, situated on  the northern coast,  the plain  is 200-700 m wide and
covers about 3.5 km2.  Its altitude, which  rarely exceeds 10 m above sea level,
is sometimes lower than  2 m.  This is especially the case in the outer section,
which  is often  characterized  by a  swampy landscape.   Sediments are  mainly
composed of sand and silt, except in the northern part where clay predominates.
The sediments are locally quite thin (50 cm-1.5 m)  and  cover marine consolidated
deposits inherited from  the Tyrrhenian stage.  The beach covers about 12 km.  At
its eastern part, well exposed  to the northwest winds, is a large field of sand
dunes (Rmel's field), now almost wholly colonized by a planted forest.

       A wide  deltaic plan formed bv a large wadi  and situated in a gulf.   The
        shoreline of this plain is characterized  bv sandy  beaches  and lagoons.

     The deltaic plain of the Medjerda, the  largest and most important river of
the country,  covers about 600 km2.  It is generally 1-10 m  above sea level, but
in some  parts  it may be  less than 30 cm above  sea level.  Its sediments are
mainly composed of sand and clay.   Swamps occupied a very  large portion of the
area before the  draining  operations undertaken  since  the  French  colonization.
Today the swamps are found only in  the lowest section of the delta,  especially
near the shore.

     The formation of this deltaic plain dates back mainly to the Holocene.   But
its progradation was significant during historic times because of the  increased
sediment carried by the river  following deforestation.  The ancient archeological



site of Utica  illustrates such a history of alluviation.  This site  is today more
than 10 km inland, whereas it was a harbor in ancient times.

     The coast is characterized by a relatively wide (10-15 m)  sandy beach and
a low (2-3 m)  and narrow (30-60 m)  foredune.  The northern part shows a typical
spit at the location of a former mouth of the Medjerda River, which was abandoned
following the  1973 flood when the river  shifted southward to  occupy an artificial
channel originally  designed to  drain  the  excess  water during  floods.   The
southern part  of the coast is  well  exposed to the  northwestern  winds, which
favored the  formation of  a  dunefield  (Raoued  Gammarth)  now  almost  entirely
wooded.   The   coast  is  also characterized  by a lagoonal  landscape  (see  the
paragraph describing lagoons).

        An alluvial  plain  at the mouth of  a  ma.ior  river and  situated  at  the
        inland margin of a deep bay.   The coast  is  characterized  by a densely
        occupied sandy beach.

     This  is the  case of the coast of the bay of Tunis, which  is largely occupied
by the  southern suburbs of Tunis, the capital of the  country.  The alluvial plain
is an accumulation mainly of the Miliane  wadi, Tunisia's second largest river.
Relatively wide  (approximately  36 km)  and low (2-10 m), this coastal plain was
created essentially during  historic times  because   its  material covers  marine
deposits dated  from  about  2,750 years  ago and certain  antique ceramics.   The
alluvial deposits are generally  fine (sand  and  clay),  but  can  locally contain
some coarse layers of mixed and more or less well-rounded pebbles.

     The beach  is about 10  m  wide and  is generally  accompanied by a small
foredune (1-2  m high and 10-30 m wide).  Dunes are much more prevalent on Tunis's
eastern coast  than on its northern coast.  An example is the small  dunefield of
Borj Cedria-Soliman,  which  is  partly  covered by a  planted forest.   The  land
immediately behind the foredune, is almost everywhere,  swampy and  colonized by
salt plants.

        A  straight coast with active streams, narrow  alluvial plain, broad sandy
        beaches,  extensive  dunefields,  and  absence of ma.ior human  settlements.

     These characteristics are prevalent along the coast between  Wadi  el Abdi and
Wadi el Mgaiez on the northwestern  face of  the  Cap  Bon peninsula.   The plain,
averaging 800  m wide and 5-10 m high, is limited landward by a dead cliff.   Its
deposits are generally made of  sand and  silt and often lie on a bedrock platform
inherited from the Tyrrhenian transgression.  This coastal type is prominent only
around  the mouth  of wadis that  in  their  higher  and  middle  courses drain steep
slopes  across  Miocene marls and  sandstones.   The beach is generally  10-15 m wide,
but can stretch 50 m wide in some river mouths.   The dune fields  are sometimes
very extensive and often cover  late Quaternary eolianites.

        An alluvial  plain at an  inland margin of a  large  gulf intersected by
        active wadis.   The  shore is characterized by a broad sandy beach,  with
        localized development,  and a laqoonal  landscape.

                                                                      Dues 1 ati

     This is  the  case of a  large  part of Hammamet  Gulf,  especially northern
Hergla and southern Sousse.  The plain covers about  150 km2; its height varies
from 2 to 10  m.   The  seaward parts  of the coast are  often  swampy and saline.
The beach is generally well developed, stretching into 40 m wide  in many places.
But foredunes  are large  in  only two cases:  in  Skanes  and between Hergla and
Selloum, where it is  largely wooded.   Lagoons characterize segments  of the
northern Hergla and southern Sousse coasts.   Except for the area between Hergla
and Bou  Ficha,  the Hammamet Gulf coast has  been  subjected to extensive human
development,  particularly   hotel  construction  in  Hammamet,  Monastir,  and
especially Sousse.

       A relatively straight coast  devoid of active wadis  and characterized by
        a narrow  coastal  plain  and  wide  sandy  beach.   The human installations
        vary from one region to another.

     In four main regions --  Mahdia,  Chebba,  northeast Jerba, and Zarzis -- the
coastal plain is sometimes only a few  hundred meters wide.   Its altitude may be,
such  as  at  Mahdia, less  than  3 m  above  sea level,  where  there  is extensive
swampland.   Generally this  plain  is  situated  downdrift   from  a  consolidated
coastal barrier or a dead cliff dating back to the Tyrrhenian stage.

     At Mahdia the beach  is about 10-15 m wide,  and the foredune  is always small
(2-3 m high)  and discontinuous.  The  coast  is partly developed, especially in the
segment next  to  the  city of Mahdia  (residences,  industries, and  hotels).   At
Chebba the  beach  is wider and  is  sometimes punctuated by Pliocene sandstone
outcrops.  It is also has an extensive dunefield  inland, now artificially fixed,
and the coast is  still unoccupied.

     The beach of  Jerba,  extending almost 20 km,  is frequently wide  (7-20 m) and
is  also punctuated  by  rocky  outcrops   (marine  limestones,  eolianites,  and
calcretes).   It is not continuous,  forming elongated  spits  at three sites.  The
foredune is  locally well  developed.   Sand  dunes, sometimes covering large areas
are often occupied by orchards and dwellings.  The major part of this coast is
occupied by hotels often built close to the shoreline.

     At  Zarzis,   the  coast  is  largely  developed,  especially  with  tourist
facilities.   The beach resembles that of Jerba in  its width and its outcrops of
rocky material.   But the foredune is relatively smaller.

       A coast marked  by a sebkha landscape  fringed by a microcliff or a sandy
        beach, especially at  the mouth of active wadis.

     These characteristics predominate along a large part  of the  coast  of the
Gulf of Gabes. The lowlands, composed mainly of  fine  sandy and silty materials,
are generally 5-10 m high.  The  most  important of them are linked to relatively
large wadis  and are 2-10  km wide.  In some cases, such  as  at Kerkna and  Jerba,
the sandy and silty material  is thin (50 cm-1 m) and  covers a marine limestone
dating back  to the Tyrrhenian.


     Sebkhas1, salt marshes found in northern Africa,  are  a major feature of the
coastline.  The largest sebkhas are inherited from Holocene eustatic sea level
oscillations and occupy the position of ancient lagoons or bays that have been
filled by continental deposits.

     Beaches occupying the mouth  of wadis are relatively wide (10-20 m) and are
accompanied by small  (2-5 m) but sometimes well-defined foredunes.  In some cases
the beach  forms  a spit.   Except for the  coasts  at  Gabes and  Chaffar,  these
beaches are still unoccupied.


     Wetlands occupy  the seaward parts of the alluvial  plains (Medjeida, Miliane,
Gulf of Hammamet, Mahdia) and can  be associated with sebkhas.  The most important
wetlands exist along  the southern coast (Gulf of Gabes and its surroundings) and
correspond to typical tidal marshes favored by the low energy of the coast and
the high tides.  Such tidal marshes occupy different positions (behind spits and
capes, bottoms of creeks,  mouths  of wadis)  and have a low vegetation dominated
by Salicornia.  They also  present  some particularities  in  comparison  to tidal
marshes of other climate zones.   They are always characterized by the existence
of dunes and plants adapted to the  aridity,  and they often extend landward into
the sebkhas and alluvial  plains.


     Lagoons are numerous  and varied along  the Tunisian coasts.   But according
to their morphology,  hydrology, and position in comparison with the  sea, they can
be  classified into  two  main  categories:    (1)  wide  lagoons with  continued
communication with the sea and (2) those isolated from the sea with a sandy bar,
and lagoons invaded  only during the stormy  season.

     Four main lagoons belong to  the  first  category:

       The Lagoon of  Bizerte  covers about 15,000  ha and connects  to  the sea
        through  a large channel,  now  partly developed.

       The Lagoon of Ichkeul (12,000 ha) is linked to  the Bizerte Lagoon through
        the Tinga  emissary and responds to  an important seasonal variation.  It
        is occupied by marine water only  during the dry season.   In the winter
        it is  the recipient of considerable  continental discharge because of the
        large wadis that divert into  it.

       The Lagoons of Ghar el Mel ah (3,000  ha)  and Tunis  (4,000 ha) are cut off
        from the  sea  by a sandy coastal  bar, but connected to the sea by dredged
   1An  arabic  term  for  a  flat  area,  close to the water table and characterized
by a salt material.


                                                                      Dues 7at/

       The Lagoon of Bhiref el Bibane, situated near the Libyan border, has a
        surface of about 30,000  ha.   It is bordered on  the  seaward  side by a
        consolidated littoral bar dating back to the Tyrrhenian.  Connection with
        the sea is possible through some natural inlets, among which the inlet
        of S.  Mohamed Chaouth is the most important.

     Lagoons of the second category are connected to the sea only through natural
inlets that generally open only during storms.  These lagoons are numerous and
exist in the Gulf of Tunis  (St. Sidi  Bakhoun,  St. Ariana), in the eastern coast
of the Cap Bon peninsula (St.  Bouzid,  St.  Klibia),  in the Gulf of Hammamet (St.
Assa Jiriba, St. Halk el Mungil), and in the Sahel  (St. Skanes,  St. Dimass).

     In all of these situations,  the  inland  area is often swampy.  The salinity
of the lagoons and the temperatures are often higher than in the open sea.  They
also increase toward the south.  In the Bhiret el  Bibane Lagoon,  for instance,
the temperature can  climb  as  high as 40C, and the  salinity  increases  in the
summer when sirocco winds blow.

     Given our inability to effectively address problems due to current relative
sea level rise, one might  pessimistically  assume  that  coping effectively with
accelerated sea level  rise will  be close  to  impossible.   But there may  be a
positive aspect:   As late as 1983, for example, the United States was failing to
address current trends  of sea level rise, but widespread public attention to the
greenhouse effect  prompted  officials to look into the issue of sea level rise and
to direct their staffs to  at  least take current trends into account.   As the
paper by Klarin and Hershman  (Legal  and Institutional  Implications,  Volume 1)
illustrates, five  years later  officials  were preparing for an accelerated rise.
The same thing could happen  here.   In  Tunisia, there  is  sufficient  technical
expertise to  begin preparing  for a rise in sea level, but  neither the  public
awareness nor the  official  recognition necessary to start  the process.


     Some very  important  regional  differences  can  be  observed  between  the
northern  and the eastern coasts, particularly in the rainfall volume and wind
characteristics.   The mean annual  rainfall  is often  higher  than 500  mm  and
sometimes reaches 1 m in the northern coast,  whereas it is generally less that
300 mm  in  the major  part  of  the eastern  coast.   Moreover,  the  rain  average
diminishes rapidly toward the south.  Near the Libyan border it is only about 100-
150 mm/yr.   Rain  is often torrential  and falls  in  concentrated  patterns of a few

     During  the  summer,  the mean monthly temperature everywhere is greater than
20C.  The  average daily maximum  temperature during  July  and  August  is always
higher than 30C and  can  reach  40C  when southern winds,  the  sirocco,  are
prevailing.    During  the  winter,  the  mean temperature of  the  coldest month
(January) is  higher than  10C  almost  everywhere along the  coast.  The mean
minimum temperature generally oscillates between  6  and 8C.   Temperatures are
rarely below 0C.

     The  strongest and most frequent winds generally blow from the northwestern
direction and occur mainly  in winter. Nevertheless, differences exist according
to seasons  and the coastline orientation.  On  the northern  coast, western and
northwestern winds  prevail  occurring approximately 35% of  the time.   On  the
eastern  and  especially on  the  southern coasts,   the  gentler  eastern  and
northeastern winds dominate.

     The  contrast between the northern and the eastern coasts of Tunisia appears
also in the hydrodynamic and the marine water characteristics.  Because of its
exposure to  northern winds  and its relatively  deep water, the northern coast has
cooler, less saline, and rougher and larger waters  than the eastern coast.   At
the end of the hot season, water temperatures are about 21-22C, and the salinity
is  about 37  0/00  (parts  per  thousand).    At  the  end  of  the winter,  the
temperatures vary between 15 and 16C, but the salinity is still almost unaltered
(36 to 37 0/00)  except in the inner  portion of the Gulf of Tunis.   Unless there
is an exceptional storm, wave height along the northern coast rarely exceeds 6
m. In the Gulf  of Tunis,  waves of  1.5  m and  higher represent only  6%  of the
observed cases.   Tides constitute a  secondary phenomenon as their range is, at
spring tides, about 0.20 to 0.30 m.

     Along the eastern coats, waves  are mainly generated by the eastern and the
northeastern winds.  They are generally characterized by a  low  energy.  The most
important waves  rarely exceed  1.20 m in  height.  From 1954 to 1961, the largest
wave registered  at Sousse was only 3.5 m in height.   The eastern  coasts have a
broad shelf.  The southern part  (Gulf  of Gabes)  is  characterized by important
tides.  Here, the tidal range is often higher than  0.70 m and may reach 2 m at
spring tides. Water temperatures of  the eastern coasts are  always  more than 16C
and increase southward, where they are about 16-19C and 22C, respectively, at
the end of winter and  summer.  However, the salinity change is less perceptible
-- 37.1 and  37.2  0/00,  respectively, at the end of the cool and the hot seasons.




     The author is greatly indebted to Prof. R.  Paskoff and Prof. N. Psuty for
their  help.   J.  Titus  has revised  and improved the  text and  proposed  some
modifications in the English text.  All of them are sincerely acknowledged.


Oueslati, A.  1986.   Jerba et  Kerkna  (iles de la cote orientale de la Tunisie):
leur evolution geomorphologique au cours du quaternaire.  Publ. Univ. Tunis, 210

Oueslati, A., R. Paskoff, H. Slim, and P. Trousset.   1987.  Deplacements de la
ligne  de  rivage en  Tunisie  d'aprea  les donnees  de 1'archeologie  a  1'epoque
historique.  Coll. Intern. C.N.R.S.  Paris,  67-85.

Oueslati, A.  1989.   Les cotes de la Tunisie, recherches geomorphologiques.  Th.
d'Btat, University of Tunis, 680 p.

Paskoff, R.  1985.  Les plages de Tunisie.   BDITEC,  Caen. 198 p.

Paskoff, R., and A.  Oueslati.   Modifications of coastal conditions in  the gulf
of Cabes (southern Tunisia) since classical  antiquity.  In:  Journal of Coastal
Research (in press).

Pirazzoli, P.A.  1986.   Secular  trends  of relative  sea level  (R.S.L.)  changes
indicated by tide gauge record.  In:  Journal of Coastal Research, Special Issue


                     SEA LEVEL  RISE  ON EGYPT
                               M.  EL-RAEY
                 Department  of Environmental Studies
                       University of Alexandria
                           Alexandria,  Egypt

     The projected sea level rise of 1 meter in the next century from greenhouse-
induced global warming is a serious concern to deltaic countries such as Egypt.
Deltas  are  particularly susceptible to sea  level   rise because the  delicate
balance at the river-ocean interface produces land that is inherently just above
sea level.  Deltas depend on new sediment delivered  by rivers to enable them to
keep pace with  sea  level  rise.   Sea level rise will  exacerbate  the  erosion
already present in the Nile River delta caused by dams upstream that have reduced
the sediment  supply.

     The population of Egypt is clustered along the  banks of the Nile River and
within the delta.  Only 3.5% of the one million  square kilometer  area  of the
country is cultivated and settled  (Quarterly Economic Review  of Egypt,  1985).
The nation's  coastline has  experienced  severe  erosion  in the  last  100  years.
Reduction  in  the  supply of sediment to  the  delta started with  the construction
of delta barrages in  1881.  Since then,  the situation has become progressively
worse with construction  of  new dams.  The  1964 construction of the Aswan  High
Dam has completely stopped the  supply   of  sediment to the delta;  since  that
time, many areas  on  the delta coast have been eroding 1 meter  every year.  In
some areas, erosion  rates have jumped to more than  100 meters  per year.

     The impacts  of global  warming on  the  Nile delta  are taken  seriously by
concerned  authorities in  Egypt.   A basic  survey  of available  information  and
implications  has been compiled  by Broadus  et al.  (1986) and  Sestini  (1989).
Sestini and others anticipated that a relative rise of 1  meter could submerge
lowlands 30 km inland of the coast or more, which accounts for 12-15% of Egypt's
arable land,  8  million people, and  10rl5% of the country's  gross  national
product.    Salt intrusion   will   also  contaminate  water  used for  drinking
and agricultural  purposes.   Many people have called  for a national  policy of
response to these anticipated changes.



     Responding to sea level rise in Egypt will  be  difficult because  most  of
the arable land is along the  Nile River or within the Nile delta. Therefore, when
this area becomes uninhabitable, moving  to higher ground will not solve all the
problems, because this land will be inadequate for growing  enough  food to support
the displaced population.  Other possible responses include building  a dike along
the delta coastline or  bypassing  sediment  around Aswan High  Dam.  This  study
investigates the impacts of  a  1-meter sea level rise on Egypt, assesses what is
at risk along Egypt's coastline,  and discusses possible responses.


     Technological developments and the conversion of agricultural communities to
industrial communities have  resulted in  excessive use of energy resources.  As
energy use  is  necessarily associated with  waste  in  the form  of materials and
heat, this waste  has increased dramatically  in the last few decades to the extent
that it has become a major threat to the environment.  In particular,  a gradual
increase of greenhouse gases (C02, CFCs,  03,  CH4, and OH) in the environment has
resulted in a measurable warming  of the  atmosphere with anticipated changes in
climate,  and  additional   effects  such  as   sea   level  rise and  changes  in
precipitation patterns.

     The impact  of these  climate  changes on the  ecosystem,  human  activities,
health,  and  welfare  should  be  carefully   assessed   before   a  policy  for
countering those impacts is developed.  National and international organizations
have coordinated efforts  to  develop measures to adapt to these climate changes.

     Models have predicted that the  temperaotureriseassociatedwithaccumulation
of  greenhouse   gases  may  range  from 2.5C  to   5C  by  the  middle  of  the
next century.  The  associated rise in  sea level,  due to both  ocean  thermal
expansion and melting of  polar glaciers and ice caps,  is  anticipated  to  range
from 30 cm to 150 cm (Titus, 1986;  UNEP, 1987,  1989).

     Egypt's Nile delta,  in  particular,  will  be adversely affected  because its
northern region  is entirely less than 1 meter  above  sea  level.   It is already
subject to  a great deal   of environmental changes due to severe reduction  of
sediment delivery after construction of  the Aswan High Dam.

     This paper outlines  the  impact of  various environmental  changes  over the
northern Egyptian coasts,  directs attention to  areas of potential risk from the
effects of climate change, and recommends a policy by which government agencies
could reduce losses and help Egypt  adapt to  global warming.


     No formal  multidisciplinary  team has  investigated the detailed impacts of
climate change  on the Egyptian delta.  However, a number of  research centers have
studied one  aspect or another of  the  problem  and  have  accumulated  valuable
information.   These  groups include the  Institute   of  Coastal   Research,  the



Institute of  Oceanography,  the Suez Canal Authority,  the  Environment Affairs
Authority,a nd the University of Alexandria research groups.  A number of United
Nations Environment Programme meetings have also stressed the seriousness of the
impact of global warming, especially sea level rise.

     An assessment of the impacts of climate  changes  on the  northern Egyptian
coasts  requires  the  documentation of detailed   information  on  land  use,
topographic variations, population distribution, soil  characteristics, coastal
erosion,  and  socioeconomic  distribution  parameters.    Unfortunately,   the
information already  available  is  outdated,  intermittent, and,  in  many cases,
inconsistent.  In addition,  large  uncertainties  exist regarding the accuracy of
important variables,  such  as  regional  subsidence  rates,  elevation,  and  the
distribution  of  economic   activities.     Nevertheless,   available  information
provides a general account of the likely impacts.

     A 1-meter  interval  elevation contour map of the  Nile Delta  and vicinity
(Figure 1) shows that the area  below the 1-meter contour  extends inland as much
as 30  km  south  of Alexandria city and  south  of Lake  Manzala  (Sestini, 1987).
Because about 40%  of  Egyptian  industry  is located  near and  around Alexandria,
we can infer that serious damage could result  from a 1-meter rise in sea level.
In addition, because of  the  sandy and porous  nature of the  soil  in this area,
waterlogging resulting from saltwater intrusion  may  affect the fertility of the
arable land below the 2-meter or perhaps the 3-meter contour.   Considering the
relatively  high population  density and extensive  resources  of  the  area,  a
tremendous socioeconomic impact would be likely.

     Recent  analysis of erosion and  accretion  patterns  (Frihy et al., 1989) has
also shown large changes over the northern Egyptian coasts. Hence, many tourist,
recreational, and economic sites will  be subjected to considerable stress.  In
addition, this  area is  generally subsiding.    Based  on these results  and  on
consideration of economic  development  axes   in  both  vertical  and horizontal
directions on the  north  coast  (ARICON,  1988), we conclude that  sea level  rise
will  pose major  risks  to  three  areas: the  Alexandria region west of the Rosetta
branch, Lake Burullus and vicinity,  and the  Lake Manzala region.

     1.  Alexandria region:  The  region at risk includes residential  areas  in
         several  localities, in addition to  industrial  sections west and  east
         of  the city.   A  large  part   of the area south  of Alexandria  city
          (Amerya)  is  also  below the   1-m  contour level.    These areas  are
         presently under extensive development.   Plans for development in  this
         area  should  be carefully revised.    Some   tourist  sites  west  of
         Alexandria  are  also  built between  the first  ridge  and the  sea  (at
         localities below the  1-meter contour),  which puts them at risk.  This
         region hosts about 40% of Egypt's industry, as well  as many historical
         and tourist sites.

     2.  Lake Burullus:   This  area  is   already  subject  to serious  erosion and
         accretion  problems.   Rising  sea  level will  increase  this  rate  and
         destroy beaches and resort  villages in the area. In addition, the lake
         is under consideration for  a water storage project.   The environmental


                            MEDITERRANEAN  SEA

                                                                 jj/iV-j Wetlands (

     A detailed quantitative environmental impact assessment should be carried
out  based  on  use  of geographical  information  systems,  making  use of  the
information  on the  northern  coasts  already  existing  at  the  University  of
Alexandria  and  other research centers.   A multistage technique  in  which  the
impact could be calculated by an interaction matrix for each 0.25 meter of sea
level rise is suggested.  An interaction matrix with  elements of the "magnitude"
and "importance" of the impact  should be calculated for each area.  The elements
of  such  a  matrix could  be estimated  from  accurate  analysis  of  geographic
information systems based on recent data of the area.


     If sea level  rises,  Egypt has only three options:

         Withdraw from coastal areas;

         Build  walls around  limited areas  to protect  valuable lowlands  or
         industrial complexes  from inundation; or

         Adjust  to  expected changes,  and perhaps  take  advantage of  them  by
         appropriately changing land use (e.g.,  shifting to crops that tolerate

     Because of  the  variable  environmental  and  economic  conditions in  the
vulnerable areas,  the choice of any of these options will greatly depend on  the
area  under consideration.   A detailed  study of  each  area  is,  therefore,

     Alexandria city is built over a number of  relatively high  hills or  dunes
separated by narrow  "tunnels"  (Figure  2).  It may be possible  to protect  the
urban and  industrial  areas  against  rising seas by building a number of  walls
to protect the southern parts of the  city.  However, such a response must  await
accurate analysis of data and studies of geological  structure  and elevation  of
these hills.

     In  general,  any policy  that would be of interest for future development  in
the area must be of the type that  will  help whether or not climate changes   --
i.e., it must  a  two-sided  policy.   Conserving energy and water  resources  and
converting  to  salt-tolerant  agriculture are  policies of  this type.   Broadly
speaking, response strategies fall  into two categories:  limiting global warming
and adapting to its consequences.

Limiting Global Warming

     This approach is intended  mainly to buy  time:

     1.   Limit the production  and emission of C02, CFCs,  and  other  greenhouse
         gases.  Enforce air pollution  control measures.  Apply  the  Clean Air



                                                                              Abu-Qir Gull
Alexandria Topography
     Delta Deposits
     Present Borders of Lake Mariut
     Regions From Lake Mariut That
                                MEDITERRANEAN SEA
     Have Been Drained


                              Alexandria Harbor

                      Raas-EI-Agami A Sea Gulf
       Mariut Valley

AI-Mex-Abu-Sir Dunes

Om-Gaghyu Island
                              AI-Amereya 2go 50
Figure 2.   Alexandria outskirts  showing ridges over  which the city is built.
          Act  in  Cairo,  Alexandria,  and Tanta,  at  least,  and  enforce  it by
          efficient monitoring networks.

     2.   Develop  and enforce the  operation of  more  energy-efficient  engines.
          Increasing engine efficiency is found to  be one of the  most important
          factors  in reducing greenhouse emissions (Lashof  and Tirpak,  1989).
          Include  a social  impact tax in  the price of polluting  fuels  to limit
          their  excessive use.

     3.   Work on  planting greenbelts, and increase the awareness  and perception
          of the public concerning overuse of fertilizers.   Encourage and support
          programs for environmental  education and  research.

     4.   Increase the proportion  of solar  energy  use and/or other  renewable
          energy sources,  such  as  wind  energy.   Support  programs  for  studying
          and implementing energy conservation techniques.




     Adapting to global  warming  involves long-range planning.   For instance,
one of the most important problems developing countries are expected to face in
the  near future,  with  special  reference to  Egypt,  is  the  availability  of
freshwater.  With  a  population growth rate of 2.8% per year,  future domestic
water use  is  expected to consume a  large part of Egypt's fixed  water budget
(55 million cubic meters  per year).   In  view  of  the  projected global warming,
water conservation programs must start --  the  sooner  the  better -- whether we
have climate changes or  not.   Other  adaptation policies  for  Egypt include the

     1.   Adopting  new agricultural   practices  with improved  efficiencies for
         using freshwater resources.

     2.   Encouraging  and developing multidisciplinary  institutions concerned
         with the  real location and use of scarce freshwater  supplies,  such as
         groundwater resources.  Developing techniques for rainfed (as opposed
         to irrigated) agriculture.   Supporting projects  based on rainfall along
         the north coast.

     3.   Strengthening mechanisms for converting land and other resources into
         and out of agriculture in response to climate change.

     4.   Adopting  a new  policy for urban development  of  coastal  regions based
         on predicted sea level rise  for  the next  40 or 50 years.  For instance,
         resort villages with massive foundations are currently built on ridges
         parallel to the shore.  In the future,  only transportable wooden cabins
         should be allowed near shores.

     Special  policy recommendations for the northern coastal region include the

     1.   Plans for building an international road  along the north coast consider
         enforcing road  foundations  to  act as a wall for protecting the Nile
         delta  in  case  of  sea level  rise.    The same could be  extended  to
         vulnerable areas west of Alexandria.

     2.   Reevaluate  the  Alexandria  and  Damietta master  plans,  based  on new
         predictions.  Build  future massive beach resorts on the ridges at least
         1 meter above sea level.

     3.   Launch  a socioeconomic  program  directed toward  increasing  public
         awareness   that  rainfall   patterns   may   change.     Use   recent
         biotechnological capabilities of saltwater-tolerant plants.

     4.   Develop and implement techniques for reducing water table levels over
         existing  lowlands  and human  settlements near  the coastal  regions.
         Develop windmill techniques of  water pumping,  and  test  capabilities
         in pumping already waterlogged areas in  Agamy west of Alexandria.



     5.  Control  the overexploitation  of  quarries along  the coasts  west of

     6.  Relocate waste dumping to suitable sites to reduce  future risk of water

     7.  Investigate  the  technical  and  economic possibilities of protecting
         Alexandria  city  by  building a  number of  discontinuous walls  over
         "tunnels,"  and  using local  natural  rocks,  such  as  granite,  basalt,
         dolomite, and diorite.

     8.  Delineate  and study regions  of erosion  and  accretion  for  better
         evaluation of conditions along the northern coasts and identification
         of areas most vulnerable to  sea level rise.

     9.  Encourage the reclamation projects to take place in areas with greater
         elevation.  Extend public services to newly developing communities in
         the highlands, giving  first  priority to people from vulnerable areas
         to move to these newly developed lands.

    10.  Explore the technical  and  economic  feasibility and impact assessment
         of bypassing Nile River sediments from Aswan High Dam.

     As a first step, a multidisciplinary team of experts  should  be  formed to
carry out a detailed environmental impact assessment of the  effects of sea level
rise and to  recommend  specific measures to  counter  these  effects.   The  same
exercise should then be carried out for other effects of climate change.


     The author acknowledges  valuable discussions  with  Dr.  S. Nasr  from the
Department of Environmental Studies,  and with  Dr. 0.  Frihy from the  Institute
of Coastal  Research.

ARICON.     1988.    Master  plan   for   development   of   the  north   delta
region and international road.   Cairo, Egypt:  Ministry of Reconstruction, New
Communities and Infrastructure.

Broadus, J., J. Millman, S. Edwards,  D. Aubrey  and F. Gable.  1986.  Rising sea
level and damming of rivers:   Possible effects  in Egypt  and Bangladesh.    In:
Effects of Changes in Stratospheric Ozone and Global  Climate, Vol 4: Sea Level
Rise. J.G.  Titus,  ed.  Washington, DC:  U.S. Environmental Protection Agency and
United Nations Environment Program.


Frihy, O.E.,  S.M.  Nasr,  M.H.  Ahmed, and M.  El-Raey.   Long term shoreline and
bottom  changes of  the  inner  continental  shelf  off  the  Nile  Delta,  Egypt.

Lashof, D.A., and D.A. Tirpak.   1989.   Policy Options  for Stabilizing Global
Climate.  Washington, DC:  U.S. Environmental Protection Agency.

Quarterly Economic Review of Egypt.  1985.    Annual  Supplement.  London:   The
Economist Publications Ltd.

Sestini, G.   1989.   The  implications of climatic changes  for the Nile Delta.
Report WG 2/14.  Nairobi, Kenya:  United Nations Environment  Program/OCA.

UNEP.  1987.   United Nations  Environment  Program.   Environment Library No. 1.
Geneva:  United Nations  Environment Program.

UNEP.  1989.  United Nations Environment Program.  The Full Range of Responses
to Anticipated Climatic  Change.   Geneva:   United Nations Environment Program.


                           EL-HAFID TABET-AOUL
                    Laboratorire  d'Etudes Man'times
                      30  Rue Asselah Hocine Alger
                            Algiers,  Algeria

     More  and  more,  the  public  is  recognizing that global  warming due to the
"greenhouse effect" will  increase the mass and volume of the water in the oceans
and will thereby accelerate the rate of sea  level  rise during  the  next few
decades. Such a rise would increase coastal erosion and other hazards of coastal

     Due to the seaward  advance of  deserts and rising sea level, the coastal
zone of North Africa is becoming narrower.  At  the same time, population growth
is causing  rapid urbanization.  Thus, it is important today to create strategies
for adapting to the global warming  of tomorrow.


     The Mediterranean shore has been populated since the beginning of recorded
history. Ancient civilizations have left a great number of remains on the coast,
which can be very helpful  in addressing the impacts of sea level  rise.  As early
as 1934, His Highness Prince Omar Toussoun ordered  a study to determine how much
the sea level  had risen in the port  of Alexandria, Egypt.

     Most people along the Mediterranean  coast  have not noticed  the sea rising,
but that does  not mean it is not occurring.   Tidal gauge records  in Marseilles
show that the sea level has been rising 1 mm per year there for the last century
(Bruun, 1987).   This rise may  be limited  by the region's  climate.  For example,
the Mediterranean Sea is already an area of net evaporation, which tends to lower
sea level.  Moreover, seasonal variations may obscure the sea level.  As Figure
1 shows, seasonal variations can be  100 times the  annual rise.

Figure 1.  Yearly evolution of mean sea level  in Trieste, Italy, which is a good
approximation of trends on the Algerian Coast.

     For Algeria,  the most  important problems resulting from sea level  rise are
likely to be the loss of usable land,  damage to port facilities,  and pollution
of groundwater.

Loss of Usable Land

     The continental shelves in the western part of  the Mediterranean  Sea are
rather narrow  --  less  than 25  miles  wide -- and are cut by  numerous  canyons.
Along  the  Moroccan and  Algerian coasts,  the  shelf slopes  an  average  of
approximately 10%.

     Above the sea,  the  limited width  of the vital belt confined  between the
desert and  the  sea implies that national population growth  will  increase the
urbanization of the coastal zone.   In Algeria,  more than  50% of the population
lives within 50 kilometers of the  sea (Figure 2).

     Park et al. (1986) forecast that 40 to 75% of existing U.S. coastal  wetlands
could be lost by 2100.  A similar  impact can be expected  in Algeria.

Quays and Port Facilities

     Given the low tidal  range  (less than 50 cm) in the Mediterranean Sea, port
facilities have been designed with levels close to  sea level.  In Algeria, ports
are designed with quays up to 2.0  m above sea level.  A rise in sea level would
flood these structures as well  as  the operational  land  behind.


     Because of the  importance of maritime trade, which  represents more than
90% of the  total  amount  of the Algerian trade exchange, port designers should
bear in mind the possible effects of sea level  rise in  future port construction.
Fortunately, existing structures can be elevated as the sea rises.

Groundwater Pollution

     Most of the cities  on  the  North African coast are supplied by groundwater.
A  rise  in  sea level  will cause  saltwater  to  contaminate  the  groundwater.
Regarding soil permeability and smooth groundwater table slope near the shore,
large quantities  of  freshwater will  be lost, proportional to the rise in sea

     Along the North African coast, both structural and planning measures will
be necessary.

     Rigid structures, such as  breakwaters,  seawalls,  and groins,  can protect
urban  areas.    However,  given  their  high  cost,  these  structures  would  be
appropriate only where there are valuable buildings or  land.   If structures are
destroyed by storms or other phenomena, they should not be rebuilt.
Figure 2.

Algerian cities with more than 100,000 inhabitants,



     In rural areas, rigid solutions would not usually be justified economically.
More flexible measures may  be  appropriate  such  as  setback lines that prohibit
construction in areas likely to be inundated within a specified period of time
(up to 100 years).  New construction criteria should be defined.  However, the
difficulty will be to convince officials to accept the loss of
precious land today to prevent the consequences  of something that will  happen
in the 21st century.


Bruun, P.  1987.   The effects of changing the atmosphere on the stability of sea
level and shore stability.  PIANC 58:129-132.

Bruun, P.  1989.  Coastal engineering and the use of the littoral zone.   Ocean
and Shoreline Management 12(5) and (6).

Lamy, A., and C. Mi Hot.  1981.  Bottom pressure and sea level measures in the
Gulf of Lions.   Journal of Physical Oceanography 11:394-410.

Park, R., T.V.  Armentano and  C.L.  Cloonan.  1986.   Predicting  the effects of
sea level rise on  coastal wetlands.   In:   Effects  of Changes in Stratospheric
Ozone  and  Global  Climate.    Volume   4:    Sea  Level  Rise.   J.G. Titus,  ed.
Washington, DC: United Nations Environment Programme and the U.S. Environmental
Protection Agency.  October.

Sharaf el  Din,  S.H.,  and Z.A. Moursy.   1977.   Tide and  storm  surges  on the
Egyptian Mediterranean coast.   Rapp.  Comm. Inter. Mer Medit.  24:2.

Vignal, J.  1935.   Les changements du niveau moyen des  mers le long des cotes
en Mediterranee.  Annales des Ponts et Chaussees 28.

Weaver, D.F., and D.L. Hayes.   1989.   Proposed response to sea level rise by a
local government.  In:  Coastal Zone  '89.   New York:  American Society of Civil
Engineers, pp.  2490-2501.



                      TO A  RISE IN SEA  LEVEL
                          DR.  SASKIA JELGERSMA
                 Geological Survey of  The Netherlands
                               P.O. Box  157
                   2000  AD Haarlem, The Netherlands

     The European coastal lowlands comprise deltas  and plains including wetlands
and natural  areas at low altitudes  that encompass extensive zones of densely
populated, intense economic and agricultural activity. Around the southern North
Sea Basin  alone,  the  coastal plains area  is the home of more than 200 million
people  who  live  close to  present  sea  level  and  are  already at  risk  from
inundation  as  a consequence  of coastal erosion,  storm surge,  and the current
trend of sea level rise of 1 to 1.5  mm per year.

     During  a session on the impact  of a future rise in sea level, part of the
European Workshop  on  Interrelated Bioclimatic  and Land Use Changes,  12 papers
presented  case histories on  the present  situation of  the shoreline.   The
consensus was that European coastal lowlands are already experiencing damage from
erosion, inundation during storm surges, storm waves, subsidence, and saltwater
intrusion  as  the  consequence  of  sea  level  rise,  increased incidence  of
storminess,  and human activities.

     Moreover, many human activities  are increasing the vulnerability of coastal
areas to a rise in sea level.   These  activities  include sand extraction  from
beaches and  offshore  areas for reclamation and the  construction industry;  the
destruction  of natural shoreline defenses,  such as sand dunes, to provide hotel
accommodations  and amenities  for the  tourist  industry;  the interruption  and
diversion of longshore sediment transport by groins,  jetties, and harbors;  the
reduction of the sediment load  of rivers by water management in drainage basins
and the construction of dams and reservoirs,  cutting sediment supply to nourish
beaches and  deltas;  the canalization of rivers for  navigational purposes;  the
reclamation  of  coastal  lowlands  for agricultural,  industrialization,   and
residential  development; and the extraction of groundwater for drinking water and
irrigation,  which  has led to subsidence and the penetration of saltwater.

North and Vest Europe

     The maximum rise of  sea  level  during the recent geological  past  did not
exceed 2.2 m/100 years.   During the  past 4,000 years, when the rate of rise was
considerably less,  sedimentation has kept up with  and  locally exceeded sea level
rise.  In natural areas, where human activities are not pre-eminent, such as the
Dutch, German, and  Danish Madden Sea, sedimentation has kept up with the present
rise of sea level  of 10  to 15  cm/100 years.  Investigations of the sediments of
the coastal lowlands indicate  that, given a natural sediment budget, these areas
responded  and  adjusted  to a  range of  rates  of sea  level change  and  climatic
change in the past.

     The coastal lowlands of  Europe have  a good  infrastructure.   Accordingly,
they will  be  able  to address  future sea level  rise more  easily than countries
that have  none,  e.g.,  the Third World.   Nevertheless,  in both rich  and  poor
nations, the socioeconomic impacts of a future sea level  rise will be profound
and widespread.


     As  the  report of  the Miami  conference  notes,  people  have always  been
concentrated  near  the  coast.    Although  the  general  lack  of  topographic
information has made it impossible  so far to estimate  how many people live within
one  or  two meters  of sea level,  we do  know that about  half of the  world's
population lives in deltas and other  coastal lowlands.  In most cases, deltas are
entirely less than ten meters above  sea level; and  in many cases at  least  half
the delta is within one  or two meters of sea level.   Even for the portions  with
greater elevations, life is affected by sea level because the heights of river
and storm surges are influenced by the base level of the  sea.

      For purposes of this paper,  we define coastal  lowlands  as areas that are
within  coastal  floodplains  or would  be  without manmade coastal  protection
structures.  Besides flooding, most of these areas are already subject to erosion
and saltwater intrusion  because of rising  sea  level  and,  mainly, as a result of
human interference with  the natural flow of rivers to  the sea and sediment along
the coast.

     Even a large  part of  relative sea level rise stems from subsidence induced
by  human  activities,  such as withdrawals of  groundwater, oil,  and gas,  and
drainage of land and the  resulting  compaction  of peat and  clay underlying it.
In some cases  -- such as  the Netherlands -- the fact that relative sea level  rise
and  its  consequences are already  being   faced  would make  communities  less
vulnerable to global warming because physical  and political  infrastructures to
address  the  problem already exist.    In  other cases, existing  subsidence has
eliminated the safety margin  that might otherwise have allowed communities to
tolerate the projected rise in sea level  over the next 50-100 years.

     This paper summarizes  the implications of  sea  level  rise for  low-lying
coastal areas around the North Sea and the Atlantic  coast of  Europe.



     Coastal lowlands comprise the lands where sediments are deposited by tides,
storm surges, and some  areas flooded  by  river water -- namely,  those in which
flooding results  because  of the backwater effect from  the sea.   The sediment
deposited  includes  peats,  clays, silts,  and sands  generally lying  below the
present spring tide  level;  at slightly higher altitudes, they  also  lie along the
inland margins of the coastal lowlands.  Although coastal lowlands are usually
within a few meters of sea level  in the case of coastal  dunes they can accumulate
to several tens of meters above sea level.

     The  coastal  lowland  itself  shows   a  great  variety of  morphology  and
lithology.  Rivers entering the sea can have deltas that show great  variation due
to dominant processes of waves,  currents,  and fluvial  input.  If river input is
low and/or  the tide  ranges  are  relatively great,  estuaries  are  found instead.
Inland from the shoreline,  there are generally coastal wetlands,  with zonations
primarily  dependent  on the  vegetations'  tolerance  of salinity  and  frequent

     Along certain coasts, coastal barriers with dunes on top of them and barrier
islands can occur with coastal wetlands in the hinterland.  During the Holocene
rise in sea level,  these zones of different environments have shifted landward;
if sea level rise accelerates,  their landward migration will  do  likewise.

     There are no important deltas  in  northern and western Europe.  Most of the
rivers end in estuaries, like the Elbe, Weser, and  Ems  estuaries in Germany; the
Rhine and the Meuse  Scheldt estuary  in the southwestern  Netherlands; the Severn
and Thames  in England;  the  Somme,  Seine,  and Gironde  estuaries  in France; the
Tajo estuary in Portugal; and the Guadalquivir estuary in Spain.

     In large measure  because  of the configuration of  the southern  North Sea
Basin, storms from the  north and west can produce extremely  high  tides, which
have caused  severe flooding many times throughout the last  several  centuries.
This configuration also contributes to large  tidal  ranges:   macrotidal  (>4 m)
conditions prevail along the English  Channel,  along  the  Strait of  Dover, and in
the Bristol channel.   The  highest tidal range  of Europe  can be found in the Bay
of Mont-Saint-Michel  (12 m) in France.  Figure 1  roughly indicates the coastal
lowlands, the river estuaries,  and the delta.


     For  centuries,   Europeans  have  drained  and  reclaimed  wetlands  for
agriculture, industry,  and housing of large cities.  The draining has caused land
subsidence through compaction of peat and clay soils;  moreover,  land surfaces
have also  been  lowered  because  the compaction of unconsolidated  sediments --
which would be occurring even without human interference -- is no longer offset
by the deposition of sediment from floods.  In many  areas, compaction has been
so great that these soils are now lying below  mean sea  level.  Accordingly, they
have to be  drained by  pumping,  and many  areas are  protected by dikes  against


North and Vest Europe

storm surges and high tides.  The only extensive natural areas left are the tidal
flats of the Dutch, German, and Danish Madden Sea.

     An important  side  effect  of  this  intense drainage  is the intrusion  of
saltwater.   The damming  of rivers diminishes the freshwater flows  that would
otherwise push saltwater  back toward  the sea.  Dredging  in  the  estuaries and
deltas in the interest of port development has also caused saltwater intrusion
farther upstream.   This shift of saline water has affected the  intake of water
from the river for  irrigation  and other water supplies.  Yet another side effect
is saltwater intrusion in coastal  aquifers  (see Titus in the section on Problem

     The coastal lowlands of Europe, especially the river estuaries and deltas,
are areas of dense  population  and heavy industrial activity.  More details about
human activities,  land use, and vulnerability  to flooding, especially by a rise
in sea level, should be  given on  smaller  scale maps  by the European countries
involved.   An example is  the maps of the southern  North Sea  Basin.   In the
region, about 20 million  people live below the high-tide  level.   The economic
value of these low-lying  areas  is  enormous.   These  areas  are also  gateways to
industrial  areas in the  hinterland as  well  as oil  and gas  fields;  there is a
heavy concentration of pipelines,  refineries, and oil  harbors  in  the southern
North  Sea.   The population density and  important  industries  in the  coastal
lowlands surrounding the southern North Sea Basin make them very vulnerable to
sea level rise.

     An accelerated rise  in sea level would (1)  increase the risk that reclaimed
lowlands will  be  inundated;  (2)  accelerate coastal erosion,  threatening both
structures and recreational beaches; (3) increase the risk of flood disasters;
(4)  impair the  effectiveness of  drainage  systems;   (5)  increase  saltwater
intrusion  into groundwater,  rivers,  bays,  and  farmland;   (6)  damage  port
facilities; (7) threaten the  wetland habitats of birds, fish, and wildlife; (8)
shift sedimentation in rivers farther upstream, hampering shipping;  and (9) alter
tidal ranges,  which might exacerbate many of the other effects.

     Other impacts of global  warming  could also be important.  If wind patterns
and climate change, the runoff from  rivers will increase in winter and decrease
in summer.  The increased runoff  can  create problems for the embankments, and a
decreased runoff can cause extensive saltwater  intrusion  upstream.   Increased
storminess  could  be even  more   important:   the most  significant damages  on
coastlines occur during storm surges  at the time of high tide.  If this increase
in storminess should occur along  the coasts of the southern bight of the North
Sea,  the  highly   populated,  industrialized  coastal  lowlands  would  suffer
disastrous losses.



     How can the coastal  lowlands of Europe respond to the  predicted rise in sea
level?  They can either try to defend the lowlands or move present activities and
development  landward.    The  land  can be  protected by  dikes,  seawalls,  beach
nourishment, and  other  engineering solutions, but  economic  and  environmental
impacts can make  such a  protection strategy  unacceptable.  On the other hand,
moving present activities  landward also will  have serious economic and social
effects.   Well-developed  countries  such  as a  united Europe  will   have  the
organization, the technology, and  the resources to make  these tradeoffs, unlike
less developed countries, which lack the above-mentioned  infrastructure.

     Sea level rise  and the  implementation  of  response  strategies  will  have
serious effects on individual, regional, and  national economic levels.  Impacts
on real income include the loss of production from land  and seas as well as the
effects of  employment changes from reconstruction.   Migration of people  and
enterprises will  disrupt existing economic and social structures.

     Many European coastal  lowlands are in critical balance with the present sea
level and are in great danger of flooding if storm surges occur.  Important parts
of the shorelines are affected by erosion, especially during storm surges.   At
places where shorelines  are eroding, stone jetties and concrete or wooden groins
are built to lessen sand draft.  This method is  disputable because it seems to
be  causing  more  erosion on  the  rest of  the unprotected  shoreline.   Beach
nourishment seems to be  a more successful  method of protection.

     But a strategy is more than a  set of physical structures or laws  governing
what and where people can build.  We need to systematically analyze which areas
are vulnerable,  as well as  the  legal,  environmental,  economic,  and cultural
implications of each of the possible responses.   Only then will  it be possible
to rationally respond to the risks of accelerated sea level  rise.


                   POLISH  BALTIC  COASTAL ZONE
                      Department of  Paleogeography
                     Quaternary Research  Institute
                       Adam Mickiewicz  University
                   Fredry 10,  61-701  Poznan,  Poland

     About 3,645 square kilometers of land (1.2% of the total area) in Poland are
less than 20 feet above mean sea level.  The area at greatest risk, located below
1 m above sea level, is  1,550 square kilometers, of which 70% lies in the delta
of the Vistula  and  12% lies in the lower Odra valley and  around Szczecin Bay.
The remaining 18% below 1 m elevation is in a 300-km section of the coast between
Wolin Island Hel (at the end of the Hel Spit).  These  areas have 1.8% of Poland's

     In  the area at risk,  there are four large  shipyards with  capacity equal to
2% of world production,  a large  chemical plant at Police, an oil refinery in
Gdansk  (processing  6 million  tons/year),  railway  junctions,   plants of  the
machine-building  industry, the lower Odra power plant, and the whole of the old
city of Gdansk,  a priceless cultural  center.  Within the low-lying area,  there
are 28 holiday resorts and sandy  beaches.  Eighteen holiday resorts are situated
above the cliffed coast and are  exposed to erosion rates of 40-150 cm/yr.

     At  present, the awareness of the impacts  of sea level  rise  is low, both in
society  in  general  and in the  administrative units.


     Intensive  emission  of C02 induces  the  so-called greenhouse effect.   This
will  increase global temperature, which will  bring  about a faster  melting of
glaciers and  inland ices, as well as  thermal expansion  of  the ocean  water.
Forecasts indicate  that  during the next 100 years, these factors may cause sea
level to rise from 50 to 200 cm.   This rise will pose  a number of threats to the
natural  and cultural environments  of  the coastal  zones of  maritime nations.

North and West Europe


Sea Level Changes and Storm Surges

     Changes  in  coastal  water  levels  in  Poland have  been  recorded  by  21
marigraphic and gauging stations (Figure 1), many of which have been operating
for the last century.  A clear cycle of changes in the  sea level can be observed
in periods  of 19-20,  7-11, and  3-5 years.   The first two  are connected with
changes in  the  activity of the  sun;  the  origin of the last  cycle  is obscure
(Jednoral,  1984; Dziadziuszko  and  Jednoral, 1987).   The regression  lines and
equations show that there has also been a gradual rise in sea level over the last
hundred years (Figure 2).  The tendency has accelerated markedly in recent years.
The mean annual sea level  rise over more  than  a hundred years amounts to +0.7
mm/yr in Swinoujscie, +1.1 mm/yr in Kolobrzeg,  and +1.2 mm/yr in  Gdansk.  For
the last 35 years (1951-85), the  rate of rise is generally higher, reaching +1.4
mm/yr in Swinoujscie and +2.9 mm/yr in Gdansk.

     Poland experiences severe storm  surges.   Surges  greater  than  570 cm have
a probability  of  0.75% in any given  year.    From  1951 to  1975,  storm surges
occurred very irregularly,  from none to seven  in a year (Majewski et al., 1983)
(Figure 3).  Over the last 700 years,  82  storm surges have exceeded 1.2-1.5 m.
In 31  of  these cases,  sea level rose by more than  2.5  m (maximum  <3.0 m),
exceeded 600 cm,  and none was higher than 650 cm (Jednoral, 1984).   During the
period of systematic observations, the highest intensity of storm  surges took
Figure 1.  Wind conditions, air temperature and precipitation (A), directions of
longshore currents (B) along the Polish coast.


                                             Rotm'cki and Borowka
                  1860     1880     1OO     1920     1940     1960
1920      1940     1960     1980



1900     1920     1940     16O     1*O
                  1860      1880     1900     1920     1940     1960

Figure 2.  Sea  level  rise during the  last century in the  Polish coastal zone.
(Czekanska, 1948).  From 1951 through 1980, 88 storm surges occurred;  15  of these

North and Vest Europe

  1.5  2        5    10   20
               .99  .9    .7   .5    .3        1    .05   .02   .01

Figure 3.   Probability  of  storm-surge  height  and of number of storms per year
in the Polish Baltic coastal  zone.   Probability curves  counted  on  the ground  of
data published in Majewski et al. (1983).
place  at  the turn  of the 19th  century.   About  55% of  storm surges develop
withwinds from the  north,  31%  from the northwest,  and 14% from the northeast.
The northeast wind creates the highest and most dangerous storm surges.

     River mouths are  important sources of longshore material  and are also  zones
of discontinuity in  the dune belt.  Therefore, they are places where storm surges
can penetrate the coastal  barriers onto usually  low-lying  areas behind  them.
On the Polish coast of  the Baltic are the mouths  of two rivers with drainage
basins exceeding  100,000 km2 (the Vistula and Odra Rivers) and six rivers with
basin areas of 1,000 to 3,000 km2 (Figure 3).


     The 493-km Polish coast consists of alternating cliffed (105 km) and barrier
beach sections (373  km).  Swampy coastal sections occupy about 15 km (Figure  4).
The cliffs  are   15-40 m  high,  with  a maximum  of  90 m;  45  km of  cliffs  are
retreating  between  0.4  and 2.3  meters per year.   At the cliff  base one  can
observe low beaches  (0.4-0,8 m) with one or no submerged sandbars in the breaker
zone (Rosa, 1984).  A striking example of  coastal  erosion is the ruins of  the
church at Trzesacz,  which was built in the 12th century about  1,800 m from  the


                                                          Rotm'cki and Borowka
Figure 4.  Geomorphology of the Polish coastal zone.  1 - ground moraine plateau,
2  -  end moraine  hills,  3  -  alluvial and  glaciof-luvial  plains, 4  -  glacio-
lacustrine plains, 5  - swampy  plains,  6  -  cliffed coasts,  7 -  barrier coasts,
8 - mean annual rate of the  cliff abrasion  (meters  per  year  - in numerator) and
cliff height (in meters - in denominator).
coast.  Figure 5 shows the church and other areas threatened  by erosion.  Figure
6 illustrates structural response to this erosion.

     Coastal  barriers are especially well developed  in  the  eastern and middle
parts of the  Polish coast.   They  separate old  marginal  valleys  and terminal
depressions of  the  last inland ice  from the sea, allowing  coastal  lakes and
swampy plains  to form.   On  the Polish  coast  three  types of barriers  can be

     1.  Barriers of a modest width (<0.5  km) occupied by a single row of dunes
        3-6  m  high.   They  are already  susceptible  to destruction  by storm
        surges,  especially because the  adjacent  beaches are  low  (0.6-0.8  m).

     2.  Wide  barriers (<2.0 km) occupied  by several rows of dunes with heights
        up to  20 m.  Beaches extend  up  to about  1.0-1.2 m above  sea level.

     3.  Wide  barriers   (about  2 km)  occupied  by  complexes  of  parabolic and
        barkhan  dunes that are 20-50 m high.    Foredunes can  be found only near
        the beach, and their heights vary from  3 to 10 m.  On the Leba Barrier,
        for  example,  there are also  fields  of migrating dunes  with  barkhans
        shifting east by about  10 meters  per year.


                                                                       Figure 5.  Coastal erosion in Poland.

                                                                       (A) Ruin of the church at Trzesacz  (middle
                                                                       coast), which was 1.8 km from the Baltic coast
                                                                       when  it  was  built in  the  12th  century.
                                                                       Tetapads have  subsequently been installed
                                                                       to slow cliff erosion.
                                                                       (B)  The  town  of Ustronie Morskie (middle
                                                                       coast)  is also  threatened  by cliff erosion.

(D)  Leba Barrier  (middle coast)
when erosion of foredunes has
exposed underlying peat.
                                                                       (C)  Swimmers and sunbathers at Wolin Island
                                                                       (western coast) where the cliff has been cut
                                                                       into glacial and fluvial glacial  Pleistocene

                                                                       Figure 6.  Erosion protection  in  Poland.

                                                                       (A) Sarbinowo (middle coast). Concrete block
                                                                       and concrete band protect the cliff against

                                                                       (B)  Fishing  village Kuznica on the Hel  spit
                                                                       (eastern coast.)  Boulder and clay ridge and
                                                                       piles of concrete  sleepers protect the coast
                                                                       where foredunes have been destroyed by storm

                                                                       (C)     Hel   Spit   near  village   Kuznica.
                                                                       Artificial beach  built of sand pumped  from
                                                                       the bottom of the Puck Bay.

                                                          Rotm'cki and Borowka

     There  are  also  well-developed spits.   Hel  Spit  is being  intensively
destroyed by erosion at present, especially in its western part.  This process
started with the construction of the harbor breakwaters of Wladyslawowo in 1938,
located at the base of the spit.

     Along the Polish coast are two large estuaries:  Szczecin Estuary (687 km2),
the Vistula Estuary (838 km2), and some coastal lakes  with a total area of about
196  km.    Low-lying  wetlands   behind  barriers  are  commonplace   (Figure  4),
particularly in the deltas of the Vistula  (ca. 1,650  km2) and Odra Rivers (ca.
300 km2)  as  well  as  numerous late glacial marginal valleys.  A substantial  part
of  these areas,  especially  on  the Vistula  Delta,   are  depressions with  an
elevation of -1.8 m  below sea level.   Since the  15th century,  people  have
controlled the hydrologic conditions of the wetlands;  hence a rise  in sea level
would not necessarily  inundate them, but  it would require  increased pumping.


Land Use of the Low-lying Areas

     The Szczecin Estuarine area and the lower Odra valley areas lie less than
1 m  above sea level.   These  areas are mainly  wet meadows and  grazing land,
similar to areas on Poland's middle coast.  Areas between  2  and 5 m above  sea
level are mostly arable land.  In the Vistula Delta  (1,653 km2), embracing  47%
of the low-lying areas  of  the  Polish coastal  zone,  agricultural  land takes up
77%, and  nonagricultural  land, 23%.   Of  the agricultural land,   62.5%  is  in
cultivated fields and 37.5% is  in  meadows  and pastures (Matusik and Szczesny,

     The Vistula Delta has very good soils  that have facilitated the development
of intensive agricultural production.  A substantial  part of the low-lying areas
of the Polish coastal  zone  (1,835  km2)  is  in  polders, of which 555 km2  are in
depressions (Cebulak,  1976, 1984).   About  67% of the polders are in the Vistula
Delta,  18% on the middle coast, and 15% in  the  Szczecin region.  The polders are
protected by a system of dikes:  975 km of  dikes in the Vistula Delta, 22 km on
the middle coast, and about 250 km in the  Szczecin area (Cebulak,  1984).


     The Polish  coastal  zone  comprises  28  towns,  which in 1985, were inhabited
by 4.2% of the total population of  Poland  (i.e.,  1.6  million  people);  of this
total,  83% live  in six towns:  Gdansk,  Szczecin, Gdynia,  Elblag, Swinoujscie,  and
Sopot (Figure 7).  In  13 of these towns, 50-100% of the land is 0-5 m above  sea
level.   Only 5-40% of the remaining  towns lie less than 5 meters  above sea level.

     Jointly, the low-lying areas  of  the  Polish coast are  inhabited  by about
680,000 people -- i.e.,  1.8% of Poland's population.  Approximately 52% live in
the Gdansk-Gdynia-Sopot agglomeration,  23.5% in  the Szczecin region, and 13.6%
in the  Vistula Delta.  The remaining 11% are dispersed  along a 300-km-long coast
between Wolin Island and the tip of Hel Spit.  The density of the population of
the coastal  belt  lying less than 5 m above sea level is 193 persons/km2, of which
25-26 persons/km2 live  in rural  settlements.


Wort/? and West  Europe
                             annual trans-shipment in ports
                             in million tons (in 19791

                             annual ship production
                             in thousand DWT (in 1979)

                            7 fishing ports and annual fish
                             discharging in thousand tons
                             (in 1976)
holiday resorts with sandy beaches:

fa   situated on a cliffed coast

A   situated on a dune coast

 0         45 km
Figure  7.   Cities, ports,  shipyards, and holiday  resorts at the  Polish Baltic
coast.   Black sector  in  the  circle marks the  part of the city  threatened by a
future  sea  level  rise.

Ports and  Industry

     The largest  Polish port is Goteborg, which lies  on  the  Baltic.  Poland has
four other  large  ports:  Szczecin and Swinoujscie  on  the west coast, and Gdansk
and Gdynia  on the east coast (Figure 7).  The joint annual transshipment of the
four smaller ports amounted  to 60 to 70 million tons in 1979.  The old harbor
in  Gdansk  and those  in Szczecin  and Swinoujscie  are natural,  situated in the
river mouths; the Gdynia harbor  and  the North harbor in  Gdansk  are artificial.
In addition,  three small  natural  harbors are situated in the river mouths on the
middle  coast.

     The  coastal   zone has a well-developed shipbuilding industry.   There are
several  shipyards, including three large ones  in  the ports  of  Gdansk, Gdynia,
and  Szczecin  with an annual  productive  capacity  of  about 2%  of  the  world
production.  The  harbors and shipyards  have a developed  industrial hinterland,
which  also  is the location  of  the electromechanical, electronic,  and  food
industries.  Also  located  in this area are  the Lower Odra  power  plant, an oil
refinery  in  Gdansk,  a  large chemical  plant at Police with  a  new  harbor for
handling  chemical  cargo  located  on the  Odra  River,   railway  junctions,  and
numerous  architectural  monuments  (e.g.,  the  Old  Town  in  Gdansk,  a priceless
monument  of culture).

                                                          Rotm'cki and Borowka


     Almost the entire coastal zone has spectacular landscapes,  which are valued
by tourists.  It has two national parks,  on Violin Island and on the  Leba Barrier,
and a coastal  landscape  park at  Hel Spit.  The coastal  zone boasts  a combination
of sandy beaches (3 ha/km of beach), cliffs, forested and partly  active dunes,
large  coastal  lakes  behind  narrow barriers,   and  architectural  monuments
(Andrzejewski,  1984).

     In 1980,  14.5  million  tourists  visited  the Polish coastal  zones, which has
138,000 beds for tourists, mostly in  small localities of up to  1,000 inhabitants.
There are also  accommodations at camping grounds, of which about  50% are up to
500 m from the  beach (Andrzejewski,  1984).

Shore Protection

     Of the 39 holiday resorts and sandy beaches  (Figure 7),  16 are on cliffed
coasts that are eroding 0.4-2.3 m/yr.  As a result, a variety of  shore protection
structures have been erected on the Polish coast.  The most expensive concrete
seawalls protect about 20 km of the shoreline.  Wooden and concrete groins are
located along  58 km of the coast, but they often do not really protect the shore
against erosion; they  merely slow erosion  and  in so doing, create  a problem
elsewhere.  Most of the low unconsolidated dune  coast  is only protected with
the help of low fences.

     In recent years, especially after storms of the 1980s when erosion caused
the shore of  the narrow Hel Spit to shrink by 50-80  m  at some places and the
water washed over in other  places, boulder-and-clay ridges  are  being built, and
piles of concrete sleepers  are being dumped along a 4-km section of the shore.
However, these are  destroyed too. In 1989,  at two points  of  Hel Spit, the sand
from the bottom of  Puck Bay was  pumped onto  the seashore to create a 50-m beach
belt 2-3 m in height.

     The entrances  to  all   the  harbors  are  protected against  storm  waves  by
jetties, usually running parallel to each  other and confining  the  navigable
channels.    There  is sand  accumulation  on  the  updrift  (western) side  of the
jetties, and erosion and landward shoreline movement on the downdrift side.


     Accelerated rise in sea level will  pose direct and indirect threats to the
low-lying areas.  Direct inundation  will confront the lowest areas,  which will
be below the  new sea level.  Indirect threats such as  flooding  will  face the
adjoining,  slightly  higher, areas.    The  natural, economic, demographic,  and
cultural resources  of Poland's coastal will  be seriously jeopardized.

Impacts of a 0.5-m Sea Level Rise

     The areas  lying less  than  0.5  m above  sea  level will  be  inundated  by  a
number of  processes:   (1)   the  narrow,  sandy coastal barriers  separating  the
low-lying areas from the sea could erode, exposing inland areas to the sea; (2)


North and West Europe

river valleys will drown; and (3) groundwater tables will  rise.   Several other
effects will be evident with a 0.5-m rise in sea level.   Other impacts include
cliff erosion and higher lake levels.

Increased Cliff Erosion and Landward Movement of the Beach

     With a  0.5-m  rise in sea level,  the probability  of particular levels of the
sea being exceeded during storm surges will increase markedly.   Flood levels that
today occur  only once in  a hundred years will recur every 3.5 to 5 years.  Based
on the cliffs that are currently exposed to  similar levels of wave  attack,  we
estimate that most cliffs will erode 2.3 m/yr.

Accelerated  Sediment Transport by the Longshore Current

     The higher  levels attained by storm surges  will  destroy foredunes and erode
barrier  islands and  spits.   The lowered barriers will then be  susceptible  to
storm washover, which  will  lead to  inlet   breaches and  sedimentation  on  the
backside of  barriers.  The sedimentation will  encroach either upon coastal lakes
or upon  the meadows and  pastures of  peat plains.  As  a result,  the  coast will
recede and the barriers will shift landward.  Especially  threatened  are the
narrow barriers of the middle coast  separating  Lakes  Jamno, Bukowo,  and Kopan
from the sea and Hel  Spit.,

Higher Coastal Lake Levels

     Coastal lakes are connected with  the  sea  through canals or rivers.   The
coastal  barriers  along the  Polish coast  have enclosed depressions  and valleys
of  the  late  glacial  age,   forming  coastal  lakes  and   peaty  marsh  plains.
Theoretically, a sea  level rise of 0.5 m should  increase the area of these lakes
by 10-30%.   This, however,  depends  on  (1)  how fast sea  level rises,  and  (2)
whether other geological  and biological  processes adjust to the  rate of the rise.

     Over the last few decades,  no increase  in the area of these  lakes has been
observed, despite  the  accelerated  rate of  sea  level  rise.    On  the  contrary,
because of their intensive eutrophication,  the  lakes tend  to  be  overgrown,  and
their area  is dwindling.  The rise in  water  level would have  to  be  very rapid
to change this tendency.  Hence,  a rise in the level of the lakes will  probably
enlarge the  area of swamps and young peat bogs surrounding the lakes and situated
on valley floors and  low-lying plains.  The sediment transported by rivers into
the lakes, the shift of coastal barriers southward through overwash and inlet-fan
sedimentation, the rapid growth of vegetation  on  the  lake sides,  and  biogenic
sedimentation controlled by  eutrophication  are all  likely  to  transform  the
coastal lakes to land, thus gradually  destroying a zone of great landscape value.
However,  theoretically  the  whole of the lacustrine-barrier  zone could shift

Expanded Depression Areas and Higher Groundwater Levels

     A sea  level  rise of 0.5 m  will  enlarge the area of  depressions  from  555
km2 to  1,720 km2, with  63% of the increased area  in  the Vistula  Delta, 23% in the
Szczecin Haff region,  13% on the middle  coast, and  1% in the Gdansk-Gdynia-Sopot
agglomeration (mostly in  Gdansk).  These areas will probably be inundated by the


                                                          Rotm'cki and Borowka

groundwater level rise; however, this too depends on the adjustment of natural
processes  to  (1) the  rate  of sea level  rise  and its  ingression  through the
valleys, and  (2)  the rate of groundwater level rise.   Most  probably this sea
level rise will make these areas swampy and will cause the development of peat
bogs and the accumulation of phytogenic layers.  Thus swamps and wet grassland
will greatly  increase  in area.  The  rise in sea level may  even  affect areas
situated 1-2 m  above sea level today.  The  range of  this  process  will  depend
primarily  on  (1) the  intensity of the  inflow of groundwaters  from morainic
plateaus onto the low-lying areas,  and (2) the  initial depth of the groundwater

     In polders,  primarily  in  the  Vistula Delta  (1,135  km),  (1)  groundwater
will rise  more  rapidly;  (2)  the probability  of particular areas being flooded
will increase, as will the breaching of dikes due to increased infiltration of
water during high stages;  and  (3)  the dikes  already  built  will  be too low for
the new hydrological conditions.  The probability that the dikes already built
in the Vistula  Delta will  be  unable  to protect polders  against  water is today
less than 0.1% (i.e.,  a recurrence  interval of 1,000 years).  However, dikes can
be disrupted because  of  their excessive permeability or by an  ice  jam  at the
mouth of a river.

     The height  of  the dikes is 2.2-2.3 m because  Polish  regulations require
them to  be 70 cm higher  than  the  50-year storm  (i.e., annual  probability of
0.02),  although  sea  level  has  risen  10  cm  since  some  of  them  were  built
(Krzesniak, 1976).  If the sea rises  another  50 cm, then the water level  during
the 50-year storm will only  be 10-20  cm below  the dikes,  50-60  cm too low for

     Thus,  it  will   probably  be necessary to   (1)  upgrade  the capacities  of
intermediate pumping stations;  (2)  rebuild and increase the height of dikes; and
possibly (3) raise  polder bottoms.  These problems would face  polders  with a
combined area of  1,500 square  kilometers, their surrounding  dikes  (some 1,300
km long),  and  120-200  intermediate pumping stations.   It  is  possible that new
polders will have to be  built  on waterlogged land that  will  keep  expanding in
area.  Given the  possibility of a  one-  meter rise in  sea  level,  the new dikes
should be 3.2-3.3 m above sea level.

Inundation of the Lower Reaches of River Valleys

     Several  changes will  take place  in  the lower  reaches of  river valleys,
depending  on the ability of a  particular river to  adjust to the rate  of the
anticipated sea level rise.

     In the Odra valley,  a sea  level rise  of  0.5 m would increase the frequency
of flooding over  an  area  3-4  km wide  that extends 50  km upstream,  due to both
higher storms surge levels and the backwater  effect  on river surges.  Near the
coast, flood  levels will generally rise 50  cm; upstream, the rise in flood levels
will be  somewhat less but  still  significant.    In  some cases, the increased
flooding may be mitigated  if global warming  reduces  ice jams,  which currently
are responsible for some floods.  Sedimentation from floods will  tend to shift
upstream, perhaps increasing the ability of a  few undeveloped areas to keep pace
with the rising sea -- at the expense of increased inundation downstream.


North and West Europe

     These  effects  will  necessitate  rebuilding  the  facilities  currently
protecting the  polders,  such  as dikes and possibly  also  intermediate pumping
stations.  In the lower Odra valley, harbor facilities and low-lying industrial
plants in Szczecin and in Police will be threatened.  Similar threats will emerge
in the  lower Vistula valley and the  valleys  of the lesser rivers  (the Rega,
Wieprza,  Parseta,  and Slupia),  at  the  mouths  of which are  located  harbors,
industrial buildings, and parts of residential buildings.

Increased Estuarine Salinity

     The lakes will  grow more  saline  as  a result of more frequent  inflows of
Baltic waters into them through river  mouths and overwash breaches of barriers.
Moreover, a  rise  in  sea level  will  facilitate contact  between  the  Baltic and
Atlantic through the  Danish Straits.  We may anticipate more frequent and massive
storm inflows of the  more saline and oxygenated Atlantic  waters into the Baltic,
which will benefit the biological life of this sea.

Increased Groundwater Salinity

     Higher sea level will  hinder the  seaward  flow of groundwater and allow the
water table to rise  in  the coastal  zone.   Higher  groundwater  levels will  also
increase  seawater  infiltration.    This  will  be  reinforced   further  by  an
accelerated water circulation  in polders and an excessive exploitation of fresh
waters on barriers,  where  the  drawing of freshwater from near-surface lenses
may cause a rise in the saline water table.

Summary of the Impacts of a 0.5-m Rise

     Because of physiographic conditions, the zones of the contemporary landscape
and land  use  probably could  not shift inland.   It  is   imperative to  keep the
present  agricultural  use  of  the Vistula Delta  and the lower Odra  Valley,
especially in  the  polder areas.   Giving  it up would mean tremendous  economic

     All  the ports and shipyards as  well  as a  part of the  industry and railway
junctions located in the low-lying areas  will  suffer damage  with a future rise
in sea level.  The extent of the danger  will  vary from  port  to port, depending
on the following factors:

     1.  The   degree  of  exposure  of  the  ports  and   their  facilities  and
         infrastructure  to  waves and storm surges.  Thus, the North Harbor in
         Gdansk and the fishing harbor  in Wladyslawowo, both projecting into the
         sea,  will  be  most  threatened  by  exposure,  whereas  the  harbor  in
         Swinoujscie,  situated  on the west coast,  will  be more threatened by
         higher storm surges in  this part of the Baltic.

     2.  The altitude above sea  level of wharves, jetties, breakwaters, and other

     3.  The  probability of simultaneous  impacts  of the rising  sea  level  and
         floods  caused by ice jams at the  mouths  of the rivers  on  which  some


         harbors are
         and Ustka.
                                     Rotm'cki and Borowka

located -- e.g., in Szczecin, Police, Darlowo, Kolobrzeg,
     4.  An increase in sediment transport by longshore currents.  This,  in turn,
         will  cause a more intensive alluviation of the entrances to the  harbors
         in Swinoujscie,  Ustka,  Darlowo,  Kolobrzeg and Wladyslawowo, as well as
         of the fairways  leading to  the harbors -- e.g., the 30-km long fairway
         in the  Pomeranian Gulf  leading to  the harbors  in  Swinoujscie  and

     5.  The  kind,  height, strength,  and  technical  condition  of the  storm
         protection  structures in the harbors.   They  are  built to accommodate
         the probability  of storm surges  of various heights.  However, the rise
         in sea level will  increase the probability of  storm surges that will be
         higher than those currently planned for.  As  a  result, various technical
         equipment in the harbors and their storm protection structures may prove
         to be too low and too  weak.  They may stop fulfilling their function and
         may suffer more  rapid destruction.  A general  answer to the question of
         whether harbor facilities and storm protection structures would suffer
         destruction  in case of  a  sea level rise  is impossible  at this stage of
         the analysis of  the problem.  It  requires detailed  analyses for each of
         the harbors.

Impacts of  a  1- to 2-Meter Rise in Sea Level

     Such a rise would  inundate another  1,200 km2 of land  (Figure 8);  a much
larger area would experience  increased flooding.  The processes and  phenomena
triggered by  the rise of 0.5  m  will  continue  and intensify, but their spatial
range  will  expand,  and  the  threat  they will  pose  to urban,  industrial,  and
agricultural  areas with  a  high capital  investment level  will be greater.   The
Figure 8.    Location of low-lying areas along the Polish Baltic coast.


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steep slopes along the morainic  plateaus  would  prevent the beach-barrier-lake
zones from shifting inland by more than 1 to 4 km.

     Lakes  will  change   shape,   unless   peat  formation    and  sedimentation
accelerate.  Some lakes will  unite;  and  cultivated  fields,  with the exception
of polders, will practically disappear from the low-lying areas of the coastal
zone.   There  will  be an  increase in the  area  of peat bogs  and water-logged
meadows.   In  the Odra valley,  the narrow  strip  of the floodplain  in  danger
stretches 80 km  south of  Szczecin; in the  Vistula  delta,  the endangered area
includes 1,560 km,  or 94% of the delta area less than 5 m above sea level.

     Rural settlement will  have  to be moved to altitudes  higher than  the 2-m
contour lines.   Agricultural  use  of this land will be possible only through the
building of polders in an ever-increasing area.   A part of the settlements and
tourist accommodations on  the low sandy coast will be destroyed or will have to
move onto newly  developed  accretionary  lands  on the inner  parts of barriers.
Threatened with direct inundation will be parts of towns located less than 2 m
above sea level and inhabited today by about 360,000 people -- mainly parts of
Gdansk, Szczecin, Swinoujscie, and Elblag.   Higher situated areas of towns will
be threatened indirectly by flooding.


      It is difficult to  make a complete  list  of threats to urbanized,  harbor,
industrial, and historical areas.  We  can only draw attention to the main sources
of danger.  The danger starts today  and will grow with the rise of sea level.
Its  main  sources  are (1)  the  insufficient  height  and  strength of  harbor
protection facilities; (2)  the increased filling up of  the entrances to harbors
and navigable  channel ways;  (3)  the  destructive  action of storm  surges  of a
higher  frequency of  given  stages and ever  higher;  (4) a  rise  in groundwater
level posing a threat to (a)  the  strength of foundations  and  grounds  under
houses, industrial  buildings, railway junctions,  and communication routes, and
(b)  the  functioning  of  the  urban  underground  infrastructure  with  such
installations as stormwater drains,  telecommunications, and power cables; (5)
the appearance of groundwater on  the  surface of  low-lying  parts of towns; and
(6) the insufficient  height of artificial  dikes and the possibility of a flood.

     The Central  Marine Office is  responsible for planning and implementing the
protection of Poland's seashores.  The existing plans consider current erosion
rates but would not accommodate an accelerated rise  in sea level.   Also, they
concern only  the shoreline,  not  the entire coastal zone.   Awareness  of the
dangers from future rise in sea level is  low,  both among the public and within
the administrative  units.   It  is highly probable,  however, that with the changes
taking place in Poland today,  the message of this  report will get  through to the
new decisionmakers and managers in the state administration.

     The processes already started by the  rising  sea  will require  town planners,
designers, planning offices,  economists, engineers,  and decisionmakers to adopt
a totally different approach and philosophy that will accommodate the analysis
of the costs,  risks,  and effects of sea level rise.  They must  learn to view the
coastal zone as a dynamic system that undergoes continual  adjustment.


                                                          Rotm'cki and Borowka


Andrzejewski,  E.   1984.   Turystyka (Sum.:Tourism).  In:   Pobrzexe  Baltyku.
Augustowski, B., ed.  Wroclaw: Ossolineum.

Cebulak,  K.    1976.   System  wodno-melioracyjny  (Sum.:The water  and drainage
system).  In:  Xulawy Wislane.  Augustowski,  B., ed.  Wroclaw: Ossolineum.

Cebulak, K.  1984.   Gospodarka polderowa  (Sum.: Polder economy).   In:  Pobrzexe
Baltyku.  Augustowski, B., ed.  Wroclaw:  Ossolineum.

Cieslak,  K.,  and W. Subotowicz,  eds.   1986.   Stan wiedzy  o  hydrodynamice i
litdynamice oraz ochronie brzegu morskiego.

Czekanska, M.  1948.   Fale burzowe na poludniowym wybrzexu Baltyku (Sum.: Flood
raised by storm on the southern shores of the Baltic Sea), Badania Fizjograficzne
nad Polska Zachodnia 11:58-96.

Dziadziuszko,  Z.,  and  T.  Jednoral.  1987.  Wahania poziomow morza  na polskim
wybrzexu  Baltyku  (Sum.:  Variation of  sea level  at the Polish  Baltic coast),
Studia i Materialy Oceanologiczne 52:215-238.

Jednoral, T.   1984.   Spietrzenia  sztormowe  wzdlux polskiego wybrzexa. Slupsk:
Instytut  Morski, Archives Reports.,  Jednoral,  T.    1985.   Fale  wiatrowe Morza
Baltyckiego w  swietle badan  empirycznych.  Slupsk:  Instytut  Morski, Archives

Kwiecien, K.   1987.   Warunki   klimatyczne   (Sum.:Climatic  conditions).    In:
Baltyk Poludniowy.   Augustowski, B., ed.   Wroclaw: Ossolineum.

Majewski, A.  1987.  Charakterystyka wod (Sum.: Characteristic of the Southern
Baltic  waters).    In:    Baltyk Poludniowy.    Augustowski,  B.,  ed.    Wroclaw:

Majewski, A.,  Z.  Dziadziuszko, and A.   Wisniewski 1983.   Monografia Powodzi
Sztormowych 1951-1975, Warszawa: Wydawnictwa Komunikacji i Lacznosci.

Matusik, M.  1984.  Gospodarka rolna (Sum.: Agricultural economy).  In:  Pobrzexe
Baltyku.  Augustowski, B., ed.  Wroclaw:  Ossolineum.

Rosa, B.  1984.  Rozwoj brzegu i jego odcinki  akumulacyjne (Sum.: The development
of  the  shore  and  its   accumulation  sections).    In:    Pobrzexe  Baltyku.
Augustowski, B., ed.  Wroclaw: Ossolineum.

Slupsk: Instytut Morski,  Archives  Reports.,  Costa,  J.R., and V.R.  Baker.  1981.
Surficial Geology Building With the Earth.  Chichester:  John Wiley and Sons.

Subotowicz, W.  1982.  Litodynamika brzegow klifowych.   Gdansk:  Ossolineum.

North and West Europe



     The climate of the Polish coast is characterized by highly variable weather
conditions because the southern Baltic is on the path of very active cyclones.
Moreover, it is an area  of  a  frequent exchange  of  air masses advancing almost
freely from different directions.   The prevailing masses are polar-maritime air
from the west (60.4%). Much less  frequently the area comes under the influence
of polar-continental  air  masses from eastern Europe  (15.5%) and arctic air from
the  Norwegian  Sea (9%).   The least  frequent are  tropical   air  masses  (1.5%)
(Kwiecien, 1987).  The mean annual  temperature of the Polish coast varies between
7.1C at Cape Rozewie and 8.0C in Swinoujscie.Q The coldest months are January
and February, with mean  temperatures  from -0.6C in the west to  -2.4C in the
east (see Figure 1).   The warmest months are  July and August (16.1-17.2C).  The
mean  precipitation  depends  on the  degree  of  exposure  of  the  coastline  to
rain-bringing westerly winds.  Thus, the highest mean annual rainfall is recorded
on the middle coast between  Darlowo and Leba (650-700 mm),  while the remaining
areas receive much less  rainfall  (550-570 mm).  The highest  mean monthly wind
velocities (5-7 m/sec) are  characteristic of the autumn-winter months, whereas
the lowest are recorded from May to August (2.5-3.5 m/sec).   The  autumn-winter
season contains the greatest number of days  with strong winds (29 days: 6-7C)
and storm winds (18 days: >8C).


     The direction of the longshore current  is  controlled  by  prevailing winds,
and sediment in the littoral zone  is generally transported from the west to the
east (see Figure 1).   It is only between Kolobrzeg and Swinoujscie that westward
sediment transport can sometimes  prevail.   During  storms,  rip currents 50-200
m apart appear that are almost  perpendicular to the coastline.   In the deep-water
zone, about 85% of waves  are not higher than 3 m or  longer than 7 sec.  As much
as 95%  of the waves  are  not  higher  than 4 m  or longer than 8  sec.   In the
offshore zone,  storm  waves  attain a height  of  1 m  above the current mean sea
level, and  reach  2 m only  in  the zone of a steeply  sloping coast (Jednoral,

                          Flood  Defense  Manager
                       National  Rivers  Authority
                             London, England

     On July 10, 1989, the National Rivers Authority was established as the major
flood defense agency for England and Wales, with the  regionally based staff
transferred from  the  regional  Water Authorities.   One  of the Authority's
principal  roles  is  to  coordinate  and plan  flood  defense strategies  and to
undertake  appropriate defense programs.

     As an  island nation, the United Kingdom has a significantly high  percentage
of low-lying  land already at risk; rising sea levels will  increase  that risk.
Coastal  land  use is  a mix  of rural,   urban,  residential,  commercial,  and
industrial  zones.  This paper identifies  the  location of flood-prone areas and
refers  to  some  of  the  socioeconomic  aspects  of  those  unprotected   areas.
Reference  will be made to the storm of 1953 and the defense systems constructed
subsequently  around  the coast and along  the river networks.

     The principles  used to develop the design  defense level for  the  Thames
Barrier is also  summarized.  We review the present policies  for  flood defense
and the short-term interim approach needed to respond to any additional  threat
from sea level rise.

     Long-term  strategies  cannot  be developed until predictions from  global
circulation models become more reliable.   This paper  refers to current research
programs to analyze the  effectiveness  of  the  present generation   of defense
structures and identifies  some  of the  constructional  adaptations   that would
increase their effectiveness.

     Some  reference  is made to the implications  for agricultural lands  if the
rainfall patterns deviate from those of the present day.  Rising sea  levels may
preclude the  use  of  gravity outfalls  and  low-head pumping stations.

     The United Kingdom has an  extensive  data-gathering  network to aid  the
monitoring of rainfall, river flows,  and  river levels in real  time.   Tidal  and


North and West Europe

storm-surge forecasts can be undertaken with a considerable degree of accuracy.
The tidal gauge network  can  be  monitored,  again,  in  real  time,  to check these
predictions.   This  paper  shows that  the  United  Kingdom's  ability  to issue
reliable  flood  warnings to  inhabitants  in  urban and  coastal  areas  is  well

     Finally, this paper comments on the use of benefit/cost analyses to support
policies, as well  as the effects of  the  new European Community Directives for
environmental and wildlife  protection  as  a  component of  the  flood defense



     The government  departments responsible for flood defense  policy are,  in
England, the Ministry of Agriculture, Fisheries,  and Food,  and,  in Wales, the
Welsh Office.   The 1989 Water Act established  the National  Rivers Authority.
This  act transferred  to the  new  Authority  from the  former  regional  water
authorities responsibility for supervising all matters relating to flood defense,
and for undertaking functions set out in the 1976 Land Drainage Act.  Among other
things,  the new  act gave  the  National  Rivers  Authority responsibility for
safeguarding the water environment; for improving water quality and resources;
for enhancing the environment,  amenities,  and recreation facilities;  and for
developing, in conjunction with the  Ministry of Agriculture, Fisheries,  and Food,
strategies for flood defense and flood warning systems.  The act also provided
for the  establishment  of utility  companies  to  deal  with water  supply, sewer
systems, and sewage  treatment.   (Scotland and Northern Ireland  have separate
legislation, so  policies and practices  in these two countries are excluded from
this paper.)

     The powers  to deal  with problems of erosion of coastal land not subject to
flooding are exercised by 88 Maritime Councils  in England and Wales under the
Coast Protection Act of  1949.  As in the case of flood defense, the government
departments that  have overall responsibility are  the Ministry of Agriculture,
Fisheries,  and  Food  in  England and  the Welsh Office in Wales.   The National
Rivers  Authority  has no responsibility  for this  area  of activity;  thus,  no
further reference will  be made  in this paper.

     The National  Rivers Authorities exercises its functions through nine regions
in England  and one region in Wales  (Figure  1).   Before the  new act's passage,
ten regional water authorities managed all  aspects of the  water cycle.

     As the principal flood  defense  agency  in England and Wales, the National
Rivers Authority  not only  has  powers to construct all  types  of flood defense
works and land drainage works,  both on statutory main rivers and on the coast,

                National Rivers Authority
                    Regional  Boundaries
Figure 1. The ten regions of the National Rivers Authority.

North and West Europe

but also has general oversight of 250 Internal Drainage Boards and the county,
district, and metropolitan borough councils.

     Within the ten regions, flood defense functions are carried out by Regional
Flood Defense  Committees,  each  under a chairman appointed  by the Minister of
Agriculture, Fisheries,  and Food.  Four of the regional committees have developed
their functions to local flood defense committees.  The boundaries of the areas
of regional and local committees  are  "river catchment  based"  and  have evolved
over  a  50-year period  as a  consequence of the  various  land  drainage  acts
preceding  today's  statutes.   These  four regions  share a  total  of  18 local

Funding of Flood Defense Works

     Any of the above flood defense agencies  undertaking improvement works that
can be regarded as a capital  investment may be eligible for  funding from the
national  government.  The level  of the grant may range from  15 to 55%, with the
actual rate depending on the  type of  flood  defense agency  and,  in the case of
the National  Rivers Authority,  the scale of local district programs  and the
ability of the  local  population  to  pay for them.  Sea  defense works or river
works to protect against tidal flooding attract a  20%  supplement  added to the
above rates.

     The balance of the cost  of the capital  works,  together with  the costs of
all maintenance works, staff costs,  all  overhead costs, equipment  costs, etc.,
are met out of revenue raised individually within the local  districts.

     The National   Rivers Authority  is currently spending some 67m  (over 100
million U.S. dollars) per annum on capital  works.   The  majority  of this amount
goes toward building or  reconstructing flood defenses.  This  level of investment
is expected to increases, in real terms, over the next decade by as much as 50%.
Through  grants,  the  Ministry of Agriculture,  Fisheries,  and  Food  provides
approximately 30%  of the cost of  the  capital  works program; this  contribution
also will increase.  Finally,  almost as much is being spent on the maintenance
of existing structures,  defenses,  and water courses.



     Until some 8,000-10,000 years ago,  much of Great Britain  was  covered with
a deep ice sheet.   The northern  part of England and Wales was  covered by thick
ice, while land to the south of this sheet suffered varying intensities of ground
freezing.  At this time, the  sea  level  would have been up  to 100 meters (330
feet) lower  than  today, and  the  present  sea bed  of  the English  Channel  and
southern North Sea was exposed as  dry  land.  Thus, Great Britain  was apparently
part of the European continent (Brunsden,  et al.,  1989).

     As a consequence  of  a  gradual  rise  in  global  temperature,  this ice sheet
melted and sea level rose.  Over time,  the ancient deep river valleys and lakes
gradually  silted  up  and  the  layers  of  the  superficial  deposits  became
interspersed  with  layers of vegetation, resulting  in  a  complex,  stratified
arrangement of organic and  inorganic materials.

     Despite the silting processes,  much  of  this land still lies below present-
day sea level.  Some of it is as low as 7  meters below the sea, but the majority
lies between  0 and +5 meters  (Figure 2).   These  areas  have a high  level  of
natural fertility,  and, over many centuries,  inhabitants have raised embankments
to exclude either  seawater  or  riverwater.   These  embankments were constructed
at what was  the edge  of  the sea.  Gradually,  the  lower lying land  that  was
seaward of the defenses  was covered and raised by  further  deposits of marine
sediments.  As the resulting salt marsh grew,  new defenses were constructed at
the new seaward limit.   Each of these  successive embankments was constructed to
a much larger cross-section and to a higher level  than the earlier ones.

     These progressively  larger defenses were  needed because the sea and river
levels were rising relative  to  the land and  because higher standards of defense
were required to protect the increasingly  larger areas of land carrying the ever-
increasing valuable agricultural and horticultural  industries.

     England  and  Wales cover  an  area of  approximately  15 million hectares.
Agricultural  land  is graded using a five-category  land classification system.
The Ministry  of  Agriculture, Fisheries,  and  Food  has  conducted  some  work  on
identifying areas at risk, and  a paper on this  subject was presented  at the 1989
Loughborough  Conference  (Whittle, 1989).   About  three-quarters of  a  million
hectares of land lie below +5 meters Ordnance  Datum Newlyn (ODN).  (Note:  ODN,
similar to NGVD in the United  States,  refers  to a  fixed  elevation that was  at
sea level  when the datum was established.)   Within this lie some 640,000 ha of
land,  (8%), Grades 1-3, of  which  nearly  200,000 hectares  are  classed as Grade
1 land.

     In  the  early  days,  these  lowlands  were   frequently  inundated  and,
consequently, not  conducive to occupancy by settlers.   So  for  the  most part,
settlements developed along  river  estuaries, especially where a high-level spit
or area of land was free from frequent inundation.   Today,  many of these early
settlements alongside  rivers have become established as major  commercial  and
industrial zones supported by the necessary infrastructure and residential areas.
Progressively, demand for developable  land has meant extension into zones where
risk of flooding  is high.  Thus, higher standards of defense have been demanded.
In common  with many developed countries,  the United Kingdom now has billions  of
pounds of real estate  investments in  rural  and urban zonesto  say  nothing  of
the hundreds  of thousands  of people, protected from sea and tidal flooding,  all
of which will require continued protection  against  a rising sea level.

Post-1953  Tidal Surge

     A major tidal  surge struck along the east coast of England in 1953.  Some
300 people died, thousands  of  hectares of land were  inundated  with  saltwater,

North and West Europe
                  Tide Gauge
Land below 5 metres  AOD

Land between 5 & 10
metres  AOD
       The boxed informetion on this mep - supplied by the
     Proudmen Oceenographic Laboratory - shows recent trends
       in sea level computed from records at eight tide guages
          in the national network maintained by M.A.F.F.

+ 1.2

Figure 2.   Low-lying land in  England  and Wales.


and vast urban areas were demolished or seriously damaged.  Many kilometers of
sea defense were  breached,  demolished,  washed  away,  or overtopped.   The surge
caused a tide-lock condition in many rivers, causing them to overflow their banks
and flood low-lying lands.

     Since that  storm,  at that time the worst  recorded  in living  memory,  the
catchment  boards  and  their  successors   (river  boards,  followed  by  river
authorities,  water  authorities,   and  the  National   Rivers  Authority)  have
reconstructed, raised, or constructed most of the 1,000 km of sea defenses and
the many  thousands of kilometers  of  tidal  defenses.  However,  many  of those
defenses have reached the end  of  their  useful  lives.  Earthen embankments may
have a  life  of only 25 years  and are being reconstructed, and  some  hard sea
defenses, which  appear to  have  led to  increased  beach erosion,  need either
complete reconstruction or,  at least, a new and deeper foundation at the front

     The surge of 1953 threatened  the center of London (Figure  3).  The decision
was taken then  to implement a long-standing proposal  to  protect London:   the
Thames Barrier.

The Thames Barrier

     The Thames Barrier is unique  in concept.   It consists  of  a series of gates
that are rotated  upwards  out of cills set  into the  river bed  (Figure  4).   The
Barrier has been designed to afford a standard of protection against a one-in-
one-thousand year storm surge, including  sea level rise expected through the year

     The level of the top of the gate was determined as follows:

     1.  Tide levels at  Southend,  the mouth of the  estuary,  were  analyzed to
         determine the one-in-one-thousand year return period.

     2.  The hydrodynamics of the  river  were analyzed to translate the Southend
         data of tide levels to the Barrier site.

     3.  The trend  line  of the rise  in river  levels  at a location  near  the
         Barrier site was  analyzed to establish  the relative rise in water level,
         and then extrapolated to  the year 2030 (i.e., 50  years  following the
         completion date of the structure).

     4.  The Barrier structure and gates are designed to resist a static force
         from some 9 meters  (29 feet) of water.

     The Barrier has been designed to  permit water to spill over the top of the
gates.   Upstream  of the Barrier,   the river extends  for a tidal  length of 40
kilometers (28 miles).   If  the Barrier  is operated  sufficiently early  in  the
tidal  cycle,  a "reservoir" of this length, and  9 meters deep, has  little chance
of being  filled  on any  one  extreme event.    Furthermore,  the gates  could be
rotated further to gain another 2  meters (6.5  feet)  in height, provided that


 North and West Europe
Figure 3.
What London would have looked like if the flood had been just a bit
minor alterations are made to the cills (Figure 4).  Thus,  the Barrier is capable
of modification to effectively protect London well into the next century against
the worst  case predictions of  sea level rise  (at least given  current  storm
severities)  (Kelly,  1989).   In  1982,  the  Barrier  and associated  riverside
defenses from Southend, at the river mouth,  to Teddington,  at the tidal limit,
were tested when  the Barrier, although  not  quite complete, was  closed against
a high-surge tide.  The Barrier  has been  operated against adverse conditions on
four occasions.

Other Structures Along the Thames

     Besides the Thames Barrier  itself,  other rivers and creeks have been given
protection by new barrier structures.  Most  of these consist of drop-leaf gates
set between towers.  Those  and  other gated structures along  the Thames  would
probably  need  structural   reanalysis  to  determine  their   suitability  for


                                                   River beg
                                                                                 DesiOnn>d level
                                                                                  1953 Hood level
                                  Open position
                                                                  Flood control position
                                Undershot low position
                                                                 Maintenance position
                                             HWSThigh water, spring tides
                                             LWSTlow water, spring tides
                          Bonier gate in four positions
Figure  4.    (A)  The  Thames  Barrier  concept  and  (B)  barrier  in  place on Thames

North and Vest Europe

     Barriers apart, many of the  remaining defenses along the Thames consist of
conventional hard defenses of varying design.  Some may have adequate foundations
and  stability  to receive  an additional crest  to gain  extra height.   Other
defenses, such as soft earthen embankments  with protected front face, may also
be capable of being  raised merely by the addition of extra material.  Elsewhere,
however, where the foundations and subfoundations consist of soft alluvial soils,
it  is  unlikely that additional  weight  can  be  added  to these  structures.   An
extensive program of geotechnical  investigation will be required  to find the
optimal solution.

Other Defenses in England

     The areas of land in England and Wales at risk are protected by a variety
of  defenses.   In the main,  these  defenses have been constructed  from  soft
materials excavated  from adjacent lands, but some occur naturally, such as sand
dunes.   Soft,  artificial  defenses  have a short life,  and  many of those built
since  1953  are now  showing  signs  of stress and  are being rebuilt,  often by
substituting a concrete or stone structure  to  meet the higher standards needed
for the future.

     Some navigable  rivers  within  the United  Kingdom  have  been  supplied  with
barrier structures,  particularly the river  at Hull and  the Fosse River at York.
These  structures  have  been  designed with significant  "air  draught"  to permit

Lowering Beach Levels

     The United Kingdom, in common with other parts of the world, is experiencing
a general  lowering   of beach  levels and, frequently,  loss of  the  protective
foreshore and  salt  marsh in  front  of the  soft  defenses.   The cause  of  this
decline  is alleged  to  be  inability  of  the  surf  zone  to move shoreward because
of the presence of some obstructing  defense.  Accordingly, it has been shown that
foreshores are becoming steeper (Halcrow, 1989), which will aggravate problems
associated with defense management  policies.

     It can be shown through experimental work that the rate at which the beach
level  is being reduced  is  affected by the type of obstructing defense.   A
vertical profile  wall  creates reflective waves, which aggravate  beach scour,
although these damaging  effects may  be reduced by  a "stepped" profile.   An
alternative profile  to combat the adverse effect  of walls is to  use an embankment
that permits waves to "run up" the face of the structure and thus dissipate wave


Allowances in Design of Sea Defenses

     It has been recognized for  many decades that as  a  result of the retreat of
the ice sheet, northern England is  rising and  southeastern England is sinking.



This isostatic change has contributed to a relative rise in sea level  in southern
England.   An overall  allowance  on the  order  of 3 millimeters  per year has,
therefore, been included in the recent designs for sea defenses.

     Most  of  the  defenses  along  the east coast  of England  are  open to a long
fetch to the  Continent and can experience severe wave action.  An allowance of
up to 2 meters may  be provided.   Soft defenses built from marine alluvium and
clay soils suffer from shrinkage in the  upper drying zone.  An allowance of up
to 1 meter for this  effect  is added to the design  still-water level.  Obviously,
concrete walls do not have this  component of  safety, so  crest  levels of such
defenses are  lower.   These allowances, together with any additional allowances
that  appear  pertinent, are  added  to the  basic  still-water  level  (tide plus
surge).  The  base still-water level is  that for 1953 or  any later event that
resulted in a higher level.

     It is appropriate to  consider the  allowances that should  be included in
the design of new flood defense works for  sea level  rise.   There  is so much
uncertainty about future storm patterns, rainfall changes, and evapotranspiration
changes that  any  allowance must  be regarded  as a  "first guess."   Some have
suggested  that  an  allowance  of  about 6 millimeters  per year,  including  the
existing isostatic  change, could be prudent  for  short-life structures pending
improved estimates  of  the  consequences of climate  change.   Design concepts of
structures should ideally permit easy modification to meet longer term needs.

     The Ministry of Agriculture,  Fisheries, and Food has  estimated  that  the
cost of constructing a defense suitable  for currently projected sea level rise
in England and Wales  could amount  to  between 5 and 8 billion pounds (7 and 12
billion U.S.  dollars).  Within this  budget  figure  is  an  allowance for new and
replacement pumping  stations,  new drainage outfall systems, and at  least two new
tide-exclusion barriers.

Alternative Solutions

     The opportunity for reconstructing  soft defenses is  diminishing.   In many
instances,  this may  be due to the  need to  provide  increasingly large structures,
the difficulty of  obtaining a cheap supply of material from nearshore or inland
sources, or the need to avoid damage caused to the  environment by digging "borrow
pits."   Similarly,  hard defenses  are becoming  more  expensive,   costing 3  to
5 million pounds per kilometer. With an appreciation of the damage  that the hard
structure  can cause  to  the  environment,  there  is  a gradual  change in  the
engineering attitudes toward seeking equally efficient alternative solutions.

     Engineers in  Great Britain are gaining experience with schemes that involve
raising beach levels  using material dredged from sources  in  stable,  offshore
zones.  The specification for this material is usually for a coarser grading than
that already  on the beach;  thus,  longer term  stability is  anticipated.   This
material may  be further stabilized  and protected by  the construction  of  large
terminal groins built from imported rock.

North and Vest Europe

     The design  of these  structures  Is complex.   A  core of  lighter weight
material is  protected  by layers of rock of  increasing mass.   Further,  in an
attempt to overcome the adverse  effect associated with terminal structures, the
"plan shape" is built  to resemble a "fish  tail,"  and  it  may be curvilinear on
plan; the crest level at the seaward end may be higher than  that at the landward
connection to encourage the littoral  drift  processes (Barber, 1988).

     Thus, if  the  "soft"  solutions  being  constructed to date  are  shown  to be
reasonably stable,  we may see an  extension of this engineering concept for future
capital schemes.   In engineering terms, the  choice  of  this solution is sound,
and it really  only represents a reversal of  natural trends through the use of
energy-dissipating structures.

     A natural  feature  to which much attention is being  paid is the salt marshes
found frequently to the seaward side of defenses.  These marshes are often found
at a  level  of  about  high spring tide.    In  addition  to  their  environmental
benefits, they are able to dissipate wave  energy  and  allow only small, depth-
limited waves to reach the defense structure.

     Many of these marches are in decline because  the seaward  edge  is  being
eroded or the  vegetative  cover  is dying back,  thus leaving  only mud  patches.
Engineering solutions  are being  sought to reverse these  trends so  as to preserve
these valuable components of a defense system.

     The behavior  and  performance of marshes  outline  in  other  recent papers
(e.g., Titus, 1988) confirms that experienced in the United Kingdom.  There is
a need, therefore,  for  an international approach to optimize the ability of this
natural type of defense to respond to future sea level  rise.


Bodies Commissioning Research

     The National  Rivers  Authority  is continuing research previously carried
out by water authorities and will be expanding its program to complement research
already undertaken by the Ministry of Agriculture, Fisheries, and Food.  Other
complementary research  is commissioned by organizations such as the oil industry,
firms of consulting engineers, or intergovernmental agencies in conjunction with
other  government  departments  using  research  facilities  at  the  numerous
universities, research laboratories,  and specialist  consultants.

     One area of research of specific  interest  to the National Rivers Authority
is the work undertaken by  the Ministry  of  Agriculture, Fisheries,  and Food on
the collection and analysis of tidal data from its system of tidal gauges around
the coast of the United Kingdom  (Figure  5).   Data  from some of these gauges are
used  in  connection with  the Storm Tide  Warning Service  (see  the  following
section).   The  program of  analysis feeds  into other  worldwide  scientific


                                           (8 8)
                                     vv^     /

                                                    VEUXSTOWE (SB)
                              ORTUHO         BRIGHTON (90)
     ST MARY'S
Figure  5.   Tide gauges  of the  national  network
installations  are underlined).
                                    -  December  1988  (modernized

North and West Europe

     Another strategic research effort is  being directed toward finding ways in
which existing defenses  can  be modified to improve their  effectiveness.   The
findings from this program are equally important  when considering designs for
new defenses.  At present, there is much uncertainty about both the timing and
the extent of sea level  rise.   Until  some of  these uncertainties are removed,
it is prudent to  build defenses to  deal only with known situations but, equally
so, to build in provisions for easy modification when the need arises.

Research Programs

     For many years,  the Ministry of Agriculture,  Fisheries, and Food has been
funding applied research  and development programs.  The principal  areas  of marine
research have centered around the interaction of tides, surges, and waves.  These
dynamic forces have effects on sediment transport processes which greatly affect
the foreshore, surf zone, and stability of estuaries.   Many other aspects of the
program are set out in the annual report (MAFF,  1988).

     The former water authorities  and now the National  Rivers  Authority also
undertake  complementary  research  programs.    At  present,  the  Authority  is
concerned with developmental  research  into the performance of embankments.  The
Authority will also  include  some  research into the  use of  new  materials and
systems to facilitate a rapid response to  be made to structures should the need

East Coast Storm Tide Warning Service

     Following the 1953 storm event,  the  government  set  up a review committee
to report  on  the event and  to  make recommendations.  The Waverley Committee
recommended the establishment of a warning service for the east coast.  Today,
the service is administered by the  Ministry of Agriculture, Fisheries, and Food
and is run from the United Kingdom's Met Office.

     Atmospheric and tidal data  are fed  into a numerical surge model to provide
hourly sea level  forecasts up to 36 hours  ahead.   If  it appears that a critical
level could be reached at  any of the reference  ports  (Figure 6), checks are made
about 12 hours before high water,  using real-time tidal  and wind data.   This
critical level,  known as Danger Level,  is  predetermined  and  related  to some
crucial   defense  within  the relevant  Division.    The Met Office  will  issue
preliminary warning notices to  the relevant police  force, the  National  Rivers
Authority region, the  local authorities, the Ministry  of Agriculture, Fisheries,
and Food, and other interested parties during  this period, and it will issue a
metric confirmation or cancellation of that  preliminary  warning  some  4 hours
before expected high water.

     The National  Rivers Authority  will  open up its relevant  flood  control
center,   either  upon   receiving  a  warning  or   whenever it  perceives  that
meteorological conditions could lead to a storm.  The Authority has access not
only to  this principal tidal gauge  network but  also to local gauges,  and it will
monitor all of these as part of its flood forecasting procedure.


                                                      EAST COAST

                                       STORM TIDE  WARNING SERVICE

                                                        National Rivers' Authority
                                                        Region              i
                                                        Rtglonal H.O
                                                        Rtcdvlng Cntr*
                                                        Coattal Division lounaary
                                                        Port with tMt gtug*
          wd rMm tor KM CwMVWMC UnK IHO) FCS ADAS MAFF
Figure 6.  The Storm Tide  Warning  Service and the east  coast  reference ports,


North and Vest Europe

     Throughout any event, the Authority maintains close liaison with the police
forces and local emergency services and others as needed.  The National Rivers
Authority work force and other private and public work forces, including military
personnel, may  be  called on  in  an extreme event.  The  police, as  the  law and
order enforcement agency,  will,  in liaison with the National  Rivers Authority,
issue any  notice  to the public.   They will  coordinate the evacuation of the
public from any threatened zone.  Following any event  that entailed the issuance
of a warning, there is  an intense  inquiry  both  to  validate the quality of the
warning and, if necessary,  to evaluate the return period of the  event.

     The performance of the warning service  has been progressively improving.
This has been made possible by the  new  computers that can handle greater inputs
of data; by improvements funded by the Ministry of Agriculture,  Fisheries, and
Food to the data-gathering systems  at the tidal gauges; and by modifications to
the numerical models.   The detailed analysis  of  the tidal data is undertaken by
the Proudman Oceanographic Laboratory at Bidston, near Liverpool, under contract
to the Ministry of Agriculture,  Fisheries,  and Food.

     The warning  service outlined  above applies only to the  east  coast.   The
remainder of England and Wales receives only the output  from the numerical surge
model on  a  twice-daily  basis.   A full  warning  system  depends on  refining the
models for the  south and west coasts and on  having better  real-time data from
the eastern Atlantic and Western Approaches  to the United Kingdom.  Much of these
data are exchanged with similar agencies on the Continent,  thus  ensuring their
optimum use within international forecasting systems.


     Land in England and Wales lying less than 5 meters above  sea level  must be
protected from  flooding.  Some  of  this land  is  below the sea  level  and has to
be pump drained.   In the main,  this low-lying  land is  backed  by  a scarp-face,
with land rising rapidly up to the +10.0 meter contour.  Much of the lowest lying
land  is  used  for agricultural  production,  but the  higher  ridges  have  been
developed for urban, commercial, and industrial  use.

     A rise  in  sea level  will necessitate a review  of present defense design
standards.  In the absence of a definitive statement on timing or amount of rise,
designers  in  the  National  Rivers  Authority  are contemplating increasing the
defense allowances and are adopting designs that are flexible  enough to permit
easy modification.  Through  close contact with research bodies,  the National
Rivers  Authority  will  develop  strategies appropriate to  the  needs  to  meet
changing circumstances.

     It  has  been  suggested  that defenses that may have  only  a  short life,
approximately 25-50 years,  be designed to incorporate an allowance of not less
than  6  millimeters per year,  which  includes 3  millimeters  per year  for the
isostatic movement in southeast England (Figure 7) (Whittle,  1989).


O>  (T>


                                                          Relative  Rise (metres)







                                                                                                       9:  3-  3
                                                                                                       C     <


North and West Europe

     Options for raising defenses should not be implemented unless  they are cost
effective.  Decisions,  however unpalatable, may have to  be  taken  not to
reconstruct some defenses..   Present-day solutions  favor  the environment by
artificially raising the beach levels.  The evaluation of benefits for coastal
defense  includes  components  for   environmental,  recreational,  and  amenity
benefits.  It  may be appropriate to include within the benefits assessment those
benefits that will  accrue to planned future development,  so that developers are
prepared to make appropriate contributions.

     Research  into climate  change,  global  warming,   and sea  level rise  is
essential to  develop  financially  sound defense and land drainage strategies.
The  National  Rivers  Authority is  conducting research  on  the  use of newer
materials and new proprietary systems to protect defenses.


     The author acknowledges the assistance given by colleagues in the National
Rivers Authority and  the Ministry  of Agriculture,  Fisheries, and Food  in the
preparation of this paper,  and the  permission of the  Ministry to use material
assembled by  the author while employed  there as  Chief  Engineer.   The views
expressed are those of the author and do not represent  the views of the Ministry
of Agriculture, Fisheries, and Food or of the National  Rivers Authority.


Brunsden, D., E. Gardner, and A.  Goudie A.  1989.   Landshapes.  London:   David
and Charles.

Barber, P.  1988.  Sea Defense at Jaywick.  Report  to Anglian Region, National
Rivers Authority.

Hal crow,  Sir  William  and Partners.   1989.   Report on Coastal  Management for
Anglian Region.  London, England:   National Rivers  Authority.

Kelly, P.M.   1989.   Global  Warming and the Thames Barrier.   London, England:
London Emergency Planning Information Center, University of East Anglia.

MAFF.  1988.  Ministry of Agriculture, Fisheries,  and Food.  River and Coastal
Engineering Report.  London, England:  MAFF.

Titus, J.G., ed.  1988.  Greenhouse  Effect, Sea Level Rise, and Coastal Wetlands.
Washington, DC:  U.S.  Environmental Protection Agency.

Whittle,  I.R.   1989.   The Greenhouse Effect:  London  at Risk.   Conference of
River and Coastal Engineers.   Loughborough, England:  Ministry of Agriculture,
Fisheries, and Food.

                              J.  G.  DE RONDE
                Ministry of  Transport and  Public Works
                Rijkswaterstaat, Tidal Waters Division
                   P.O.  Box  20907.  2500  EX Den  Haag
                             The  Netherlands

     In the Netherlands,  politicians are becoming more and more aware of the
potential  problems  that could be caused  by  climate change.  Rijkswaterstaat, a
part of the Ministry of Public Works and Transport, started some smaller studies
on this topic  in  1985  (De Ronde, 1989; De Ronde and De Ruijter,  1986).


     In 1989, an extensive policy analysis was completed on  the future management
of our  sandy  coast with  regard  to  present erosion problems and the  expected
increase in sea level rise (Rijkswaterstaat, 1989).  The analysis was  based on
morphological  predictions  of coastal development  (erosion and  accretion) for
every kilometer of the 254-km length of our  dune coast.   The total length of the
Dutch coast without estuaries is 353 km.  The predictions were made for the years
2000, 2020,  and 2090 for three scenarios:

     Scenario  A  --    present sea level  rise of 20 cm per century,
     Scenario  B  --    sea level rise of  60  cm, and
     Scenario  C  --    sea level rise of 60 cm plus an  increased wind  velocity
                      of  10%.

     Impacts like loss  of  safety and loss of (dune) area  were compared with such
measures as  beach nourishment,  groins, and dikes.   An inventory was  made of the
whole coastline with a width of 500 m, and  this was entered  into a  GIS  system.
The grid used  was 1,000 by 50 m; the 50 m was perpendicular to  the coastline.
The predictions of coastal erosion/accretion together with the GIS system could
be visualized, and  totals  could  be made  of  lost areas.   The areas  can  be
subdivided into different types, such as nature, nature with  a  high ecological
value, housing, industry,  and areas used for drinking water.

North and West Europe

     Figure 1 gives an example of the results, showing the predicted total losses
of dune area in hectares up to  the year  2090.   The  lower line depicts the
predicted  losses  if  the present sea level  rise of  20 cm per  century were to
continue,  and the upper line  depicts the predicted  losses if the expected sea
level rise of 60 cm  up  to  2090  were  to occur.   In the case  of scenario C, the
lost area  in 2090 is expected to be about 5,000 hectares.  It can be concluded
from these predictions that,  in  the case  of  the  sandy coast of the Netherlands,
the expected future sea level  rise is worsening the erosion problems, but present
erosion is the main problem.
       3000  -
       1000- -
                             LOST DUNE  AREA
          1990  2000
 Figure 1.  Predicted loss of dune  area  up to 2090 in the case of  present  sea
 level  rise of 20 cm per century (scenario A)  and  in the case of the expected sea
 level  rise of 60 cm for the  next 100 years (scenario  B).


                                                                      De Ronde

     It is believed that present  sea  level  rise  is  only a minor cause of this
present erosion.   It  is  thought  that this  erosion is partly  a  late coastal
response to more  severe sea  level  rise  in  the past  and partly due to sediment
moving from the coast  into the estuaries.

     Concerning dikes,  the  story is of course different. Here, present problems
consist of just maintenance plus minor adaptations,  while  in the case of future
sea level rise, the necessary adaptations are much greater.

     The  length  of  dune  coast  where  measures  like  beach  nourishment  are
necessary, in  the case of scenarios A and  B,  can be  found in  Figure  2.   The
large increase in the beginning  is due to the fact that up  to 1990, many beaches
already will  have been nourished.  So in 1990, the length of "unsafe" dunes is
zero.  If nothing is done, this  length will  increase rapidly  in the beginning
until the effect  of past nourishments will  have  been diminished after roughly
10 years.  At present,  about 15 km of beach needs to be kept in place by beach
nourishment.   This area will  increase to 45, 60, or 80 km  (of  a  total  of 254
km) up to 2090  for scenarios A, B,  and C.   At other parts of  the coast, where
safety is not at  stake, erosion will still  occur.

Future Policies

     During the coming  year, politicians will have to decide what kind of policy
will be followed  in the  near future.   This  study describes and compares four
possible future policies:

        RETREAT  -- At  all  places  where safety is not  a problem,  nothing will
        done, and these parts of  the  coastline may  retreat.   Everywhere where
        safety  is at stake, the coast will  be defended.

        SELECTIVE  DEFENSE  --  In addition to the  actions  described  above,  the
        most valuable areas (e.g., dunes with a high  ecological value) will also
        be defended as well.

     .   TOTAL DEFENSE  -- No retreat at all  will be tolerated.

     .   SEAWARD DEFENSE -- "Weak parts of the coast" will be strengthened.

     Examples of the necessary measures for  retreat  and selective defense are
shown in  Figure  3.  Here the planned beach nourishments are given over the period
1990-2000 in  the case of present sea level  rise of 20 cm per century.

     The  expected costs for the  four possible policies  over the coming 10 years
are given in  Table 1.   Especially  during the  first 10 years, seaward defense is
very expensive.   The "cheapest" policy is,  of  course,  retreat.   The  costs for
scenario B are  nearly  the  same  as those  for scenario  A.  For  scenario  C,  the
costs are again a lot  higher, due to  the 10% increase  of  the  wind,  with great
effect on dike  height  and dune strength.   In the long run,  however,  seaward
defense is only a bit  more expensive  than the  other policies.   In the case of


North and Uest Europe
               70 I-
               SO- -
               4Q. -
               30- -
               20- -
               10- -i
                                UNSAFE DUNE COAST
                                                                0.6 m*tw
                                                       ^ .^ -- "  0,2 nwur
                1990   2000
Figure 2.  Predicted length of unsafe dune coast  in the case of present sea level
rise of 20 cm per century (scenario A) and in the case of the expected sea level
rise of 60 cm  for the next 100 years (scenario B).
 Figure 3.   Parts of the  coast where beach nourishments  are  planned during the
 period 1990-2000 with policy RETREAT  (A)  and with  policy SELECTIVE DEFENSE (B)
 in  the case of present sea level rise.

                                                                      De Ronde

Table 1.  The Expected Costs Over the Coming 10 Years for Four Policies and Three
          Scenarios  (millions of U.S. dollars per year)


20 cm




Sea level rise scenario:
60 cm




85 cm
us 10% wind)



a sea level rise of 20 cm per century,  the average costs over 100 years are 16,
18,  21,  and  23 million  U.S.  dollars  per  year, respectively,  for  the  four

       The Minister of Transport and Public Works recently  advised policy makers
to use the policy of total defense.


       Another  policy analysis will be finished at the  beginning of 1990.  This
so-called  Impact of Sea  Level Rise on  Society  (ISOS)  study is  being conducted
in  cooperation   with   the  United  Nations  Environment  Programme  and  Delft

       This study focuses on the impacts of  and possible responses to sea level
rise.  It  also  examines  other effects of climate change,  including  shifts in
storms, river discharges,  precipitation,  and  evapotranspiration.   Storms may
become more severe or more  frequent, having great consequences  for  the design
of coastal structures.   River discharges may increase  and cause more frequent
flooding during  the  winter  season,  or may decrease  during summer  and  cause
shortages of water needed for agriculture or drinking.  These  impacts and the
possible measures against them will also be studied, but  more  along  the lines
of a sensitivity analysis.

       The ISOS  study will  include the entire Netherlands.  Besides the coast,
it will look at  3,000  km  of  dikes along estuaries, rivers,  and lakes.   Further,

North and West Europe

it will  analyze the impacts of sea level rise on the ecology and water management
of the Netherlands.  Table 2  shows  some  of  the scenarios that  will  be used in
this study.

        Of  course,  looking at  only impacts is insufficient  when discussing sea
level rise.   Equally (or  even more)  important  are the possible measures to be
taken and when they should be taken.

Table 2.  Main Scenarios of the ISOS Study -- Changes Between 1990 and 2090
      Mean sea level rise  + 35 cm

      Wind force           - 10%

      Wind direction       - 10

      Mean rise of design
        level              - 20 cm

          Summer           + 20%
          Winter              0%
          Summer           +
          Winter           +

      River discharge
                  + 60 cm



                  + 65 cm
                  + 10%
                  + 10%
+ 10%
+ 10%
                  + 85 cm

                  + 10%

                  + 10

                  + 150 cm
                  + 20%
  + 20%
  + 20%
+ 10%
- 10%
+ 0%
- 10%
+ 10%
      First of all, impacts with the so-called T0 alternative (no measures taken)
will have to be quantified, starting with the changes in hydraulic conditions;
the effects on morphology; and the  consequences  for  safety,  water management,
environmental  management, and costs.  With this knowledge, alternative measures
and constructions can be designed.   Given a certain measure or set of measures,
the impacts on hydraulic  conditions, morphology, etc.,  must  be  studied.   When
this has been done, the different alternatives can  be evaluated  and compared.

     With the  ISOS  study for the Netherlands, it  will  be possible  to answer
questions such as the following:

                                                                      De Ronde

       Depending on the rate of acceleration of sea level rise, what measures
        should be taken, and when should we initiate them?  (or: How long can we
        wait before we  have to do something?)

        If  not  only  relative  sea  level  rise  is  changing,  but also  storm
        frequency  as  well  as  river  discharges,  then  how important  are  the
        various  impacts compared to each other?  In other words, should we not
        be as worried about these other changes as we are about sea level rise?
        For example,  in the case of  the Dutch coast,  a  10%  increase  in wind
        force has about the same influence as a 60-cm rise in sea level.

     The results of the  first phase of the  ISOS  study, with an inventory of all
important relations between --on  the one hand -- sea  level  rise,  changes of
storm surges,  and changes of river discharges, and -- on the other hand -- the
impacts, were published in  1988  (Rijkswaterstaat  and  Delft Hydraulics, 1988).
The  second  phase  of the  study  is   not yet  finished.    Here,   though,  some
preliminary results will be given for dikes only.

     The 3,000  km of primary dikes in the Netherlands were divided  into about 50
so-called dike-rings, each  with its  own safety standard  and  subdivided into
about  150  dike-parts.    For each dike-part,  cost functions  were calculated,
depending on the amount  of heightening of the dike, the dike's construction, and
the extension  of buildings along and  on the dike.  The raising of a dike within
a town with  many houses  in and on the dike is many  times more expensive than the
raising of a simple dike in the countryside.  On the other hand, the model can
calculate for every dike-part the necessary  raising, depending on sea level rise,
changes in storminess,  changes  in river discharges,  and changes in management
(e.g., the management of the Ussel  Lake).

      In  the case of the expected sea level  rise of 60 cm for  the  coming 100
years, total costs  for  dikes will amount  to about $7.5  billion  U.S.  dollars
(Figure 4).  In  the case  of the  unfavorable scenario,  where  besides  the 60-cm
sea level rise an increase  of the wind of  10% and an  increase of winter river
discharges of 10% were considered, the total  costs increase to $14 billion U.S.

      Within the  model,  the number of  dike  heightenings during  the  coming 100
years and the  amount of  heightening can be  differed.  When the dikes are raised
in small steps, the costs  will  be incurred  as late as possible in time, but the
total costs  will  be greater because of the initial costs that occur  at every step
of raising.  On  the other hand,  when  they  are raised  in one  or two big steps,
the initial  costs will occur only once or twice, but the relatively high costs
of the  first  raising will  occur early  in  the heightening.    These  different
strategies can  be  worked  out with the model, and an optimal  strategy can be

      Given a certain scenario (e.g.,  60-cm sea level  rise), finding an optimal
strategy will  not be difficult.  The  target  in the  ISOS study will  be to find
an optimal strategy, given all possible  scenarios with their  chance of


North  and West Europe
                    mm T
                   i: ONG
                -SCE: Z68
1.88  !
                                  time  i.n  years  x  (10  )
            IPOS2 1.1
     delft hydraulics (c)
Figure 4.   Integrated costs  of dike raising  for the  scenarios.  Expected sea
level rise of 60 cm and the unfavorable scenario with 85-cm sea  level  rise plus
10% wind and 10% river discharge.

                                                                      De Ronde

occurrence.  This will  be much  more  difficult.   On the one hand, one will try
to minimize the chance of being in an unsafe situation (when real changes will
be greater than expected),  while on the  other hand, extensive measures might be
overdone when changes will  be smaller than expected.


De Ronde, J.G.  and W.P.M. De  Ruijter,  eds.  1986.  Zeespiegelrijzing, worstelen
met  wassend  water.    Report  GWAO-86.002.     The  Hague,  the  Netherlands:
Rijkswaterstaat, Tidal Waters Division (in Dutch).

De Ronde,  J.G.    1989.   Past and  future sea  level  rise  in  the Netherlands,
Proceedings of the  Workshop  on  Sea Level  Rise  and Coastal  Processes, Florida,
March 9-11, 1989.

Rijkswaterstaat  and Delft  Hydraulics.   1988.    Impact of Sea  Level  Rise  on
Society:  A Case Study for the Netherlands, phase I.  The Hague, The Netherlands:

Rijkswaterstaat.  1989.   Kustverdediging na 1990, discussienota.  (In Dutch,  an
English version of this report will appear in 1990.)


                      Centre  de Estudos Geograficos
                           University of Lisbon
                              Lisbon,  Portugal

      Because of the physiographic characteristics of the Portuguese coast and its
 population distribution, the main potential  impacts of sea level rise will  occur
 in  the  estuaries  and  coastal  lagoons,  on the barrier islands, and along  the
 active sandstone cliffs.   The large estuaries and coastal  lagoon  systems  will
 be  the most severely affected  areas  because they are densely populated  and are
 the  sites  of  extensive economic activity.  Approximately 70% to 95% of  their
 intertidal areas, 0.5 m to 2.0 m in elevation,  are  reclaimed  or used in  their
 natural capacity.  These reclaimed lands are occupied by salines (salt pans) and
 aquacultural ponds (40%),  agricultural fields (34%,  primarily rice)  associated
 with extensive pasture land  (2%),  port development (12%), urban and  industrial
 development (8%),  and airports (1%).

      Among the impacts already being observed  as  a result of sea level rise are
 damage to   several  artificial coastal  structures,  beach erosion,  retreat of
 sandstone  cliffs,  salt  marsh  retreat,  and  salinization  of  the  reclaimed
 agricultural  soils.   The first  two and  the last  of these impacts  require
 immediate responses  from the responsible central  and local government agencies.

      Wherever  harbors  and  tourist  beaches  are  affected  by erosion,   the
 institutional reaction has been,  and will  be in the near future,  to  rely on
 technology to repair or reinforce  the existing development.

      Regarding the impacts  on the agricultural  soils (rice  fields), the responses
 of the agencies to the current situation have been to build freshwater  reservoirs
 along the freshwater fluvial systems to assist in flushing the fields.  Future
 responses to the increasing  salinity in  the soils and  in  the  water  table,  and
 also to the  submergence (up to  2  m),  will  need to be different from  current
 responses.   The  initial reaction  by central  governmental  bodies  to the  soil
 salinization probably will be to shift the main crop  from rice to  more  salt-
 tolerant plants  (e.g., barley or sugarbeets),  or  more probably to shift  the use
 of these reclaimed areas from  agriculture to some sort of development.  At  the

North and Uest Europe

municipal level, agencies will probably rely on technological improvements and
will continue to produce rice.


     This  paper  briefly  lays  out   the   climate,   hydrology,   and  coastal
geomorphology of Portugal.   It then discusses potential  impacts  of sea level
rise and summarizes our discussions with officials of Portuguese agencies that
must respond to sea level rise.

Climate and Hydrology

     The Portuguese coast  is in the  subtropics,  on the  boundary  between the
Atlantic temperate  climate  and  the Mediterranean climate  (Figure  1).   This
geographical position explains the different climate regimes that can be found
along the  coast, which  contributes to  the different  local  geomorphological

     All of the  western coast  is exposed to the influence of the Westerlies that
dominate the annual  and the  seasonal wind  regime blowing  from  the  north,
northwest,  and west.  Strong  storm  winds  blow  from the southwest in the winter,
associated with tropical depressions.

     Wave heights vary:  the  annual mean wave height  is 2.9  m on the northern
sector  (Leixoes), 2.3 m on the central sector from Aveiro to Cabo da Roca, 1.0
m on the southwestern  sector,  and 1.1-1.4 m on the southern coast of the Algarve
Figure 1.  Location of Portugal in the subtropical zone.



(Figure  2).    The greatest  wave heights,  observed in  Sines on  the western
Portuguese coast in 1978, were around 16-17 m; they originated from the southwest
during a 100-year storm that  destroyed the jetties of the harbor of Sines (Feio,
1980).  On the  southern coast,  the  calm seas dominate and the infrequent high
waves very seldom reach 5 m.  They occur when the strong Levante wind blows from
the Gulf of Gibraltar,  usually  in winter but also in spring or in autumn.

     On the western coast, calm  seas (wave height less than 1 m) are infrequent,
as are extreme storm waves  (higher than  6 m,  Figure  2).   The storm waves do not
occur every year, but they are more frequent in the northern region, occurring
every winter.

     As  a  consequence  of  the  wave regime,  a general  longshore  current  is
generated from north to south on the western coast  (Ferreira,  1981; Ribeiro et
al.,  1987).   Deflected and  refracted by the capes,  the current  can reach the
coast  from  opposite directions,  from  the  west,  the west-southwest,  and the
southwest.  A  strong  littoral current from  the southwest also occurs when the
waves  run  from  the  southwest.    The  morphodynamic  effects  of  both  of these
littoral transport directions can be  seen on  the growth and  migration of the
spits and barrier islands along all of the coast.

     The tidal  regime on the Portuguese coast  is semi-diurnal and mesotidal.  The
tidal range is around  3.8 m along the western coast,  3.4 m on the  southern coast
during the spring tides, and between 0.9 m and  1.2 m during neap  tides.  In the
estuaries, the tidal range is 60-80 cm higher during spring tides.   In time of
the fluvial  floods, or even during the high fluvial water flow,  these values can
increase a few centimeters.  The  spring  tide level  reaches 2  m above mean sea
level on the open coast, if the sea is calm.


     The Portuguese coast  (excluding  the islands)  is  around 870 km  long and
presents a great variety of geomorphologic features,  as shown in  Figure  3.
According to  the published geomorphologic map (Ferreira,  1981) and measurements
taken from the  1:50,000 national  topographic maps,  sandy beaches occupy 37.5%
of the total  length of the coastline; coastal wetlands,  36.9%;  and cliffs, 25.6%
(Figure 3).

     Excluding the beaches located near the main estuaries, which are nourished
by the fluvial  sediments, the beaches of the western  coast are  narrow (70 to 150
m) --  even those with dunes.   The  widest beaches  have  gentle slopes  and are
located along the spits, or on the coastal sectors sheltered from the waves by
prominent capes.

     On the  southern coast,  the  beaches  are  narrow with gentle slopes.  On the
western side, there are pocket beaches  interconnecting through the karst caves
and galleries cut into the calcareous sandstone  of the cliffs.   Along the eastern
sector, there are linear beaches extending along a cliff face or  in the form of
barrier islands and barrier spits.


North and Vest Europe
      Southwestern Coast
East Southern Coast

                         Southern Coast
Figure 2.  Spectra of the annual mean wave directions along the Portuguese coast
(1974-1978).  Frequency distribution of the annual mean wave height.  Data from

                                                          Figure 3.   The coast of Portugal.

                                                          (A)    The  rocky,  sourthern Algarve
                                                          coast of Portugal.

                                                          (B)  A combination fishing and tourist
                                                          village on the Algarve coast.

                                                          (C)  A highly-populated tourist beach
                                                          in Nazare.

                                                          (All photos by Karen Clemens)

North and Vest Europe

     Excluding the beaches located  near the main estuaries, which are nourished
by the fluvial sediments,  the beaches of the western coast  are narrow  (70 to 150
m) -- even  those with dunes.  The widest beaches have gentle  slopes  and are
located along the spits, or on the coastal sectors sheltered from the waves by
prominent capes.

     On the southern coast, the beaches  are narrow with gentle slopes.   On the
western side, there are pocket beaches interconnecting through the karst caves
and galleries cut into the calcareous sandstone of the cliffs. Along the eastern
sector, there are linear beaches  extending along a  cliff face or in the form of
barrier islands and barrier spits.

     Most of the western Algarve  beaches are almost completely submerged during
the high spring tides.   This  feature and the retreat of the cliffs (Dias, 1988)
are already serious problems to the tourist industry there.

     The coastal wetlands  include  the low tidal platforms,  which  are sandy or
muddy, and the upper tidal platforms covered by salt marsh vegetation.  They have
developed on the sheltered estuarine margins,  along the creeks,  and around the
lagoons between 1.5 m below sea level  and  2 m above sea level (Figure 3).  They
represent 70% of the total intertidal area of the  Portuguese coast.

     Approximately 70-95%  of the  nation's  salt marshes  have  been  reclaimed
(Moreira,  1986).   The  land  is  defended  from tidal  submergence  by dikes  or
embankments.  The remaining  marsh  is characterized  by a  flat  surface  and  is
pocked by tidal  pans and  by a  dense network of creeks.  The microcliff of the
vegetated salt marsh almost always shows a tendency to retreat,  being undercut
by the currents  and collapsing afterwards.  The resulting silty sediments are
accumulating on the tidal platforms where they are stabilized by the low salt-
marsh vegetation. The platform is sandy and muddy,  with layers of broken shells,
and cut by the creeks  that are  more deeply excavated into the mud than into the

     The tidal platforms developed  in the Ria Formosa  (Faro)  lagoonal system are
sheltered by the barrier islands (Figure 3).  They are essentially sandy, with
layers of clay and silt (Granja,  1984),  and form islands that are colonized by
a Mediterranean  type of  salt  marsh.  The creeks are  not  very deep,  and their
margins evolve mostly by the  sliding of the sandy layers that overlay the silt.
Here, as well as in Aveiro and in the Sado, the salt marsh is being covered by
the sand coming from the transgressive dunes (on the spits and barrier islands)
and from the beach ridges, blown by the  wind,  or carried by overwash events.

     The cliffs  differ  in  height, profile, and lithological composition (Figure
3).  The highest  cliffs  (more  than 50 m)  are  cut  into hard rock,  granite, and
metamorphic rock on the northern coast, compact calcareous formations and schists
on the southwestern coast, and interbanded limestone-mudstone-sandstone in the
central coast, north of Serra de Sintra.   They are connected to  abrasive rocky
platforms that  have  a  lot of  stacks, especially  when cut  into granite.   The
processes of retreat,  consisting  of large  rotational landslides,  are evident on
the limestone and the mudstone cliffs.



     Low cliffs, around 10 m, also can be found cut into granite in the north,
and into calcareous  formations  such  as  at Cabo Raso on the central portion of
the coast.   Low cliffs,  15-20  m  high,  cut into the  Miocene  and the Pliocene
sandstones  are  very  frequent on the central and the  southwest coast, and the
Algarve  coast between  Sagres  and Quarteira.   They  are connected  to  narrow
limestone platforms with abundant  stacks and patches of sandy accumulations that
form several  pocket  beaches.  These cliffs retreat  by collapsing  after being
undercut at the base.  Cliff retreat  rates of 2 m/year due to human effects and
a sea level rise were measured by Dias (1988).


     The coastal fringe in  Portugal  is  largely natural.   Intertidal  areas and
adjacent land within the public maritime domain are  administered by  the Navy and
by the municipalities.  No  construction  is allowed there,  and even the public
infrastructure  for  sanitary facilities,  safety, and  leisure  is regulated and
needs special authorization.  These laws,  the tidal range, and  the annual storm
waves of 5  m to 7 m discourage permanent human occupation of the  very low coastal
fringe.  There is a strong contrast between the modest human occupation of the
low  coastal  fringe  and  the  very  high  population  density  of the  coastal
municipalities (Figure 4).

     Among  the coastal natural systems, the dunes and  the  estuarine and lagoonal
wetlands are the most disturbed systems due to the permanent human occupation.
The dunes are inhabited  along most of the coast, except in the natural protected
areas that  occupy  25% of the  total  coastal  area.    Major  tourist  settlements
occupy 29% of the secondary dunes, and some are even found on the primary dune
(foredune), as  occurs on  the northern sandy coast and on  the  eastern Algarve
coast,  including the Ria Formosa barrier islands (Figure 5).

     The traditional  fishing  settlements,  located  on the beach  and  in  the
foredunes,   are  now  quite  scarce (4% of the dune area) because they  have been
transformed into tourist villages or modern fishing ports.   The most important
traditional fishing settlements that are permanently occupied are found on the
barrier islands of the Algarve and are dispersed on the central coast.

     Other  artificial structures, such as  harbors  and military airports,  have
been built  on the dune  fringe (Figure 5).   In general,  the foredune is occupied
by natural  vegetation that is regenerated or planted to minimize the migration
of the  sand inland.   Forty-two percent of the total  coastal dune area is planted
with pines  (primarily maritime  pine),  acacia, and eucalyptus.  The coastal dune
areas have  high concentrations of tourism,  but the  highest  concentration  of
population  (Figure 4) is along the estuarine margins and the  coastal fringe from
Cascais to  Lisbon (the Costa do  Sol, the first tourist area of Portugal) (Cavaco,

     The coastal  fringe  of Alentejo,  from Troia (Setubal) to Sagres, shows very
low population densities, and some places are  deserted.  The sector near Sines
is an exception, due to  the  industrial complex  and  harbor of Sines,  and also to
the increasing tourist demand on this coast.


North and Vest Europe
 Figure  4.    Distribution  of  the population  density  in  Portugal  (1981)  by
 municipality  (Concelho)  (E.P.R.U., 1988).


Figure 5.  Principal types of land use on the coastal zone: (1) planted forest
(pinelands); (2) natural coastal  shrubland;  (3)  urban and tourist occupation;
(4) cultivated  areas;  (5) natural reserves and protected areas;  (6) harbors; and
(7) airports.


North and West Europe

     The coastal  wetlands, which have developed on the intertidal platforms of
the estuaries and lagoons  (Figure 3),  have  been  hurt  by human activities more
than any other part of the coastal  zone.  The salt marsh, as a natural system,
occupies only around 10% of its  original area, where it is protected as Natural
Reserves or Parks due to its ecological  value.  More than 90% of the total area
of the salt marshes  are reclaimed; of this, 40% is totally or partly transformed
into salt works  and  fish  ponds.  Agricultural  fields  (especially rice fields)
represent 34% of the land use in association with pastures or  grazing fields
(2%).   Harbors  (commercial,  fisheries,  and  leisure)  occupy  12%;  urban  and
industrial areas (8%) and airports  (1%) form the remainder of the land use.

     The salt works  are  on  the  high tidal mudflat, after  building dikes that
are more  or  less 0.5 m to  1  m  above the  spring high tide water level.   Very
often the dikes need to be repaired,  and some of them are permanently reinforced
by rock embankments or by wooden bulkheads that try to avoid or to minimize the
erosive effects of the storms or the fluvial floods.

     In most of the  rice  fields,  the  drainage water is discharged through gates
into the estuarine deep channels during the low tides.  In a very few cases is
this drainage water pumped from  the  rice field drains to be discharged into the
estuary, because the  rice fields occupy the  surface of  the upper mudflat (1-3
m above sea level).

     Salinization of the  rice field  soils  occurs  in summer owing to the dryness
of the climate (Daveau et al., 1977).   This situation happens frequently on the
southern estuaries during the dry years,  when the evapotranspiration is  very high
and there is insufficient freshwater to inundate the rice fields and to reduce
the salinity of the water table.

     The  urban and  industrial  areas,  as  well as the harbors,  represent  the
highest investment on the  reclaimed areas.   The most important towns and harbors
of Portugal are located on the estuarine or on the lagoonal margins, and their
artificial structures, such  as  harbor  platforms,  roads,  and railways, are 2-4
m above sea level.   It is the same with the airports that  were built on  the upper
mudflat, as the  airport  of  Faro, whose runways have  cracked as the underlying
muds settled.

     Some of the impacts the Portuguese coast could suffer from sea level rise
will affect all of  the  coast,  independent  of its  morphology.   The erosion and
submergence (partial or total)  of the former  intertidal area will increase, and
the extent of  other impacts  will  depend  upon the  coastal  morphology, the rate
of  the  sea level  rise, the  topography,  and  the  resistance of the lithologic
materials  against  the  erosion.    Therefore, the  impacts  in  this  paper are
presented relative to the coastal  morphology,  classified as estuaries and coastal
lagoons, beaches, and cliffs.

     In the estuaries and coastal  lagoons, the consequences of  a 2-m rise  in sea
level  (Figure  6c)   will  be  the  great  enlargement  of  the   estuarine   area,



penetrating  into the fluvial  system;  the  increase  of the  salinity  into the
estuaries and aquifers; the salinization of the soil  water table in the fluvial
plains and  in the  reclaimed  lowlands;  the submergence of part of the salines,
the fish ponds,  and the  rice  fields; the submergence of the total tidal platform
("slikke")  and  the low salt marsh; the retreat  and  disappearance of the salt
marsh  area;  a  great risk of erosion  and  flooding of the harbors and the low
coastal urban areas; the submergence of the Faro airport; and  the increasing risk
of flooding and  backup  in the urban waste drains.

     On the  beaches,  the  main impacts  will  be the narrowing  of  the  beach by
about  50% and the  retreat  of the  foredune;  the disappearance of  the pocket
beaches; and new pocket beach formation close  to the eroding sandstone cliffs.
The Ria  Formosa barrier islands will  lose  more than 50% of  their  area.   New
inlets will form,  and washover will increase.

     On the cliffs, the  impacts of sea level rise will  be  the  submergence of the
abrasion platforms  and  the  increasing  retreat  of the sandstone cliffs, of the
limestone cliffs,  and  even  of the hard-rock cliffs  (especially  in  the active
tectonic areas).

     From the listed  impacts,  the  more important will be those  affecting the
estuaries (low coastal wetlands and estuarine waters) and the lagoons, because
they are both the most vulnerable and the most populated.

     In the case of a sea level rise of 1 m (Figure 6B),  the greatest economic
impact will  be  the investment  associated with  coastal tourism.    The  most
important tourist  beaches of the country  will  disappear.  On the  coast of the
Algarve,  this problem will be  in addition to  the retreat of the  cliffs,  whose
tops are very often highly developed.

     For  a sea level rise of 0.5 m  (Figure  6A),  the  increased salinity of the
estuarine waters, aquifers,  and soils will be economically more important than
the submergence  of the  lower tidal  flats, or  the erosive effects on  the salt
marsh not offset by accumulation of peat and sediment.  Salinization will affect
the freshwater supplies for domestic and industrial uses  and the water table of
the agricultural soils,  especially in the rice fields.  Sea level rise will also
be costly for rice agriculture because of the need to pump drainage water from
the rice fields before discharging it into the creeks.

     Because of  the  reclamation  of  the salt marshes, this  ecosystem  will  not
migrate on the inland boundaries  because they are  formed  of dikes  or very steep
dune slopes.  In some places, the dikes are less  than 50 cm higher  than  the
spring high tide water  level.  Here,  the  erosive effects will be  considerable
because they already are a real problem to the owners of the rice fields.


     The responsibility  for managing the coastal zone rests with several entities
of the central, regional,  and  local  administrative authorities.    The  most
important  decisionmakers  are  the  Navy  (central   administration)  and  the


North and West Europe

municipalities (local administration).  The Department of the Environment must
be consulted,  as  well  as the other  agencies  that are related  to  the spatial
organization of this zone.

     Among the several  organizations  and  services  that take care of the coastal
zone's protection and management are those that should be  involved with the main
problems concerning the impacts of sea level rise on the coastal lowlands.  To
some of these agencies, the impacts of sea level rise constitute surprising news,
first because they had never considered it, and second because they thought that
it was  not  so urgent a  problem.   To other  agencies,  the impacts  are  a real
problem and they  have been applying the classic engineering solutions to protect
the coastline.  We  briefly summarize what officials in  various  agencies think
about sea level rise.

National Navy

     As the coastal  fringe is  a public domain, the national navy is responsible
for managing the  coastal  margin that  occupies  the  space between the high spring
tides and a line located 50 m inland.

     The Hydrographic Institute is the Navy surveying department with an interest
in coastal dynamics. It produces the cartography of the sea bottom and does the
research  for  controlling  and  monitoring  all  the  conditions  related  to
navigability.  The phenomenon of sea level  rise is, actually, one  of the research
programs partly supported by  the  Institute.   Although the results demonstrate
that sea level  is  rising between 1.27 mm and 1.54 mm per year (Taborda and Dias,
1989), the consequent impacts have not been viewed as a problem.  Naval officials
generally believe that protection structures should be built.


     The response  of the municipalities where tourism is the main economic source
is to keep the  beach as large as possible.  They will  rely  on technology (coastal
engineering structures,  nourishment).   Some municipal officials  suggest that
swimming pools be built at seaside as an insurance in case beaches are lost.

State Secretary of the Environment

     The  impacts   on  the natural   systems  will  be  controlled  by  several
organizations  connected  to  the environment:   the General Directorate  of the
Environment (DGA);  the General Directorate of the Quality of the Environment
(DGQA);  the General  Directorate  of Natural  Resources   (DGRN);  the  General
Directorate of Hydraulic  Resources  (DGRH); and the General Directorate of Parks
and Natural Reserves (DGPRN).  These  organizations,  which report  to the State
Secretary of the  Environment,  are responsible for all aspects of environmental
protection at this time.  There is no  Ministry  of the Environment currently, and
thus there is no  cabinet-level representation for the environment in Portugal.

     To some of these entities, the sea level rise issue was surprising, as was
the evidence  that it could have  such severe  impacts on the natural  coastal
systems, as well  as on  the economic systems.  DGQA is developing some research


Figure 6.  Location and relative importance of the  impacts of potential  sea  level  rises  of (A)  0.5 m;  (B)  1
m; (C) 2 m.  1, 2, and 3 - increasing erosion; 4 - submergence;  5 - salinization.

North and West Europe

projects about climate change due  to  the  greenhouse  effect and the consequent
warming of the atmosphere.

     The discussion of the impacts of  sea  level  rise on the coastal hydraulic
systems will continue in  the near  future,  although these agencies have a very
small capacity of direct  intervention.  Clearly,  they must advise the private
owners and other official entities about the risks of certain investments.

     Some impacts that have been  controlled  are those affecting the  natural parks
and reserves (DGPRN), especially on the coastal  wetlands (Natural Reserves of
Pancas-Tejo estuary, estuary of Sado,  Ria Formosa, and Castro Marin-Guadiana),
because the salt marshes will  retreat  and disappear as a result of the erosion
and the submergence.  A  solution that  must  be considered  is to allow marshes to
migrate inland, replacing the  existing estuarine brackish  marshes,  which are
not very extensive because of the reclamation of the  low fluvial plain and the
channelization of the river courses.

General Directorate of Harbors

     The potential  impacts on  harbors,  and on  other structures,  of coastal
engineering to protect beaches,  such as avoiding  the  infilling of the estuarine
navigation channels, monitoring the growing of the bars, and dredging, will be
controlled by the General  Directorate  of  Harbors (DGP).   This agency controls
the national  and regional  management of the harbors and other coastal protection
structures, according to the regional and local civil administration (Commissions
of Regional Coordination and Municipalities).

     This  office  is  not  very  concerned  about   sea  level  rise  because  the
consequences will  unfold  slowly.   They need  to  rebuild  the coastal  structures
anyway, from time to time,  so sea level rise can be incorporated gradually.  The
reinforcement of structures whose effective lifetime  will be decreased and the
building of new structures are the solutions most commonly suggested.

National Survey for Civil Protection

     The National Survey  for Civil Protection is  part  of  the Ministry of Defense
and protects  the  people  against  natural  hazards.   It  is concerned  with the
impacts of a sea level  rise of  1  m and 2  m  because  of  the increased flooding
risks in the urban  drainage systems and the  risk to  buildings affected by the
storm waves.  They  told  us that they  have no immediate  answer to the problem,
but they will consider it.

General Directorate of Agricultural Resources

     The General  Directorate of Agricultural Resources  is  responsible for the
study of soils and  the coordination of agricultural  productivity.  It is very
concerned about the  problem of salinization of the reclaimed estuarine soils and
the alluvial soils.   The subject is being studied,  and  several  solutions and
their  economic  feasibility are  being considered, especially because  of the
potential for decreased rice productivity.  At the same time, the cost of rice
production will increase  because of the cost of  energy  to  pump the water from



the drainage channels of the rice fields.   One  of  the possible solutions may be
to substitute other crops (oats, barley, or sugarbeets) for rice or to use the
land for purposes other than agriculture.

General Directorate of Tourism

     The Directorate of Tourism  is one of the organizations  connected to coastal
management and  planning.   It is very concerned with the  impacts  of sea level
rise on the coast, mostly on  the beaches.  Together with other agencies, it will
try to  find  options that  can provide practical solutions,  such  as jetties or
artificial nourishment of the beach.  A proposed solution to decrease the tourist
pressure on the coastal fringe will be accepted with very great difficulty.

     The impacts of  the possible sea level rise will be  controlled by several of
these organizations as well  as by the owners of the land. Very seldom will such
impacts be responded to by only one agency.


     One of the few conclusions  we are able to draw is that the solutions will
appear gradually as sea level rises.   Neither structural solutions  nor land use
changes are  yet part  of  the planning  process in  Portugal.   This  is  hardly
surprising given the recent nature of the issue.  Nevertheless, because sea level
rise could have important impacts, the time to start planning is now.


Cavaco, C.  1983.   A  Costa  do Estoril.   Esboco Geografico.  Ciencia e Tecnica
6, Lisboa, Ed. Progresso Social  e Demografia:261.

Carvalho,  J.R.R., and J.P.  Barcelo.   1966.  Agitacao maritima na Costa Oeste de
Portugal Metropolitano. Lisboa,  Laboratorio Nacional de Engenharia Civil, Mem.

Daveau, S., et al.   1977.  Repartition et  rythme des precipitations au Portugal.
Lisboa, Centre de Estudos  Geograficos, Mem. 3:184.

Dias,  J.M.A.   1988.   Aspectos geologicos do Literal Algario.  Geonovas,  10:113-

E.P.R.U.   1988.   Portugal   em  Mapas e  Numeros.    Lisboa,  Centre de  Estudos
Geograficos,  Rel. 28.

Feio,  M.  1980.  0 Porto de Sines: prejuizos e reparacoes.  Finisterra 15(29):74-

Ferreira,  D.B.  1981.  Carte Geomorphologique  du  Portugal.   Lisboa,  Centro de
Estudos Geograficos, Mem.  6.


North and West Europe

Granja, H.M.  1984.   Etude geomorphologique, sedimentologique et geochimique de
la Ria Formosa (Portugal).  These de 3, troisiemme cycle, Univ. Bordeaux 1:254.

Institute Hidrografico.   1978,  1988.   Tabela  de Mares,   1979  and  1989  -  I,
Portugal, Lisboa.

Institute  Nacional  de  Meteorologia  e   Geofisica.     1974-1978.    Anuario
Climatologico de Portugal,  Lisboa, 1974,  1975, 1976, 1977, and 1978.

Moreira, M.E.S.A.   1986.    Man made disturbances  of  Portuguese salt-marshes.
Thalassas 4(l):43-47.

Moreira, M.E.S.A.  1989.  Geomorphology and sedimentation rates of the tidal mud
flats of the Sado estuary.  IGU-CCE Annual  Regional Symposium Guide Book, Lisboa,
130 p.

Psuty, N.P.  1986.  Impact of impending sea-level rise scenarios:  the New Jersey
barrier island responses.  Bull. New Jersey Academy of Science 31(2):29-36.

Ribeiro, 0., H. Lautensach, and S. Daveau.  1987.  Geografia de Portugal  I.  A
Posicao Geografica e o Territorio.  Lisboa:  Sada Costa, 334 p.

Service Meteorologico Nacional.   1970.  0  Clima de Portugal.   Fascicule  XII -
Normais climatologicas do Continente,  Acores e Madeira, correspondentes a 1931-
1960, Lisboa.

Taborda, R., and J.M.A. Dias.  1989.  Tide-gauge data in deducing sea level rise
and  crustal  movements rate:  the  Portuguese  case.   IGU-CCE Annual Regional
Symposium Guide Book, Lisboa. 130 p.

Titus,  J.G.    1986.   Greenhouse  effect,  sea  level  rise,  and coastal  zone
management.   Coastal Zone Management Journal  14(3):147-171.



                               OF BRAZIL
                             DIETER MUEHE
                       Departamento  de Geografia
                        Institute de Geociencias
                Universidade Federal do  Rio de Janeiro
                   Rio  de Janeiro, RJ 21945, Brazil

                            CLAUDIO F. NEVES
                Programa  de Engenharia Oceanica,  Coppe
                Universidade Federal do  Rio de Janeiro
                           Caixa  Postal 68508
                   Rio  de Janeiro, RJ 21945, Brazil

     The  impact of sea level  rise on Brazil  would be similar to  the  impacts on
other nations:  Wetlands and  lowlands would  be  inundated, beaches would erode,
coastal areas would flood more frequently, and saltwater would encroach inland.
But the question remains:  How severe will  the effects be,  how  much will they
cost, and what should we do?

     Because  Brazilians have only recently  begun  to ask these questions and
almost no  research  has  been done to  answer  them,  we can  not  yet provide
quantitative  estimates of the impacts.  Thus, it has not yet  been possible to
demonstrate the  significance of the issue to public  officials, which will be
necessary before we can confidently recommend policy responses.

     What  we can offer  is  the  perspective of scientists  who  are beginning
preliminary assessments which we hope will  eventually assist  policy makers in
the decision  process.

     We are persuaded by the  point of view  that the primary responsibility of
researchers is to gradually develop an understanding of the implications of sea
level rise in one's  own  country  and  develop  recommendations  based  on that
research,  not on the results  of analysis  in other countries.  Because serious
analysis  has not  been undertaken, we would rather simply tell the IPCC that this
is so than speculate on the implications of response strategies.  We are pleased
that our  point of view  is reflected in the conference report's section on South


Central and South America

     Simply put, our  strategic  response  to sea level rise  at  this  time is to
understand  the problem  so that  in a  couple of  years we  will have  useful
information for policy makers.   This will  require us  to develop a comprehensive
understanding  of the coast  of Brazil,  then  estimate inundation,  erosion,
flooding, and other effects, then evaluate the costs of alternative responses,
and only then,  recommend policies.   Accordingly, the bulk  of this paper is on
the first step  -- understanding the coast.


     Brazil   is divided  into  five  major  geographic  regions,  according  to
geological, climatic, and  economic  characteristics  (Figure  1).   Four of these
regions border the Atlantic Ocean (North, Northeast, Southeast, and South) and
the coastline  has an  approximate length of 7,400 km, without  considering the
contour of bays and islands.  Extending  from latitude 4 north to 34 south, with
climates ranging from tropical  to subtropical, within  each region the coastline
may be further divided into different segments  according  to the geomorphological
features or processes.

     In Brazil,  erosion problems have not been  generally  considered as caused by
sea  level  rise,  although  a  few reports  (e.g.,  Muehe,  1989;  Tomazelli  and
Villwock, 1989) have addressed this issue very recently.  Frequently, the idea
that sea  level  is dropping still persists.   In fact,  the  relative  sea level
curves established for several  sectors of the Southeast and South regions for
the last 7,000 years (Delibrias and Laborel, 1971; Suguio et al., 1985), indicate
that during two or three  occasions,  sea level  has been up to 5 m higher than at

     Despite the continuous drop in relative  sea level during the  last 2,300
years, evidence of coastal  erosion begin to be  noticed at different parts of the
coastline.  Lack of sediment supply,  increase of storm intensity, local tectonic
movements,  and  human  interference  may all contribute  to  this erosion.   The
absence  of  long-term  tidal  data  and  also the scarcity  of  topographic  and
cartographic material  makes it  difficult  to follow coastal changes for a longer
time span into the past.  Most  of the studies  about coastline changes have been
limited to typically unstable areas such as tidal  inlets and river mouth bars,
and therefore cannot  be considered as  evidence  of  erosion due to  a  marine
transgression.   Nevertheless,  there  is  an  increasing feeling,  among  some
researchers, that a rise in sea  level  may also  be  responsible  for some of the
detected erosion.

     In a shorter time scale,  though,  there might  be a trend  for a  sea level
rise.  Pirazolli (1986) presented relative sea  level  curves for  six locations
in Brazil  during the period 1950-1970.  There was a rise at rates varying between
5 cm/century  to 35 cm/century,  except  for one location near the mouth  of the
Amazon River, which showed a trend  for decreasing  sea level.   This  subject is
further discussed  in the section about tidal information.  Although the time span
of observation was too short to  derive a definite conclusion,  it  is strong enough


                                                                Muehe and Neves

Figure 1.  Geographic regions of Brazil.

Central and South America

to justify the beginning of comprehensive studies about the subject in Brazil,
as well as special care in obtaining tidal  data.


     The coast of Brazil was divided into five sectors,  and  for each of them the
geomorphologic characteristics and the population distribution were presented.
It is reasonable  to assume that  places  with  higher  numbers of inhabitants per
kilometer of coastline would be more susceptible to the  impacts from a one-meter
ri$e in sea level.  Therefore,  it  can be derived from maps  that the major impacts
would be limited to the neighborhood of about fifteen coastal  cities where the
deny ty'is higher than 5,000 inhabitants per kilometer of coastline.
  >*"" * .-'
     As a guide for evaluating these impacts,  five areas are suggested for study
in  each  of  the  sectors  owing   to  their  geomorphologic  and  socioeconomic
characteristics.   From North to  South,  these  areas  are Salinopolis (PA), near
the mouth of the Amazon; Fortaleza (CE); Recife (PE); Rio de Janeiro (.RJ); and
Rio Grande (RS).                                                      (     .

     We briefly summarize concerns  for  four coastal regions:   the Nqrth, the
Northeast, the Southeast, and  the South.                             i

The North

     The most important impact here would be  the  rising  water  levels  in tidal
rivers.  Flooding of river valleys will confined to a fairly narrow  area due the
presence of high  ground somewhat  inland.  Low-lying  alluvial  areas such as in
the Marajo Island at the  river mouth,  however, might be inundated.  Because the
low-lying areas in northern Brazil are now sparsely populated, major consequences
for the  economy  can  be avoided  as  long as  future development  in  the  regions
occurs takes sea level  rise into  account.

The Northeast

     In this region, low-lying  deltaic  areas such as the Sao  Francisco Delta will
suffer an expansion of the mangroves into and used today  for temporary housing
and agriculture.   A more serious  problem will  face coastal  cities like Recife,
Aracaju, and part of Maceio, where low-lying areas are flooded when heavy rains
coincide with spring tides  (Nou et al.,  1983); with-50-cm rise in sea level the
same effect would occur even during neap  tides.  Drainage problems and flooding
will probably also confront the  low-lying  areas of the  coastal  plains  of the
Todos of Santos Bay in Bahia.   These  problems could  be particularly severe in
the heavily populated city of Recife, where urbanization has expanded throughout
the floodplain the Capibaribe  and Beberibe Rivers,  exacerbating  flooding and
drainage problems (Figure 2).

The Southeast

     The diverse types of coasts in this region (barrier  beaches, pocket beaches,
rocky shores, coastal  lagoons,  bays,  estuaries) will respond in different ways


                                                               Muehe and Neves
Figure 2.  Retreating bluffs  on  the  coast  of Paraiba (northeast region); note
a tree at the edge of the bluff (center).
to a  sea level  rise.   Some  areas  are already  eroding  -- even  though  human
interference is negligible --  suggesting that these areas are already exhibiting
some of the signs of rising sea level.

     For example, during  the  last  fifteen years, the mouth of  Paraiba  do Sul
River has seen  extensive beach erosion with a resulting loss  of valuable property
(Argento, 1989).  On the southern part of the delta, grayish black sandstone has
been exposed,  indicating that shores are retreating.  Similar processes have been
identified by  Muehe (1984,  1989) at  the  barrier  beaches  between Cape  Frio and
Guanabara Bay,  and  the back  side  of  the  barrier that faces Araruama  Lagoon
appears to be eroding.

     Another area in the State of Rio de Janeiro  that may suffer from a rise in
sea level is the fluvial-marine plain along the estuary of Sao Joao River located
about 200 km  south  of Paraiba do  Sul  River.  Currently,  rice  is extensively
cultivated along  the  valley,  using  river water  for irrigation.   Besides the
potential of   flooding, sea  level   rise   could  threaten  the  water supply  as
saltwater advances farther upstream, a process that has already been observed.

     Finally,  the flat areas around  Guanabara Bay  appear to be vulnerable.  These
areas currently flood during heavy  rains, especially along  rivers and  drainage
canals.   The  combined effects of a  rise  in sea level and siltation  of those
canals will  aggravate the  flooding.   Moreover, because the relative sea level
was 5 m  higher during the  Holocene  than  today   (Amador,  1974),  the terrain in


 Central  and South America

 this area  is very flat and hence extensive areas are vulnerable to flooding from
 storm surges.  Similar problems seem likely to afflict other coastal  plains and
 river valleys  in the region (Figure  3).

 The South

      Little data have been collected on current shoreline changes.  However,  in
 Santa Catarina peat  has emerged near the scarps of coastal  barriers,  indicating
 that shores are retreating.   Similarly, peat  is  present on the  foreshore and
 along the  base of the foredunes along the beaches of Rio Grande do Sul.   Erosion
 along the  margin  of Patos Lagoon also  appears  to be  another   indication  of
 relative sea level rise.  All of these trends would be exacerbated if sea level
 rise accelerated.

     A  study  of  the  impacts  of sea  level  rise  must  consider  not  only  the
 geomorphological  features of the coast,  but also the economic impact  it  would
 have on the  population.   Due to the fact that  no detailed assessment of  the
 entire  coastal zone of Brazil has ever been conducted,  and also  because  it is
 always  assumed that the population is not evenly distributed along the coast,
 the authors chose to characterize the human occupation of the coastline  (measured
 in  terms of inhabitants/km of coastline).  This parameter is used to  identify
 areas where potential  impacts would be stronger for the following reason:   an
Figure 3.  Barrier island of  Ipanema-Leblon, city of  Rio  de  Janiero.   Erosive
processes have been observed on Leblon Beach (top) and waves reach the longshore
avenue during storms.


                                                               Muehe and Neves

area with a higher degree of occupation would most  likely  have more diversified
activities  (e.g.,  housing,  water supply  needs,  waste disposal,  harbors and
marinas, tourism, agriculture), that would ultimately be  affected by sea level
rise.  The  cost  for  facing the adverse impact would probably be divided among
all  local   residents  in  the  form  of  increased   taxes,  reduced revenues  or
reallocated funds, even though the population might not be at risk of flooding
(which is the first thought  of impact).

     Micro-regions,   established  by  the Institute  Brasileiro  de Geografia  e
Estatistica  (IBGE),   as  a  group of counties  with  homogeneous  geographical
characteristics, were chosen as the basic unit of the coastline.  Then, for each
micro-region located on the coast, only those  counties that have a coastline were
considered  in this study, measuring the length of  its coast and its population
(based on 1980 census).  The  towns would be  located  at most 30 km from the coast.

     First, a comparison was  made between the population living  in those coastal
counties and  the population  of the state  (figures  are  presented  in  Table 1).
For the country  as a whole,  about 20.4% of the population might be potentially
affected by the  consequences of sea level rise (not necessarily flooding).  In
the  north  region,   both   states,  Amapa  (AP)  and  Para  (PA),  show  a  high
concentration of population  near the coast, respectively 82.9% and 50.7%, even
though their total population is not significant compared to other states.  This
is because  they  are  both  located  in  the Amazon region,  and their capitals are
are  located on  the  margins  of the  Amazon delta.   In the  northeast  region,
Pernambuco (PE) has the highest percentage (38.5%) which is explained by the dry
weather in the interior and by its historical  development  since the 1600s as an
important area of sugarcane plantations.  In the southeast region,  Rio de Janeiro
(RJ) shows a percentage of 68.6%, which  is a high figure.   The reason is because
the capital, the  City of Rio  de Janeiro, and its metropolitan region are located
around two  bays  and  represent  the second largest  urban  center in the country.
Finally, in  the  south region,  Rio  Grande  do  Sul  (RS)  is the state with the
highest percentage of population (28.7%) in the coastal  zone, mostly concentrated
around Patos Lagoon,  which has an  area of 10,000 km2 and whose coastline will be
affected by sea level rise.

     A second  study was conducted in order to quantify the population density per
unit length of coastline.  Four classes were identified:  those where the density
was less than 1,000  hab/km,  which characterizes  remote  areas;  those  where the
density was between  1,000 and 5,000 hab/km,  characteristic of most  urbanized
areas, where the economical  activities  should be  more important;  those  with  a
density between 5,000 and  10,000 hab/km, typical of medium size cities,  usually
around state  capitals;  and,  finally,  above  10,000  hab/km,  typical  of  large

     It was observed  that  47.4% of  the  coastline has very low  occupation  (a
weighted average value of  522  hab/km).   These localities  include preservation
areas, small  towns  without  appropriate surveying,  or areas where data  about
coastline evolution would not be available at all.  Consequently, it is difficult
to make an assessment of  impacts  of  sea level  variations.   On the  other hand,
it also suggests that a  planned occupation -- which  should take  into  account


Central and South America

        Table  1.   Population  Living  in the Coastal Zone  (1980 Census)
Region State
1 AP
2 MA
3 ES
4 PR
In the state On
3,403,391 1
3,996,404 1
5,288,253 1
6,141,993 2
9,454,346 2
11,291,520 7
7,773,837 2
119,001,427 24

the Coast
NOTE:  Region --  1 = North; 2 = Northeast; 3 = Southeast; 4 = South.

                                                               Muehe and Neves

data  about  sea  level  trends  in  neighboring  areas  --  would  be the  "best
response"to avoid future problems.

     In other areas,  which  amount to  fifteen cities and 12.7% of the coastline,
the population has already been established.   Usual  coastal engineering works
for shore  protection would be  feasible  there and detailed  studies  (for past
evolution and future observations) are economically justifiable.


     Tide data in Brazil has usually been obtained by the port authorities and
by  the  Navy for  navigation purposes.   For various  reasons  -- like  cost  of
maintenance  and  repair of  equipment  --  the  time  series has many  gaps; this
prevents a study of long-term variations.

     As a rough guide of the tidal  variation along the coast of Brazil, Table 2
presents figures obtained  from  the 1989  Tide  Table  published by the Diretoria
de  Hidrografia e  Navegacao (DHN) for different ports along the  coast.   It  is
interesting to observe the  decrease in tidal range, from  5.0 m near the Equator
to  0.5 in Rio Grande, at the southern part of the country.

     Studies conducted by  Pirazolli  (1986), including  six locations in Brazil
during the period  1950 through 1970, indicated  a trend for sea level  rise in four
stations (Recife (PE),  27 cm/century;  Salvador (BA),  16 cm/century; Canavieiras
(BA), 31 cm/century; and Imbituba  (SC), 5.5 cm/century; in Fortaleza (CE), the
sea level has oscillated by an amount of 6.6 cm in fifteen  years,  showing a trend
for rise at the end  of  the period  of observation;  in Belem (PA),  there was  an
oscillation of 2.2 cm in twenty years, with a trend for decreasing in the last
seven  years  of  observation.    This  data justified the  need  for  further
investigation.   Currently,  groups of  researchers at the Universidade Federal  do
Rio de Janeiro (UFRJ) and at the Institute Oceanografico da Universidade de Sao
Paulo (IOUSP) are studying long-term sea level variations at various points along
the coast.  The work, which should be completed by  the end of 1990, includes:
retrieval of tide data from graphs  to  digital  format; correction for changes in
datum; verification of errors and gaps; and determination  of daily, monthly, and
yearly mean sea level curves.

     Brazil  already participates in the GLOSS  program of the Intergovernmental
Oceanographic  Commission  (UNESCO),  and  the  DHN  of  the  Brazilian  Navy  is
responsible for the  installation of  ten  permanent tide gauges  in the country,
including three stations at oceanic islands.  The IOUSP and the Brazilian Port
Authority holding  company  (PORTOBRAS) also participate  in this effort  being
responsible for two stations.  Combining the data already  available for the past
twenty years with  the  data to  be  obtained  during  the next twenty  years will
enable us to have  a clear picture of relative sea level changes at the beginning
of  next century.

Central and South America
               Table 2.  Tidal Range Along the Coast of Brazil
                                                        Spring tide





Barra Norte
Luis Correia
Areia Branca
Barra do Riacho
Cabo Frio
Rio de Janeiro
Sao Sebastiao
Rio Grande
 a Region: 1  =  north;  2a  ==  northeast,  from Maranhao to  Cape Calcanhar; 2b  =
  northeast, from Cape Calcanhar to Bahia;  3 = southeast;  4 = south
b Type of location of the tidal stations: 0 = open coast;  B  =  inside  bay;  E  =
  in estuaries; M = at the mouth of the estuary or bay
0 HW = mean values of high water spring  tide  (elevation in meters  relative to
  local datum).
d LW = mean  values of  low water spring tide (elevation in meters  relative to
  local datum).
e AH = HW -  LW.
Source:  Values from 1989 Tide Table.

                                                               Nuehe and Neves


     The Constitution of 1988 and the state Constitutions that followed brought
the  environmental  issues into  a legal  framework  by  declaring in  one  of its
chapters  that  "all  have  the right  to  an environment  that is  in ecological
balance."   It  also  includes  the coastal zone  among  the  areas  classified as
"national heritage."

     Brazil's National Coastal Zone Management Plan  (PNGC) was established  in May
1988.  The Comissao  Interministerial para os Recursos do Mar -- the government
agency for sea resources  --  is  responsible,  through its Secretary for Coastal
Zone Management,  for establishing general goals and  common  policies,  and for
giving technical  and financial support to state and municipal agencies.  However,
each State is responsible for developing its  own Coastal Management  Plan.  Each
plan is supposed  to  include  "macro-zoning" of the coast,  the monitoring program,
and a geographical  information system.  Because the program  is new, macro-zoning
is progressing in only six states, including Rio de Janeiro.

     The  various consequences  of sea  level  rise  --  erosion,  flooding,  and
saltwater intrusion -- are intrinsic  to any management  plan. However, officials
are not yet convinced that there  is  a problem.  Many researchers still  believe
that sea level  is falling around  the coast of Brazil; and information on current
sea level and even shoreline trends  is unavailable for most of the coast.

     Regarding  the  climate  changes  issue,  the  Brazilian  government took an
important step  in October  1989  by enacting a  law that creates  the  Comissao
Interministerial  sobre Alteracoes Climaticas  --  an internrinisterial committee
for climate changes, which includes the Secretaries of  eight federal ministries,
the Secretary of the Comissao Interministerial para os Recursos do Mar,  and the
directors  of seven  institutions related  to research  on  meteorology,  space
science, environment, and agro-sciences.

     Finally, studies are  currently being developed  in Congress  in order to
establish a national management  plan  for water resources.   Dams for irrigation,
water supply, and hydroelectric  power plants can alter the  balance of estuaries
downstream; The significance of these impacts may be much greater than currently
anticipated if sea  level  rise accelerates;  and transition to  a  drier  climate
could  further  amplify the  interactions  between  water  resources  and  coastal
management.  Thus,  these two programs  need to work  together to  ensure  that
solutions  to one  type   of  problem  (e.g.,   increased  water  supply needs  to
counteract increasing droughts)  do not create other problems downstream (e.g.,
increased saltwater intrusion and loss of sediment in  deltas).

     The results  of the new  programs  will  not be known for many years.   Whether
they are going to work depends mostly on  the amount of funds  and effort that will
be invested in  environmental education.

Central and South America


     The  National  Coastal  Zone  Management  Plan  was  established  in  Brazil
according to the Federal  Law  No.  7661  on May 16, 1988.   It  is  made up of the
National Policy for the Environment and the National Policy for Sea Resources.
The Comissao Interministerial  para os Recursos do Mar -- the government agency
for sea  resources  --  is  responsible,  through  its Secretary for  Coastal  Zone
Management, for establishing general goals and common policies,  and for giving
technical and financial  support  to state  and municipal agencies.  However, each
state is responsible for developing its own Coastal Management Plan.  Each plan
should  include  the  macro-zoning of the  coast  (which is  summarized  in twelve
thematic  maps),  the  monitoring   program,  and  the  Geographical  System  of
Information.  A detailed explanation of PNGC can  be found  in Frischeisen et al.
(1989) and Azevedo et al. (1989).

     The PNGC is still in  its  infancy:  the macro-zoning program is in progress
in only six states  (Rio Grande  do  Sul  and  Santa  Catarina  in  the south region,
Sao Paulo and Rio de Janeiro in  the southeast region, and Bahia and Rio Grande
do Norte in the northeast region)  and  it  is expected to be completed by 1992.
The concerns about  a  possible sea level  rise are intrinsic  to  any management
plan.  However, in  practice, it  becomes very difficult to consider relative sea
level variations either because  tidal data are not available, or because there
is no  reference line that  can  be  used  to control   erosion  along  unpopulated
stretches of the coast.

     Regarding  climate changes,  the Brazilian government took an important step
by passing  Federal  Law  No.  98352  on October  31,  1989.    This law  created the
Comissao  Interministerial sobre Alteracpes Climaticas  --  an interministerial
committee for climate  changes.  The committee includes the Secretaries of eight
federal ministries,  the  Secretary of the Comissao  Interministerial  para  os
Recursos do Mar, and the directors  of seven institutions related to research on
meteorology, space science,  environment,  and  agro-sciences.

     Finally,  studies are currently being developed  in Congress  in  order  to
establish  a national  management   plan  for water  resources.   The  Brazilian
Association for Water Resources (ABRH),  an association  of engineers and other
professionals  who  deal  with  hydraulic  engineering  and  water  resources,
contributes  to this  plan by forwarding  several  proposals  to the  Congress
committee.   Multiple   uses  of  water resources (irrigation,  water  supply,
hydroelectric  power plants,  construction of  dams)  cause  changes  in  river
discharge, which alter the environment of estuaries downstream. The significance
of these impacts may be much greater than currently anticipated if the climate
becomes drier and sea level  rise  accelerates.  Thus,  it is desirable that the
management plans for water resources and  for  the  coastal zone work together to
ensure that solutions to  one  type  of problem  (e.g.,  increased  needs for water
supply) does not create other problems downstream  (e.g.,  increased saltwater
intrusion and loss of sediment in deltas).

     Perhaps the most  difficult  part is to establish stations and routines for
collecting data, which  is usually  a  very  expensive  task.   Taking into account


                                                               Muehe and Neves

all regional differences in socioeconomic needs and priorities,  as well as those
differences  in  impacts due to  global  weather and  oceanographic changes,  the
establishment of those national committees gives a promising perspective.

     The results of all  these plans will be felt in  the future,  though.  Whether
they are going to work depends mostly on the amount of funds and  effort that will
be invested  in environmental education.

     The most important  step in environmental legislation, with consequences yet
to be perceived, was given by the Brazilian Constitution of 1988 and the State
Constitutions which followed.   Environmental  issues  were  brought into a legal
framework by the declaration in one of its  chapters that "all have the right to
an environment which  is  in  ecological  balance."   It  also  includes the coastal
zone among the areas classified as "national heritage."

     Since 1934, the  "Code  of Water  Resources"  has  been  the basic  law which
regulates the uses of water resources, the occupation of the margins of rivers
and lakes, and the occupation of the coastal  area.  It establishes that a strip
of land 33 m  wide,  inland from a specific high-water line, belongs to the Union.
Together with a resolution of the Brazilian Navy, public access to the shore is

     The National  Policy for the  Environment  (1981) established the creation of
a National Committee for the Environment (CONAMA)  including representatives from
federal ministries  and  civil organizations.   CONAMA has since  then  approved
several resolutions for protection of sensitive areas and  for establishment of
ecological stations.  The following areas are included among those of permanent
protection (Resolution 004,  1985):   barrier islands,  spits, and barrier beaches
up to 300 m inland  from the highest water line;  mangroves; vegetation for fixing
dunes; wetlands and other areas  used  by migrating birds; and  land up  to 100 m
around lakes, lagoons,  and  reservoirs.   As a matter of fact, since  1965,  the
"Forest Code"  had  considered mangroves  and vegetation on  dunes as  being  of
permanent protection

     The legal  framework which grants  a  balanced use  of  the environment  is
essentially established.   In  addition to the federal laws  listed  above,  each
state has its own regulations and policies.  In a  scenario of sea level rise and
climate changes, some of these legislations may need  to be  reviewed in face of
scientific studies.  However, the most urgent problem for  the country seems to
be how to enforce  these  laws,  in  such  a vast  area, with very limited resources.
Furthermore,  without the social and educational development of a large percentage
of the population,  it is extremely hard to  achieve  the goal  of  living  in  an
ecologically balanced environment.

Central and South America


     We have only begun  to  assess  the implications of sea level  rise and the
greenhouse effect.  Upon further investigation, we may find  that we have been
overlooking impacts that are more important than those described here; and some
of the impacts that now seem serious may prove to be manageable.  Any conclusions
thus must be viewed as  tentative and illustrative hypotheses necessary to guide
future research.

     In our view,  the expected global  rise in sea level implies that municipal,
state, and federal authorities should  take a preventive approach when selecting
sites for urban expansion and location of industries.   Due to the high cost of
protecting developed areas from such a rise, this "preventive approach" includes
the following steps:

     1.  Enforce coastal management programs,  as the one currently in progress,
         and establish  urbanization plans according to those programs;

     2.  Install long-term tidal gauges  in order to  furnish,  twenty years from
         now, reliable  data  for inferring sea level trends;

     3.   Establish  a methodology for observing (and quantifying) the evolution
         of shoreline,  mangrove areas, and other coastal features;

     4.   Maintain  a systematic  data  bank  for oceanographic  and meteorologic
         information according to international standards;

     5.  Incorporate  the  results  of  scientific   assessments  into  coastal
         development plans, for example, by requiring construction to be set back
         from the  shore;

     6.  Adopt flexible criteria for  designing  harbors and coastal structures,
         which take into account  all the  information available  for  the  site and,
         at least,  a "lower  expectation" of sea level  rise; and

     7.  Formulate   educational  programs  about   environmental   (particularly
         coastal)  protection and  global climatic effects, addressed to different
         levels  of the  population.

     The  costs  involved in  these  cautious measures  could  bring significant
benefits  in the future and could avoid greater socioeconomic impacts.


Amador, E.S.  1974.  Praias  fosseis do reconcavo da baia de Guanabara.  An. Acad.
Brasil. Cienc. 46(2):  253-262.

                                                               Huehe  and Neves

Angulo,  R.J.   1989.  Variacoes  na configuracao da linha de costa no Parana  nas
ultimas  quatro decadas.  II Cong, da Assoc. Bras, de Estudos do Quaternario.  Rio
de Janeiro, July  10-16,  1989.  (in press).

Argento,  M.    1989.    The  Paraiba  do  Sul  retrogradation  and  the Atafona
environmental impact.     In: Neves,  C.  and Magoon. O.T.  (ed.) Coastline of Brazil.
American Society  of Civil  Engineers,  New York. p. 267-277.

Azevedo, L.H.,  D.M.W.  See,  and D.R.  Tenenbaum.   1989.  Coastal zone  planning.
In: Neves, C. and Magoon, O.T. (ed.)  Coastline  of  Brazil.  American Society of
Civil Engineers,  New York.  p.  70-83.
Bandeira Jr., A.N.; S. Petri,  and  K. Suguio.
Brasileiro S.A.,  Internal Report, 203 p.
1975.   Projecto Rio Doce: Petroleo
Cruz,  0.,  P.da N. Coutinho,  G.M.  Duarte,  A.M.B. Gomes, and  D.  Muehe.   1985.
Brazil.   In:  Bird E.C.F.  and M.L.  Schwartz (ed.), The World's Coastline.  Van
Nostrand Reinhold Co., New York. p. 85-91.

Delibrias, C., and J. Laborel.  1971.  R ecent  variations  of  the sea level along
the Brazilian coast.  Quaternaria, XIV: 45-49.
Dias, G.T.M.   1981.   0 complexo deltaico do Rio  Paraiba  do Sul.
Quaternario no Brasil. Publ. Especial. 2:35-74. Rio de Janeiro.
                      IV simposio
Dias, G.T.M., and M.A. Gorini.  1979. Morfologia e dinamica da evolucao do delta
atual do rio Paraiba do Sul. Anais da V Semana de Geologia, UFRJ.  Rio de Janeiro.

Dias, G.T.M., and C.G. Silva.  1984. G eologia de depositos arenosos  costeiros
emersos  --  exemplos ao  longo  do literal  fluminense.    In:  Lacerda,  L.D.  de,
Araujo,  D.S.D.   de,  Cerqueira,  R.  and  Turcq,  B.  (ed.)    Restingas: Origem,
Estrutura, Processes. CEUFF, Niteroi. p. 47-60.

Dominguez, J.M.L.   1989.   Ontogeny  of  a strandplain:  Evolving concepts on the
evolution  of  the  Doce  river  beach-ridge  plain  (East  coast  of  Brazil).
International Symposium on Global Changes in South America during  the Quaternary:
Past -- Present  -- Future.  Sao Paulo, May 8-12.  Special  Publication 1:235-240.

Dominguez, J.M.L., L.  Maratin,  A.C.S.P.  Bittencourt, Y.  de A.  Ferreira, and J.-
M. Flexor.  1982.  Sobre a validade da utilizacao do termo delta para designar
planicies costeiras associadas as desembocaduras  dos  grandes rio brasileiros.
32 Congr. Bras.  Geol., 2 (Breves Comunicacoes): 92, Salvador.

Franzinelli, E.   1982.  Contribuicao a geologia da costa do Estado do Para (entre
a baia de Curaca  e Maiau).  In:  K. Suguio, M.R.M. de Meis, and M.G. Tessler (ed.)
Atas IV Simposio do Quaternario no Brasil.  Rio  de  Janeiro, July,  27-31. p. 305-

Centra/ and South America

Frischeisen,  E.R.,  M.S.F.  Argento, R.  Herz,  and R.P.  Carneiro.    1989.   The
Coastal Management  Program in  Brazil.  In: Neves,  C.  and Magoon,  O.T.  (ed.)
Coastline of Brazil. American Society of Civil Engineers, New York. p. 1-9.

Marques, R.C.C.  1987.   Geomorfologia  e  evolucao da  regiao costeira do complexo
estuarino  lagunar  Mundau-Manguaba. M.Sc.  thesis,  Departamento de Geografia,
Universidade Federal do Rio de Janeiro.  Rio de Janeiro. 152 p.

Martin. L., and  K.  Suguio.   1989.  Excursion route along  the Brazilian coast
between Santo (State of Sao Paulo) and  Campos (North of State of Rio de Janeiro).
International Symposium on Global Changes in South America during the Quaternary.
Sao Paulo, May 8-12, 1989.  136 p.

Martins,  L.R.,  and J.A. Villwock.    1987.   Eastern South  America Quaternary
coastal and marine  geology: A synthesis.  In: Quaternary coastal geology of West
Africa and South America.   INQUA-ASEQUA  Symposium, Dakar, April 1986. p. 28-96.

Muehe, D.   1984.   Evidencias  de recuo  dos cordoes litoraneos em  direcao ao
continente no literal  do Rio de Janeiro.   In:  Lacerda,  L.D. de, Araugo, D.S.D.
de, Cerqueira, R. and Turcq, B. (ed.)  Restingas:  Origem, Estrutura, Processes.
CEUFF, Niteroi. p.  75-80.

Muehe, D., and C.H.T.  Correa.  1989.  The coastline between Rio de Janeiro and
Cabo Frio.  In: Neves, C. and Magoon,  O.T.  (ed.)  Coastline  of Brazil. American
Society of Civil Engineers, New York.  p. 110-123.

Nou, E.A.V.,  L.M.  de  M. Bezerra,  and M.  Dantas.    1983.   Geomorfologia.   In:
Projeto Radam Brasil.  Levantamento de Recursos Naturais V.  30,  Folhas SC 24/25,
Aracaju/Recife.  Ministerio das Minas e Energia.   Rio de Janeiro.

Nunes, T.  de A.N., V.L. de S.  Ramos, and A.M.S.  Dillinger. 1981.  Geomorfologia.
In: Projeto Radam Brasil.  Levantamento de Recursos Naturais V.  24,  Folha SD 24,
Salvador.   Ministerio das Minas e Energia.  Rio de Janeiro.

Pirazolli,  P.A.   1986.  Secular trends of relative sea  level  (RSL)  changes
indicated by tide-gauge records.  Journal of Coastal Research, SI, 1:1-26.

Prates, M., L.C.S.  Gatto, and M.I.P. Costa. 1981.   Geomorfologia.  In: Projeto
Radam  Brasil.    Levantamento de  Recursos Naturais  V.  23,  Folhas  SB  24/25,
Jaguaribe/Natal.  Ministerio das Minas e Energia.  Rio de Janeiro.

Prost, M.T., M.  Lintier, and B. Barthes.  1988.   Evolution  cotiere en Guyane
Francaise:  La  Zone de Sinnamary.    35  Congr.  Bras. Geol.  and  7  Congr.
Latinoamericano Geol.   Abstracts.  Belem, Brazil, Nov 6-13, 1988,  p. 407.

Silveira,  J.D. da  1964.  Morfologia do literal.   In: Azevedo,  A. de. ed. Brasil
a terra e o homem.   Sao Paulo,  Cia. Editora Nacional. p. 253-305.

                                                               Muehe and Neves

Suguio, K. and L. Martin.   1976.   Brazilian coastline Quaternary formations -
The State of  Sao  Paulo and Bahia littoral  zone evolutive  schemes.   An. Acad.
Bras. Cienc.,  48 (Suplemento): 325-334.

Suguio, K.,  and L.  Martin.   1981.   Progress  in research on Quaternary sea level
changes and coastal  evolution in Brazil.   Proc.  Symp. on  Holocene  Sea Level
Fluctuations,  Magnitude and Causes, 1981, Dept.  Geology, USC: 166-181.

Suguio, K.,  L. Martin, A.C.S.P. Bittencourt,  J.M.L.  Dominques, J.-M. Flexor, and
A.E.G.de  Azevedo.    1985.    Flutuacoes  do  nivel   relative do  mar durante  o
Quaternario Superior ao longo  do  literal  brasileiro  e  suas  implicacoes  na
sedimentaca costeira.  Rev. Bras. Geoc., 15 (4): 273-286.

Tomazelli, L.J., and A.  Villwock.   1989.   Brasil:  evidencias  de uma provavel
tendencia contemporanea de  elevacao do nivel  relative do mar.  II Cong, da Assoc.
Bras, de Estudos do Quaternario.  Rio de Janeiro,  July 10-16, 1989 (in press).

Central and South America


     General  classifications of the main  features of the Brazilian coastline have
been  presented  by Silveira  (1964)  and  by  Cruz  et al.  (1984).    Martins  and
Villwock  (1987)  presented  a  modified  version   based   on  the  other  two
classifications.  In  the present paper, a similar pattern is followed with a few

     The Barreiras group,  which is  mentioned  in this  classification scheme,
represents tertiary sedimentary accumulations of varied composition and extends
from the North up to  the Southeast  Region.   Its flat-topped, table-like surface
was  deeply   incised  by the  drainage system  during  the  Pleistocene climate
fluctuations.  At the coast these deposits occur in the form of active or dead
bluffs, several tens of meters high, carved by the action of waves.  Lateritic
concretions,   found  inside  the  deposits  in  the  zone of the  groundwater table
fluctuation,   are frequently  preserved  at  the  inner  shelf,  indicating  the
amplitude of coastal  recession.

The North Region

     The North  Region  extends  from Cape Orange  in  Amapa (AP), at  the border
between Brazil  and  French  Guyana,  up to the  south  of the State  of  Para (PA)
(Figure A-l). The 1,080-km-long coastline is strongly influenced by the sediment
discharge of  the Amazon, which  is  responsible for  the enormous enlargement of
the continental shelf.  In  front of and  northward from the river mouth, the 10-
and 50-m isobaths occur, respectively, at distances of about  100 and 150 km from
the coast.  The influence of  the Amazon  sediments could be followed, during the
recent AMASED expedition,  up to about 200 km offshore,  where a sharp boundary
between turbid and clear ocean water marked the  distal influence of the river.
Southward from the river mouth,  the distances of the 10- and 50-m isobaths reduce
to respectively 10 to 80 km.   Both  the  north and  south segments,  the coast is
characterized by a fringe of muddy sediments, deposited in front of a Barreiras-
like  hinterland and  covered by  mangroves.  The   south  segment   presents  an
irregular coastline,  while the northern  segment  presents a smoother shoreline.
These differences are obviously due to the large amounts of sediments from the
Amazon River transported to the north.

     Due to a tidal  range  of more  than  3 m  (reaching  10 m  at some locations),
erosive processes are  strong.   The  low gradients  of the rivers  allow a wide
penetration  of tides.   Problems  have  not been  reported so  far,  but  large
destruction of mangroves at the ocean front occurs  at the  north  sector (Dias,
personal communication).   Naturally,  without long-term observation  it is  not
possible to  know  if  this  is a  general  trend  or only  a cyclic phenomenon,  as
related by Prost et al. (1988) for the mangrove coast of French  Guyana.  For the
south  sector Franzinelli   (1982)  described  the  presence  of active  bluffs  at
Atalaia beach in Salinopolis, where the  sediments of the Barreiras group lie on
top of  the calcareous  sediments of the  Pirabas Formation  (Figure A-2).   Dead
bluffs, 7 m high,  are  also  found at distances of  about  100 m from the shoreline,
in places where the Barreiras group has  been eroded by a higher sea level.


                                                                      Muehe and Neves
                                                                         MUD DEPOSITS,BARREIRAS GROUP
                                                                         BARREIRAS GROUP. R1AS,MANGROVES
Figure A-l.    Classification  of main physiographic  features  of the  Brazilian
coastline:  North Region.

 Central  and South America
                            f I a n t i c
                                                c g 
             LEGEN D

             E~^-~  Mangrove  deposits
                   Tidal flat deposits.
                       Sand and  Silty sand
                   Barreiras  Group
             /~N>-'-> Lithologic Contact


                   Beach ridges



Modified from  Fronzinelli, 1982
Figure A-2.  Geologic map of part of the ria coast of Para, between Maracana and
Salinopolis.   (Frazinelli,  1982; Martins and  Villwock, 1987).

                                                               Muehe and Neves

     For the  whole region, a  sea  level  rise will  significantly increase the
penetration of the tidal  wave  into the rivers.  Flooding along the river valleys
will be laterally  confined by  the higher areas of the Tertiary and Pleistocene
sedimentary deposits.   Depending on  the sediment  budget,  low-lying alluvial
areas such as in the Marajo Island at the river mouth, will  be inundated.

The Northeast Region

     The Northeast Region  consists of  nine  states:  Maranhao (MA),  Piaui (PI),
Ceara  (CE), Rio  Grande do Norte (RN), Paraiba  (PB),  Pernambuco  (PE),  Alagoas
(AL), Sergipe (SE), and Bahia  (BA) (Figures A-3 and A-4).

     With a length of  about 2,480 km, the coast can be  divided into two distinct
sections.  The first has  a  coastline 1,540 km long, roughly aligned in the east-
west direction; the climate is  dry and consequently extensive dune fields extend
from the State of  Maranhao up  to Cape Calcanhar.  The other  section, southward
from Cape Calcanhar up  to the State of Bahia in the vicinity of Abrolhos plateau,
has a coastline 1,940  km long,  is  aligned in the general north-south direction,
and is subject to  a humid  climate.

     The shelf width  is narrow when compared to that of the North Region.  The
width of the inner shelf,  roughly based on the 50-m isobath, decreases from up
to 70 km,  in the  northern sector of the region, to only 25 km in the south, with
a new enlargement  to more  than 100  km  at  the  Abrolhos plateau in the southern
extremity of the State of  Bahia.

     Deposits  of  the Barreiras group are typical for the whole region,  as are the
alignments of  beach rocks ("recifes") in front of the shoreline (Silveira, 1964).
The recifes frequently provide an important protection  against  the  action of

     Coastal  plains are  generally  narrow,  depending on  the distance  of  the
retreat of the front scarp  of  the Barreiras group, but increase their extension
by penetration along the  lower  courses of the river valleys (Nunes et al., 1981;
Prates et al., 1981;  Nou et al., 1983).  In some places bluffs are still under
the action of waves.   In others, the coastal  plain  enlarges in front of major
rivers and at the deltas of the Parnaiba River (at the border between Maranhao
and Piaui), Sao  Francisco  River,  at the  border  of the States of Alagoas  and
Sergipe, and  in  front of  the  Pardo  and  Jequitinhonha Rivers  in the southern
State of Bahia.

     A large number of estuaries  are  found inside or in  the proximity  of the
Todos os Santos Bay in Bahia.

     As in  the North Region, very few studies are available about  recent coastal
evolution.  Marques (1987), in  her study about the barrier beach in front of the
Mundau-Manguaba  estuarine  lagoonal  complex  in Alagoas,  showed  a  continuous
lateral progradation of the barrier northeast  from  the  tidal inlet  during the

 Central and South America

                                                                       DUNCS .BARREIRAb CROUP
Figure  A-3.   Classification  of main  physiographic  features  of the Brazilian
coastline:   Northeast Region  from Maranhao  to Cape Calcanhar.


                                                                       Muehe and Neves
                                                             BARREIRAS GROUP, DUNES.BEACH ROCKS

                                                             BARRERASGROJP.DELTASJEACH RDGES
Figure A-4.    Classification  of main physiographic features  of  the Brazilian
coastline:  Northeast  Region  from Cape  Calcanhar to Bahia.

Central and South America

period 1956 to 1984 and a net  erosion, during the same period, at the southwest
segment.  But these changes may reflect only a local instability of a naturally
unstable coastal segment and  not a consequence of  a sea  level  rise (Figure

     Flooding in most of the coastal  area due to sea level rise will be limited
in extension  by the scarps of the Barreiras group.   Low-lying areas  of the
deltas, like the Sao Francisco Delta,  may show changes in mangroves (both in area
and  in species  of trees)  and  a possible  limitation  of the  areas  used for
temporary cultures.  A more serious  problem will arise in coastal  cities like
Recife, Aracaju, and Maceio, where the expansion of urbanization into low-lying
areas actually provokes inundations when heavy rains coincide with spring tides
(Nou et al., 1983); with a 50-100 centimeter rise in sea level  the  same effect
would  occur  even during neap  tides.   Drainage  problems and  inundations will
probably also affect the  low-lying areas of the coastal  plains in the confluence
of the Todos os Santos Bay  in Bahia.  These  problems will  become critical in the
heavily populated city of Recife, where urbanization has expanded over the valley
floor  of the  rivers Capibaribe and Beberibe,  and  where  drainage problems and
flcodings very often occur.

     Just north  of the mouth  of these  rivers,  a  long and  severe  history of
erosion has been recorded  in the nearby historical  town of Olinda.   The causes
of erosion  are  not  completely clear yet.   The area  suffered subsidence in
geological   time.   However,  several  engineering  works  --  groins,  detached
breakwaters, dredging --  that  have been built might  have accelerated the eroding
process.   A rise  in sea  level  will  strongly affect  this  area,  and further
problems will arise due to an intensification of erosion.

The Southeast Region

     The 1,530-km-long coastline of the Southeast Region  consists of the States
of Espirito Santo  (ES),  Rio de  Janeiro (RJ), and Sao  Paulo  (SP)  (Figure A-6).
Like the other  regions examined, the table-like Barreiras group is still present,
governing the width of the coastal plains up to  the northern part of the State
of Rio de Janeiro.   An increase  in the width of the  coastal plains is due to the
Rio  Doce Delta in  Espirito Santo  State  and the Paraiba do Sul Delta  in the
northern part of Rio de  Janeiro State (Figure A-7).  The adequacy  of the term
"delta" for both of these depositional features has  been questioned by Dominguez
et al. (1982),  based on the argument that  the progradation in front of the river
mouth  is a result of longshore drift of sediments derived from the  inner shelf
and not of fluvial sediment accumulation,  as assumed by Bandeira et al. (1975)
for  the  Doce River Delta  and by Dias et  al. (1979)  and Dias  (1981)  for the
Paraiba Delta.   More recently, Dominguez (1989) changed  his interpretation about
the Doce river delta or strandplain,  attributing a  more significant role to the
river  as a sediment supplier than in his  earlier model.

     Southward from the Paraiba Delta, at Cape Frio, the  coastline changes from
northeast-southwest to an  east-west direction.   This stretch ends at Marambaia
Island and is formed by barrier beaches,  the only interruption being the rocky
coast near the mouth of Guanabara Bay.  The barriers may  occur as either single


                                                              Muehe  and Neves
                             2 Km
Figure A-5.  Shoreline modifications of the barrier beach in front of the Mundau-
Manguaba lagoonal-estuarine complex in Maceio,  Alagoas (Marques,  1987).

  Central and South America
                                                                        U ounill', HI ff.n UttXS.



                                                                   BEACH wnoi ',.MY5,.MHCI!OVE5
  Figure A-6.   Classification  of main physiographic features  of the  Brazilian
  coastline:   Southeast Region.

                                                                   Muehe and Neves
             (DHolocene marine terraces,(2) Lagoonal deposits, (3) Fluvial
             deposits  (Intralagoonal delta). (4) Pleistocene  marine ter-
             races, 15} Barreiras Formation  (Tertiary),(6) Crystalline base-
             ment (Pre'cambrian). (7) Beach-ridges  alignments', (8) Fluvial
             paleochannels , (9) Lakes.

Figure A-7.   Geologic map of the  Paraiba do Sul Delta or coastal plain,
and Suguio,  1989).

Central and South America

or double  alignment,  with  a  sequence of coastal  lagoons at  their backside.
Araruama is the largest of these lagoons, with its mouth near the town of Cabo
Frio.  The barrier beaches follow the west direction up to the bay of Sepetiba
near the border with the State of Sao  Paulo.   From this point on, and along the
whole  State  of Sao  Paulo,  the  coastline  returns to  its  northeast-southwest
direction, with submergence characteristics in its northern part and emergence
characteristics in  the  south.   The  transition between the  drowned,  indented
coast, with its steep  crystalline promontories, and few, narrow coastal plains,
like Ubatuba and Caraguatatuba,  and the  emergence  southern sector,  with large
plains up to 40 km wide (for instance, the southernmost Cananeia-Iguape plain)
is very gradual.   The region  of Sao  Sebastiao forms  approximately the limit
between these zones.  The width of the inner shelf also follows the trend with
the isobath of 50 m situated at a distance of 8 km from the coastline in front
of Santos estuary and at  50 km in front of  Iguape  (Suguio and Martin,  1976).
These authors explained that  such phenomenon  are  due  to a continental flexure
where the inflexion axis strikes asymmetrically to the coastline.

     The geomorphology of this  region presents many diversified features (barrier
beaches, pocket beaches, rocky  shores, coastal lagoons,  bays,  estuaries)  that
will  respond in  different  ways to a  sea level rise.    Some  locations already
present signs of erosion,  even though human interference has been minimal.

     The mouth  of Paraiba do Sul  River has shown strong instability  in the past
fifteen years,  with  extensive  erosion of the adjacent beaches  and  loss of valued
property (Argento,  1989).   On  the southern part of the delta, the coastal plain
shows  a  sequence  of  ridges;  at the beach  face,  formations of  grayish black
sandstone  --  humic material  cemented with  ferruginous oxides  -- have  been
exposed, indicating a process of erosion or retrogradation.  This same process
becomes also evident  by the truncated configuration of coastal  lagoons  on the
back side of transgressive barriers (Dias and Silva, 1984).  Similar processes
have been identified by Muehe (1984,  1989) at the barrier beaches between Cape
Frio and Guanabara Bay,  besides evidence of erosion along the back side of the
barrier that faces Araruama Lagoon.

     Another point  in  the State of Rio de Janeiro  that  may  suffer  from a rise in
sea  level  is  the fluvial-marine  plain  along the  estuary  of Sao  Joao  River,
located about 200 km  south  of Paraiba do Sul River.   At  present,  there is an
extensive culture of rice  along the valley, which uses  the water  from the river
for irrigation purposes.  Besides potential  risks of flooding,  the rise of sea
level will cause a stronger saline intrusion, which has already been observed.

     The flat areas around Guanabara Bay  have  flooded  very often during heavy
rains, especially along rivers and drainage canals.  The combined effects of a
rise in sea  level  and siltation  of those canals will enhance  the  problem of
flooding.   On  the  other hand, because the  relative sea level  was  5  m higher
during the Holocene than  at present,  not only were beach  sediments deposited
far from the present coastline (Amador,  1974) but the  terrain also became very
flat and appropriate for marine flooding of extensive  areas.  Similar problems
should affect all low-lying areas of coastal plains and river valleys.


                                                               Muehe and Neves

The South Region

     This region is formed by the States of Parana (PR), Santa Catarina (SC), and
Rio Grande do Sul (PS)  (Figure A-8).  The coastline is 1,310 km  long.  Along its
northern portion, the  coastal  plains are narrow  and  less  significant,  having
pocket beaches separated by rocky headlands.  Paranagua Bay is the most important
feature of this segment.   Toward the  south, the coastal plains gradually become
wider, and important  estuaries appear, like Guaratuba Bay (PR),  the Itajai River
(SC), and Laguna (SC), although along  the coast of Santa Catarina, pocket beaches
are very frequent.

     Reaching the State of Rio Grande do Sul,  though, the coastal  plain widens
considerably,  reaching  120 km  for an extension  of  almost 520 km,  being the
largest coastal  plain in the country.  This is  where Patos Lagoon is located,
which has an area of  10,000 sq.  km and an average depth of 4  m,  and is connected
to the ocean through  a single inlet at Rio Grande.  The mild  slope of the coastal
plain extends  offshore:   the 50-m deep contour  is about 30 km away  from the
beach, twice as  far as in Santa Catarina.

     Processes of erosion and accumulation  have been reported by Angulo (1989)
for the littoral  of Parana, but observations of coastline changes were restricted
to typically unstable areas like mouths of estuaries (a similar  comment has been
made  already  for Maceio,  in  the Northeast region).   In Santa Catarina,  the
emergence of peat at the  backshore near the scarp of  the  barrier indicates a
trend of retrogradation.   Tomazelli  and Villwock  (1989) present  well-defined
information about the presence  of peat on the  foreshore and along the base of
foredunes along the beaches in Rio Grande do Sul.  Erosion  along the margin of
Patos Lagoon is also interpreted by these authors as an indication of relative
sea level rise.  Due to the dominant  onshore direction of  local winds,  a dune
field tends to be built with sand removed from the beach.  The erosive effects
already observed might be intensified if this  dune field is removed.

Central and South America
Figure A-8.   Classification of main  physiographic  features of  the  Brazilian
coastline:  South Region.

                                J.R.K. DANIEL
                            University of Guyana
                             Georgetown, Guyana

       The northeastern coastal zone of the South American continent, known as the
  Guiana coast, stretches between the estuaries of the Amazon and the  Orinoco
  Rivers and forms  the  coastline of Guyana,  Surinam, French Guiana,  and parts of
  Brazil and Venezuela.   The  coastal  strip is of varying width  and  is below sea
  level at high tide in  most places.  As a result, extensive areas are covered with
  swamps, mangrove  forests, and tidal  and mud  flats.

       Early colonizers  managed  to  establish  plantations by draining the land.
  Because agricultural  development has taken place in  this  zone,  today over 90%
  of the population of Guyana, Surinam, and French Guiana live on the Guiana Coast.
  Therefore, most  of the urban centers and communication lines  are  concentrated
  on the coastal zone in  the three countries.

       A  rise  in  sea   level  would  have  serious  economic  and  environmental
  consequences  for  the  Guiana  coast.   The  coastal  stretch  that  is naturally
  protected by  cheniers and shell  beaches is likely to  recede with the  rising sea
  level.  Much of Guyana and Surinam will be inundated, even if the sea level rises
  by as little  as 30 cm.

       Mechanisms are in place in  both  Guyana and  Surinam to construct and maintain
  sea defense structures and to take emergency measures in case of breaches.  But
  long-term plans  to counter  the  consequences of sea level  rise  are nonexistent
  in the three  countries.  The governments concerned have not taken  the possible
  threat of  sea level  rise  seriously,  and  the coastal communities are mostly
  unaware of the possible danger.


       Along the northeastern coast of South  America  between the mouths of the
  Amazon and the Orinoco  Rivers  lies a  1,600-km-long,  low coast dominated by
  swamps, mangrove forests,  tidal  flats, mud  banks, and flat  coastal plains.  This


Central and South America

Guiana coast forms the coastline for Guyana, Surinam, French Guiana, and parts
of Venezuela and Brazil.

     More than 90% of the population of the Guianas live on the coastal plain.
As a result, most of  the  urban  centers,  including  the  capitals,  communication
networks, and industries are concentrated there.

     A rapid  rise  in sea  level  would  inundate  low-lying  areas,  erode  the
coastline, increase  salinity of the lower courses of the rivers, disrupt coastal
wetlands, and raise the water table.  Although the heavy sedimentation that takes
place on the Guiana coast may offset some of the  erosion and wetland loss from
a rapid sea level rise, it would do little to mitigate  the other problems.

     About 50% of the coast of  Guyana is protected  by sea defense structures, and
provisions exist to  take emergency measures in case  of major breeches or failure
of the sea  defense  system.   However,  the  entire  coast of Surinam  and French
Guiana, and the  western  portion  of the Guyana coast, remain  in  their natural

The Coastal Plain

     The coastal  plain  forms  a distinct geomorphological region in the Guianas.
It occupies only a small percentage of land  in  each  country  but  is considered
an important  economic  zone.   It  can  be  subdivided  into  two geomorphological
regions: the young and the old coastal plains (Figure 1).   The former does not
rise more than 2.5 m above mean sea level and in  places lies 1.5 m below high
tide; the old coastal  plain has  an average elevation  of 3  m rising to 8 m near
its southern border.   Both are underlain  by clays  of  different periods.


     The Guiana coast has a humid  tropical climate with its characteristic high
rainfall and high temperatures.   Two distinct wet  periods  can be  recognized in
the rainfall pattern:  the  first  lasts  from mid-May to July, and the second from
November to January,  with  the former having the  most  rainfall.

Marine Environment

     The waves, in accordance with the wind  direction,  are northeasterly, and
they meet the shoreline at an oblique angle.   The  coast may be considered as a
low-moderate energy coast.    Unlike the Caribbean  islands, the Guiana coast is
not subjected to hurricanes and storm waves.  Wave energy is considerably reduced
off the coast of Guiana because  of the presence of fine sediments, which remain
in suspension in the near coastal area.  The tide  is semi-diurnal and its effects
are felt far inland along  major  rivers.


   A. Guyana
     B. Surinam
                     C.French Guiana
             Esluorine and Riverain deposits
             Saline marine cloy sediments
             Desalinised marine clay sediments
             Pegosse (Peal groning above S.L.) |
             Mottled cloy sediments
             Mottled cloy sediments           S
             Remnants of old chemers Isondl  	I
             White sandt
             Crystalline  basement complex

    _____ Cooital Ptain
Figure   1.    Geomorphology  of  the  Guiana  coast.

Central and South America

Sediment Transportation and Deposition

     It is estimated that  100  million  tons of sediment are transported westward
every year by the ocean currents.  A large proportion is kept in suspension by
the changing tidal conditions, waves,  and currents.

     When the concentration of sediment in the water exceeds a critical level,
it flocculates to form a  coherent mass  of viscous  mud  known as sling mud, and
settles to form mudflats on the shoreline and mudshoals in the offshore region
(NEDECO, 1972).

     The mudshoals influence  the development of  the  coastline of the Guianas.
The coast that lies directly opposite the mudshoal is  protected from wave action
because the viscous nature of the mud damps out  the  waves.   This coast may be
designated as  an  accretionary coast.    A coast that lies directly  opposite a
trough (between two mudshoals) is subject to wave erosion and may be designated
as an erosional  coast  (Augustinus, 1978).  It has  been shown  that  the mud shoals
migrate westward at an average rate of 125 m/month and  the recurrence interval
of a mudshoal  is approximately 30 years (NEDECO, 1972).   Thus,  at  any one point,
the coast is subjected to either accretion or erosion.

Accretionary Coasts

     An accretionary coast begins as a tidal  flat  at the  landward  end of a shoal
and can extend as  far as  0.8  km.  As soon as  the  tidal  flat  begins to emerge
above the high-water level, mangrove establishes itself  and stabilizes the flat.
The mud  that emerges above  the  high-water  level  is  subjected  to physical,
chemical, and  biological  ripening,  leading  to soil  formation  favoring  other
vegetation types in addition to mangrove.

     Sand accretionary coasts are rare,  and where  they  do occur, they are not
as extensive as the clay accretionary coasts.  Cheniers are extensively developed
on the Guiana coast.   Stretches of beaches entirely composed of shell fragments
occur in several places along the northwestern coast of Guyana.

Erosional Coasts

     Erosional coasts  lie  opposite a trough  (between two mudshoals).  When the
eastern end of a mudshoal  is eroded,  the coast directly opposite it increasingly
comes under wave action.   Erosion on the shoreline begins at  the edge of the mud
flat.   As the  mud  flat is gradually eroded, waves  are  able to come closer to the
coast.   The  removal   of mud exposes the root  system of the  mangrove  to  wave
action, which eventually  destroys the vegetation.   Since  the  seedlings of the
mangrove are  not adapted to development under  continuous  inundation they are not
replenished.    Once   mangrove  is destroyed,  erosion  of the coast  proceeds

Vegetation and Fauna

     Mangrove vegetation fringes  the shoreline of  the Guiana  coast.   Either a
herbaceous swamp  or  a swamp  forest occurs behind  the  mangrove.   The largest
swamp is located between the Pomoroon  and Orinoco Rivers.



     The wetlands on the Guiana coast  have  an exotic variety of animals, birds,
insects, and marine  life.   The northwest coast is one of the breeding grounds
for the  scarlet  ibis and many other  birds.   In  the  nearshore region, several
shrimp species and two species of crabs are common.  The northwestern coast is
the  annual  nesting  grounds  for  at  least four  types of  giant  sea turtles
considered  to   be   endangered  species:   greens,  hawksbills,   Ridleys,   and
leatherbacks.   In the numerous  canals  and drainage  ditches,  freshwater  fish

Groundwater Resources

     The geologic formation  of the  Guiana  Shield favors  the  occurrence  of
groundwater on the  coastal  plain.   More than 90%  of  the  potable water on the
Guyana  coast  is  obtained  from two aquifers  that occur  at  two  levels.   The
groundwater recharge area is the exposed portion of the white sand  that underlies
the rolling hills south of the coastal plain.



     The predominant  economic  activity  on the  Guiana coast  is agriculture,
followed by fishing.  The coastal belt  has favorable soil and climate for lowland
crops, such as sugarcane and  rice.  Among  the  three  countries,  Guyana has the
most  cultivated   land  (Figure 2).    In  both  Guyana  and  Surinam, almost all
agricultural activities  are  confined  to the coastal  belt.   Apart from market
gardening near large cities, agriculture is insignificant in French Guiana.

     Agriculture is  the major source of employment, economic growth, and foreign
exchange in the  Guyanese economy  (Table 1).   Most of  the  irrigation  and  land
development programs are geared to two major crops, sugarcane and rice.  Since
fertile agricultural  land is located very close  to the coast, large sums of funds
are allocated for drainage, irrigation, and sea defense works.

     The land use pattern on the coastal belt of Surinam is similar to that  of
Guyana, but in Surinam agriculture contributes only 9.1% of the Gross Domestic
Product (GDP).

     In French  Guiana,  the  main  occupation  on  the  coast  is fishing,  which
constitutes 59.3% of all exports.  Very  few  food  crops are produced  in French
Guiana.  Being an overseas  territory  of  France,  most  of its  food is  imported.


     Over 90% of the  population of the three countries live on the Guiana coast
(Table 2).   The capitals are also located on the coast, as are major  towns and
urban centers.

     The main communication lines of  the three countries  are  along the coast.
Since most of the  rivers on  the Guiana  Shield flow in a  south to north direction,


 A. Guyana
   B. Surinam
                    C. French Guiana















i  | | RAILWAY

                                                                   IILOMETRES    50
Figure  2.   Land  use  of the  Guiana  coast.


                      Table 1.  Agricultural Development
Total population
Area (km2)
Agriculture contribution
to GDP(%)
Total cultivated land (ha)
Irrigated land (ha)
Sugarcane (metric tons) 3
Rice (metric tons)
Fish catches
French Guiana
N.A. = Not available.
ferry service and other forms of river transportation are provided at major river

     With the exception of  the  bauxite  processing  industry in Linden (Guyana)
and Brokopondo (Surinam),  all  the major  industries  and factories  are located on
the coastal belt, particularly in the capitals and port cities.



     To estimate erosion from 50-,  100-,  and  200-cm  sea level rise scenarios,
we used the Bruun Rule:

                                            S = 

where S = approximation of shoreline movement,  a = rise in sea level, h = maximum
depth of exchange of material between the nearshore  and the offshore,  and 1  =
length of the profile of exchange.

    On the Guiana coast, the sea bottom  profile in  the nearshore zone is shaped
by the wave action to a depth of 2  meters (NEDECO,  1972).   The orbital  motion
of waves is reduced  to  an almost  horizontal to-and-fro movement.  Wave velocity


Central and South America

       Table 2.  Population of Cities/Towns Located on the Guiana Coast

                                                            Distance  from
   City/Town                   Population                    the  coast (km)
New Amsterdam
Rose Hall
Paramaribo (1987)
Cayenne (1988)
St. Laurent
"Unless  otherwise  noted  all  values  are  for  1981.
exceeds 0.70 m/sec, a critical  velocity  that is required to initiate erosion on
the sea bottom (Augustinus, 1978).  Therefore for  convenience, the maximum depth
of exchange of material  between  the nearshore and offshore (h)  is  taken  as 2

     The average distance between  the 2-meter bathymetry  and  the shoreline is
about 300 meters, but it varies according  to the  position of the mudshoals.  To
determine the length of  the profile of  exchange  (1),  distances  between the
2-meter bathymetry and  the shoreline were measured at  intervals of 20 kilometers
along the coastline on the map (scale 1:1,000,000).



     Projected coastline positions for a 50-,  100-  and 200-cm rise in sea level
are  shown  in  Figure  3(A-C).    The  future  coastline  shown  here   is  highly
generalized because of the small  scale (1:1,000,000)  of the map.  Based on the
EPA study of sea  level  rise (Titus, 1985),  two  scenarios, the mid-range high and
mid-range low -- henceforth simply referred to as high and low,  respectively -
- were selected.   Measurements taken  from the map  were  compiled under the two
scenarios to show the future rate of coastal erosion.  They were also compared
with both short-term and long-term historical  rates of erosion (Table 3).   The
latest available maps  were published  in  1980.  Therefore,  1980  was  considered
the baseline.

                                	10m Depth Contour (Closure Point)

                             Change in Sea Level
                                	 50cm Rise
                                	100cm Rise
                                	200cm Rise
       Figure  3A.   Scenarios of  sea level  rise  for  Guyana.

                                   10m Depth Contour (Closure Point)
                          Change in Sea Level

                             	 50cm Rise

                             	100cm Rise

                             	200cm Rise
      Figure 3B.   Scenarios  of sea  level rise for Surinam.

                                    10m Depth Contour (Closure Point)
                           Change in Sea Level

                              	 50cm Rise
                              	100cm Rise

                              	200cm Rise
                                                                                                                      KILOMETRES    50
      Figure 3C.   Scenarios  of sea  level rise for  French  Guiana.

        Central  and South America
Table 3.   Projected Recession on the Guiana Coast (Meters of shoreline retreat  relative to its
           current  position)
                    50 cm
    100 cm
                    200 cm
                Total shoreline
                  retreat (m)
Total shoreline
  retreat (m)
Total shoreline
  retreat (m)
                                                                          Historical records
record (m/y)
record (shill)
record (shill)
Wainini-Pomoroon       1200

  Essequibo Estuary     2500

Essequibo Estuary*      	



Mahaica-Berbice        1100

Berbice-Corentyne        900


-sea defense-

-sea defense-

-sea defense-









S i nnema ry- Cayenne
1400 20
4600 4 15
* We assume no erosion in areas that already have sea defenses.
              Since  the erosional  environment  on the coast  varies  significantly,  each
         coastal segment between  the major rivers is treated separately.  A 50-cm  scenario
         forecast  would affect almost the  entire coast.   Further rise  in sea level  would
         only exacerbate the  situation.  Therefore, the  scenario for a 50-cm rise in sea
         level  is  considered  in detail.

         50-cm  Scenario

              For a 50-cm  rise in  sea  level,  it  is  estimated  that the  wetland loss  would
         be highest along the northwestern coast of Guyana.  Several  factors lead to this
         conclusion.   The  tidal  range  is very low  in  this  area,  which  implies  that
         existing  wetlands are at low  elevations.  The area is also very flat and  has many
         water  courses.  Above all, the area  is  subject  to subsidence.  Despite  the high
         rate of peat growth  and sedimentation,  until recently the relative rate of sea
         level  has been rising in  the  area (Brinkman  and  Rons,  1968).


     Being  sparsely  populated  with  little or no development or infrastructure,
the effects of sea level rise would be minimal  compared  to the densely populated
coasts.  The wetlands would simply migrate  landward,  as the coastland is very
low and occupies a large area.

     Saltwater  intrusion  would also disrupt the  swamps since they  lie  at the
same elevation as the mangrove.  A rise  in  the water  table would convert most
of the low-lying swamps to brackish, open-water environments.

     The  estuaries generally  have maintained a fairly  stable  shoreline  on the
Guiana coast (NEDECO, 1972).  The estuarine areas receive much more sediment than
the coasts.  Erosion is balanced by sedimentation on the larger islands  in the
estuary (Daniel, 1984).  However, the estuarine coasts facing the northeastern
direction would be affected by the  increased wave velocity when sea level rises
to 50 cm.

     Wetland  loss  would be greater  along the  coast where  sea  defenses  exist.
With the erosion of  the mangrove and the  tidal  flats, large waves would be able
to approach the seawall more frequently,  thereby increasing the pressure on the
seawall and increasing the incidents  of  overtopping.   Laboratory studies have
indicated that if the sea level rises by as little as  30 cm, overtopping would
increase threefold (NEDECO, 1972).  Saltwater intrusion in the rivers and creeks
is also likely to increase with rising sea level.

     Western  Surinam,  particularly the  area  adjacent to  the  mouth of  the
Corentyne River, has development similar to the eastern coast of Guyana.  Rice
cultivation is extensive and,  with  improvement of  drainage and irrigation,  is
expanding.    Several  acres  of  swamps  have  been drained and converted to rice

     Most of the urban  and  agricultural development in  Surinam is located on a
chain of cheniers that occurs farther inland.  The vast  swamp that exists between
the cheniers and the coast is undisturbed.  Furthermore,  several  hectares of land
on the coast are preserved as nature reserves.  Therefore higher  sea levels would
simply cause the wetland to migrate inland.

     In French Guiana, a 50-cm  rise  in sea level implies  a very low erosion rate.
This area  experienced  a  slight uplift in the  past  (Brinkman  and  Rons,  1968).
A  few islands  that  lie  in  the  offshore  area  are   underlain  by  resistant
crystalline basement rocks.   Since the extent of the lowland is limited  by the
rapidly rising land  southward, wetland loss would be proportionately higher on
this coast  than elsewhere.   Initial  sea level  rise  is likely to affect only the
mangrove-fringed coast.  Other problems associated  with  sea level rise, such as
higher water table and increased salinity in  the  surface and  groundwater,  can
also be expected,  although economic loss  is not likely to be significant.

    A  slightly higher  erosion  rate is forecast for the coast  east of Cayenne,
an area also subject to subsidence (Brinkman and Rons,  1968).  If the subsidence


Central and South America

continues, erosion is likely to be greater.   Because  of sparse settlements in
the region, very little economic development has taken place.

100-cm Scenario

    A 100-cm rise in sea level  for a  high scenario would occur by the year 2062
according to the EPA estimates,  and a low scenario as interpolated from the EPA
estimate would  occur  by  the  year  2080.   On the northwestern  coast  of Guyana,
further encroachment of swamps by mangrove  vegetation  can be expected.

    Total  land  loss would be great (over 5,000  m).  Along  the eastern part of
the Guyana coast  and  parts  of Surinam coast, land loss would be considerable
(over 2,000 m) and much farmland would be affected.

    The  area  most affected would  invariably  be the coast  that  is  protected,
unless foreshore erosion is  prevented.  Mangrove in the foreshore area in front
of the sea defense  structures  will be completely wiped out by the  rising sea
level.  Georgetown,  a  city that is well  fortified against sea erosion, is likely
to come under increasing pressure as  the  sea level  rises.

200-cm Scenario

    A 200-cm rise in sea level  for a  high scenario would occur by the year 2095
and for  a  low  scenario  in  220  years'  time,  as  interpolated  from the  EPA
estimates.  The effects of a sea level  rise of this  magnitude  are difficult to
determine at this time.   On  a  few unprotected coasts, strips of  land  up to a
kilometer wide would be permanently inundated, forcing the  mangrove  to migrate
landward, and swamp  vegetation  would  be drastically changed.  The lower courses
of several rivers that flow parallel  to the coast would be  altered as the land
separating the river channels from the coast is eroded away.  Urban development
and roadways previously located on the unprotected  sections of the coast would
have been relocated  on the old coastal  plain.

    Major  cities  and  towns  protected against sea erosion  would  have embarked
on a beach fill  program, and perhaps  a few  kilometers  of breakwater  would have
been  built,  but  the costs  of  such programs  would   be  prohibitively  high.
Increasing problems  in sewage disposal,  stormwater disposal, rising water table,
and saltwater intrusion  in  the  cities  would be enormous.  The effects  of sea
level  rise described previously  would be exacerbated.  Some coastal settlements
have already experienced some of these effects, although not necessarily due to
rising sea level.

    Sedimentation along  the coast may  partially offset  the effects  of wetland
loss,  but sedimentation occurs  unevenly along the coast and is influenced by a
cyclic pattern,  resulting in  net decrease of land area.  The scenarios forecast
in  this  study   do   not   take   into  consideration  the  possible  effects  of
sedimentation.  Calmer  sea  conditions  have caused  heavy sedimentation  on the
Guiana coast  in the  past.   Furthermore,  at  the  mouth  of the Amazon  River,
suspended solids increase as much as fivefold during  the wet period compared with
the dry  period  (Gibbs,  1967).   Thus, an increase  in  discharge  in  the  Amazon



system through  increased  rainfall  or increased deforestation and runoff could
supply more sediments.


     Contradictory  views  have been  expressed on the severity of erosion on the
Guiana coast.  NEDECO (1972) concluded that there  had  been a  net erosion on the
Guiana coast.   On  the  other hand,  the  Hydraulics Research Station  (MRS)  at
Wallingford refuted this claim.  In a recent study, Augustinus and Mees (1984)
claimed that the coast of Guiana has been receding.

     Based on the positions of cheniers,  NEDECO (1972)  calculated that the coast
of  Guyana  was  receding  at  the rate  of 20 m/year  and the  Surinam  coast was
receding at  the rate of  12 m/year between  1947/48 and 1957, and  8.5 m/year
between the years 1957 and 1966.  Augustinus and Mees  (1982)  also observed that
on the Surinam coast,  erosion has diminished and accretion has taken place.  On
the whole,  recession  has averaged  10-30  m/year  on the Guiana coast.   NEDECO
(1972) observed that with the rise of sea level in the past century, the 10-30
m/year historical rate of erosion has accelerated in recent years.  Various rates
of erosion calculated by NEDECO are given in Table 3.

    Historical  records also show that the shore has  advanced  along some coasts.
For example, at Pt.  Isere  (French Guiana) and Totness (Surinam), rapid accretion
has taken place.

    Seawalls  do not  always  prevent erosion.  Although the coast  may appear
visibly stabilized after the construction of a  seawall,  erosion can continue in
the foreshore area.  NEDECO demonstrated  that the foreshore area is oversteepened
where sea defense structures exist.  Augustinus and Mees (1984)  attributed the
receding shoreline in Guyana to the lack of mangrove development.

    Seawalls  without  adequate toe  slope  protection are particularly  prone  to
oversteepening of the  foreshore and the eventual collapse of the seawall itself.
This happened  in  Clonbrook  near the Mahaica  River mouth,  where a  152-meter
section of seawall  sank more than 0.6 meters after  the  foundation collapsed into
the sea (Starbroek News,  1989a).



    In Guyana,  settlement has meant  a  constant  battle against the sea.  The
settlers built artificial  dams and  sluice  gates between the naturally occurring
cheniers to form a defense against  erosion.

    Because of  the complexity of the coastal processes and their  effect on the
low-lying areas for the past four decades,  successive governments in Guyana have
sought the  help of international  consultants  to  study  the  coast.   Two  such


Central and South America

consultants, NEDECO and MRS, made in-depth studies of the coastal problems.  The
former also studied Surinam's coastal problems.  The two consultants perceived
the coastal problems differently and suggested conflicting strategies (Daniel,

    NEDECO's  model  for the Guiana coast predicted  a 30-year  cycle of erosion
and accretion with a net land loss of 10-30 meters annually.  They observed that
strengthening  the seawall at  the present  site  would not  help,   because  the
accelerated erosion in the foreshore  region would eventually undermine the sea-
wall.   They recommended a  seawall  of  a different design for the priority areas,
such as Georgetown and its environs.  The priority areas were determined on the
basis  of  a cost-benefit analysis.   In  the low-priority areas, such  as rural
areas, a new seawall several  meters inland from the present sea defense system
was  suggested.    This  simply  means  abandoning  several  acres  of  valuable
agricultural land fronting the coast.

    Based  on  economic, statistical, and  historical data, HRS  suggested that
Guyana should be prepared to respond to emergencies rather than build a strong
sea defense system and supported  the present policy of strengthening the  sea
defense as and when necessary.

    Comparing  the  two reports, it is clear that NEDECO'S suggestions are valid
in light  of the accelerated  sea  level  rise.  HRS's  report  is based  on more
conservative estimates and does not take into consideration the possibility of
future sea level rise.

    The seawall  has to be considerably  strengthened and raised to counter  the
effect of rising sea level.  Other defensive measures would include increasing
the toe  slope  on  the  seaward  side  and  systematic beach filling.   On  some
vulnerable coasts  these measures have already  been  taken.  The present height
and width of seawalls  is determined according to the cost factor.  Overtopping,
even at present  levels, is not desirable,  but  because  of  the  high costs, they
are so designed.  Raising the seawall by as little as 30 cm would  increase  the
cost so exorbitantly that a country like Guyana could ill  afford it.

    A  plan proposed  by NEDECO  (1972)  to  build a  breakwater to  the  city's
coastline may have to  be implemented.  A beach fill  scheme would also lessen the

    Disposal  of sewage in densely  populated urban centers would  pose  severe
problems when  the water table rises along with the rising sea level.  At present,
a majority of houses are equipped  with septic tanks.  A rise in the water table
would  render most of them useless, unless drainage is drastically  improved.

    In  the eastern part  of Guyana, where most of the  agricultural  land is
located,  a  well-integrated plan will  have to be  implemented to  counter  the
effects of sea  level  rise,,  Sections of seawall  will  have to  be rehabilitated
and drainage facilities improved.


     At  present,  Guyana is equipped to take emergency measures in the event of
breaches in the sea defense system.  The Hydraulics Division of the Ministry of
Agriculture is responsible for the  maintenance of the sea defense  system. It can
obtain resources from the government and the  private  sector without legislative
approval to incur expenses under "force account"  to repair seawalls and contain
flow whenever necessary.

     Routine  surveillance and maintenance work is carried out by the regional
councils,  but they  do  not  carry out  major  repairs.   Increasing  problems
associated with  shortages of  manpower,  materials,  machinery, and  funds  have
prompted the government to reconsider centralization of sea defense.

     Although  the government  is prepared to take  emergency  measures  for sea
defense, a rapid sea level rise in the future and its potential impact are not
envisaged by the engineers.  The problem of coastal erosion is perceived simply
as a cycle of erosion  and accretion associated  with  the movement of mudshoals
in the nearshore region.

     The  Ministry of Housing, which  regulates land use  and  implements housing
policies, does not restrict the construction  of buildings near the seawall.  In
Georgetown,  some houses  are less  than 15  meters  from the  seawall.   Major
government and private housing developments are located  close  to the seawall in
Enterprise, Nuitenzuil, Success, Lusignan, and along many  parts  of the coast.
The Ministry does not  perceive  the possible  sea  level  rise  to be an immediate
threat and has no policies  to curb the construction  of buildings close to the

     Similarly,   the   Guyana  Water  Authority   (GUYWA), which  controls   the
distribution of potable water in Guyana, does not have a policy to deal with the
impact of  future sea  level  rise  on water resources.   Even  records  of water
quality, transmissivity, recharge  rates, and discharge rates of each well  site
are not kept.  Such data are obtained only when major surveys are carried  out.
The last major survey was carried  out by Worts  in 1958.

     Mining of sand from the cheniers is prohibited by law, a measure that would
prevent accelerated erosion.   Similarly,  several species of  animals and birds
that take sanctuary  in the coastal swamps and forests  are  included among the
endangered species  specified in the Guyana  Wild Life  Preservation Act.   The
recently formed Guyana Agency for  Health Education  and Food  Policy is required
to review all development  projects  and submit  environmental impact reports.   Its
function is similar to that of the U.S. Environmental  Protection Agency.  Despite
all of these developments, there is no coherent policy to take countermeasures
against the possible rise of sea level  in the future.

     Coastal dwellers who  live in areas that are repeatedly  affected by erosion
and flooding  are  fully  aware  of the implications of a  failure in the sea defense
system, but are unable to perceive  the  larger problem of sea level rise because
of lack of information.  Recently,  the possible  threat of sea level rise and its
possible consequences were mentioned at two regional conferences held in Guyana.
The Commonwealth Secretariat  also  has  completed  a study on Guyana's coast and


Central and South America

has warned the government of the possible consequences of sea level rise.  These
recent developments  have  helped the government  to perceive more clearly the
problem of sea level  rise.


    Surinam's  land development  on  the  coast  has  followed a pattern  similar to
that of Guyana.   Most of its agricultural  land  is restricted to the coastal
plain.   But  unlike  Guyana,  it  is not  close  to  the  coastline.   Therefore,
extensive flood control and sea defense were unnecessary.  In addition, Surinam's
coast is fairly stable, and coastal erosion is  not as acute as on the coast of

    The western Surinam coast,  east of the  Corentyne River where a  large area
is under rice cultivation,  is considered a stable area.  The small  farmers who
hold  less  then 4  hectares  of  land  are  mostly  located  along  the  rivers  in
Comowijne and Surinam.  Therefore,  farmers in Surinam do not encounter erosion
and flooding as frequently as their Guyanese counterparts.  They are not used
to perceiving the sea as  a threat.  However, an increase  in sea level may cause
the rivers to overflow and damage low-lying rice  farms.

    Because large areas along the coast have been preserved as nature reserves
and Paramaribo is located several kilometers from the coast,  the  Surinamese do
not  seriously consider the  effects of sea level  rise.   Nevertheless,  the
administration in Surinam commissioned  NEDECO (1968) to study erosion along the
coast. NEDECO later conducted a  more elaborate survey of the entire Guiana coast

    Surinam follows a vigorous environmental policy.  Several  organizations in
Surinam have carried  out joint surveys with their Dutch counterparts on various
aspects of  the environment.   The  Soil Survey Department of the Ministry  of
Natural Resources has  carried out research in collaboration with the Soil Survey
Laboratory of Wageningen, the  Netherlands, on soil and erosion along the coast.
The Dutch navy has conducted hydrographic surveys off the coast of Surinam and
a  Dutch   engineering  firm  has   been  dredging  the  rivers frequently.    The
International Maritime Organization (IMO) has also  been  conducting  studies in
Surinam waters, as well as in Guyana and French Guiana.  The Department of Lands
and Surveys and Aerial Photography has  compiled maps of the coastal  area based
on aerial  photographs taken at regular intervals, and the Ministry of Agriculture
and Fisheries and the Department of Surveys of Waterways  and Water Courses have
also carried out several  hydrologic studies.

    Since the  coastal  problem in Surinam is not  as  acute  as  in  Guyana,  there
is hardly any awareness among  the coastal dwellers about the possible danger of
sea  level  rise.   Because  Surinam collaborates  closely  with  several  Dutch
organizations,  it  would  not   be  difficult  for   the'  government  to  take
countermeasures against the impacts of  sea level  rise when the need  arises.


French Guiana

     Economically, French Guiana would be least affected  by  a future rise in sea
level.  But physically it could suffer extensive losses of wetland areas.

     The  coastal  area  is  included  in  the  Cayenne  arrondissement  (district)
according to administrative divisions.  It is subdivided into 14 communes, the
smallest French division.   Each  commune is no more  than a village  with basic
facilities, such as running water.  Most decisions are made in Cayenne, if not
in  Paris.   Being an Overseas  Department  of France, French Guiana  is totally
dependent on the metropole.  Modern ideas on the environment, greenhouse effect,
future rise in  sea level, etc., hardly trickle down to Cayenne.   It still remains
in its colonial  lassitude.  The only modern development has been the construction
of a space center at Korou.

     Few  studies of the  environment  have been  carried  out in  French Guiana.
Studies conducted along the Guiana coast by  international consulting firms have
included the  offshore  region  of French  Guiana.   The French  navy  also  has
conducted regular hydrographic  surveys off the coast of French Guiana.  Any long-
term plan  of  action to  counter  the  effects of  sea  level  rise would  have  to
originate  from  France.  Unless  urban  centers  along the   coast are  seriously
threatened, responses from the administration in French Guiana are unlikely.


     A  rise in  sea level,  predicted  as  a result of  global  warming  processes,
would severely affect  the  low-lying  areas of  the Guiana coast.  They would  be
affected by wetland  losses,  coastal  erosion, a  rise in the water  table,  and
saltwater intrusion into surface water and groundwater resources.

     These  impacts would vary along the entire length of the coast.  Most parts
of Guyana would be affected because its  coast  lies below high water level.   The
northwestern coast would be the most  affected because of subsidence.   The area
east of  the Essequibo River,  where  most of  the cultivation takes  place,  is
protected against wave  erosion by some form of sea defense, ranging from concrete
seawalls to the naturally  occurring  cheniers.  Wetland loss  in the  foreshore
area of this coast would be  considerable, and the pressure on manmade sea defense
structures  would increase even under  a  low  scenario  forecast  for  a  50-cm  rise
in sea level.

     Most of Surinam's  coast is fringed by mangrove, and parts of it  are formal
nature reserves.   Furthermore, erosion is  not  as severe  as  on the  coast  of
Guyana.  Under  a low scenario forecast for a 50-cm rise, wetlands would migrate
inland.  Wetland losses in French Guiana would  be  higher because low-lying areas
are  limited.   But  economic losses would be minimal  because  its coast remains
largely undeveloped.

     In general, the responses  to  the  accelerated sea level  rise in  the region
are poor.  Although Guyana's coastal  dwellers have been battling the  sea since


Central and South America

the colonial  period, such problems as erosion and flooding are perceived as local
phenomena. Few government organizations or local inhabitants consider the future
rise of sea level to be a serious  threat.  Recently, however, concern about the
consequences of future  sea level rise has been shown at  higher government levels.
Nevertheless, no efforts have  been made to  restrict developments  along  the
coastal highway.

     In  Surinam  and  French Guiana, the  possible effects  of sea  level  rise are
not seriously considered because most economic development,  with few exceptions,
has largely taken place away from the coastline. Coastal  dwellers  in both these
countries do  not endure as many problems as their Guyanese counterparts, and are
therefore less vulnerable..

Augustinus, P.G.E.F.  1978.   The  changing shoreline of Surinam (South America).
Ph.D. Thesis  Publication No.  95,  Foundation for Scientific Research in Surinam
and The Netherlands Antilles, The Netherlands:  University of Utrecht, 232p.

Augustinus, P.G.E.F.  1982.  Coastal changes in Surinam since  1948.  Proceedings
Furoris Congress  on Future  of  Roads and  Rivers  in Surinam  and Neighbouring
Region.   University of  Surinam.   The  Netherlands: The  Delft  University of
Technology, pp. 329-338.

Augustinus, R.G.F.G.,  and R.P.R.  Mees.    1984.   Coastal  erosion  and coastal
accretion between the estuaries  of  the Corentyne  and the  Essequibo Rivers:  A
contribution to the coastal defense  in the Republic of Guyana.  The Netherlands:
State University of Utrecht,  Laboratory for Physical Geography.

Brinkman,  R.,  and L.J.  Pons.   1968.  A pedo-geomorphological classification and
map of the Holocene sediments in  the coastal plain of the three Guianas.  Paper
No. 4.  Wageningen, The Netherlands: The Soil  Survey Institute.

Daniel, J.R.K.   1984.   Geomorphology of Guyana.  Occasional  paper.   Dept. of
Geography, University of Guyana.   Release Books,  72p.

Daniel, J.R.K.  1988.  Sea defense strategies and their impact on a coast subject
to a cyclic pattern of erosion and  accretion.   Ocean  and  Shoreline Management

Gibbs, R.J.  1967.  The geochemistry of the Amazon River System:   Part I.  The
factors that control the salinity and the composition and  concentration of the
suspended solids.  Bull.  Geol. Soc. Am.  78:1203-1232.

NEDECO. 1968.  Surinam transportation study.  Report on hydraulic investigation.
The Hague, The  Netherlands:   Netherlands  Engineering  Development Consultants,
293 p.


NEDECO.   1972.   Report on sea defence studies.    The  Hague,  The Netherlands:
Netherlands Engineering Development Consultants,

Starbroek News.  1989a.  News item, May 3, 1989.  Guyana Publications Ltd.

Titus, J.G.   1985.   Sea  level  rise and  the  Maryland  coast.    In:   Potential
Impacts of Sea Level Rise on the Beach at Ocean City, Maryland.  J.G. Titus et
al., eds.  Washington, DC:  U.S. Environmental Protection Agency, p. 1-32.


                           ENRIQUE  J.  SCHNACK
                 Laboratorio  de Oceanografia Costera
                    Facultad de Ciencias Naturales
                  C.C.  45,  1900 La Plata,  Argentina

                             JORGE L. FASANO
        CIC y Centre de  Geologia  de  Costas  y del Cuaternario
                Universidad Nacional  de Mar del  Plata
              Funes  3350, 7600  Mar del  Plata, Argentina


                           NESTOR W.  LANFREDI
                             JORGE  L.  POUSA
            CIC y  Facultad  de Ciencias Naturales y  Museo
                   Universidad Nacional de  La Plata
             Paseo  del Bosque,  1900  La Plata,  Argentina

     The Argentine coast exhibits a variety of environmental  settings, including
estuarine and deltaic areas, marshes,  sandy  and  pebbly  shores,  and cliff
exposures.  Different wave and tide regimes operate  along the coast.

     Although erosion typifies much of the nation's  5,000-kilometer coastline,
these problems are particularly severe in the  Province of Buenos Aires with 40%
of the country's total population and one third of its coastline.  The main urban
developments, harbors,  industrial complexes,  and tourist resorts are located in
this province.   Floods are very dramatic on the Rio de  la Plata shores, which
have the highest population density.  Here the water level rose 4.75 m in 1940
and 3.85 m  in 1958.  In the  latter  case, more than  a half million  inhabitants
were affected in  different  ways.   The  Coriolis effect  has  been regarded as a
major cause for the storm surges on the  Argentine  side of the Rio de la Plata.

     South  of the Rio de la Plata, the oceanic  shorelines  show  dissipative
characteristics with  a significant littoral drift (between 400,000 and 1 million
m3/year).  There is high erosion in many areas; for exalmple,  the Mar  Chiquita
beach has been  retreating more than 5 m/year during the last  three  decades.
Beach-sand mining  for construction also contributes to erosion.  Unplanned urban


Central and South America

development can also account for property Loss and damage.  At Mar del Plata, the
main  tourist  resort  in  Argentina, groins,  jetties, and  seawalls have  been
constructed since the  beginning of the century without the utilization of basic
geomorphological  information,  thereby  partially  solving  local  problems  but
increasing erosion along downdrift areas.

      Fifteen  tide-gauge  stations, a few  of  them  with extensive records,  are
distributed along the Argentine coast.   The 64-year  record  of Puerto  Quequen,
located 120 km  southwest of Mar del Plata, shows a rise  in  sea level  of 16.09
cm/100 years.   This locality  seems to  be the most reliable,  in terms of both
historic data and tectonic stability.

      Coastal  plain flooding  is also critical  in areas such  as the Rio Salado
Basin, where topographic  gradients are extremely low and the phreatic surface is
very shallow.   In addition, salt intrusion of coastal  aquifers can be predicted
as a  combined  result  of  sea  level rise and coastal  retreat.   Overpumping has
already created this type of problem in the city of Mar del  Plata.

      Urban  development  on the  sandy  coastline of the  northern Buenos  Aires
Province has caused the elimination of extensive sand dunes, which are the only
available storage bodies  for  groundwater.  Beach erosion in this area is partly
due to the restriction in sediment supply from the  sand dunes.

      The accelerated rate in  sea level  rise predicted for the next century will
exacerbate the described processes.  Although several impacts can  be predicted
for the Patagonian coast, they are far less dramatic than those in the northern
coast  because  of the  much  lower population  density  and  urban/industrial

      In the absence of a general legal/organizational framework,  institutional
responses to  coastal  problems  are limited  to  specifically oriented government
offices, mostly at the  provincial  level  (e.g.,  hydraulic  departments,  water
resources agencies).   Some municipal counties backed by community organizations
are involved in  dealing with the development and management  of coastal resources,
although they usually  lack expertise.  It is expected  that future efforts, based
upon scientific evidence, will result in  the adoption of legal and administrative
procedures for proper use and protection of the coastal  zone.


      In  recent years, increasing  atmospheric concentrations  of  C02  and other
greenhouse gases is producing a global  warming,  which could expand ocean water
and melt polar  ice sheets.  Predictions of future  sea level  rise suggest a 1-m
rise within the next 60 to 150 years (Hoffman,  1984).  Estimates of future sea
level  rise  vary according to  the relative  contribution of  different factors
involved (thermal  expansion, retreat of alpine glaciers, melting of the Greenland
and Antarctic ice-sheets).  Gornitz et al. (1982) established  that "eustatic" sea
level is presently rising at a rate that exceeds 1  mm/year.


                                                               Schnack, et al.

      Lanfredi  et al.  (1988)  have estimated that sea level is currently rising
1.6-mm/year  in  Puerto Quequen, which probably has the only reliable tide-gauge
station  in Argentina.   This station has a 64-year  record and is located in a
technically  stable  area, which  allows for a  true eustatic component  to be

      Even without considering the present or predicted rates  in sea level rise,
the Argentine coastal areas are undergoing  several impacts (shore erosion, salt
intrusion, pollution,  etc.)  as  a  response to  both  natural  and predominantly
human-induced processes.   If the rate  of sea level  rise were to accelerate as
predicted, it would be necessary  to adopt policies and management regulations to
adequately deal  with it.   Government  and community  structures  would play an
important role  in this regard.


Natural Features

      According  to the Koeppen climatic system,  the Argentine  coast is temperate
from  the Parana Delta down to 40 km SW of the Rio Negro,  arid  from there to Rio
Gallegos, and "cold humid" to the south of that  location.

      The coastline of Argentina is  about 5,700 km long (Figure 1), not  including
the  Malvinas and Antartica.   (Note:   While  Argentina  claims  both  of these
sectors, the  United Kingdom currently administers the Malvinas  (Falkland Islands)
and Argentine ownership  of the Antarctica sector is not universally recognized.)
A very wide continental shelf extends offshore,  reaching in some places, over 800
km in width.   Main coastal landforms  (Figure  1)  are deltas, estuaries, marshes,
cliffs and wave-cut terraces, sandy and  pebbly shores, and  ice-fringed coastlines
(Antarctic area).  Sandy  coastlines are typical  along the strip extending from
Cabo San Antonio to Mar Chiquita Lagoon, in northeastern Argentina, where a 150-
km-long  barrier develops.    In  this  area,  the shoreline  shows  dissipative
characteristics with a significant littoral drift (between 400,000 and  1 million
mVyear).   Figure 2  illustrates a number of coastal  features.

      Pebbles are a typical component of the Patagonian shores.  They originate
in  the  reworking  of mainly  Quaternary  pebbly  substrates   from  continental
terraces, pediments, and  fluvial deposits.  Wave and tidal action at different
sea level positions  resulted in several raised  shorelines of Pleistocene and
Holocene age, which are  a typical  feature on  the coastal  plain.  These high sea
level stands are  also well  represented in the  Mampas coastal plains.   In all
cases, fossil molluscs are present in the sediments; these constitute the best
tools for correlation and dating (Feruglio, 1950; Rutter et al.,  1989).

      It  is  known that  sea  level  was  higher than  today  at  least  three times
during the Quaternary:   (1) during the Holocene  (maximum sea level  about 6,000
years ago),  (2)  during the last interglacial (120,000 years ago), and (3) during
a previous interglacial.  On  the Argentine  shelf, the Wisconsin  shoreline was
dated in about 18,000 years ago,  at depths beyond 100 m  (Fray and Ewing, 1963)


Central and South America
                      j  Bt


Figure  1.   Distribution of predominant geomorphic features  along the Argentine

coast  (Schnack,  1985).


                                                               Schnack, et al.

     Brackish  and saltwater marshes  are  present along the  coast,  the former
mainly  in  the  northeastern sector of Buenos  Aires  Province (Samborombon, Mar
Chiquita) and also in Bahia Blanca and further southward (Figure 1).  The latter
are predominant  in Patagonia, where macrotidal  environments  prevail.   The
Patagonian coast  is  predominantly rocky,  and  cliffy,  whereas the Buenos Aires
(Pampas) coastline alternates between extensive low-lying and cliffy areas.

     Cliffs  in  the  Province  of  Buenos  Aires are  generally  composed  of
semi-consolidated, deposits of the Plio-Pleistocene  age, reaching their maximum
altitude (25 m) in the vicinities of Mar del Plata.  Only  in  this city, an old,
lower Paleozoic  quartzite  outcrops  at the sea.   The Patagonian coast exhibits
mainly  Tertiary  sediments, both  of marine and continental  origin.   Lastly,
Quaternary, glacially derived  sediments  outcrop  in eastern Tierra del Fuego, and
Cretaceous marine rocks are the main feature on the Beagle Channel area.

     Although there are several  embayments along the whole Argentine coast, Mar
Chiquita Lagoon  inlet is the only one that has the proper attributes of such a
feature.  At a typical microtidal setting,  the Mar Chiquita inlet  (less than 100
m wide  and less than 3  m deep  in  the  channel  axis)   shows  both  seasonal (or
storm-driven) and historic shifting.  As can be seen in Figure 3 (for location
see Figures  1  and 4),  the inlet has a historic trend of  northward  shifting
coincidental with the regional net littoral drift.  However, engineering works
have modified  the natural  adjustment  of the  inlet.   In  the tide-dominated
Patagonian  coast,  a  few  embayments  exhibit  some  features  that  are  common
attributes of tidal  inlets. At  San  Antonio Bay,  in  northern  Patagonia  (Figure
1),   a well-developed flood-ebb delta is active,  but  no  freshwater inflow exists
in the area.

     Wetlands are distributed all along the Argentine  coast.  The most typical
and extensive are those in Bahia Samborombon,  where muddy, tidal flats develop
along 100  km of  coastline, at the Salado  Basin  depression  (Figures  1  and 4).
Also,  tidal flats and marshes are present from Bahia  Blanca southward.  Wetlands
along the  Patagonian  coast  are  not  so extensive.  They are more restricted to
low-lying areas at the several embayments.  In all cases, marshes are temperate
and show the presence of typical  vegetation (Soartina.  Salicornia).  The general
topography at low-lying areas would allow marsh and vegetation to shift inland
if a rapid sea  level  rise occurred.  In  some cases,  e.g., restricted marshes in
Patagonia, where a rocky slope borders a narrow coastal plain, migration would
be limited to a few hundred meters,  thus causing marshes to disappear.

     The most prominent  estuarine environment  is the  Rio  de  la Plata,  a water
body shared by Argentina  and  Uruguay.   As a continuation of the  Parana River
Delta,  the Rio  de la  Plata has a  submerged deltaic front composed of silt-clay,
but sand banks  also occur.  The main body is freshwater,  but the outer part is
brackish.   Although   no  river discharge  occurs at present,  Bahia Blanca,  a
brackish-water  environment with mesotidal action, hosts  one of the most important
harbors.  Here,  muddy environments and suspended material's, as well as drifting
sandwaves and channels,  are driven by tidal currents.

Figure 2 (A-C).  Coastal features of Argentina.

(A)  Erosive coastline at the edge of the Pampas plain,
looking  north.    In  the  background  is Mar  Chiquita
Lagoon, where  a  sandy barrier develops  to  the north.
The  coastal  plain  has an  extremely  low  topographic
gradient.    A   sea   level   rise  makes  this  region
vulnerable, both  to beach erosion (dune destruction) and
to flooding.  Both processes are  already occurring to a
high degree because of human influence.

(B)  Low (<2 m) eroding cliffs approximately 20 km north
of the Mar  del Plata.  Beach sediments are scarce.  Note
the coastal road.

(C)   Protected beach  (see  groins)  at Santa  Clara,  a
resort town 18 km north of Mar del  Plata.

ff Figure  2  (D-F).

;t| (D)   Stone defense  to rebuild  beaches  at  Mar  del  Plata
 ' (constructed in the early 1980s).  By the 1970s,  beaches
   in  this  area  were lost.    Many  other  beaches  are
   protected by groin  systems.

   (E)   15  km south  of Mar  del Plata  center,  eroding
   beaches in an area where  sand mining for construction is
   doen.  Note the improverished dune "relicts" resting on
   an  approximately 10 m  high cliff which  now  is  being
   reactivated by  dune disappearance.

   (F)   Part of  a tidal  salt marsh in Coleta  Mabespina
   (Patagonia).  Many similar environments of varying area
   (usually small  in Patagonia and lareger in Buenos  Aires
   Province)  are  distributed  along  the Argentine coast.
   Some may not migrate landward as sea level  rises  because
   of  topographic  (hills)  or  human barriers,  hence, a
   significant wetland loss may result.

                           goo  too  o
                                           1000	3OOO
                            IOOO 500  0
                                      -~-'        *"
1000  800 __ 0
                                                    IN ICW
                                                 gg  mere*?
*** ^ T7sc''"-T^"*'""'"""" ---"""- -^t Li- -*"""

v.v^.v,. ^wvvv ...v , :,--'"

x N

Figure 3.  Historic migration of Mar Chiquita  Lagoon  inlet.
     Several  other  estuaries are represented in the coast  of  Patagonia by the
river outlets  under macrotidal  conditions,  but few detailed studies  have been
done in relation to  water chemistry and dynamics.  Bottom sediments are variable,
with gravels,  sands, and muds in different  proportions  according to the source
and dynamics.    In  this macrotidal  setting, most  of the  fine sediments  are
transported in suspension.   Because of the large tidal amplitudes, some of these
estuaries have extensive uncovered areas during  the  ebb tide.  One such areas is
the Rio Gallegos outlet, where  tidal  ranges reach 12 m  (Figure 1).

Cultural and Economic Features

     According to  Brandani  and  Schnack (1987),  human  activities along  the
coastal zone of Argentina include urban development and recreation; industry and
commerce; port activities;  fishing,  military and  naval  bases; research;  arid
conservation of natural resources.   In  certain  areas, beach sand is mined for
building purposes.   Other  activities  include:   mining  of  coastal  gravels arid
shells (from Quaternary deposits), offshore oil  exploration and extraction, and
algae exploitation.   The general features  of the  major Argentine  harbors are
shown in Table 1.

                                                               Schnack, et a7.
Figure  4.   General  topography of  the Province  of Buenos  Aires.    Note  the
extremely gentle slope in the Salado  Basin depression and in the Rio Colorado-Rio
Negro region.

Central and South America
      Table 1.  General Characteristics  of the Main Harbors in Argentina
Buenos Aires
Mar del Plata
Quequen and
Bahia Blanca
Puerto Madryn
Zone of Comodoro
Puerto Deseado
0 = 34
0 = 58
0 = 38
Q = 57
0 = 38
0 = 58
0 = 38
n = 62
0 = 42
Q = 65
0 = 45
Q = 67
0 = 47
fi = 65
0 = 54
General cargo,
bulk and con-
tainer bulk
Fishing port
and bulk
Grain in bulk
terminal and
fishing port
General cargo,
grain in bulk
terminal, and
fishing port
General cargo
Oil terminal
and fishing
Fishing port
Fishing port
and general
Wharves, berths,
cranes, ware-
houses, sheds,
grain elevators
Wharves, berths,
cranes, ware-
houses, sheds,
grain elevators
Wharves, berths,
grain elevators,
Wharves, berths,
cranes, grain
elevators, ware-
houses, sheds
Wharves, berths,
cranes, ware-
Wharves, berths,
Wharves, berths,
cranes, ware-
Wharves, berths
and small
and small
Chemical, textile,
metallurgical, and
food industries
Fishing irrLstries,
packing houses,
agricultural and
cattle- raising
Fishing and food
industries (meat
and flour), agri-
cultural and
cattle- raising
Agricultural and
Aluminum factory,
fishing indus-
tries, and sheep-
raising activities
Oil fields, sheep-
raising activi-
ties, and fishing
Sheep- raising
activities, and
food industries
                0 = 68 13' W   cargo

                                                               Schnack, et a 7.


     In  Argentina,  over  41%  of  the  population inhabits  the  coastal  zone.
Population densities  vary along the coast.  A  general  gradient develops from
north  to south,  with the  greatest  population   numbers  and densities  in  the
nation's capitol, Buenos Aires city, and associated urban centers.  The lowest
population concentrations and variety of activities are found in  Patagonia, south
of the Colorado and Negro Rivers, where a few small  urban centers support most
of the regional population  and activities.

     Most of the  largest  urban  centers  and  25%  of  its  urban centers with more
than 5,000 inhabitants are coastal.   However, the fact that the federal capital
(Buenos Aires  city),  with only 17 km of coastline along  the Rio de la Plata,
contains 10% of the country's total population must be considered.  Buenos Aires,
together with its  suburbs  (Greater Buenos Aires)  is estimated to  have  ten million
inhabitants  (30%  of the national population).

     The continuing  historical pattern of population  migration to  the  city
(averaging a yearly growth rate of 47% between 1869 and 1980, against  13% for the
national population growth)  has been caused by mutually reinforcing factors: the
Port of Buenos Aires  handling 90% of the total  waterborne transit and commerce
of the country; the siting around the city of many of  the  nation's  industrial and
productive activities; and  the concentration of a strongly centralized federal

     The Province of  Buenos Aires,  with more than  1,500 km of  coastline  and
nearly 12 million people  (40%  of the national   population)  is  by far the most
important coastal province  (state) of Argentina.  The  average  density is 35.3
people/km2  and  over 90% of the population lives in urban  centers,  the largest of
which are all coastal  (Figure 5):  La Plata with  460,000  people, followed by Mar
del Plata with 410,000 people,  and Bahia Blanca  with over 220,000 inhabitants.
Rural areas are dominant along most of the coastline. It is here --  not the
cities -- where the topography  is  vulnerable to  major inundation  from sea level
rise,  as  can be  observed  in the Salado  Basin  depression with  extremely  low
topographic gradients (Figure 4).

     The Patagonian  region  varies in  population distribution according to  the
specific province.  In Rio Negro Province, only  12.5% of the population live in
coastal centers.  This is  due to the  strong economic influence of the Rio Negro
Basin and the city of  San Carlos de Bariloche, at the foot of the Andes.  Farther
south, in Chubut,  more than  80% of the 263,000 inhabitants  live in coastal urban
centers.  Santa Cruz  Province,  the third largest  in Argentina, has only 114,900
people and its density is correspondingly very  low:   only 0.5 people/km2.   The
National Territory of Tierra del Fuego has only  40,549  inhabitants with 38,515
people living in just  two coastal cities:  Rio Grande  (21,969) in  the north,  and
the capital of Ushuaia in the south (16,546).

                                                        5000 - 20000
Figure  5.   Population  of urban  centers on  the Argentine coast.

                                                               Schnack, et al.

Land Use

     Low-lying  coastal  lands  are  mainly rural  and are  found mostly  in the
Province of Buenos Aires (Salado Basin  in the north, and the southern tip of the
state, from  Bahia Blanca to Bahia Anegada).   The  Salado Basin coastal plain,
facing Samborombon Bay,  is largely devoted to  agriculture  (mainly cattle).
Because this is a flood-exposed  area,  activities are somewhat restricted.

     The area immediately above the highest tide levels in Bahia Blanca is partly
occupied by housing developments related to the various industries  established
nearby; much of this area is  subsiding.  South of Bahia  Blanca,  the coastal area
is mainly devoted to agriculture.  In  the northern, sandy  belt of Buenos Aires
Province  (Figure  1), and  extending  southward to  Mar  del  Plata  and Miramar,
tourism is the main land use.

     At the Salado Basin, the recurrence of historic floods led  the Public Works
authorities to construct drainage canals toward Samborombon Bay at the beginning
of the 20th  century.   However, results have not been  optimal,  as  floods have
occurred ever since.

     As a general  case,  the Patagonian coastal lands are mainly  devoted to sheep
raising; a very localized algae  farming also takes place.


     Most  Argentine fisheries  are  export-oriented.    In  1981,  the  country
contributed 1.69% of the world exports (Espoz, 1985).  Fisheries are mainly found
in  shelf waters.    Fish catches  are  by  far  predominant,  but molluscs  and
crustaceans are also important resources.  Oyster and scallop beds  are present
in shallow waters in northern Patagonia.  Crustaceans (e.g., prawn, king crab)
represent typical catches in Patagonia and Tierra del Fuego.

     Commercial  sea-farming is  not  commonplace  along the Argentine coast.  Only
a few oyster and  mussel  farming projects  are being carried out in  San Antonio
Oeste, and  crustaceans  projects in Mar del  Plata  and  Puerto  Madryn.   In all
cases, they are only at the experimental stage.

     The main fishing activities are centered in the ports of Mar del  Plata, with
most of the fishing  fleet and processing installations,  and more than 70% of the
total yearly catch.   Other important  harbors are:   Ingeniero White  (Bahia
Blanca),   San Antonio  Este,  San  Antonio  Oeste,  Puerto  Madryn   (Figure  4).
Additional small harbors are distributed along the Patagonian coast.


     Considering the variety of environments and the socioeconomic importance of
certain regions of Argentina, a rapid sea  level rise, as predicted for high and
low scenarios (Hoffman,  1984),  would  result  in  major damage to coastal areas in
low-lying, flood-exposed plains and in open marine beaches and cliffs.


Central and South America

Beach Erosion

     Erosion is an ongoing process,  even at the present rate of sea level rise
which has been  estimated for the region as  1.6 mm/y (Lanfredi et al.,  1988).  The
coastline  between  Cabo San  Antonio  and  Mar  del  Plata  is  undergoing  severe
erosion, partly due to natural causes  (e.g., lack of fluvial sediment input, sea
level rise) and mainly because beach-sand mining and dune urbanization take place
without any planning or environmental assessment.  Engineering structures have
been installed to protect  the shore,  but in many cases they operate locally and
cause downdrift erosion by trapping the transported sediments.  At Mar del Plata
(Figure  6)  several  groins  and  jetties have   been  installed  throughout  this
century.   Also,  Mar del  Plata harbor certainly  influences  erosion  in  the
downdrift  direction (northward  in  the whole  region) by  breakwaters  at  its

     Since erosion is a typical  problem of the  sandy shoreline  and of the cliff
exposures of Buenos Aires Province,  sea level  rise should  only exacerbate the
existing problems.  At Mar Chiquita  beach  (Figures 4 and 7), a  shore retreat of
more than  5 m/y  has been  determined  (Schnack, 1985),  causing  land  losses and
property destruction. This is the highest  rate  in shoreline retreat established
for the whole coast of Argentina.  Many other  localities  north of Mar Chiquita
also show increasing erosion as a consequence  of human intervention.

     In a  well-known  paper,  Bruun  (1962)  describes a method  for  determining
shoreline retreat produced by sea level  rise.  He assumes that after a sea level
rise the  beach profile will  simultaneously undergo an upward and  a  landward
shift,  though  retaining  its  original  shape.   Thus,  the  final  beach  profile
displacement can  be considered as  the result of  two rigid translations:   a
vertical one and a horizontal one, the latter  being the shoreline retreat.

     For the given  scenario  (Hoffman, 1984),  considering a  0.50-,  1.00-,  arid
2.00-m sea level  rise to take place  in a period of 50 years, a  beach profile at
Punta Medanos  (Figure 4)  would undergo a retreat of 1.93,  3.86, and 7.73 m/yr,
respectively.   These estimates show the dramatic impacts of predicted, rapid sea
level rise.  Furthermore,  human-induced erosion represents  a major factor that
must be considered at least as effective as sea level  rise  itself.

Hvdrological Impacts

     Although  hydrological problems  along most of the Argentine coast  may be
foreseen as a  direct consequence of  sea level  rise,  the  Buenos Aires  Province
shows most clearly the effects of anthropogenic activities due  to its high
population density,  despite the fact  that this population is concentrated  at very
specific points.  These activities are responsible for  the shifting or breakdown
of the natural  equilibrium..  This is particularly true when dealing with
groundwater resources, for processes operate at different  intensities  and time
scales.    Moreover,  as groundwater  motion  is  slow, thus  hindering  direct
observation, the  consequences  arising  from management decisions  may  not  be
noticed  for several  years,  and  so  the  results could  be  irreversible  when


                                               Punlo Igltsta
                                                                          Schnack, et  al.
                                                                 LOCATION  MAP
                                                    }gj2l930 - modified in  I960

                                                 1930 - 1932
                                                   Punto  Pltdroi
                                                    (Torrtrfo dil  Monjt)
                                                        1924- modified In 1961
 (1932 Groin construction

 Contour interval: 10m

0      1     2km
Figure 6.   Engineering  structures at  Mar del  Plata.   Except for  the harbor,  all
the  structures  have been installed  to protect  the shore from erosion.

Central and South America
                                                          Mar Chiquita

                 II   M   II   I
                SOUTH  ATLANTIC OCEAN
            200  300 meters
             '	1
Figure 7.
Shore retreat at Mar Chiquita beach.  Note the land losses, including
     Besides  the  highly  disturbed deltaic  area,  on  which  little,   if  any,
background  information  is available,  three  main  coastal  environments  can  be
considered in the province:  cliffed,  sandy,  and marshy shores.  As a result of
sea level rise, saltwater encroachment can take place, the impacts being mainly
dependent  on  the  physical  coastal   setting,  climatic variation,  and  human

     A  common  feature of the three  environments  is  the  lack of  sufficient
available data, with  the exception of some urban areas.  This  poses  serious
restrictions on the reliability of numerical solutions, for they depend upon both
the quality and quantity  of the input data.

     In Mar del  Plata, located at the easternmost extreme of the Tandilia Sierra,
the aquifer consists of partially reworked Plio-Pleistocene loess-like sediments,


                                                               Schnack, et al.

with an average depth of 100 m.  It had undergone  over-pumping  until the 1960s.
As a result,  seawater intrusion was detected, and nearly all the pumping wells
located within the city and close to the coast were abandoned.   The exploitation
zone  had  to  be  shifted to the north.   This action  led to a restoration of
groundwater  tables  which had flooded buildings,  and  has  acted as a hydraulic
barrier preventing  a landward migration of the freshwater/saltwater interface.
Today the situation in the well field can  be  considered  at equilibrium.  Hence,
in Mar del Plata the landward migration of the saltwater front  due to sea level
rise would be negligible when compared with the human-induced migration.

     A different situation can be observed toward the north of Mar Chiquita (a
small town located  about 30 km north of Mar  del  Plata).  A sand dune barrier,
which extends for more  than 150 km and becomes  progressively wider northward,
overlies marine-estuarine  sediments of Holocene and Pleistocene age (Fasano et
al., 1982; Parker,  1980).   At the  low-lying  coastal  plain of Samborombon Bay,
sand dunes are replaced  by  shelly beach ridges (Sala et al., 1977).  Both sand
dunes and shelly ridges  are the only available freshwater storage bodies.  These
storage bodies can  be idealized as if they were an elongated island surrounded
by seawater  on  the  east and brackish-to-salty continental  waters  on the west.
Because of this, the sandy barrier could be largely influenced by a eustatic sea
level rise.   According to  the  erosion  rate  measurements, e.g., 5  m/y  at Mar
Chiquita (Schnack,  1985) (Figure 6),  the horizontal component exceeds in orders
of magnitude the rise in sea level (1.6 mm/y)  in  the vulnerable  sandy coastline.
The landward migration of the  interface would be  largely  controlled by the beach
retreat.  Changes in altitude of the base  level  play a minor role.  In fact, as
stated by Urish and  Ozbilgin (1989),  the groundwater/free seawater interface is
a highly dynamic boundary.  On sandy sloping beaches, tidal  fluctuations and wave
run-up cause an effective mean sea level generally higher than free-water mean
sea level.

     Kana  et  al.  (1984) summarizes the different opinions about the  effect of sea
level rise on the position of the freshwater/saltwater interface in  a water table
aquifer.   Some  state that the whole  system  would  shift upward  and  landward
proportionally to sea level  rise and shoreline  retreat, respectively.   Others
consider that freshwater rise would not follow sea level rise at the same rate,
but would be some fraction of it as  a consequence of decreasing  recharge and
increasing discharge.

     Under nondeveloped  conditions, the lens-shaped groundwater  reservoir can be
regarded as being in dynamic equilibrium by direct recharge from precipitation
and discharge to  the sea.  It  seems  reasonable  that  a sea level  rise  of the
magnitude considered here is sufficiently slow to allow groundwater to reach a
new equilibrium position.

     Floods are very dramatic on the  Rio de  la  Plata  shores, with the highest
population density.   Here the water level rose  4.75 m over datum  in 1940 and 3.85
m  in  1958.    In  the latter  case,  more than  a  half million inhabitants  were
affected by property losses and other damages.

Central and South America

     The marshy  areas  of Buenos Aires  Province  extend mainly south  of Bahia
Blanca and also border Samborombon Bay.  In these  environments, erosion does not
seem to be a dominant process.  Due to the extremely gentle topographic gradient,
minor positive variation  in sea level  causes the flooding of extensive areas with
consequent land loss  (Figure  3).    This would  allow  an  inland movement  of
seawater, resulting in its intrusion  into  the  groundwater  system.   Additional
effects, such as longer-lasting  floods are linked to higher water tables, which
inhibit the infiltration process during precipitation.  From the point of view
of groundwater as a resource, these effects would  not pose a severe risk because
brackish-to-salt water dominates.

Other Impacts

     A rapid  sea level  rise would result  in several  disturbances  of various
degrees of importance,  depending on the urban development,  industries, general
resources, and installations.

     Impact on harbors (Table 1), in  any of  the  predicted  scenarios,  would be
high in Buenos Aires  and  Bahia Blanca because of the flat, low-lying terrain of
the surrounding  areas where very important economic activities take place.  At
Mar del Plata, Quequen, Puerto Madryn, and Comodoro Rivadavia the impact would
be only moderate and the affected areas  would  be those  next  to  the shoreline.
Landscape damage and  pollution effects can be predicted.  At Puerto Deseado and
Ushuaia the impact would be low, mainly  restricted to the  port  facilities and
their adjacent areas.

     Wetlands would also  be affected,  either by migration and recolonization or
by disappearance when migration is  restricted by  highlands  or hard substrates.
As we consider  a rapid  sea  level rise, it is  likely  that  inland migration of
wetlands would  keep pace in vertical  growth  relative  to the  rate of sea level
rise.  Under these conditions, a rough estimate suggests an average loss of 50%
of the wetlands  area.

     The inland transportation of pollutants  would also  be a direct effect of a
rising sea level.  This  would be particularly  important in heavily populated,
industrial, and harbor areas (Buenos Aires, Mar del Plata, Bahia Blanca),  as well
as in Patagonia,  where oil spills may be transported  inland (Comodoro Rivadavia).
Although they are not yet in existence, sea-farming establishments may also be
affected to some extent.

Institutional Background

     Government and legal instruments for coastal  planning  and protection are
dispersed and  no  specific: framework for coasts  is available.  A  document on
national priorities for marine and coastal  research (SECYT, 1983) identified the
lack  of properly  trained personnel  and  of  coordination between  research and
management activities as significant issues.


                                                               Schnack, et  al.

     At present, coastal issues show several  problems  related  to organizational
levels:  lack of coordination  and overlapping among public agencies; confusing
and contradictory laws and regulations, and insufficient resources  for adequate
coastal zone management.

     The conflicts  between  pollution,  recreation,  and coastal protection,  for
instance, are significant in the  larger summer resorts of Buenos Aires Province,
such as Mar del  Plata.   Coastal erosion has led to the construction  of a variety
of costly defenses  in order to prevent the disappearance of beach resources  and
to reverse  the  destructive  tendencies caused by sand-trapping devices (mainly
groins).    These  defenses  produce   the  desired  effect  in  one place,   i.e.,
accumulation of sand,  but at the expense of other beaches,  which end up  being
heavily eroded, as  is  the case between Mar Chiquita and  Miramar (Figures  4  and
6).  These conflicting  activities in  Buenos Aires Province have an institutional
background.   Construction  of  coastal  defenses  is  the responsibility  of a
Directorate  of  the  Provincial   Ministry of  Public  Works,  and   a  separate
Directorate of the same Ministry  grants permits for sand extraction  from beaches
and dunes,  an erosion-triggering activity.   No integrated planning procedures
exist among the Directorates within  the  Ministry.  Moreover, while  tourist  use
and exploitation  of the shore  are  the  domain of  municipal  governments,  port
activities  (a major source of pollution and erosion in Buenos  Aires  and Mar  del
Plata, among others) are under federal government jurisdiction.

     Table 2 presents a summary of governmental units related to functional or
sectorial aspects of marine  and coastal zone management.  The hierarchical  level
for each  government unit (whether  national  or provincial)  is  shown  in   Roman
numerals  (I  is  the highest  and  corresponds to the  chief executive's  office,
whether the  nation's  president or  the governors).   When some  sector  is  also
represented  within  the  government   structures  of  coastal   provinces,    its
hierarchical level  is   indicated.   Only names  of the federal  institutions  are
listed under the "nation" heading.   Provinces  are,  from north to  south:   BA ,
Buenos Aires; RN,  Rio Negro;  Ch, Chubut;  SC,  Santa Cruz, and  TF,  Tierra  del

     Table 2 lists  only those sectors currently related  to coastal zones  for
which some  governmental unit exists.   For farming,  ranching,  education,  and
forestry,  no special   orientation   to  coasts  is   found within  governmental
structures.  For  the  last  sector, this  is  understandable since  the Argentine
shoreline  is  essentially a  treeless  corridor  (Brandani and Schnack,  1987).
However, farming practices  affect estuaries and coastal  wetlands  through  the
concentration of runoff products, agrochemicals, and sediments.

     Defense and  production  are concentrated  in  units of  relatively  high
hierarchical level  within  the federal  government.    Development and  wildlife
management have a higher priority in the provinces than at the national  level.
Development is mostly industrial in nature, and ecological management emphasizes
the exploitation of specific renewable  resources for production or consumption,
rather than the conservation of integrated environmental systems.

Central and South America
Table  2.  Argentine  Governmental  Organizations  With  Primary  Policy Authority
          for  Marine  and Coastal  Resources
Defense operations
Foreign policy
Port administra-
Port activities
Port maintenance

Fisheries control
Coastal tourismd
Research (civil-

Research (mili-

Shore protection
Wildlife manage-
Parks- -conserva-
tion control*
Oil and gas

Name level
Ministerio de Relaciones Exteriores
Direccion de Aduanas

Administracion General de Puertos
Capitania General de Puertos
Direccion de Construcciones
Portuarias y Vias Navegables
Prefecture Naval
Direccion de Pesca
Subsecretaria de Turismo

Consejo Investigaciones Cientificas
y Tecnicas
Universidades Nacionales
Institute de Investigaciones
Direccion del Antartico
Direccion de Investigacion y
Servicio Hidrografia Naval

Direccion de Fauna Silvestre

Direccion de Ordenamiento Ambient a I
Obras Sanitarias de la Nacion

Secretaria de Energia
Yacimientos Petroliferos Fiscales
Gas del Estado
Secretaria de Hineria

Secretaria de Desarrollo Regional




























































 More than one governmental unit deals with sector.
bln addition to several governmental units, national companies participate in sector.
Separate units are dedicated to sector with different objectives.
University research is actually carried out by Departments or Institutes, with lower  hierarchy than
\ocated in coastal provinces where they research according to regional needs.
'some coastal cities may have a company providing primary services.
ne = Non existing.
Source:  Brandani and Schnack (1987).
     There  is  no specific  legal  framework  for  coastal  issues at  either  the
national or provincial level  in  Argentina.   Some legislation  related  to other
aspects (e.g.,  control of pollution by naval vessels, fisheries, etc.)  considers
a few  coastal  aspects.  Also,  a number of provincial  decrees  (e.g., to prevent
sand  mining on  beaches)  and  municipal resolutions  provide some  approaches  to
solving coastal problems from a legal  point  of view.

                                                               Schnack, et a7.

Expected Responses to a Sea Level Rise

     If we consider the  preceding paragraphs, it is clear that sea level rise is
not an  issue  at  the  institutional  or the general  public levels.   Only a small
part of the scientific population  regards  this  as an  important problem.   In
addition, there is insufficient evidence, from an observational basis, to really
evaluate if a true sea level  rise  is occurring throughout the  entire coastline.
Most of the erosion and  environmental disturbances are due to  human intervention
on coastal areas.  Moreover, it must be considered that other hazards, such as
inland flooding,  earthquakes, landslides, and other phenomena,  seem to have more
dramatic effects and general concern among the public and institutions because
they tend to affect the economy more noticeably.

     However, if an integrated, environmental policy is established, the coastal
issue may  become progressively more  important.   Coastal protection  would be
seriously considered and sea level rise properly regarded as an important factor.

     Based upon scientific evidence, future efforts should result in the adoption
of legal  and administrative procedures  for  proper use  and  protection  of the
coastal zone.

Brandani,  A.A.  and  E.J.  Schnack.    1987.    The Coastal  Zone  of Argentina:
Environmental, Governmental  and  Institutional  Features.   Journal of Shoreline
Management 3:191-214.

Bruun,  P.   1962.   Sea Level Rise  as a Cause  of Shore erosion.   Journal of
Waterways and Harbors Div.  88:117-130.

Caviglia, F.J.  1988.   Intrusion  salina en el Rio de  la Plata.  I.T.B.A., Buenos
Aires, 38 p.

Espoz Espoz, M.   1985.  Introduccion a la Pesca Argentina.  Fundacion Atlantica,
Mar del Plata, 336 p.

Fasano, J.L., Hernandez,  M.A.,  Isla,  F.I.  and  E.J. Schnack.   1982.   Aspectos
evolutivos y ambientales de la laguna Mar Chiquita,  Provincia de Buenos Aires,
Argentina.  Oceanologica Acta No. Esp., 285-292.

Feruglio, F.  1950.  Descripcion geologica de la Patagonia.  Y.P.F.

Fray,  C.  and M.  Ewing.    1963.   Pleistocene  sedimentation  and fauna  of the
Argentine Shelf.   In:  Wisconsin Sea Level as Indicated in Argentine Continental
Shelf Sediments.   Proceedings of the  Academy of Natural  Sciences of Philadelphia.

Hoffman, J.S.  1984.  Estimates of future  sea level rise.  In:  Greenhouse Effect
and Sea Level Rise.  M. Barth & J. Titus, eds.  Van Nostrand Reinhold Co., New
York. 79-103.

Central and South America

Kana, T.W., Michel,  J.,  Hayes, M.O. and J.R. Jensen.   1984.  The physical impact
of sea level rise in the  area of  Charleston,  South  Carolina.   In:   Greenhouse
Effect and Sea Level Rise..  Van Nostrand Reinhold Co.,  New York, 105-150.

Lanfredi, N.W., D'Onofrio, E.E.  and C.A. Mazio.  1988.   Variations of the mean
sea  level   in  the  southwest Atlantic  Ocean.    Continental  Shelf  Research.
Parker, G.  1980  Estratigrafia y evolucion morfologica durante el Holoceno en
Punta Medanos  (Planicie  costera y plataforma interior).   Provincia  de Buenos
Aires.  Simp,  sobre  Problemas  Geologicos del Literal Atlantico Bonaerense, Com.
de Inv. Cient. de la Provincia de Buenos Aires.  Resumenes (La Plata). 205-224.

Rutter, N., Schnack, E.,  del Rio, J., Fasano, J.,  Isla,  F. and U. Radtke.  1989.
Correlation and dating of quaternary littoral zones along the Patagonian Coast,
Argentina.  Quaternary Science Reviews 8:213-234.

Sala,  J.M.,  Gonzalez, N.  and  M.  Hernandez.    1977.    Efectos  de la  barrera
hidraulica natural en las aguas subterraneas del  literal de Bahia Samborombon.
Obra del Centenario  del Museo  de La Plata, t. IV, Geologia.  La Plata, 153-166.

Schnack, E.J.   1985.  Argentina.  In:  The World's Coastlines.   E. Bird and M.
Schwartz, eds.  Van  Nostrand Reinhold Co., New York,  69-78.

SECYT  (Secretaria de  Ciencia  y Tecnica).   1983.   Programa  de  investigacion y
desarrollo en  Pecursos Marines  Costerns y lagunares de la  Provincia  de Buenos
Aires.  Buenos Aires.  30 p.

Urish,  D.W.  and  M.M. Ozbilgin.    1989.   The  coastal groundwater  boundary.
Groundwater 27(3) :310-315.

                         RUBEN APARICIO-CASTRO
                           JULIAN CASTANEDA
                Institute Oceanografico de Venezuela
                        Universidad de  Oriente
                       Cumana-Sucre,  Venezuela

                            MARTHA PERDOMO
                  Ministerio  del Ambiente y de  los
                    Recursos Naturales Renovables
                       Caracas 1010,  Venezuela

     Sea  level data on the marine  boundaries of Venezuela have been analyzed
using several tidal-gauge stations with continuous records ranging from 21 to 36
years. The rates of change in sea level  have been  highly variable.  All  of the
time series examined, except two, show a  tendency toward increase  in sea  level,
with values ranging from 3.26 mm/year in Maracaibo Lake (an area of remarkable
petroleum and groundwater extraction during the  last 50 years) to 0.91 mm/year
at Amuay.  The easternmost tidal-gauge stations,  located on Carupano and  Puerto
Hierro, exhibit a lowering trend, which can be explained in terms of technically
induced uplift of this regional  land mass due to its proximity to the boundary
between the Caribbean and the South American tectonic plates.

     In an attempt to determine the Venezuelan coastal  zone's vulnerability,  this
paper indicates the lowland areas  likely to be affected by this phenomenon and
discuss  the  resulting  environmental,  social,  economical,  and  geopolitical
implications  of  these changes.    Among  other factors associated  with  global
climate change, the frequent occurrence of tropical storms and hurricanes  in the
Caribbean Basin, and the changes in their track and destructive potential,  emerge
as some of the most negative effects influencing  the Venezuelan coastal zone in
the near future.

Central and South America


     Global  warming  could  disrupt  environmental  conditions  and  political
institutions  throughout  the  world.    In the  recent  past,  the  threat of  a
greenhouse warming has been studied by the United Nations Environment Programme
(UNEP) through  its  Regional  Seas Action Plans, in conjunction  with the World
Meteorological  Organization  (WMO)   and  the  Intergovernmental  Oceanographic
Commission of UNESCO.

     A 1988 UNEP  study of  the  Wider  Caribbean  Region  (including the Caribbean
Sea, the  Gulf of  Mexico,  and the Florida-Bahamas area of  the  Atlantic Ocean)
emphasized the marine and  coastal  environment and addressed the implications of
climate changes in  that region.   That  research served as  a  starting point to
initiate local scientific concern about  anthropogenically  induced global climate
changes in Venezuela.

     This paper characterizes the Venezuelan coastal zone and summarizes  its main
geodynamic  and geomorphological  features,  its  typical  ecosystems,  and  its
socioeconomic  importance.   It presents  some  evidence of  local  variations in
climate conditions along the marine boundaries of Venezuela, examines the local
signal of relative  mean  sea  level  variability from  tidal-gauge  records,  and
discusses the resultant environmental, social,  geopolitical, legal, and economic
implications  of the  regional  pattern  of alterations in  climate  conditions.
Finally, it presents, for  the consideration of Venezuelan authorities, a set of
recommendations of domestic importance toward implementing an effective national
response policy.


     Venezuela's coastline constitutes approximately 52% of  the southern coastal
boundary  of the Caribbean  Sea and an appreciable portion  of shoreline on  the
Atlantic Ocean. Many types of coastal environmental stages are exposed along the
approximately 4,000  kilometers of the Venezuelan  shoreline:   sandy marshland,
beaches, cliffs, deltaic plans, coastal  lagoons,  barrier islands, estuaries, and
bays.   These  environments are distributed  on  both Venezuela's  Caribbean  Sea
boundary  (2,720 kilometers)  and  its  Atlantic Ocean  border  (1,300 kilometers).
In addition,  its  200  nautical  miles  of  Exclusive  Economic  Zone  (EEZ),  with an
area of 630,000 square  kilometers,  comprises  around  300 islands,  islets,  and

     While sandy shorelines and beaches appear frequently along the Caribbean Sea
border, sandy marshlands  are confined to the Peninsula of the Paraguana at the
western section.  The presence of cliffed coastal  portions  is  clearly evident.
Deltaic zones are  few, with the Orinoco Delta,  on the Atlantic margin, emerging
as the most extensive one,  occupying 88,000 square  kilometers  in its drainage
basin and 22,500 square kilometers in its receiving basin.  The Unare Delta, in
the central section of the Caribbean boundary,  with a drainage  basin of 22,300
square kilometers  and only 28 square  kilometers of area in its receiving basin,
consists of two big  coastal lagoons (Unare and  Piritu)  separated from the sea by


                                                       Apan'cio-Castro, et a7.

very  low-lying sandy barriers  and partly protected  by a mangrove  forest of
limited extent.

     Any general attempt to summarize a broad geodynamic characterization of the
Venezuelan coastal area  should consider the following features:

        It  lies  on  a  very tectonically  active  zone.    Located  along the
         country's easternmost  coastal  section  is a significant proportion of
         present-day global seismicity (see Figure 1).

        The local surface wind field presents a remarkable persistency in its
         mean directional distribution,  reflecting the  regional predominance of
         easterly winds and implying favorable conditions for coastal upwelling
         throughout the  whole year.   However, with regard  to the wind field's
         strength,  a   notable   westward  intensification   is  evident,   and
         consequently, the local rate of evaporation on the western Venezuelan
         coastline is enhanced.

        The  seasonal  fluctuation  of the  Intertropical  Convergence  Zone is
         usually thought to be the most important factor controlling the  local
         rainfall pattern.

        The local tidal  regime presents a microtidal  mean  range and gradual
         westward increase of the form number, implying the  occurrence of mixed,
         mainly  semidiurnal,  tides at the easternmost  section;  mixed, mainly
         diurnal tides at the  central part; and diurnal  tides  at the westernmost

        Tropical  cyclone  activity  has  not been  significant  in the   past.
         Specifically, up to 1972,  only three tropical  storms  occurring  over the
         southern coastal boundary  of the Caribbean Sea had  reached the  category
         of "hurricane" during the entire century.

        The coastline  along the  marine  boundaries of Venezuela shows  clear
         signs  of  geomorphological changes.   Table 1  shows  the area of the
         Venezuelan shoreline where coastline changes have  been well documented
         (see, for example, Bird,  1985).


     The socioeconomic and ecological  importance of the Venezuelan coastal area
is well established.

Oil Resources

     About 50% of the  total  population of Venezuela, estimated  to  be 20 million
people for 1990, resides in the coastal  zone.  Additionally,  the oil  industry,
which  is  the primary resource  for national  income,  bases its  operations on
structures located  mainly on the coastal margin.  In particular,  these structures


  Central and South America
                                                 70" W
10'N -
                                                                               - ION
  Figure 1.  Venezuelan marine territory in the Caribbean Sea.
  are located on the westernmost portion. They include the estuarine system formed
  by the Lake of Maracaibo,  the  connecting  waterways of El Tablazo Bay,  and  the
  Maracaibo Straits.   Expansion of the national oil industry implies,  in addition,
  the  establishment   of macro-facilities  on  the  easternmost  section  of  the
  Venezuelan coastal  margin  (Araya and  Paria Peninsulas) during  the next  five

  Fishery Resources

       The entire coastal zone of Venezuela possesses valuable fishery resources
  that have the potential of continuous production if they are efficiently used.
  The wind-induced coastal  upwelling observed  in the area  is  the key  physical
  mechanism responsible  for  the  high  biological  production characterizing local
  fishery activities.

       The northeastern section of the country has been  an  important fishing area
  for a wide variety of pelagic and demersal species.  Specifically,  the Gulf of
  Cariaco, the  western coast of the Araya Peninsula, and the southern and


                                                       Aparicio-Castro,  et al

                    Table 1.  Venezuelan Coastline Changes
1.   Orinoco Delta

2.   Gulf of Paria

3.   Western shore of the
       Araya Peninsula

4.   Coastal boundary of the
       Unare Bay

5.   Tucacas

6.   Eastern shore of the
       Medanus Isthmus

7.   Falcon Province on the
       Paraguana Peninsula

8.   Mi tare Delta

9.   Southern side of the
       Guajira Peninsula

10.  Western coast of the
       Gulf of Venezuela

11.  Swampy southern shore of
       the landlocked embayment
       of Lake Maracaibo
Progradational long-term trend

Encroaching of swampy shores at the north

Sea gaining


Beach erosion

Extensive beach erosion

Active cliffing


Active cliffing

General recession os sandy coastline

                                CARIBBEAN  SEA

Central and South America

northeastern coasts of the Island of Margarita are zones of above-average sardine
fishing (Sardinella anchovia).  The northwestern coastal  portion,  including  the
Maracaibo estuarine system and the Gulf of Venezuela, has been the source of  the
large increase in the total  Venezuelan production of shrimp.  Additionally,  the
central  and  eastern  areas  of  the  Venezuelan  coast  present a  set  of  marine
physical  conditions  favorable  to  surface  catches  of Atlantic  skipjack  and
yellowfin tuna.  This has been extremely beneficial  to the local  economy during
the last five years.

Marine Ecosystems

     Some of the most  productive  and  biologically complex marine  ecosystems in
the world, such as coral  reefs,  seagrass beds, and mangrove forests, are present
along the Venezuelan  coastal  zone (see Figure 2).

     Coral reefs, consisting of the consolidated skeletons of corals,  accumulate
rapidly in geological  time  and  constitute the basis of many  coastal  fisheries.
They provide food,  shelter,  and nursery areas for commercially valuable fishes
and crustacean species.  In addition,  the reef forms breakwaters,  which protect
harbors and bays, and  limit  coastal erosion.

     Mangrove  forests,  a coastal  feature of tropical regions, develop  in low-
lying coastal areas where freshwater is supplied  by rivers or terrestrial runoff.
The  forests  provide,  through  their  prop  roots,  a  surface to  which  marine
organisms can  become  attached.  This,  in turn,  reduces tidal and  wave  energy.
                                CARIBBEAN  SEA
65    66"
       1C.     II     I W    U5    VJO    VI     OU    UO    UT     63     62     61

Figure 2.   Spatial distribution of mangrove  forests  ()  and seagrass beds
along Venezuelan marine boundaries.


                                                       Aparicio-Castro, et al.

     Seagrass beds, which  cover  the  bottoms  of coastal  bays, provide sediment
retention and stabilization processes that are very important  for adjacent coral
reefs.  The beds prevent the abrasion and burial of the reefs during conditions
involving high wave energy. Additionally, seagrasses serve as nurseries for the
juvenile populations  of commercially important species,  including  fishes and
invertebrates (lobsters, conches, bivalves, etc.).


     Evidence  of long-term  climate  variations  along the  coastal  margin  of
Venezuela  in  recent decades has been reported by Aparicio  (1988).   The main
qualitative findings of that study, based on data records no older than 35 years,
are summarized in Table 2.

     The pattern of variability in  relative mean sea level along the Venezuelan
marine boundary,  extracted  from tidal-gauge  stations, shows strong local tectonic
signals at the easternmost  zone (see Table 3).   In fact, signals given by sensors
located on  Puerto  Hierro and Carupano reflect a  clearly tectonically induced
uplift of this local land mass, which can be explained  in  terms of the proximity
of  this  zone to  the boundary  between  the Caribbean  and the South  American
tectonic plates.  The global  signals  of  sea level  rise seem to be present along
the central  part of  the Venezuelan  coastal  margin,  such as is  evidenced  by
examination of the records  at Cumana and La Guaira. Another strong local signal
can be seen by examining sea level  data from the Maracaibo tidal-gauge station.
A clearly anthropogenically induced local subsidence characterizes that signal,
due to petroleum/groundwater extraction activities in the area during the last
50 years.


     The most obvious negative effect is submersion due to mean  sea level rise
and loss of low-lying lands.  The areas that seem to be particularly vulnerable

Table 2.  Long-Term Temporal Variability of Climatological and Surface
          Oceanographical Conditions Along the Marine Margin of  Venezuela*

Parameters                                Long-term linear trend

Air Temperature                           Increase
Evaporation                               Increase
Precipitation                             No significant change
Zonal  Wind Stress                         Decrease
Sea Surface Salinity                      Increase

"Based  on data collected on land  site coastal weather  stations.


Central and South America
Table 3.  Relative nean Sea Level Variability Along the Venezuelan Coast Long-
          Term Linear Trend
Station                                   Record
 Code    Location     Lat.      Long.     length





Puerto Hierro  1037'N  6205'W

Carupano       1040'N  6315'W

La Guaira

Amu ay

1028'N  6412'W

1028'N  6656'W

1145'N  7013'W

1041'N  7135'W















                              CARIBBEAN   SEA
are the most external  portion of the Orinoco Delta, the easternmost area of the
Peninsula of Paria,  and the region enclosing the small  Unare Delta and the Unare
and Piritu lagoons,  which constitutes, perhaps, the Venezuelan coastal area that
may have received the most negative influences from human activities in recent
years.  Specifically,  this region is experiencing (1) erosion, mainly induced by
deforestation and industrial  and urban development, and (2) salinization of the
Piritu Lagoon, which  is due,  in  part, to  restriction  of  the  freshwater supply
(gradual damming of the  Unare River)  and to  uncontrolled use  of  chemicals in
certain agricultural processes.

                                                       Aparicio-Castro,  et al.

     Saline intrusion in local  groundwater resources is another negative effect
produced by  sea level  rise  that  will  affect  the  Venezuelan coastal area  --
specifically,  those  coastal  aquifers  located  in  the  Peninsula of  Paraguana
region, which, in turn, have been under indiscriminate exploitation during the
last 25 years.  Surely,  a sea level rise will worsen the actual water quality of
these  aquifers,  with  negative consequences  to  local  agricultural  resources
(Alvarado,  personal communication, 1989).

     Coastal  erosion  of beaches will  have a tremendous  impact on national efforts
to develop  the tourism industry.   The most vulnerable areas seem to be Tucacas,
on the Falcon Province; beaches on the Mochima  National  Park, which is located
in the country's eastern coastal  region; and Margarita  Island,  which has  very
high economic activity along its margin.

     A particular case to be considered concerns  the  geopolitical  implications
for Venezuela derived from the  reduction in  area affecting Aves Island, which is
the only outcrop of the Aves  Ridge above sea level  into the Venezuelan Basin of
the Caribbean Sea.  This island  constitutes a large portion (about 135,000 square
kilometers) of  Venezuelan  marine  territory (see Figure  3).   A comparison  of
geological  surveys of Aves Island, which  is only  3.7  meters  above  sea level  at
its highest point, reveals that  the island has been progressively reduced in size
during the  last 30 years.  Probably the factors responsible  for  this  reduction
are mainly  local erosional  processes and  the  subsidence rate  of  the Aves Ridge
(Schubert and Laredo,  1984).  Sea level  rise in the Caribbean Sea, which has been
actually estimated to average approximately 4 mm/year (Maul  and  Hanson,  1988),
could  exacerbate  the  present-day  erosional  instability of  Aves   Island  with
unpredictable consequences for  Venezuela  from  a legal  point  of view.

Figure 3.  Aves Island generates approximately 135,000 Km2  of marine  territory
for Venezuela.

Central and South America

     Displacement  of  traditional  fishing,  sites,  even  on  a  relatively  small
spatial  scale,  could  emerge  as  a  consequence  of the  alteration  of  the
thermohaline structure of the coastal marine surface layer along the Venezuelan
shoreline.  This could harm local artisanal  fisheries,  with a negative effect on
domestic economies, especially those located  along the  eastern  section of the

     Sea surface  temperature (SST)  in  the Atlantic  Ocean/Caribbean  Basin is
supposed to increase in response to global  warming of the lower atmosphere.  As
a result,  this part  of  the  world would present,  in the near  future,  better
thermal conditions for the genesis of hurricanes and tropical storms.  A recent
work (Emanuel, 1987) reports  that  an increase  in SST of 1.5C would enhance the
potential maximum hurricane wind  by about  8%.   It  also  has  been reported that
more frequent  intensification of  tropical  systems  to  tropical  storms  could be
expected (Shapiro,  1988).   As has  been mentioned previously,  the Venezuelan
marine margin  has been  out  of  the  standard  track of hurricanes  during this
century. However, two recent facts related to cyclonic activity in the Caribbean
region deserve special consideration:   (1)  the strongest recorded hurricane of
this century,  Hurricane Gilbert,  beat  the Caribbean Sea in  1988, and  (2)  a
hurricane (Hurricane Joan) hit the Venezuelan  coastal territory for the first
time during this  century in 1989 (see  Figure  4).   Changes induced  by global
climate variations  in  the  location  of the geographical  area  favorable  to the
genesis of hurricanes  and tropical storms  on  the  tropical Atlantic Ocean are,
then, of crucial importance for Venezuela.


     Despite the efforts of the local scientific  community, the need  to adopt
strategies to  manage  the impact  of global  climate changes on  the Venezuelan
coastal geography has not yet been clearly understood by national  authorities.
This  seems to  be  a  logical   consequence of the  considerable  uncertainty
characterizing technical reports regarding the magnitude of  future alterations
of global  lower  atmospheric  and  surface marine conditions  typifying  regional

     Actually, Venezuelan scientists involved  in this problem face the task of
motivating official decision-making  agencies.   In this sense, the international
pressure placed on the Venezuelan government, which has been recently invited to
subscribe to global  agreements related to the matter (The Montreal Protocol, The
Hague Declaration), has been considerably beneficial.

     Arrangements are being made to form a  local technical committee that would
have as  its  primary  task the  preparation of a government  response to  the
implications of global  climate changes on Venezuela's  geography.  In this sense,
local  official  agencies  dealing  with  environmental policy,   and  Venezuelan
scientists related to the earth  sciences, are being encouraged to  initiate  a work
platform on the basis of collective  action and shared efforts.

                                                       Aparicio-Castro,  et  a7.
Figure  4.   Track  of the  most destructive  hurricanes affecting  the greater
Caribbean Sea region during 1988 and 1989.

     This committee will be sponsored  by  the  Ministerio del  Ambiente y de los
Recursos Naturales Renovable (MARNR), which is the national agency responsible
for environmental  policy in Venezuela.  The following specific objectives are to
be addressed by that committee in the immediate future:

        Coordinate national activities related to  research  and monitoring of
         meteorological  and oceanographic  surface conditions among all  regional
         institutions charged  with  the  responsibility  of  studying  climate
         variability and its local  impact.

        Expand the  actual tidal-gauge  network  operating  on  the  Venezuelan
         coastal boundary,  taking advantage of our participation in the Global
         Observer System (GLOSS).

        Evaluate  the  feasibility  of   establishing   onshore  and  offshore
         structures on critical coastal areas facing high risks  due to sea level

Central and South America

        Coordinate a long-term policy for reducing  and  reversing the ongoing
         deforestation of Venezuelan territory.

        Establish public education plans to promote better understanding of the
         topic of climate change and to assess its potential impacts on society.

        Motivate regional scientific  centers related to environmental research
         to establish  studies that will  address  and  identify the  degree  of
         vulnerability   of   particular   geographical   areas   to   specific
         climatological  anomalies.

        Stimulate research on alternate, nonconventional  energy sources as part
         of a  long-term  policy devoted to reducing  the  use of fossil  fuels,
         combined with more efficient  use of energy, over the next few decades.

        Organize the Venezuelan contributions to global research programs about
         climatic  changes and  their  implications,  such as  the World  Ocean
         Circulation Experiment, Tropical  Ocean  Global  Atmosphere Programs and
         the International Geosphere/Biosphere Program.


     In view of the clear evidence that climatological anomalies on the coastal
area of Venezuela have the potential to induce serious  social,  economical, and
ecological implications,  the Venezuelan government should  consider this topic to
be a matter  of urgency.    The need  to compile inventories of  natural  coastal
resources and existing environmental information  must  receive first priority, so
that a worst-case climatological scenario can be developed for the country.  This
could provide an impact analysis that  would facilitate the early implementation
of an effective national  policy.


     Without  the  cooperation of the  following   members  of   the  Venezuelan
scientific community, it would not have been possible to  produce this report.

     Beatriz Vera (Universidad Central  de Venezuela), Carlos Carmona (Universidad
Nacional  Experimental  Francisco de Miranda), Jorge  Alvarado  (Ministerio del
Ambiente  y de  los  Recursos  Naturales  Renovables), Teniente Mario  Capaldo
(Direccion de Hidrografia y Navegacion),  and Jose  Luis  Naveira  (FUNDAOCEANO).

     Also  highly  appreciated  are  data records provided  by the Venezuelan Air
Forces, Venezuelan Navy,  and MARNR.

                                                       Aparido -Castro, et a7.


Aparicio, R.  1988.   Some meteorological and oceanographic conditions along the
southern coastal boundary of the Caribbean  Sea  (1951-1986).  In:  UNEP(OCA)/CAR
WG.l Report Implications  of  Climate  Changes  in the Wider Caribbean Region (in

Bird, E.C.  1985.  Coastline Changes.  A Global Review.  New York:  John Wiley
& Sons.

Emanuel, K.A.   1987.   The dependence  of hurricane intensity on climate.  Nature

Maul, G.A.,  and  K. Hanson.  1988. Sea level  variability in the intraamerican sea
with concentration on Key West as a regional  example.  In:   UNEP(OCA)/CAR WG.l
Report Implications of Climate Changes in the  Wider  Caribbean Region (in press).

Schubert, C., and  M. Laredo.   1984.   Geology  of Aves  Island  (Venezuela)  and
subsidence of Aves Ridge, Caribbean Sea.    Marine Geology 59:305-18.

Shapiro, L.J.  1988.  Impact of climate change on hurricanes.  In:  UNEP(OCA)/CAR
WG.l Report Implications  of  Climate  Changes  in the  Wider Caribbean Region  (in


                            BELISARIO ANDRADE
                             CONSUELO CASTRO
                         Institute  de Geografia
                    Pontificia  Universidad Catolica
                             Santiago,  Chile

     The latitudinal extent of Chile's  Pacific coastline offers a wide  variety
of geomorphological and oceanographic situations.  The coast extends from 18 to
56 south, roughly equivalent to the latitudinal  difference  between Mexico's
border with Guatemala and the Alaskan/Canadian border.  If the indentation of the
coast is taken  into consideration,  as well as the perimeter of numerous  islands
situated in  the fiords region, the length of Chile's coastline is greater  than
25,000 km.  Figure  1 shows the variation  of  Chile's coast.


Natural Features

Coastal Climatology

     The Chilean coast is under the influence of  tropical,  subtropical, and
temperate climates  of western continental  margins.  The ocean  has an  important
moderating influence upon the temperatures.  As Fuenzalida (1971) points out, the
temperatures  between 20 S and 30  S are  2.8C colder than the latitudes would
suggest; between 50  S and 60 S  they are  4.6C warmer.   Therefore,  despite
having a difference of almost 37 degrees of latitude, the difference of the  mean
temperature  is  only  12.8C.   By contrast, there  is  a marked difference in the
total  amount of precipitation.  In Arica at 1828' S, the total  amount is 1.1 mm;
on the other hand, in San  Pedro at  4743'  S,  the total annual amount is  4,076.1
mm (Figure 2).

Tides and Waves

     Tides in Chile  are generally mixed-semidiurnal;  that is, two high waters and
two low waters  during a tidal day,  with a diurnal difference.

Central and South America
Figure 1A-B.   Chile's  25,000-km coast varies considerably.
48'S) -- artificial foredune; and (B) Longotoma (32 22'S) -

  (A)  Ritoque (32
- sandy coastline.

                                                              Andrade and Castro
Figure  1C-D.    (C)  Papudo  (32  30'S)  -  storm  surge effect.   Beach  is now
replenished with dune sediments.  (D) Punta Con Con (32  55'S) -- Rocky coast,
high terraces, with old stabilized dunes.   By human interference,  these dunes
nave oeen reactivated.


                    Ut. 18 SB'S Long. 70 20' W
                         altitude  6 mta.
                   LA  SERENA
              Ut 29 64'S Long. 71 16'W
                   altitude 32 mta.
fc*.ICI r^dp. (*!.
< ^ ^-\
                                                       .Itov. 1C!
                           Pnoo. Imml.

                  TEMP.  ^ PRECP
              Lat. 33 OVS  Long. 71 38'W
                    altitude 41 mta.
                                                                                           	TEMP.  E2PBECI>
      Ut. 36 20'S Long. 72 26*W
           altltud* 2 mta.
Ut. 39 48'S  Long. 73 14'W
     aJtituda 6 mta.
UL 45 24'S Long. 72 42*W
     ahltud* 10 mta.
                CABO SAN ISIDRO
              Lat. 53 47-S  Long. 70 68'W
                   altitude 20 mta.

                                                                                         Prvoix I
                                                                               - TEMP.
   Figure 2.   Chilean coastal  climatic  types.   Note  the  great  pluviometric  contrast  and  thermic  homogeneity.

                                                            Andrade and Castro

     The  tidal  ranges  vary.    Between 18  and 41  S latitude,  the maximum
amplitude  is between  1.5 and  1.9 m, respectively.  Within the fiords  region to
the south, especially between the Gulfs of Ancud and Corcovado, tides are 5 to
8 m because of a resonance effect.  South of this sector, down to  Punta Arenas
at 52 S, the amplitudes vary between 1.8 and 2.5 m.  There  is a great contrast
between  the  west and east  entrances of the  Straight  of Magellan.   At Punta
Dungeness, the  easternmost point,  the amplitude reaches  10 m, while  at the
western entrance of the straight the amplitude  is only about 2 meters.  At the
Tierra del Fuego islands to Cape Horn, the range is between 1.5 and 3 meters.

     The information  about waves on  the  coast,  especially that collected with
instruments,  is  scarce.   Data exist  primarily for the  central   area  of the
country, where there seems  to  be good correlation between wind patterns and wave
patterns (see Appendix 1:  Waves of Chile).


     Storm surges occur occasionally on the Chilean coast; these are caused by
large  and  intense  atmospheric  perturbances  in the  South  Pacific,  known  as
"Bravezas" in Chile.    According to  Paskoff (1970), they  progress  along the
coastline from south to north in the form of  great waves, many meters  above the
usual  height  reached  by  the  storm waves,  and linger  24  to  48  hours1  (see
Appendix 1).


     Since 1652,  over 30  tsunamis  have  been  recorded  on  the  Chilean  coast
(I.H.A.,  1982).    With  an  expected  1-m  rise,  surges  will   increase  their
penetration inland.  Generated by earthquakes and submarine movement, these have
devastating effects.   As an example,  on  13 August 1868, the tsunami that affected
the Port of Arica dragged  the North  American  ship Wateree  for more  than 2 miles
from its anchoring ground and  finally deposited it 400 m inland over the coastal
     'This  author's description of the morphologic effects and the wave levels
reached during an event that occurred in 1968, which affected a coastal sector
of  approximately  2,500 km  between Arica  and  Talcahuano, coincides  with one
presented by Araya-Vergara (1979).   In 1968, a number of roads  located more than
5 m above  sea  level  were  destroyed by  waves,  as  were hotels,  houses,  and
restaurants, which had  foundations 5-7 m above sea level.  In general, all points
near the coastline situated at the holocene  level "La Vega" (1-2 m) were affected
by  the  "Bravezas,"  and  various points situated  above  the  Pleistocene level
"Cachagua"  (5-7 m) were also affected  (for example,  the airstrip of the naval
aviation base at Quintero).  The foredunes of various beaches of central Chile
were eroded.   The  effects produced  by these  spasmodic phenomena,  not  very
frequent, are long lasting and much more notorious than the effects of continuous
wave action related to the usual storms occurring over several years.


Central and South America

Coastal Geomorpholoqy

     The Chilean coast  between 18 S and 41  S  is dominated by marine processes,
acting under hyperarid, semiarid, Mediterranean, and oceanic temperate climates,
with rocky coasts and pocket beaches dominating.   To  the south of this sector,
oceanic temperate climate dominates, with domination  by marine processes along
the open coast to the west and fluvial  domination in  the inland fiords (Figure
3) (Appendix 2 provides more detail).


     A particular characteristic  of  the Chilean coastline is its great vertical
mobility, the result of  its location in  a plate  convergence  zone.   Because of
this,  strong  movements of  uplifting and sinking occur with  magnitudes  that
surpass those expected from a sea level rise induced  by the greenhouse effect.
For  more  than  a  century, the  data of  various  authors have shown  that  the
magnitude of the vertical  movements  can frequently exceed 150 cm (Meneses Toro,
1897; Vidal  Gormaz, 1901; Saint Amand, 1963; Pflaker and Savage,  1970; Fuenzalida
and Harambour, 1984;  Gonzalez, 1985).

     It cannot be clearly distinguished whether the tendency is toward downfall
or uplifting, because in  some  latitudes the coast has moved in both directions.
However, there seems  to be a slight predominance of uplifting  north of  39 S and
sinking south of this latitude.

     The most recent  movements have  been determined by  I.G.M.  (1985), who found
a  mean  uplift  of  33  cm  in  the  coastal   sector  of San  Antonio-Algarrobo
(3320'-3330' S) due  to  the  earthquake  of  March 3,   1985.   Barrientos  et al.
(1981), using the tide  gauge of  Puerto Montt (41 S),  indicated an uplifting of
the region of about 4.7 cm/year between  1964 and 1973, diminishing to 2.4 cm/year
between 1980 and 1985; this same  site sank 200 cm during the May  1960 earthquake.

Cities and Population

     The population of Chile is approximately 12.5 million, 80% of which is urban
and mainly concentrated in Santiago.   The urban coastal  population represents 21%
of the total population,  and a large part of it resides in urban  areas of more
than 100,000 inhabitants.  The  regions of Valparaiso and Bio-Bio  together contain
55.35% of the total  urban coastal population of the  country.

     The main coastal cities are  located on coastal stepped plains separated by
dead coastal cliffs.  At  first,  the  cities were located over the low (between 5
and  20  m)  and narrow  marine  terraces  but later  they grew toward  the  higher
terraces (Figure 4).

     The main tourist centers  are the sandy  coasts of Coquimbo Bay (29  S) and
the central  coast (3330' S).  The  bathing  resorts extend  over coastal  dunes,
including the foredune.  Protection structures for wave action are infrequent,
except in places where adequate  structures for ports  have been built, e.g.,


                                                                               Andrade  and Castro
                      '', ', .] Older resistant
                         '-.''I Low resistant
                        '  *
                      .-'i*-I 13/ociol ond glacial fluvial
                      .^ * | High relief - cliffed
                      t^jL_A. I Low relief - cliffed
Figure 3.    Coastal  landform  types.

Central and South America
        WUIOUE(200 12' SJ   I
ANTOFAGftSTA ( 23 39' SJ
                                                               LA SERENA (29 54' SJ
        VflLPARAISO  (3302'SJ
                                                            PUNTA ARENAS (SIO'SJ
Figure 4.  Some Chilean cities  located  over marine terraces.


                                                            Andrade and Castro

docks, marinas.  With a sea level rise of about 1-2 m, these bathing  resorts will
be only somewhat affected.

Economic Aspects

     The National  Accounts give  an  idea of  the relative  importance  of some
economic activities  held in the coastal  zone.   The Gross Domestic Product was
$18.5  billion  (U.S.  dollars).  Tourism (primarily  coastal, but incorporating
activity from  all  over  the  country) accounted  for 0.94%  of  this total,  and
fishing accounted for 0.88%.


     The existing coastal national maps of  Chile do not permit a quantitative
evaluation of the area affected by a  sea level rise of 20 and 200 cm, given that
maps have contour intervals of 25 m  or  greater.

The Rocky Coastline

     Considering the  steepness  of the rocky coast  along  its  30,000  km,  a sea
level rise of 20 cm  will not  have any noticeable effect.   A 50- to 100-cm sea
level rise would probably affect scarce  coastal tourist  installations, but only
during storms.

     A rise of 200 cm would  produce effects on harbor structures, requiring their
redevelopment, as happened  in  the  tectonic sinking of 1960.  A  sea level rise of
100 to 200 cm would accelerate the recess of cliffs in  soft rocks (sandstone) of
the  central  zone of Chile affecting  populated  centers,  essentially  tourist

     South of 41 S, the attacking of  the cliffs created in  soft glacial outwash,
will  affect  a great number  of  populated  centers of the eastern coast of Chiloe.
Coastal protection works would  be necessary in this sector.  We estimate that
over 60 km of seawall will  be necessary to shelter the threatened areas.

The Sandy Coastline

     Although they constitute  only 2.1% of the  total coast,  sandy shorelines
support  important  economic  activities  (tourist and  industrial   as  well  as
residential). All the pocket  beaches are located  in  front  of cliffy landscapes,
so they cannot migrate inland in the eventual case of a sea level  rise.

     A sea  level  rise of 50 cm or more will  substantially diminish the area of
pocket beaches.   A rise of 2 meters would eliminate them completely.

     The sandy shorelines associated with dune fields have  an important sediment
supply from the rivers and enough space to  shift inland.   In  this  case,  a sea
level rise of 50  cm or more will affect  the  foredune, making it retreat inland.
Important industrial  facilities would  be  affected,  particularly  those at Quintero


Central and South America

Bay (3246' S),  San Antonio  (3333' S), Constitucion (3518' S), and Talcahuano
(3642' S).  Approximately two-thirds of all the coastal bathing resorts would
be partially inundated.


Institutions and Agencies Associated With the Coastal  Zone

     The national  administrative organizations related to the coastal zone are
within three independent ministries:

     1.  Ministry of National  Defense,  Marine Subsecretary,  which consists of

         a.  General Office of the Marine Territory and Merchant Marine.  This
             organization has the control and  monetary responsibility for the
             entire coast, territorial  sea,  and exclusive economic zone of the
             Republic.   Its inland jurisdiction  extends 80  m inland, starting
             at the limit of the spring high  tide line.   The essential mechanism
             for control  of the  coastal  area lies with  the members  of this
             office, who permit  the particular use in any form of beaches, beach
             lots,  the sea floor, portions of water, and rocks within and/or out
             of the bays.   The  agency  also  has  responsibility  for issuing
             permits  for extraction  of  sediments  and  landfill   for  coastal

         b.  Navy Hydrographical  Institute.   This  agency is in  charge of all
             studies and preparation  of documents for navigational  aid, such as
             tide tables, marine navigational charts,  and navigational tracks.
             It is  also in charge  of meteorological forecasting and doing basic
             research  in  oceanic  and  coastal physical oceanography.   It is a
             member of the International  Tsumani Alarm System of the Pacific.

     2.  Ministry of  Public  Works,  Harbor  Works Office.   This agency  is  in
         charge of  the  design,  calculation, and studies of  harbor works, and
         conducts research in  coastal  oceanography.

     3.  Ministry of Economy, National Fishery Service.  Administers the fishery
         sector, promotes and coordinates investigation  in  this  domain.   This
         office is   in charge of the methods and installations  of aquaculture,
         fishing quotas, and extraction of live products from the littoral zone.

     The previously named institutions, together  with other institutions  from a
group of Chilean universities, form the CONA or "Comite Oceanografico Nacional"
(National Oceanographic Committee).

     The CONA has prepared a National  Oceanographic  Plan for the period 1987-97,
which is based on a four-year survey of national institutions concerned with

                                                            Andrade and Castro

oceanic scientific technological work.  Five research programs are proposed to
investigate the structure  and  interrelationships  of ecosystems within Chilean

Agency Perceptions About Greenhouse-Induced Sea Level Rise

     Conversations held with members  of some  of  the relevant agencies suggest
that a sea level  rise of 20-50  cm is not perceived as a problem.  Because there
is a lack of awareness concerning a greenhouse effect-induced sea level rise, no
one  is  planning  a response  to it.   Local  planners are more  concerned about
solving  current  problems; nevertheless,  they indicate  that when  it becomes
necessary to protect small fishery facilities or installations in contact with
the beach, they will support solutions based on seawall  tetrapods.

     Also, due to  the effects of strong winter storms, some tourist beaches have
been nourished with  sand.   The filling is done with sediments extracted from
inland deposits.   In some cases, the foredune has been elevated using mechanical
and vegetational  methods.  This is done because of dune management and not as a
response to a marine erosion.

     Frequently, local planners have been forced to respond to tectonic  sea level
rising, but this is not predictable and for this reason  they do not consider a
slow sea level rise of 20 to 50 cm over many years to be an emergency.

     Chilean government agencies  will  be  able,  from a  technological  point of
view,  to apply  protective  actions   in  critical  areas  when  the problem  is
adequately evaluated.

Central and South America

                          APPENDIX  1:  WAVES OF CHILE
     The  reports  that  give  the  most  adequate  synthetic view  are  those  of
Araya-Vergara (1971, 1979); both are on central  Chile.  The information provided
by Davies  (1980)  based  on the works of Holcombe  (1958)  and  Meisburger (1962)
gives a very useful integrated view.

     Holcombe (1958) concluded that in the Southern Hemisphere,  the mean latitude
of the zone of maximum value of gale force winds oscillates only between 54 S
and 56  S during the winter-summer period.   Because of this persistence of high-
frequency gale-force winds and the length  of the fetch, the southern storm belt
is the most evident and  important wave-generating area  in  the world and produces
a high proportion of the world's ocean swell  (Davies,  1980).

     The path followed by the  swell  generated at latitude 55 S in front of the
Chilean  coast produces wave trains with a  west and southwest component from 41
S toward the north.  This pattern of waves  makes  the coast of Patagonia the most
attacked by storm waves during the year.

     With  the  data compiled  by  Meisburger  (1962),  Davies  presents  various
synthesis  charts  in  which it is  possible to  appreciate that for  the Chilean
coasts the frequency of occurrence, in at  least half the year, of waves of 2! m
or higher  is as follows:

                      South Latitude                %

                      38  - 56	   > 40
                      38  - 30	30 - 40
                      30  - 25	20 - 30
                      25  - 18	10 - 20

     The greatest  height  reached  by waves occurring with a frequency of 3% or
greater in at least half the year is as follows:

                      South Latitude    Height  (m)

                      56  - 45	    >  6.0
                      45  - 40	.6.0 -  5.0
                      40  - 22	5.0 -  3.7
                      22  - 18	3.7 -  2.2

     In   a  more  detailed   scale,   Araya-Vergara   (1971)  shows   the  wave
characteristics in Chile, according to  the  works of D.O.P.-Tudor Eng. Co. (1965),
as well   as the unedited  reports  of the   Laboratoire Central  d'Hydraulique  de
France,  for Constitucion (3518'  S)  and San Antonio (3335' S).  The results of
his analysis indicate that the  origin of  the most frequent waves  is from the
southwest, which coincides with the prevailing  winds.

                                                            Andrade and Castro

     In Arica in December 1975 and July 1977, with a total of over 3,396 waves
recorded, the mean  period  during the summer  had  a value of 12  seconds  and a
significant height of 1.15 m; during winter the mean period was 9 seconds and the
significant height was 1.3 m.

     In  Iquique  there are only data  for  the month of June  1987.  Using  1,336
waves,  the mean period was 11.02 seconds with a significance height of 1.08 m.

     The wave data  are scarce  and  discontinuous.   They refer only to a sector
of the coast dominated by the southern west coast swell environment.

     There are no automatic wave records situated along the coast dominated by
the southern storm wave environment, especially south of 41 S.

     Important differences between  the  coast  facing  directly the open Pacific
and those of the interior waters of the fiord coast probably exist.

Central and South America

                      APPENDIX  2:   GEONORPHOLOGY OF CHILE

Distribution of Cliffed Coasts

     According  to  Araya-Vergara (1982), the  length  of the cliffed  and rocky
coastline is 33,711 km;  700 km of the northern region  of Chile correspond to the
mega-cliff described  by Paskoff (1978),  along which  can  be distinguished four
sections.  The first section,  between  1828'  S and 2013' S, is an active cliff
with unevenness between 400 and 1,000 m; a second  section between 2013' S and
2124' S  is  a dead cliff behind  a terrace 2 to 3  km wide;   a  third section
between 2124' S and 2328' S,  with unevenness between  500 and 1,200 m, is also
a dead  cliff with  a  terrace  in front,  composed  of marine Miocene  deposits,
sculpted by the sea; the fourth section, which reaches 2522' S, presents active
and dead sectors, with mean heights of 500 m,  but in some places it can reach an
altitude of 2,000 m.  This is a major feature of the north coast of Chile.  In
general,  in  this  sector  hard  rocks  appear  on  the  surface,  giving  a  stable

     South  of 25  to 3344'S there  are predominantly  cliffs and  bluffs  in
essentially igneous formations.  Another section also with predominance of cliffs
but in tertiary soft sedimentary rocks as well,  is  developed to 3630'S.  From
this sector to 4330'S are hard cliffs sculpted in micha-schists alternating with
soft tertiary sandstone.  It  is  also possible to distinguish an internal  sector
between 41 S and 43 S with soft cliffs sculpted essentially in glacial outwash,
but in sheltered environments.  From 43 S to  56 S, hard rock cliffs and bluffs
dominate with some morainic intercalations.

Distribution of Low Unconsolidated Coasts

     The  lower coasts,  including  the deltas, constitute  2.1% of the  total;
according to Araya-Vergara (1982) they add up  to  580 km.  They are discontinuous
and concentrated in groups related with the existence of  fluvial  sedimentary
sources and with a minor association, to soft sedimentary rocks at the shoreline.
The main groups of beaches which can be distinguished are the  following:

                   29 S  - 30 S	Coquimbo  - La Serena
                   32 S  - 33 S	Longotoma - Concon
                   33 S  - 37 S	Chile Central
                   38 S  - 43 S	Arauco - Chiloe

     In  general  they are  in  dynamic equilibrium,  with  not much  evidence  of
retreat or advance  in the long range.  However, Andrade (1985) has found evidence
of recession in the Chiloe coast,  in the internal  sector.   It  may be  explained
by a relative sea level rise due to recent subsidence movements and applications
of the Bruun rule.

     Most  of the constructed coasts  correspond to  beach  ridges,  composed  of
sand.  In the interior coast of Chile  spits and hooks are very frequent,  formed
by sand  and  gravel  that the  sea extracts from the cliffs  sculpted in glacial


                                                            Andrade and Castro

outwash.  At Tierra del Fuego it is common to find  beaches  supplied by morainic

     A great number of beaches  along Chile correspond to pocket beaches, which
are located over rocky platforms between resistant rocky promontories.  Although
data are scarce, our observations from fieldwork in central Chile  indicate that
they have a general thickness less than 4 m  at  the  backshore.

     A frequent phenomenon in central Chile is the development of coastal dunes,
associated with beaches which are generally  located north of the  river inlets.
This ensures a good sedimentary supply because of the longshore drift generated
by waves mainly from the southwest, which coincides with the prevailing winds and
which also transports  the sand  inland.

     The  principal  coastal  dunes are  located between  29  S and  42  S.   They
cover  approximately  131,000 hectares,  according   to  the  inventory  made  by
IREN-CORFO (1966). Most of the modern active dunes are located between 33 S and
38 S according to Castro (1985).

     Castro  (1985) provided  a synthesis of the different morphologic elements
found in the coastal dunes, distinguishing:

     a)  The foredune.

     Located in contact with  the backshore forming a parallel  band  to the beach,
its width is variable between 50 to 200 m;  the average height  is 5 m.  There is
a close  association between the morphologic aspect of the dune  and the vegetation
found on  it.   Thus in  central  Chile,  the foredune is composed of  a  group of
hummocky dunes, elongated in the direction of the wind, with a pointed tail to
leeward. They  are separated  by  deflation  corridors.  There are obstacle dunes
produced by the capture of sand by  vegetation . The most  frequent  species is
Ambrosia chamissonis,  which possesses a radicular system which develops to great
depth;  it is an accidentally  introduced  species  from California (Kohler,  1970),
which apparently is substituting for the native species Carpobrotus  chilensis,
which helps form lower dune hummocks.

     The Chilean foredune does  not  have the  aspect of a continuous  wall  as in
North America or the northwest coast of Europe, colonized by Ammophila arenaria,
but has   aspects of a  nebkha  field.  In  some  places  where dune control  has been
applied  with Ammophila arenaria,  the  foredune gives a massive appearance as in
the case of Chanco (35 S).

     b)   Interdune depression.

     A depression  separates  the foredune  from  the moving sand ridges  of  the
interior.  It  has a  variable width;  its major  axis  is  parallel to  the  beach,
frequently comprising  an active deflation area and sand transportation area.  But
on occasions,  it may be occupied by a coastal  lagoon or a marsh.  In this  sector
the water table is very close to the surface, so it has vegetation adapted  to


Central and South America

these conditions such as Scirpus nodosus.  The depression may also develop by the
deflation of old coastal ridges.

     c)  Moving sand ridges.

     These occupy the greatest area within  the dune field.  They have a variety
of forms, in which we can distinguish some individuals, such as barkhans.   The
coalescence of barkhans leads to transverse dunes which are organized as waves
moving to the interior  many  hundreds  of meters, invading agricultural lands and
villages.  They do not have vegetation cover.

     d) Stabilized dunes.

     Frequently in contact  with  active dune fields are various generations of
dunes  stabilized  by natural  vegetation.    A  variety  of this  group are  the
longitudinal dunes, which appear within this axis in  the same direction  as the
prevailing wind.  They present associations of Puva chilensis and Cereus sp.

     Other  morphological  types are  the undulated dunes.   Their  vegetational
layer is composed by low gramineous and bushes such as  Baccharis concava.

     Both of the described stabilized dune forms  are dated as Holocene (Paskoff,
1970; Caviedes,  1972).  Holocene dune reactivation can be verified in many places
starting as blowouts, evolving on occasion as parabolic dunes.  The origin of the
reactivation is normally because of human  interference.

     A third variety of stabilized dunes corresponds to  hills which are smoothly
undulating and which have not lost totally their original form due to natural and
anthropic causes.  Paskoff  (1970) assigns  them a Pleistocene age.   They  may be
covered by mesomorphic scrub bush more or  less dense.

     A sea level rise of 1 m could affect rapidly the  foredune, but the Holocene
dunes would not be affected immediately.

Distribution of Aquatic Features


     Although  there has  been no  inventory of  wetlands in  the country,  or
estimates  as  to the dimension or  nationwide  distribution  of wetlands,  a few
reports  give us  a  general  idea  of  their  morphology and  their  floristic

     Geomorphologically, Andrade (1985) described some tidal  marshes  on the Gulf
of Ancud showing morphological patterns similar to those of the temperate zone
of the Northern  Hemisphere.  In this study area they show evidence of  erosion by
the  sea due  to  a technically  induced   sea  level  rise   caused   by  crustal

                                                            Andrade and Castro

     In relation to their requirements of low wave energy and great tidal range,
they tend to develop better between 40 and 43 S in protected positions in
estuaries or behind sand barriers.  In the botanic studies done by Ramirez et al.
(1988), Schwaar (1978),  and Reiche (1934),  some of the halophytes described are
Triqlochin maritimun. Cotula coronopifolia. Eleocharis melanostachvs.  Selliera
radicans. Spartina densiflora.  and Salicornia sp.   In general, the tidal marshes
develop adjacent to a cliffed landscape in the Gulf of Ancud.  A rapid sea level
rise would probably endanger the permanency of these intertidal ecosystems, since
in many cases they do not have space to  migrate upslope because they are bounded
by bluff coasts.

Central and South America
                           AERIAL PHOTOGRAPHIC DATA
     The actually available cartographic documents  are produced and distributed
by two agencies of the Ministry  of  Defense:   the Institute Geografico Militar
(IGM) and  the Institute Hidrografico  de la Armada  (IHA).   The  first agency
produces topographic charts, and the second agency produces navigational charts.

     The  IGM  charts exist  in  various  scales  and  projections,  and  cover the
country partially according to the scale:


        Coastal Sector
        18 S
        18 S
        53 S
        55 S
        18 S

        18 S
        30 S
        31 S
        37 S
        40 S
56 S
27 S
27 S

47 S
Contour Interval

Form Curve
250 m
250 m
250 m
50 & 100 m

25 & 50 m
25 & 50 m
25 & 50 m
25 & 50 m
25 & 50 m
     The IHA navigational  charts  include only bathymetric data in meters.  They,
as well as the  IGM  charts,  cover the country partially.   Due  to  its specific
purpose, there is a greater scale variety; therefore we will only indicate the
number of charts for each scale.

No. of Charts

                  No. of Charts


                                                            Andrade and Castro

     There  are various  vertical  aerial photo  missions.    The  Photogrametric
Service of the Air Force  (SAP) is officially in charge of producing this type of
document.  However, many other missions produced by other agencies in the past
are available.


Approx. Scale
                     1730'-  3710'S
                        37-  3820'S
                        37-  4330'
                     3215 -  34
                     4330 -  51
                       33 -  41S
                       18 -  56S


      On occasion, other charts and aerial photographs, which were produced for
specific uses, can be obtained through public and private organizations.  These
documents are not standard issues; therefore,  there are no general  indices for

Central and South America


Andrade, B.  1985.  Estudio morfosedimentologico de marismas del Golfo de Ancud,
Chile.  Revista de Geografia Norte Grande 12:27-33.

Araya-Vergara, J.F.  1971.   Determinacion preliminar del las caractersticas del
oleaje  en  Chile central.    Not Mens. Museo  Nac.  Hist. Nat.  Santiago,  Chile
Araya-Vergara, J.F.  1972.  Bases geomorfologicas para una division de las costas
de Chile.  Informaciones Geograficas 22:5-36.

Araya-Vergara, J.F.  1976.  Reconocimiento de tipos e individuos geomorfologicos
regionales de la costa de Chile.  Informaciones Geograficas 26:9-30.

Araya-Vergara, J.F.  1979.  Las incidencias cataclismaticas  de  la bravezas en la
evolucion de la costa de Chile.  Informaciones Geograficas  26:19-42.

Araya-Vergara, J.F.  1982,  Analisis de la localizacion de los procesos y formas
predominantes  de  la  linea   literal  de   Chile:   Observacion  Preliminar.
Informaciones Geograficas 29:35-55.

Barrientos, S., S.N. Ward,  and E.  Lorca.  1981.  El terremoto de 1960 en el  sur
de Chile y sus deformaciones cuasi-permanentes.  Comunicaciones 39:158.

Canon, J.R.,  and E.  Morales.   1985.   Geografia del Mar  Chileno.   Colecion
Geografia de Chile.   Santiago, Chile: I.G.M. Vol.  IX.,  244  p.

Castro,  C.    1985.    Resena  del  estado  actual  de  conocimiento  de las  dunas
litorales en Chile.   Rev. de Geografia de Chile Terra Austral is 28:12-32.

Castro, C.  1988.  The Artificial Construction  of foredunes  and the interference
of dune-beach interaction.   Journal  of Coastal Research  (Special  Issue No.  3).

Caviedes, C.   1972.  Geomorfologia  del cuaternario del Valle  del Aconcagua. Chile
Central.  Cuad. Geogr. Friburg No. 11.

Davies,  J.L.   1964.   A  morphogenic  approach  to  world shorelines.  Zeit.  fur
Geomorph. 8:127-142.

Davies,  J.L.     1980.     Geographical  variation   in   coastal   development.
Geomorphology Texts No.  4.   London:  Longman. 212  p.

D.N.H.A.   1961.   El  maremoto del  22  de  Mayo  de  1960 en las  costas de Chile.
Publicacion No. 3012.  Valparaiso,  Chile: Departmento de Navegacion e Hidrografia
de la Armada.  129 p.

Fuenzalida,  R.,   and  S.  Harambour.    1984.    Evidencias de  subsidencia  y
solevatamiento en la peninsula de Brunswick, Magallanes.  Comunicaciones No.  34.
Sanitago, Chile:   Universidad De Chile, p.  117-120.


                                                            Andrade and Castro

Fuenzalida-Ponce, H.  1971.  Climatlogia de Chile.  Santiago, Chile:  Universidad
de Chile, Departmento de Geofisica y Geodesia.  Publication Interna de la Seccion
Meteorologia. 73 p.i

Gonzalez, O.M.  1985.  Mapa neotectonico preliminar de America del  Sur.  Ceresis.
Santiago, Chile: I.G.M.

Holcombe.  1958. Similarities and contrasts between the Arctic and the Antarctic
marine climates.  In  Polar Atmosphere Symposium.  Parti.  Metheorology.  London:

I.G.M.   1985.   El terremoto del 3 de Marzo de 1985 y los desplazamientos de la
corteza  terrestre.  Rev. Geog. de Chile Terra Austral is 28:7-12.

Inman,  D.L.,  and  C.E.  Nordstrom.   1971.   On the  tectonic  and  morphogenic
classification  of coasts.  Journal of Geology 79:1-21.

I.H.A.   1982.   Institute Hidrografico  de  la Armada.   Maremotos en la costa de
Chile.   Publicacion 3016.  Valparaiso, Chile:  I.H.A.  48 p.

IREN-CORFO.   1966.   Inventario de dunas en Chile (29 48' - 41 50' Lat. sur).
Publicacion No. 4.   Institute  de Investogaciones  de  Recursos Naturales CORFO.
20 p. July.

King, C.A.  1977.  Classification and morphometry of the coast between 20 S and
42 S.   Rev.  Geog. Valparaiso 8:27-57.

Kohler, A.  1970.  Geobotanische untersuchungen ankustendunen Chileswischen 27
and 42 Grad.  Sud. Breite.  Bot. Jahrb 30:50-200.

Kohler, A.  1967.  Die entwicklung der vegetation auf kustendunen mitelchiles.
Umschau  in Wissenschaft und Technik.  20/67:666-667.

Meisburger, E.P.  1962.  Frequency of occurrence of the ocean surface waves in
various  height  categories for  coastal  areas.   U.S. Army Engineer Research and
Development Laboratories.  Report 1719-RR.

Meneses,  T.J.N.   1897.  Jeografia  de Chile.    Santiago,  Chile:   Imprents  El
Comercio. 159 p.

Orson, et al.   1985.  Response of tidal salt marshes  of U.S. Atlantic and Gulf
coast to rising sea level.    Journal of Coastal  Research  l(l):19-37.

Paskoff, R.   1970.   Le Chili semi-aride.   In:   Recherches Geomorphologiques.
Bordeau, France:  Biscaye Freres.  420 p.

Paskoff, R.   1978.  Sur 1'evolution geomorphologique du grand escarpement cotier
du Desert Chilien.   Geogr.  Phys.  Quat. 32(4):351-360.

Pflaker, G.,  and J.C. Savage.  1970.  Mechanism of the  Chilean  earthquakes of May
21 and 22, 1960.  Geol. Soc.  Amer.  Bull.  81:1001-1030.


Central and South America

Ramirez, C. et al.  1988.  Estudio vegetacional  de una marisma del centro-sur de
Chile.  Medio Ambiente 9(2):21-30.

Reiche, C.   1934.   Geografia botanica  de  Chile.   Santiago, Chile:   Imprenta

Saint-Amand, P.  1963.  The Great Earthquakes of May 1960 in Chile.  Washington,
DC:  Smithsonian Institution,  pp. 337-363.

Schwaar, J.   1978.  Halophyten-gesellschaften  in Sudchile.   Verhandlungen deir
Gesellschaft fur Okologie Kiel 1:409-411.

Tudor Eng. Co.  1965.   Report for a Waterfront Facility.   Constitucion, Chile.
San Francisco, CA:   Tudor Eng. Co.  276 p.

Vidal Gormaz,  F.   1901.   Hundimientos  i solevantamientos verificados  en las
costas Chilenas.   Revista Chilena Hist. Nat. (Valparaiso) 5(10):213-224.

                           IN  LATIN  AMERICA
                             CRISTINA MASSEI
                Fundacion Ambiente y Recursos Naturales
              Moreno 2142, 1428 Buenos Aires,  Argentina

     Accelerated  sea   level  rise  will  produce  multiple   and   irreversible
transformations locally,  regionally,  and nationally  in  Latin  America.   Such
changes will  not only involve geographic and economic aspects of the countries,
but also will produce  irreparable losses to their historical  and sociocultural
inheritance,  particularly  in the affected communities.

     This paper focuses on how to study  the implications of relocation, not the
implications  themselves, with particular emphasis on "strategies for living" with
the relocation  of affected communities, which is at present a  well-known concept
in the Latin  American  social sciences field.   This  criterion  makes it possible
to  account for all the  dimensions  of social effects  --  i.e.,  demographic,
socioeconomic,  or  cultural.   It  is defined as  "the way  in which the community
is organized  and uses  its environment."  The  family group is the primary unit
of analysis;  the local  community is also considered.

     Because  most inhabitants  near the shore are subjected to  marginal economies
bordering on poverty,  such  "strategies  for  living"  may be  little  more than
strategies for  survival.


     In Latin America,  sea level  rise will have multiple and irreversible social,
economic,  and  cultural  effects  locally,  regionally,  and nationally.   These
effects will  be so extensive that even the interior provinces  will be affected,
because national transport, services, trade, and production centers are located
on the coast.  Direct damages to these centers will affect national activities
and will bring about new physical, social, economic, and cultural configurations,
significantly restructuring communities and the future historical process.

     The resettlement process  is  a social process  that  frequently is overlooked
in favor of  the costs  of  flood  damages,  coastal  defense,  and  other physical
effects of flooding.   Frequently,  poor families  settle  in coastal  areas near
cities because  urban centers supply services, consumer goods,  and transitory and


Central and South America

informal work sources.  Consequently, we must  design  a relocation policy that
takes  into  account  not only the losses of goods and dwellings,  but  also the
disruptions  in  the  formal  and  informal  links of  the local community  at all

     We have developed a  "living  strategies" concept  for the  population  in
general and  "survival  strategies"  for the most  impoverished sectors.   These
strategies  account   for  all  the  demographic,  socioeconomic,  and  cultural
dimensions that must be considered when relocating communities.   According to
Cernea (1989), in general, previous efforts to relocate communities have often
failed  because  people focused  on  physical  logistics and  underestimated the
social, cultural, political, and labor-market effects.

     This paper lays out  an analytic  structure by  which one could analyze the
social effects  of relocation  strategies.    We  warn the reader at  the outset,
however, that the paper does not specifically address the effects themselves.


     Involuntary displacements of population due to sea level rise would cause
economic and cultural shocks to many communities and destroy production goods,
valuable natural resources,  and the local environment.  Such displacements would
also create problems in areas  that receive  the transplanted population, because
if vacant land were  scarce, the  available  natural  resources would be severely
taxed  (Cernea, 1989).  Partridge (1983)  wrote "the relocation process destroys
a pre-existent  form  of life."   It  transforms "every  form of life,  in all its
different aspects,  such  as institutional  and  social  ones,  economic  systems,
guidelines to the  community organization, power structures, everyday activities,
or the cultural tradition."

     Because  having  one's  hometown  destroyed can give people  a  feeling  of
helplessness, relocation strategies should  focus on returning to the people some
control over their own lives,  similar to the control they previously had.  (It
cannot  be   exactly  like   the   original   control,  because  the  preexisting
socioeconomic organization will not exist after the  resettlement.)  In addition,
officials in Latin America must  take three  important factors into account:  (1)
the characteristics  of the people to be  relocated:   in general  these people
belong to the lowest socioeconomic  stratum, which is why the relocation problem
is inseparably linked  to  the  survival of  these sectors; (2) the sociocultural
identity crisis, which makes people question the efficiency and validity of their
traditional  strategies and survival schemes and increases their uncertainty to
such an extent that  it  immobilizes their capacity to respond;  and  (3) the impact
produced on social relations networks, on the existing  leadership structure, and
on the behavioral guidelines.


     Analyses of  resettlement  strategies  should follow three guidelines:  Do
not collect socioeconomic and cultural  data without taking into account  the model
of possible  relocation policy.   On the contrary, put  the  data  in the order of



the  model  from  the precise  moment of  their recollection,  description,  and
analysis.  Otherwise, the data  will  not  be read  in their proper context.  The
model must consider the specific characteristics  of the  flooded  area  (which are
seldom included), and its type of links with the  affected population.  Finally,
the scheme must carry out an analysis  in a more complex field than that of the
usual socioeconomic descriptions.  Actually, sudden relocation  basically affects
the population living strategies that include a number of relationships -- e.g.,
economic cooperation, neighboring links --  the modification  of which  gives rise
to the main social and economic cost that we are trying to reduce.

     Defining this theoretical scheme is necessary for creating  living  strategies
that are  equivalent to the  present ones,  so  as  to satisfy  the  needs  of the
transplanted population.  This  "equivalent reposition"  not  only refers to the
replacement of affected dwellings  and goods  but  also  to  the  possibility of
obtaining work and earnings.


     According to the previous scheme, we define as "universe under  study" the
population whose  link to the area  represents a significant  component  to its
living strategies.  That is,  not  only  are  the residents in  the area included,
but also the nonresidents who maintain ties  (of labor, patrimony,  etc.) with that
area, developing in this way some aspect of  their overall  living strategy.  Then,
the  main  question  is,  Which  are  the modalities  of  that  link between  the
population and the affected area?  These relations occur  at different dimensions
(demographic,   social, cultural,  and economic) and  result from  the  particular
historic development of the area, from its cultural reality,  from its regional
economic institutions, and from  its  physical features (COMIP, 1984).   It is also
necessary to analyze  the  compulsory vs.  uncompulsory character of  that link.
Among all  the  possible modalities, the  most essential  is that  of the compulsory
link on an economic basis.  This category includes  the economic activities that
require the concurrence of some of the features of the area,  such as obtaining
the  area's  raw  materials   (ichthyic  fauna,  soil  materials,  etc.)  and  food
(fishing), using its water for transport, using the area's coastal features or
its proximity  to urban centers  and  ports  for supplies and  services,  and using
its resorts for recreational activities and its land for  production or dwelling.
The uncompulsory  link,  which can be  easily reproduced in  another  area,  will
include agricultural activities that are not inherent to the  area,  industrial
and commercial  activities that do not require the area's raw materials, community
services (health, education, dwelling, etc.), and the familiar or  community links
(cultural, religious, political, ethnic,  etc.).


     In developing relocation strategies,  we  are  not  dealing  with good  or bad
players who follow  strategies either to win  or to lose. Rather, we are concerned
with human beings who are doing  their best  to survive  (Bartolome, 1983).   Also,
the unit of analysis is  not the  individual,  but rather the family, since people
organize themselves in families so as to  face the problem of living.


Central and South America

     First  of all,  the  survival  strategies  concept  is  used  to study  the
implications between the population factors  (fertility,  and familiar structures
and  types)  and a community's  economic structure  (productive  patterns,  labor
markets, etc.)-   Later  on,  the concept is  enlarged  to include  politics  and
organizing behavior, provided the basic needs are satisfied  not  only in the area
of economics  but  also the areas of  the  society and politics.    First,  of the
strategies the poor social  groups or  sectors  were analyzed.   Then,  with the
prompt diffusion  of the concept, the  middle  and even the most privileged layers
of society  were  investigated.   This approach  allowed  for the  literature  to
include generic definitions as well as more restricted and specific formulations.

     As an example of the first type,  it is worth mentioning the definition that
describes the survival  strategies "as  the attitudes or  arrangements  that take
place in the  family  to  face  the problem  of  existence  or living, which in many
cases does not surpass the survival level" (Rodriguez,  1981).  Consequently, any
type of family belonging to  any social group or  stratum can  be the subject of
a strategy.  Because of this definition,  the living strategies  notion has been

     In contrast,  among  other authors who use restricted  formulations are Duque-
Pastrana (1973),  who introduced this  concept to the social sciences.  They have
sustained that in order to  ensure the family  income, the  survival strategies
must delineate the economic roles  of every member of the family, even extended
family members.  From this point of view, the subjects are exclusively families
belonging to the  impoverished sector  of society, and the strategies are only of
an economic sort.  Aside  from their discrepancies,  the different  approaches have
overlapped on the following items:

     .  the unit  of analysis is the  family instead of the individual;
     .  the survival or living  strategies vary according to social strata; and
       the strategies are subjected  to the prevailing "economic structure."

     In this work we will define the  "living  strategies"  concept  as the modality
in which the unit organizes itself and makes use of its  resources to  reproduce
and/or optimize its  material  and nonmaterial conditions of existence;  "survival
strategies" has a corollary  definition,  applied to  the  poorest social strata.
This definition  is  chosen  because the problem of relocation involves all  the
social sectors of the area to be flooded  and these people are affected not only
economically but  also socially, demographically, and culturally.

     Groups who develop  the  living  strategies consist  of  individuals who are
linked to one another by  bonds that admit a common  past and that jointly project
toward the future.   The living strategy they  use assigns  the participatory roles
to each member of the group.  The strongest group is the  family,  the fundamental
unit of analysis.  We define  this group as people whose  association is based on
sharing  a  residence; being  linked  by blood  or marriage;  interacting  daily,
regularly,  and  permanently;  and  tending jointly  to  the  reproduction  and/or
optimization of their material  and nonmaterial  conditions of existence.



     Because of the complexity of the problem of relocating, it is not easy to
delimit precisely the components of the living strategies,  at least  at the level
of those categories and variables  that constitute them.  Nevertheless, advances
provided  by the  specialized  literature define  a  basic  group of  aspects  or
dimensions of them that can be arranged according to different fields in which
they appear.

     For example,  in the socioeconomic field, the relevant elements are connected
with activities that involve obtaining goods and services to fulfill the unit's
basic needs.  They include ways of being part of the productive structure, such
as in the employment arena; how the work is organized within the unit; ways and
sources for consuming goods and services; the network of interchanging goods and
services; and the network of mutual  aid or extrafamiliar cooperation.

     In the cultural field, special relevance is acquired by the values and the
rules put into practice in the acquisition and preservation  of goods  and services
(e.g.,  attitudes  toward  the  role of women).   These  habits,  attitudes,  and
behavior are passed on through social inheritance (Bartolome, 1983).  In fact,
they become such  a  part of the culture  that they can  obstruct the possibility
of improvement of the survival condition (Arguello,  1981).

     The demographic field  includes the considerations of  the structure of the
units and their characterization in terms  of sex,  age,  fertility,  construction
ways of unions, mortality,  migrations (especially those of a labor sort),  the
familiar living cycle stages (initial, expansion,  and fission),  duration of said
stages, etc. These  aspects  are important to plan resettlement policies that may
take into account the family requirements  in the long  run.

     Many variables  have  ambiguous  implications according to the  context  in
which they appear.  For example, in the demographic factors case, the fact that
a farming couple has many children could be considered as  a survival strategy,
based on the reasoning that the more  children they have, the more manpower they
can count on,  and consequently the  better resources they  can  have to  fulfill
their needs.  However, the large number of offspring can be a burden and, as a
result, a conditioning could occur that could influence  negatively, because they
are in the family cycle's first stages and they have scarce productive resources.


     Table 1 lists a number of contextual factors that must  be taken  into account
for an exhaustive understanding of the  strategies.

Local  Level

     The local  level or the immediate social environment  is  where  we find  the
articulation of relationship  or  neighboring  links that  form the basis  of
sociocultural identities and informal economic relations.   In many cases,  these
links contribute more to the support  of  the family  than the monetary or formal
income.  To  know  these links  is  very important because, apart  from having  an


Centra? and South America

     Table 1.  Factors That Should Be Considered in Evaluating Relocation

            Contextual factors            Endogenous characteristics

            - Access to the land                - Demographic
            - Social organization               - Migratory
            - Work market                       - Occupational
            - Productive organization           - Educational
            - Goods market                      - Sociocultural
            - Goods and services offered        - Consumption
            - Public policies
            - Development projects

Source:COMIP - Precensus Tasks (1985).

effect on the strategies, they  determine  the  behavior  of population in social
processes, such as resettlement.

Regional/Subregional Level

      This  leads  to  a  careful   consideration  of  the  surrounding  regions  or
subregions and of the area's interactions with them, even beyond the frontiers
among  countries,  surpassing  the reductions  to  both  the  ecological  and  the
political administrative aspects.  It is at  this level where we will detect, on
the one hand,  the  structure of production and employment and,  on the other hand,
the  mechanisms  to  obtain goods and  services  through  the   so-called  "needs
fulfillment circuits." The analysis of these circuits allows us to know the type
of needs to  be fulfilled, to what extent they are fulfilled (especially the basic
needs), the area (space)  where the  goods and services are acquired, and the way
of approaching them.

National Level

      The  national   level  determines  the  historic  and  cultural   context  of
development.   It  is also  at  the national  level where it would  appear  to be
convenient  to  evaluate  the  public  policies  that  could affect  the  living
strategies and, above all, the  scope and  covering  of the actions arising from
such policies in the regional  field of the affected area, provided that process
will affect said field.

      A specific census was carried out  according to this conceptual scheme for
the relocation  policy of an Argentine-Paraguayan  multipurpose hydroenergetic
project  in  the Parana  River,  Corpus Christi.   Contrary to  the  conventional
census, it accounted  for  strategies,  sociocultural  components,  and the formal
and informal links that exist in the affected area, apart from the demographic
and economic components.



      The  same proof  also  verified the  methodology's  consistency  and  the
relevance  of  the  constitutive  variables.   The  typology elaborated  on  these
variables and on the previous knowledge about the population.  These variables
appeared to be effectively discriminating, despite  the  fact that some "mixed"
productive insertion strategies were detected together with the cyclic character
of some  of them,  which revealed  the necessity of  incorporating  the historic
prospect to achieve  their adequate characterization.  The important fact here
is that an exploratory proof has  been carried  out.   This census does not rule
out the necessity of using  other types of instruments  and  careful  studies to
become more knowledgeable  as  regards  cultural rules  and  values and the circuits
that lead us to fulfill the needs of people being relocated.


      Resettlement  is  not simply  physical  evacuation,   but a  complex social
process.  The following criteria are essential  to a successful  resettlement:

      1. To fix as an aim of the policy that the whole of  the affected population
         could reconstruct   its  living  strategies,  generally  improving  its
         conditions of existence.  This reconstitution would consist of:

           keeping  or substituting  its  resources  and  their  optimization

           keeping its social articulations and the cultural components of its

            introducing in its strategies changes positively valued by the people
            in terms of their life projects;  and

           obtaining the recognition of the involved actors that the subject
            of this  process is the population at an  individual level as well as
            under  the  different  associative forms.   Involved  actors  include
            agency,  the affected people, and  the authorities.

      2. To define  as  policy subjects  all  those who might  be  linked to  the
         affected  area and whose link might constitute a significant component
         of their  living strategy (residents  or nonresidents).

      3. To define  the  living  strategies as  an  affected object,  because  the
         disruption  between the units and the particular field where they develop
         basically  affects them.   Consequently,  they  also  appear to be  the
         replacement object  --  that is to say,  what the  relocation policy must
         restore  to  the population.   This strategy's reconstruction  will  not
         imply a mechanical  transposition,  but  rather a  functional  replacement
         equal to the economic and social conditions  that are necessary to carry
         out the strategies.  This implies that  other aspects, positively valued
         by the people,  could be generated functioning as alternatives of those
         that cannot be reconstructed.

Central and South America

      4. It is not likely that  the replacement can be carried out at comparable
         levels, especially for those  sectors whose conditions of existence are
         definitely  inferior  to the  socially accepted  minimum standards  of
         existence.   As  a result,  we  will  aim to  generally improve  those

      5. To encourage the people's participation  in relocation decisions, both
         direct and channeled through the different  associative forms (either
         formal or informal).  The policy's formulation and its application will
         grow  out  of that  participation,  positive  modalities  valued by  the
         affected people, and from specific modalities for each social sector.

      6. To set the relocation units on two levels:   one based  on  family,  and
         the other based on customs  for the preservation of links and networks
         among units.

      7. To contemplate  the reconstruction  of the community's  structure,  and
         the integration of the relocated people  among each other and with the
         receiving population.

      8. To aim at establishing the new settlements in places as near as possible
         to the former location, so as to maintain most of the preexisting links
         and to  count on  circuits  to obtain resources  and to fulfill  needs
         already proved and recognized.

      9. To  include  all  the   aspects  --  social,  economic,  judicio-legal,
         technical,  etc.  --  to guarantee  the  integral management of  such

Arguello, 0.  1981.  Estrategias de supervivencia:   un concepto en busca de su
contenido.  Economia y Demografia XV.  Buenos Aires.

Bartolome, L.J.   Estrategias  adaptativas  de los pobres urbanos:   El  elemerito
entropico de la relocalizacion compulsiva.   Entidad Binacional Yacyreta y Depto.
de Antropologia Social, Universidad Nacional de Misiones,  Argentina.

Bartolome, L.J.  1983.  Aspectos sociales  de la relocalizacion de la poblacion
afectada por la construccion de grandes presas.  UN-OEA.   Buenos Aires.

Borsotti,  C.A.    La organization  social  de  la reproduccion  de los  agentes
sociales,  las  unidades familiares y  sus  estrategias.  Demografia  Economica.

Cernea, M.   1989.   Reloca!izaciones  involuntarias en  proyectos de Desarrollo.
Banco Mundial, Report No. 805, Washington.

COMIP.  1984.  Tareas precensales, primera etapa.  Buenos  Aires-Asuncion.

COMIP.  1985.  Tareas prcensales, segunda  etapa.  Buenos Aires-Asuncion.


COMIP.  1986.  Formulacion preliminar de  al Politica de Relocalizacion.  Buenos

Duque-Pastrana, E.   1973.   Las estrategias de  supervivencia  economica de las
unidades familiares del sector popular urbano:   una investigacion exploratoria.
PROELCE.  Chile.

Jelin, E.  1983.   Fatnilia, unidad domestica y division del trabajo (que sabemos,
hacia donde vamos).  CEDES.  Buenos Aires.

Massei, C.   1983.  Methodologia general   para el  analisis  socio-economico del
emprendimiento en la zona de Corpus.   Efectos sociales de las grandes presas de
America Latina, Seminar.  UN-OEA.  Buenos Aires.

Massei, C., and G. Borches.  1983.  Evaluacion y planificacion regional de una
obra publica de propositos multiples de gran  envergadura.   Buenos Aires.

Massei, C.,  and  G.  Borches.    1984.   Concepto de estrategias  de vida  y  su
inclusion en la elaboracion de  politicas de relocalizacion,  Seminar.   UN-OEA.
Posadas, Argentina.

Partridge, W.  1983.   Relocalizaciones en las distintas etapas de desarrollo de
los emprendimientos hidroelectricos.  UN-OEA.   Buenos Aires.

Rodriguez,  D.     1981.   Discusion  en torno  al  concepto de estrategias  de
supervivencial.   Relatorio  del  taller  sobre  estrategias de  supervivencia.
Demografia y Economica, Nro. 46.  Mexico.
Torrado, S.  1981.   Sobre  los  conceptos  de estrategias  familiares  de  vida and
proceso de reproduccion de al fuerza de trabajo:  Notas teoricas-metodologicas."
Demografia y Economica, Nro. 46.  Mexico.

Torrado, S.  1983.  La familia  como  unidad de analisis en censos y encuestas de
hogares.  CEUR.  Argentina.




                              JAMES  G. TITUS
                       Office  of Policy Analysis
                 U.S.  Environmental  Protection Agency
                          Washington,  DC  20460

     The process of responding to accelerated sea level  rise in the United States
is well under way, at least for a phenomenon that  is  not expected for several
decades.  Over the last seven years,  almost all  of the coastal  states have held
at least one major conference on the subject,  and a few of them have altered
coastal development policies to accommodate a future rise.  Public  officials are
generally   familiar  with  the  issue, as  are  representatives  of the  press,
nongovernmental organizations, and coastal  investors.  The federal government has
conducted  assessments of possible nationwide responses, and  of implications for
specific types  of decisions, such as the design of coastal drainage systems,
maintenance of recreational  beaches, and protection of coastal wetlands.

     This  paper  examines possible responses  to sea level  rise  in  the United
States.  Because  the most  important  question is what  should we actually do in
response to rising sea level, we focus primarily on the planning and engineering
strategies that will  determine  how  activities  on the  coast eventually change.
Nevertheless, because the process by which society comes to  understand the need
for action is also important, we conclude with a brief summary of  the evolution
of U.S. sea level  rise  studies in the 1980s.

     The most important responses to  sea level rise in the United States can be
broadly classified as  responses  to shoreline retreat, increased flooding, and
saltwater  intrusion.    In  each  case, the fundamental question  is  whether to
retreat or to hold back the sea.

     Shoreline retreat has  received by far the greatest attention; nevertheless,
because flooding   involves  the  same  strategic  questions,  we  combine  the
discussion.  Because there is a general  consensus  in  the  United States to "let
nature take its   course"  in national  parks and  other  undeveloped  areas,  we
examine only developed areas.  We divide our  discussion of this impact  into two

Wort/7 America

parts:  barrier islands and the open coast, and sheltered areas.  We conclude the
section by discussing when action is likely to be necessary.

Barrier Islands and the Open Coast

     Oceanfront communities  could  respond  to  sea level  rise  by  protecting
developed areas with dikes, pumping  sand onto  beaches  and other low areas, or
retreating from the shore.  Along  mainland  beaches,  the last option generally
implies no coastal  protection;  in barrier islands, however,  it would also be
possible to engineer a landward retreat  of the entire island, creating new land
on the bayside to offset that lost to oceanside erosion.  The four options are
illustrated in Figure 1.

     To obtain a rough  understanding  of  the relative costs of these options, we
examined  Long  Beach Island --  a long,  narrow  barrier island  developed with
single-family homes and one-  and two-story businesses (see Figure 2).  Table 1
Table 1.    Cost of Sea Level Rise for Four Alternative Options for Long Beach
         Island, New Jersey  (millions of U.S. dollars)
Sea level
Levee with
                Levee    Sand
   Total  Cost

      105           41
      285          109
      522          178
      786          247
     1048          308
     1310          371
     1574          431
     1835          492

Incremental  Cost
                  total loss
                  total loss
total loss
total loss
total loss
Source:  Weggel et al.  (1989) (dike cost); Yohe (1989) (no protection).


                 Initial Case
                 No Protection
                 Engineered Retreat
                 Island Raising

Figure 1.  Responses to sea  level  rise  for  developed barrier islands.

illustrates the costs of the four options for a rise  in sea level between 30 and
240 cm.  For a rise greater  than  50  cm,  any of the protection options would be
less expensive than  allowing the sea to reclaim the  valuable resort property.
Although surrounding the entire island with a dike would be less expensive than
raising  the  island,  it  would  be culturally  unacceptable  because  it  would
interfere with access to the  beach, and people would lose their views  of the bay.

      Engineering a retreat  would  also  be much less  expensive than raising the
island in place, because the latter  option  would require more (and higher

 North America
                                        ,,             Harvey
                               Ship      Swrl   North    cedar*
                               Bottom    City   Beach
 Figure  2.   Long Beach Island, New Jersey.



quality)  sand.   However,  this  option  would  be vigorously  opposed  by  the
oceanfront owners who would have  to move their houses to the bay side, as well
as  by  bayfront owners who  might lose their  access  to the water.   Moreover,
filling new  bays,ide  land  would disrupt back-bay ecosystems unless the estuary
were also allowed to migrate landward onto the mainland (which we discuss below).
As  Table  2 shows,  island  raising would cost less than $600 per house per year
(U.S. dollars) until after  sea level  had risen  more  than  60 cm;  this would be
less than the  rent for one week.  Thus,  we  suspect that the more expensive but
less disruptive approach of pumping sand onto beaches and the low bay sides of
barrier islands would be the most commonplace, at least in the beginning.

      Table  3  compares the  ability of  the four  options  to  satisfy various
desirable criteria.  (Most  of  the rationale for this table is found in Titus,
1990.)  An important lesson from  the Long Beach  Island study is that the least
expensive  solutions  are  not  always  the most   likely;  dikes are  culturally
unacceptable,  and   an  engineered   retreat  is  administratively  difficult.
Nevertheless, the noneconomic criteria should not always outweigh economics.

      Leatherman  (1989) estimated the quantity of sand necessary to hold back the
sea for every coastal state but Alaska,  and estimated the cost assuming  that sand
does not  become  more  expensive.    Titus  et al.  (1990)  adjusted  those cost
estimates on the  assumption that as  least-cost supplies are exhausted, it will
Table 2.    Evolution Over Time of the Relative  Costs of Retreat Island Raising
            (Long Beach Island, New Jersey)
Sea level
above 1986

Years before
sea will
rise 15 cm
Cost (mil

lions) Cost (U.S.

*  Assuming global sea level rises one meter by the year 2100.
NOTE:   All  costs  assume  that  until  the particular  year,  the  community  has
responded to sea level rise by raising the island in place.
Source: Titus (1990)


North America

Table 3.  Ability of Alternative Responses to Satisfy Desirable Criteria, Long
          Beach Island,  New Jersey  (assuming  1  m rise  by  2100)
Dikes Raise Engineered
Islands Retreat
Forced Unplanned
Social Cost
   Cumulative           584         786     247              1548      1548
   Present Value
   ($millions, 3%)      115         130     46                170       170

Environmentally         No      Usually     Usually            Yes       Yes
Culturally              No       Yes        Yes                No      Maybe

Legal                   Yes      Yes        Maybe             Maybe     Yes

Constitutional          Yes      Yes        Yes               Maybe     Yes

Institutionally         Yes      Yes        Maybe             Maybe     Yes

Performs Under          Poor     Good       Good              Good      Good

Immmune to              Yes      Mostly     Somewhat           No       Mostly

Source:  Titus (1990).

be necessary to go farther out to sea for suitable sand.  Table 4 illustrates the
resulting estimates of dredging costs  for  current trends and rises in sea level
of 50,  100,  and  200 cm.  Titus  et   al.  also estimated the cost of elevating
buildings and utilities as sea level rises.

      These  calculations  are   only rough  estimates.    Leatherman  probably
underestimated total sand requirements by assuming that beaches would  be designed
only for a  one-year  storm; designing them for a 100-year storm would increase the
cost by 50-100 percent.  Moreover,  Titus  et  al.  ignored the  cost of elevating
multifamily  buildings,  and  sea  level  rise  would  be  factored   into   routine
reconstruction of water and  sewer lines at no  incremental  cost.   On the other
hand,  our  calculations assume  that all    developed  areas will  be  protected.
Although this is  a reasonable assumption for Long Beach Island and  similar areas,
it would be less  expensive to abandon more lightly developed islands.  Moreover,



      Table 4.   Nationwide Impact of Sea Level  Rise on the United States

     Trend                        50 cm           100 cm            200 cm

 If No Shores  Are Protected

 Dryland lost  (sq mi)          3,315-7,311      5,123-10,330      8,191-15,394
 Wetlands lost (%)                 17-43            26-66             29-76

 If Developed  Areas Are Protected

 Dryland lost  (sq mi)          2,200-6,100      4,100-9,200       6,400-13,500
 Wetlands lost (%)                 20-45            29-69             33-80
 Cost of coastal defense
 (billions of  1988 dollars):       32-43            73-111           169-309
  Open coast:
    Sand                          15-20            27-41             58-100
    Elevate structures            9-13            21-57             75-115
  Sheltered shores                5-13            11-33             30-101

 If All Shores Are Protected

 Wetlands lost  (%)                 38-61            50-82             66-90

 Source:Titus et al. (1989).

 a number  of  states  have already required  construction  to  be set  back from
 theshore a few hundred meters, suggesting that no protection would be required
 for the first 50 cm of sea level  rise.

 Sheltered Waters

      Americans'  affinity  for beaches  and  concern  for  the  environment have
 created a  strong constituency  against  holding  back the  sea with dikes  and
 seawalls,  counterbalancing the  natural  tendency of  all  landowners to protect
 their property.   Along  the  open coast,  both  interests  can  be accommodated,
 because  beach  nourishment  protects  property  by  maintaining  the  natural
 shoreline.    Along  sheltered  waters,  however,  the  prospects for avoiding  a
 conflict are not as great.  As  Figure 3 shows, protecting property with dikes and
 bulkheads would  prevent  wetlands from  migrating inland  and  could eventually
 result in their complete loss in  some places.

      In a recent EPA report to Congress  on the implications of global  warming,
 Park et al. (1989)  examined  the potential loss of wetlands  and dryland  for a
 sample of 46  sites  comprising 10 percent of the U.S.  coastal  zone,  for three
alternative responses:    no  protection, protecting  areas  that   are  densely
developed today with dikes and bulkheads, and protecting all  shores.   For each
 site,  Weggel et al.  (1989) estimated the cost of protecting developed areas from


 North America
                5000 YEARS AGO                                TODAY
                           - SEA LEVEL                ^"ttllBpWilt	2 CURRENT
                                                        ^l*i^#^               SEA LEVEL
                                          SEDIMENTATION AND
                                          PEAT FORMATION

                                SEA LEVEL
 Figure 3.  Evolution of  a  marsh  as sea level  rises (Titus, 1986).

 a 2-meter rise.  Titus et al. (1990) used cost functions  suggested by Vleggel  et
 al.  and  estimates  of inundated  land  from Park et  al.  to interpolate  the  cost
 estimates, and developed confidence intervals for the estimates of lost  land.

       Table 4  illustrates  the nationwide  results  (the  source studies  provide
 regional detail).  For a one-meter rise, the cost  of protecting the most densely
 developed  1,000  square  miles  of coastal lowlands  would work out  to  $3,000 per
 acre  per  year,  which   would  generally  warrant  protection.    However,  such
 protection would increase the  loss of wetlands by 300-500 square miles, and would
 reduce the  area  of shallow water for submerged  vegetation  by another  500-700
 square miles.  Moreover, many  vacant areas are being  rapidly developed.  If all
 areas must  be  protected, the additional loss  of  wetlands would be 1,800-2,700
 square miles,  and another  3,000-7,000 square  miles of shallow  waters would be

       The political  process will  have  to decide  whether to  abandon  coastal
 lowlands to protect the environment.  To help the necessary discussions get under
 way we  are circulating  a  draft that  investigates seven  options  for  enabling
 coastal wetlands to migrate landward (Titus, 1989).  The first two apply only to
 undeveloped areas:   prohibiting development and purchasing coastal lowlands.  The
 next three involve  doing nothing today and purchasing land and structures when



inundation is imminent;   forcing people to move out when  inundation is imminent;
or hoping that protection will  prove to  be  uneconomic.   The final two  options,
which we call "presumed mobility," allow people to use  their property as they
choose, but on the condition that they eventually will abandon it if and when sea
level rise threatens  it with inundation;  presumed mobility could be implemented,
whether by  prohibiting  construction of  bulkheads  and levees  or  by  converting
property ownership to long-term or conditional leases that expire when sea level
rises a particular amount.

      Table 5  summarizes our  assessment  of  each   option  to  satisfy  various
desirable criteria, including low social  cost, low cost to taxpayers, performance
under uncertainty, equity, constitutionality, political feasibility, and the risk
of backsliding.   Unlike the table for  barrier islands, we  omit  environmental
criteria because each of these options is each designed to achieve roughly the
same level of environmental  protection.

      Our  overall assessment is that presumed mobility would be the best general
approach.    A general  prohibition  of development would probably violate  the
takings clause of the Bill  of  Rights; buying 20,000 square  kilometers  of land
would be expensive, and  in any event, these  options apply only to areas that have
not yet been developed.   Doing  nothing today seems unlikely to protect wetlands
because (1) purchasing property in the future would be even more expensive if it
is developed; (2) forcing people to move out of their homes would be
politically  impossible  if they are willing  to tax  themselves to pay  for  the
necessary protection; and (3)  economics  alone is unlikely to motivate people to
abandon developed areas.

      One  of the most overlooked  but important criteria is  performance under
uncertainty.  No  one  knows how much sea level will  rise in the  future; only rough
estimates are available.  Thus, policies likely to succeed for a rise anywhere
between 0  and 3 meters should be preferred over those that might be superior for
a  particular  scenario  but  might  fail  if  other  scenarios  unfold.   For  this
criterion, the approach of presumed mobility is clearly superior: ecosystems will
be protected no matter how much sea level rises; real  estate markets will be able
to efficiently incorporate new information on sea  level  trends; and  if the sea
does not  rise significantly,  the policy  costs nothing.  By  contrast,  buying
coastal lowlands or  prohibiting  development requires policy makers  to  draw a
(disputable) line on  a map above which the  policy does not apply.  If sea level
rises more than assumed, ecosystems eventually will  be lost;  if it rises less,
society will have unnecessarily forfeited the use  of valuable coastal land.

When Will  a Response Be Necessary?

      A recent study by  the  National  Research  Council (Dean  et  al.,  1987)
concluded that because dikes can be erected  in a relatively short period of time,
no action  is necessary today.   This  argument also applies for beach nourishment
on the open coast.  However,  our analysis of wetland-protection options suggests

Table 5.  Alternative Strategies for Protecting Natural Shorelines:  Areas That Have Not Yet Been Developed
Policy to public
1. Prohibit None
2. Buy Speculative
coastal premium
Defer Action
3. Order None
people out
4. Buy land and
out later structures
5. Rely on None
Presumed mobi I i ty
6. No None
7. Leases <1X of land &
residual value
Social Cost
(vs. no sea level rise)
premium +<1X
of base value
premium + <1%
of base value
<1X of land
and structures
<1X of land
and structures
<1X of land
and structures

<1X of land
<1X of land
Performance under
Economic uncertainty:
Const i- Political New
tutional feasi- Risk of institutional Likelihood of
value Cumulative Efficiency Sea Level Economics Equitable bility backsliding requirements succes:
Land and
Land and
Land and

Land + residual
value of
Land + residual
value of
Poor No Yes
Poor No Yes
Fair Yes Perhaps
Fair Yes No
Fair Yes Useless
(if it

Optimal Yes Yes
Optimal Yes Yes
No No None Possible
Yes Yes None Possible
Maybe Doubtful Low Very
Yes Yes Low Very
Yes Yes Good Low

Probably Good Likely
Yes Yes Fair Very
Park Service
Park Service

Change in
titles of
Almost certain
at first, un-
likely in long
Almost certain
at first,
unlikely in
long run

Very likely


that these  measures  are likely to  be  effective only if  they  are implemented
several decades  in advance: people  would  need several decades  to depreciate
structures and to become accustomed to  the  idea  that property must be abandoned
to the sea to protect the environment.

      A number of  planning  mechanisms  are  in  place  along the ocean  coast to
foster a retreat.  North Carolina and a number of other states require houses to
be set a few  hundred  meters  back  from  the  beach and  prohibit hard engineering
structures  along  the  beach.    South   Carolina prohibits  reconstruction  of
storm-damaged property  if such property is too close to the shore.

      Along  wetland shores, however,  only Maine has implemented planning measures
to allow ecosystems to migrate inland.   That state has explicitly incorporated
presumed mobility into its development  regulations, which state that structures
are  presumed  to  be movable;  in  the case  of apartments that are  clearly  not
movable, the regulations state that if the buildings would block  the landward
migration of wetlands  and dunes resulting from a one-meter rise in  sea level, the
developer must supply the state with a demolition plan.   Although other states
require construction to be set back somewhat from the wetlands, the setbacks are
small compared with the  inland migration of  wetlands that would accompany a one-
meter rise in sea level.

      Louisiana is  currently losing over 100 square kilometers of land per year
because  human  activities are  thwarting  the processes  that once  enabled  the
Mississippi Delta to expand  into the Gulf of Mexico.  For thousands of years, the
annual river flooding  would  deposit enough sediment to enable the delta to  more
than keep pace  with sea level rise and its own tendency to subside.  In the last
century, however, the  federal government has built dikes along the river and has
sealed off "distributaries" to prevent flooding and to maintain a sufficiently
rapid riverflow to prevent  sedimentation  in the  shipping lanes.  As  a result,
sediment and nutrients from  the river no longer  reach  most of the wetlands, and
they are being rapidly submerged.  Moreover, with  flows in distributaries cut
off, saltwater is  penetrating  inland, converting cypress swamps  to open water
lakes and  otherwise disrupting wetlands.   If sea level rise accelerates,  the
already rapid disintegration of coastal  Louisiana would follow  suit.

      As  with other coastal  areas,  both  dikes  and abandonment  are  possible.
However, there is  a general  consensus that these options should  be avoided if
possible, because in  either event,  most  of the  delta's wetlands would be lost,
and those wetlands  support 50 percent of the nation's shellfish and 25 percent
of its fish catch.  Thus,  federal and state officials are focusing primarily on
options to restore  natural processes that would  enable at least a large fraction
of the delta  to survive even an  accelerated rise in sea level. The U.S. Congress
has authorized  a number of projects to divert freshwater and  sediment to wetlands
by effectively  cutting holes in the dikes.  Under current policies, however, such
projects will likely divert only a small  fraction of  the river water to avoid
siltation of shipping  lanes.


North America

      In  the long run,  protecting Louisiana's  wetlands  would require people to
allow the vast majority of the river's discharge to  reach  the  wetlands.   This
would be  possible if navigation were separated  from  the  streamflow of the river.
One way to do this would be to construct a series of canals with locks between
New Orleans and the Gulf of Mexico, and to completely restore the natural flow
of water to the delta below the canal.   Unfortunately,  requiring ships to pass
through locks  would  hurt  the economic viability of  the Port  of  New Orleans.
Another option would  be to build  a  new deep-water port  10-20 miles to the east.

      Perhaps the far-reaching response,  one  that has been advocated  by the
state's Secretary for Environmental Protection,  would  be to allow the river to
change course and flow down the Atchafalaya River.   Without a $1 billion river
control structure, the  river would  already have done so. Although from a purely
environmental  perspective this  option  is  most  appealing,  it would  further
accelerate the loss of wetlands in the eastern part of the state  and would enable
saltwater to  back up  to New Orleans, requiring  the  city  to find a  new water

      It  is  somewhat  ironic that  human  activities designed  to prevent flooding
may leave the entire area permanently below sea level in the  long run.  There may
be a lesson  for Bangladesh  and other nations who are considering flood-protection
dikes to protect  land  from surges  in  river levels:  build  dikes  around  a few
cities, but make  sure the river is still able to flood enough  areas for the flow
of water to  slow  sufficiently to deposit  sediment  onto farmland and wetlands,
rather than washing sediment out to sea where  it  will benefit no one.


      Responses to saltwater intrusion,  like shoreline retreat and flooding, can
involve either holding back the sea or adapting to  a landward encroachment.
Preventing Salinity Increases

      Figures 4 and 5 illustrate why sea  level rise  increases  the salinity of
estuaries and aquifers, respectively.   In the  former case,  a rise in sea level
increases the cross-sectional  area of the estuary,  slowing  the average flow of
water to the sea, the major process that keeps the estuary from having the same
salinity as the ocean.  Assuming that the tides continue to carry the same amount
of water  and that mixing stays constant, salinity will  increase because the force
of freshwater is reduced while the saltwater force  is increased.  Moreover, if
the  bay  becomes  wider, the tidal  exchange of  water  will  increase,  further
increasing  the freshwater  force.   (Because  it  is  difficult  to  graphically
represent the previous  explanation,  Figure 4 expresses it in  a different fashion
by comparing the  amount of freshwater entering the estuary with the amount of
seawater from the tides.)

      Salinity increases  can be  prevented either  by impeding  the  ability of
saltwater to migrate upstream or by increasing  the amount of freshwater entering
the estuary.  During  the drought  of 1988,  the New Orleans District of the Corps
of Engineers designed a barrier  across the bottom of the Mississippi River that



blocked saltwater on the bottom while allowing the ships and freshwater to pass
on the top.  In many cases where human withdrawals of freshwater have increased
estuarine  salinity e'nough  to  have adverse  environmental  consequences,  water
resource agencies have constructed projects to divert freshwater  into  estuaries.
Elsewhere in Louisiana, the Corps has  designed projects to divert water from the
Mississippi River  to  wetlands  that are suffering adverse effects  of saltwater
intrusion; and Everglades National  Park has long had a similar arrangement with
the Corps of Engineers  and  the  South  Florida Water  Management District.

      The Delaware River Basin  Commission (DRBC) releases water from its  system
of  reservoirs  whenever  salinity  reaches  undesirable levels,   to protect
Philadelphia's freshwater intake and  aquifers in  New Jersey  that are recharged
by the (usually)  fresh part  of the river.  Hull  and Tortoriello (1979) estimated
that a 13-cm rise  in  sea level  would  require an increase in  reservoir capacity
of  57  million cubic  meters (46,000  acre-feet),  while  Hull  and Titus  (1986)
suggested that a 30-cm rise would require about  140 million  cubic meters,  about
one-fourth the  capacity that would  be provided  by the proposed Tocks  Island
reservoir.  Hull  and  Titus also noted  that  the DRBC has identified reservoir
sites sufficient to offset salinity increases from sea level  rise and economic
Initial Condition

After Sea Level Rise
Figure 4.  Increasing bay salinity due to sea level rise.


North America
                                                       \. . j Freshwater

Figure  5.   Impacts  of sea level rise on groundwater tables.  According  to the
Ghyben-Herzberg relation, the freshwater/saltwater interface is 40 cm below sea
level for  every  cm by which the top  of the water table lies above  sea  level.
When water tables are well below the surface, a rise in sea level  simply  raises
the water  table  and the fresh/salt interface by an equal  amount  (A-B).   Where
water tables are near the surface,  however,  drainage and evapotranspiration may
prevent the water table  from rising.   In  such  a  case  (C),  the  freshwater table
cour narrow greatly with a rise in sea level: for every 1-cm rise in sea  level,
the fresh/salt interface would  rise  41  cm.



growth well into the 21st century.  Williams (1989)  conducted  a similar analysis
of the  impacts  of and responses to sea level rise  in  the Sacramento Delta in

      Although dams can be  useful,  one must understand their  limitations.  Most
important, there is a finite amount of water  flowing in the typical river; dams
can increase the freshwater flow during the dry season because they reduce the
flow during the wet season.  Because droughts are generally the only time when
high  salinity  is  a concern, the  impact  on salinity during  the wet  season is
generally  not  a problem.    Dams  also  reduce  flooding, which  (as  we  discussed
above) can be  viewed as a benefit by people who might otherwise lose property (or
drown) in a flood;  but this is a liability to the extent that flood prevention
keeps sediment  from reaching wetlands and  enabling  them  to keep pace with sea
level.  A final problem is  that if climate  change makes droughts more severe in
the future, it may be difficult to find sufficient reservoir  capacity to offset
the resulting reductions in riverflow, let alone  increase riverflow  enough to
offset sea level rise.  Salinity increases  in aquifers can also be prevented by
either  increasing  the  force  of  freshwater  or by  decreasing  the  force  of
saltwater.  The most notable application of the former approach is in southern
Florida,  where  water managers  maintain  a series  of  freshwater  canals  whose
primary purpose is  to  recharge  the Biscayne  Aquifer with freshwater.  Various
types of barriers have also been identified for blocking saltwater intruding into
the estuary (Sorensen et al.,  1984).

      Decreasing depletive  uses  of water can  help to offset salinity increases.
For example, during droughts the Delaware River Basin  Commission has  the power
to curtail diversions of   water  to New York  City.   Reducing  water consumption
within the basin is a critical  component of water management  strategies in this
and many other regions.

Adapting to Salinity Increases

      If measures are not undertaken to prevent increase of salinity, people will
have to adapt  to it.  Some cities  could respond by moving their intakes upstream.
Note that this appears to  be the only response to increased salinity that would
work  with sea  level  rise  but  (at least  in many  cases)  not  with  decreased
riverflow.  In the case of sea level rise,  moving the  uptake  upstream the same
distance as salinity advanced would leave the public (and if ecosystems were able
to migrate upstream and inland, the environment) in roughly the same  condition
as before the sea level rose.   By contrast, if less freshwater is flowing into
an estuary, there may no longer be enough freshwater to  supply  the previous level
of consumption.

      Another  response is  to shift to  alternative  supplies.    For  example,  if
flows in  the  Mississippi  River  decline, or  if wetland  loss  motivates  policy
makers to allow the  river to change course, New Orleans  would have to abandon the
river as a supply of freshwater.  Many argue  that the  river is polluted  enough
to view such a situation as a "blessing in disguise," and have  suggested that the
groundwater under  Lake Ponchartraine would  be a  suitable  source  (Louisiana
Wetland Protection Panel,  1987).   Nevertheless, alternative supplies are  finite


North America

and may become  increasingly scarce as the economy grows,  especially in areas
where the greenhouse effect  fails to increase precipitation  enough to offset the
increased evaporation that warmer temperatures invariably imply.

      Water conservation is  likely  to play an increasingly  important  role in
efforts to  adapt to reduced  availability  of freshwater.   Many jurisdictions
already place restrictions on depletive uses, such as watering lawns and washing
cars.  Officials  in New Jersey are planning to  ration the water  that farmers
withdraw  from the Potomac-Raritan-Magothy  Aquifer,  which  is recharged  by the
Delaware River.   Nevertheless, regulations of water use are  difficult to enforce
and generally apply only to a limited number of visible  activities.

      In  our view,  the best  long-term  response would be to treat water like any
other scarce commodity:   sell water at a market-clearing  price, rather than at
a price based on cost.  There is an emerging trend in this direction among large
water users  in  the  western  United  States,  but  the principle is likely to face
severe cultural  and institutional barriers.  First, Americans generally  believe
that water  should  be as  free as  the air  we breathe.   Second,  public utilities
generally  are  not  allowed  to  make a  profit.    Nevertheless,  with increasing
government deficits and a gradual  acceptance of the scarcity of water, the public
would probably learn to accept water markets.

The Need for Near-Term Action

      As  with dikes built to prevent inundation,  there is no need to build dams
or canals to counteract future saltwater intrusion. Nevertheless, setting aside
sufficient land for future dam sites is similar to allowing wetlands to migrate
landward:  it will be less expensive to prevent people from developing the land
today than to buy people out  later.  Accordingly, to the extent that regions will
rely on dams in the future,   it would be best to identify  those sites today and
implement policies that will  keep  options open for  future reservoir construction.

      The  matter of reserving land  for dams or wetlands illustrates a principle
that may apply to other  commodities:   even  when a  particular action will not be
necessary for a few decades, it is  best to  establish the "rules of the game" in
advance so that people can gradually take whatever measures are necessary based
on how they perceive the probability and eventuality of the particular situation
that  is  anticipated.   If  we want  to use water efficiently,  its  price  will
eventually have to rise.  Political  realities prevent a substantial rise today,
but if the government put everyone  on  notice  that  it would charge a fair-market
price beginning in the year 2030,  the public would probably accept such a policy.
It is easier to  agree on what is fair when no  one  is immediately threatened, and
honorable  people  do  not object  to  fulfilling  the  conditions of  treaties,
contracts, and other arrangements made by a previous  generation.


      For most practical  purposes,  the United States began to seriously examine
potential responses to accelerated  sea level rise in the  summer of 1982.   Two



officials of the U.S. Environmental Protection Agency (EPA), John Hoffman and the
head  of  his office, Joseph  Cannon,  were  troubled  by an  apparent  failure in
information  transfer.   For several years,  climatologists had   warned that a
global warming due to ,the greenhouse effect was likely (NAS, 1979, 1982).  Yet
federal,  state,  and local officials  responsible for coastal  decision making
either were generally unaware of this prospect or viewed it as mere speculation.

      No one had estimated the  likely rise  in sea level for specific years, and
even if they had,  the EPA officials were not  sufficiently  familiar with coastal
activities to know whether consideration of a possible rise would warrant changes
in current decision making.  But Hoffman had  a  hunch that  sea level rise  would
justify changes in at least some decisions, and convinced Cannon to initiate a
small program to begin the process by which the United States prepared to live
with a rising sea on a warmer planet.

      In   retrospect,  it  may  seem  strange  that   EPA,   a  regulatory  agency
responsible  for controlling  pollution, first  addressed  the  greenhouse effect
issue by initiating a program to adapt to a global warming, rather than a program
to reduce emissions of greenhouse gases into the atmosphere.  Even then,  a number
of environmental groups were initially suspicious that the Agency was effectively
"throwing  in the  towel."   But  in  the  context of  what  could actually  be
accomplished  at the time, the strategic  decision  Cannon made  was  perfectly
rational.  The nation had  just elected a new president  who had promised to relax
environmental regulations; nonregulatory approaches to protecting the environment
seemed to have more promise.  The planned sea level rise project would encourage
state and  local officials to  anticipate  sea  level  rise,   with the  hope of
averting  situations  that  would otherwise  eventually  necessitate regulations.
Moreover, there  was no public consensus  to reduce global warming; a project aimed
at increasing awareness would help create the political conditions necessary for
policy makers to consider reducing emissions  of C02 and other greenhouse gases.

      The  first  major   activity  of  the  Sea  Level  Rise  Project  was  an
interdisciplinary study in which Hoffman et  al.  (1983)  estimated the range of
future sea  level  rise;  Leatherman  (1984)  and Kana et  al.  (1984)  used those
scenarios to estimate the physical  effects  on Galveston, Texas, and Charleston,
South  Carolina;  Sorensen  et  al.  (1984)   provided  rough  cost  estimates  for
engineering  responses  to sea  level  rise;  and  Gibbs  (1984) and Titus (1984)
performed  economic  analyses   using  the  information  provided  by  the  other
researchers.  The results were presented at a conference in Washington in 1983
and were published the following year (Barth and Titus 1984).

      The initial  effort  was  only partly  successful.   On the  positive side,
Hoffman's study  estimating sea  level  rise  prompted  the National Academy of
Sciences to prepare their  own estimate (Revelle 1983),  so that by  the end of the
first year,  there  were two available studies,  both of which suggested that a
substantial   rise  in  the  next  century was  likely.  We were  also successful  in
making officials and coastal scientists aware of the potential for a significant
rise:  (1) our reports were written for the layman --  no matter how technical the
subject  matter  of  a study,   they always  included  an  overview  chapter  that
explained the contents; (2) we sent out  form letters to most of the people in the


North America

country working on coastal issues, telling them how to obtain our reports, and
about one-third of them responded by requesting at least one document; and (3)
we gave about 50 speeches and briefings every year on the subject to government
offices and public meetings.

      However,  we failed to obtain our most important objectives.   By 1984, we
had identified only a handful of issues where we could make a case that sea level
rise required  changes  in current practices.   Moreover, while  we  continued to
study the issue,  we were generally unable to convince  federal and state agencies
with a stake in  sea level  rise  to undertake efforts  themselves to address the
issue. There were four notable exceptions:  (1) the National  Academy of Sciences
formed panels to (a)  estimate the future contributions of glaciers to sea level
rise  (Meier  et al.,  1985)  and  (b) assess the  engineering implications  of a
possible  rise   (Dean  et  al.,   1987);  (2)  Orrin  Pilkey,  the  most  prominent
environmental activist on coastal matters,  began to incorporate global warming
into his many  speeches to  civic groups on  the need for coastal development to
be more sensitive  to environmental processes; (3)  the  Army Corps  of Engineers
agreed to cofund with  EPA a $25,000 study on the implications of sea level rise
for coastal protection works (Kyper  and Sorensen, 1985);  and  finally (4) the
legislature of Terrebonne Parish, a  local government  in  Louisiana,  passed a
resolution calling on Congress to  improve estimates of future sea level rise and
initiated a $100,000 study on response  strategies for their community, which was
already facing substantial erosion due to subsidence (see Edmonson,  Volume 1).

      It was clear that we were doing  something wrong, so in mid-1984 we changed
the focus of our studies.  From  then  on,  we decided to fund studies  only after
we  had  internally developed   a specific  hypothesis  demonstrating  that  a
consideration of sea level  rise  would alter decisions  people make today.  In the
ensuing two years, we commenced studies to investigate the following hypotheses:
(1) sea level rise would destroy a large fraction of our coastal  wetlands unless
planning solutions were soon implemented to require development to be abandoned
to allow wetlands to migrate inland (Titus et al., 1984); (2)  because groins help
to control  erosion  due to alongshore transport  but  not the offshore erosion from
sea level  rise, a consideration  of the issue would prompt the State of Maryland
to drop its  plans  to build  more  groins  at Ocean City, Maryland, and instead
employ beach nourishment; (3) because it is much easier to put  slightly larger
pipes in a coastal  drainage system during construction than subsequently to add
new pipes, it would be rational  to design new  coastal  drainage  systems with an
allowance for  sea level  rise; (4) sea level rise  would accelerate the already
alarming rate of land loss  in Louisiana, and hence,  imply  that action is much
more urgent than currently assumed;  and (5) increased salinity  in  the Delaware
Estuary  might   eventually  necessitate   additional   reservoirs  to   protect
Philadelphia's water supplies,  and although they need not be built today, the
risk of this  eventually happening warrants land  use planning to ensure that all
the suitable sites are not developed.

      Because   we  had  conducted  "back  of  the  envelope"  assessments  that
demonstrated the need to  consider  sea level  rise  before  funding  them, all of the
studies turned out to demonstrate that even a 50-50  chance of  accelerated sea
level rise would warrant changes in current decision making.  Although sea level



rise was probably not the only reason, within a month of the  Ocean City  study's
(Titus et al.,  1985)  release, the State of Maryland announced that it would shift
its erosion-control strategy from groins to beach nourishment (Associated Press,
1985).  (The wetland study (Titus,  1988) was  not released until much later, but
even  while it was  still in draft,  the State  of  Maine responded  by  issuing
regulations requiring that structures  be removed if necessary to enable wetlands
and dune ecosystems  to migrate landward.)

      Although   the  other studies  (Titus  et  al.,   1987;   Louisiana  Wetland
Protection Panel,  1987;  Wilcoxen,  1986) did  not precipitate specific actions,
they provided additional  examples to buttress our claim that  people should begin
preparing for sea level rise, even though it is uncertain.  We continued to give
about 30 speeches a year  on  the  subject to various communities and professional
organizations,  trying  where possible to  talk to enough people  beforehand to
develop a hypothetical example relevant to their own activities where planning
for sea level rise  today would be warranted.  The fact that we could cite studies
demonstrating the rationality of  planning today increased the credibility of our
assertion that the particular audience should consider it as  well; and the fact
that Maryland and later Maine had made a decision based on sea level rise helped
convince people  that policy makers are  capable of  planning for  the long-term

      Although  many scientists,  reporters,  low-level  officials,  and members of
the public continued to  request  our reports,  in the  beginning  of 1986  we knew
that we had failed to achieve our primary  goal of motivating people to  prepare
for sea level  rise.   We  had the sense that we  were  fulfilling  a  need  to have
someone thinking and telling people about the  long-term implications of current
activities, but  that for most  people, our activities were  little more  than  a
curiosity; practical people could safely ignore the issue  of sea level  rise.

      But  then  the British Antarctic  Survey discovered an  emerging hole in the
ozone  over the  South  Pole.   This  seemingly  unrelated  event  attracted  the
attention of several  U.S.  Senators, who held hearings on the  subject and decided
to include the  related  issue of global  warming.   Suddenly,  widespread  public
attention was focused on  the greenhouse effect and its impact on sea level.  The
unusually hot year of  1988  further increased  public  awareness.   For the first
five years of  our project, we  were  able  to  motivate only   a few  agencies to
undertake any substantive  efforts; in the last two years,  the momentum of the
issue has motivated  dozens  of  initiatives,  as  Klarin  and Hershman  (Volume 1)

      We would like to think that  our initial efforts laid the groundwork for the
emerging response to sea  level rise, even though at the time  our efforts seemed
futile.  By  this line  of reasoning,  our initial reports explaining  the issue
convinced low-level  officials, low-level environmental  spokesmen,  and  coastal
scientists that sea level rise is important,  but failed to  convince high-level
officials, heads of nongovernmental organizations, or prominent scientists that
the time was  ripe for addressing  the issue.  When the  ozone hole and hot year of
1988 convinced  leaders that global warming  is  a serious  issue, their lower-level
counterparts were already informed and ready to recommend  action.


North America

      We will  never know whether our efforts made much of  a  difference in the
final analysis.  Nevertheless, on the assumption that they did, we briefly offer
a few lessons  that  may be useful  for nations beginning to prepare for future sea
level rise.  First, it is important to designate an individual  to work  full time
on the issue.   A key  to  the  success  of the  EPA project is that Hoffman was able
to find someone who was  sufficiently interested in the issue to stay with it for
the better part of a decade.  It takes time to develop  expertise
when a new issue emerges:  much  of the relevant information is unpublished, and
disciplines ranging from law and economics  to  biology  and  engineering  must be

      Second,  because responding to sea level rise is  likely  to be decentralized,
public  information is sufficiently  important  to warrant 10-20 percent of the
total budget and 25 percent of the project manager's time.  Thousands of one-hour
conversations with  reporters and professionals working on related issues will be
necessary, as well  as many shorter conversations with curious citizens.   Anyone
who views their time as too valuable  to  completely satisfy all  inquiries is
doomed  to  failure.  College  students  and  low-level assistants  who have the
initiative to question the project manager  about the  implications of future sea
level  rise  often  surface  later  as influential  researchers  or directors  of
organizations.  Although the typical conversation on  the subject may accomplish
little, the totality of thousands of conversations  over the  course  of  several
years produces a critical mass by which people begin  to talk to each other about
the issue and spend their own time investigating its implications.

      If the need to satisfy all  inquiries  is  recognized,  the  project  manager
will find that he or  she can save time  by preparing summary  reports that explain
the issue to  someone with no background in the  issue.  Managers  of government
projects often  commission numerous  studies, and  in  their own minds,  develop a
broad  vision  of the  issue.   But  while  they make the studies  available,  they
rarely prepare reports summarizing  their perspective.  This is unfortunate both
because preparing such reports disciplines  one to examine the weaknesses  in their
opinions, and  because their  overviews of the issue would correspond more closely
to what the public  needs to  know than would  the reports  prepared by specialists
in particular disciplines.

      Finally, studies should  begin with  a socially  relevant  hypothesis before
being  funded.   In  our  case,  the  hypothesis was  that  a particular  change in
current activities  was warranted even if one allows for the  possibility that sea
level might not rise.  In some cases, it is worth examining an  issue just to make
sure that no  action is yet necessary.   However, any  project manager  unable to
present a cost-benefit argument  in favor of action today in  at least a few cases
should  be criticized for,  at best, a  lack of imagination  and for,  at worst,
directing resources to the wrong issues and thereby forfeiting any savings that
might  be  realized  from preparing  for  sea level rise  in other  ares.   Such
criticism may not always be fair, but the fear of receiving  it will be a powerful
incentive to ensure that "no stones go unturned."



      No one would accuse the United States of overreacting to the prospect  of
a rise  in sea level' from the greenhouse effect; the process has been slow, but
steady.   After  seven years,  we have  reached the  point where  the relevant
disciplines and the relevant government agencies are considering the issue and
looking for opportunities to respond.  Everyone realizes that it is difficult  to
convince politicians  to make short-term sacrifices for the long-term good, but
we have a public that is concerned about environmental quality in general  and
the greenhouse effect in particular.

      We understand that many of the assumptions American researchers take for
granted would not  apply in other nations.   Nevertheless,  we  believe that two
recommendations are universally appropriate for any foreign colleague who decides
to dedicate a number  of years helping a nation prepare for rising seas.   Focus
your efforts on  identifying actions  that  need to be taken today and make sure
that no one ever considers you an expert on the issue.  What you learn will  be
important only if its knowledge becomes commonplace.


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throughout the  United States.   In:   Greenhouse  Effect,  Sea  Level  Rise, and
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Park, R.A., M.S.  Treehan,  P.W. Mausel, and R.C. Howe.  1989.   The effects of sea
level rise  on U.S. coastal  wetlands.   In:   The Potential  Effects  of Global
Climate Change on the  United States.   Volume B:  Sea Level  Rise.  Smith, J. and
D. Tirpak, eds.  Washington, DC:  U.S. Environmental Protection Agency.

Revelle, R.  1983.  Probable future changes in sea level  resulting from increased
atmospheric carbon dioxide.  In:  Changing Climate.  Washington, DC:  National
Academy Press.


Sorensen,  R.M.,  R.N.  Weisman,  and  G.P.  Lennon.   1984.   Control  of erosion,
inundation, and salinity intrusion.   In:  Greenhouse  effect and  sea level rise:
A challenge for this generation.  Barth, M.C., and J.G. Titus,  eds.  New York:
Van Nostrand Reinhold.

Titus, J.G.   1984.   Planning for sea level  rise before  and  after  a coastal
disaster.   In:   Greenhouse effect and  sea level  rise:   A challenge for this
generation.  Barth,  M.C., and J.G. Titus,  eds.  New York:  Van Nostrand Reinhold.

Titus, J.G,  S.P.  leatherman,  C. Everts,  D.  Kriebel,  and R.G. Dean.   1985.
Potential  impacts  of sea  level rise on the beach  at Ocean  City,  Maryland.
Washington, DC:  U.S. Environmental Protection Agency.

Titus, J.G.    1986.   Greenhouse  effect,  sea  level  rise,  -nd coastal  zone
managment.  Coastal Management  14:3.

Titus, J.G.,  ed.  1988.  Greenhouse effect,  sea level rise,  and coastal wetlands.
Washington, DC:  U.S. Environmental Protection Agency.

Titus, J.G.  1989.   Greenhouse effect, sea level  rise, and wetland policy:  will
Americans  have  to  abandon  an  area the  size  of Massachusetts?   Submitted to
Environmental Management (draft).

Titus, J.G.   1990.  Greenhouse effect,  sea level rise,  and  barrier islands.
Coastal Management 18:1.

Titus, J.G., T. Henderson,  and  J.M. Teal.   1984.   Sea level rise and wetlands
loss in the United States.  National Wetlands Newsletter 6:4.

Titus, J.G., C.Y. Kuo, M.J. Gibbs, T.B.  LaRoche,  M.K. Webb, and J.O. Waddell.
1987.  Greenhouse effect, sea level rise, and coastal  drainage systems.  Journal
of Water Resources Planning and Management  113:2.

Titus, J.G., R.A.  Park, S.  Leatherman,  R.  Weggel,  M.S. Greene,  M.  Treehan, S.
Brown, and C.  Gaunt.   1989.  Greenhouse effect and  sea level rise:  Loss of land
and the cost of holding back  the sea.   Submitted  to  Natural Resources Journal

Wilcoxen,  P.J.   1986.   Coastal  erosion  and sea level  rise:  Implications for
Ocean  Beach  and San  Francisco's Westside Transport  Project.   Coastal  Zone
Management Journal  14:3.

Williams,  P.   1989.   The  impacts of climate change  on  the salinity  of San
Francisco Bay.   In:  The Potential Effects of Global Climate Change on the United
States.   Volume A:  Water Resources.  Smith, J. and D. Tirpak, eds.  Washington,
DC:  U.S. Environmental  Protection Agency.


                                K.B. YUEN
                           Assistant  Director
                 Oceanography and  Contaminants  Branch
             Physical  and Chemical  Sciences Directorate
                  Department  of Fisheries  and Oceans
                             200  Kent Street
                   Ottawa, Ontario,  Canada,  K1A OE6

     Canada  is a coastal nation bordering on three oceans  and  possessing  over
244,000 kilometers  of  coastline -- the longest of any nation in  the world.  A
number of major cities  and highways border on the ocean.  There are also  hundreds
of fishing villages, over one thousand small-craft harbors,  and numerous fishing
plants. Many  native communities are also  located close to the  shore,  near the
marine natural  resources upon  which they traditionally depend for food.  Various
industries,  such as pulp and paper mills, coastal shipping,  container ports, and
oil refineries, are also located at the shore for  obvious marine transportation

     A rise  in mean  sea level  is  expected to have major impacts  upon  Canada's
coastal resources and infrastructure.  Fortunately for Canada, a large proportion
of the coastline rises  fairly steeply out of the sea, in the form of rocky shores
and fjords,  and is thus not at risk of flooding and erosion.  Much of Canada  is
also remote. As a  consequence  of  Canada's  particular geography  and relatively
low population densities, the potential  impacts in Canada of rising sea level,
while expected to be of substantial significance and requiring specific  policies
and  strategies for  adaptation, are  not  expected to be catastrophic   or  even
severe.  This  is  very much  in contrast to countries that possess much  more
exposed coastal lowlands  or  that simply do  not  have the physical space  to
consider alternatives  for human resettlement,  even if they wanted to do so.

     In much of Canada, coastal  impacts arising from higher ocean temperatures,
changes to river  runoff, and  related  changes to the oceanography,  circulation
patterns,  ice cover, and  hydrological  cycle  may  be  more  important  than  those
resulting  from sea level  rise.   For  example,  Pacific cod are already at the
southern limit of  their distribution  and may move north if water temperatures
increase substantially.  Canadians are generally more  concerned with noncoastal
impacts,  such as   potential  shifts   in  agricultural  and forestry patterns,


North America

hydroelectric power generation and lower water levels in the Great Lakes.  (These
impacts are addressed by the "RUMS" subgroup of IPLC work group 3.)

     In Canada,  the assessment of sea level  rise and the development of adaptive
options is still in its infancy.   In the context of climate change, four recent
studies have been carried out:   three relate to the impacts of sea level arise
on specific coastal cities (Charlottetown,  Prince Edward Island; St. John, New
Brunswick; and  Vancouver, British Columbia),  and the fourth provides an overview
of impacts in Atlantic Canada.  Generally,  these studies have been based on the
hypothetical scenario of a one-meter rise,  which is then superimposed upon the
20- and 100-year flood  levels.   This  information  is  then  superimposed on maps
of coastal resources to estimate the resources at risk. The Vancouver study also
looked at scenarios of 2- and 3-meter  rises in sea level (Figure 1).  It can be
concluded from these studies  that the  economic impacts of sea level rise can be
estimated reasonably well. However, the ability to predict the  impacts on natural
ecosystems  generally,  and on  marine  ecosystems  in particular,  has not  yet
advanced very far, which reflects  the complexities of those systems  and the level
of scientific ignorance.


     To review some of the specific  impacts that might occur in Canada and some
of the potential adaptive options,  it  is useful to  adopt  a general  hypothesis
of a one-meter rise in sea level  (as opposed  to looking at a 5-meter rise) over
the next  50 years.  Based on present  trends  and predictions,  a change of this
magnitude is  a  useful  starting point  for examining the need  for  coastal  zone
management decisions over the next 10-25 years.

     We caution  that  Canadian studies  have  not yet  considered  the  vertical
movement  of  the Earth's  crust.   Data  for  the east  coast  show  considerable
spatial variability.   For example,  in the  Gaspe Peninsula,  land  is  rising as
much  as  40  centimeters  per century;  while  in  southern  Newfoundland  (400
kilometers to the east),  land is subsiding about 50 centimeters per century; and
at the northern  tip of  Newfoundland  (a further 400 kilometers  north),  it is
rising at 100 centimeters per century (Figure 2).   Thus a rise  in  global  sea
level would not  necessarily imply a relative rise in sea level at all  locations;
it might simply  decrease the current rate at which sea level  is falling.  Similar
spatial variability has  been observed on  the west coast,  where  both  tectonic
processes and glacio-isostatic rebound contribute to sea level  change.   The
removal of groundwater and the extraction of  offshore and nearshore hydrocarbon
resources may also  cause subsidence  and compaction. The key points are that all
of the contributing processes have to be integrated to arrive  at the overall net
change of mean sea  level,  and that these changes will vary from place to place.

     Following are  some of the  key impacts  expected  in Canada and the adaptive
options to deal  with them.

                                                                 swamp r^1

                                                                  marsh EJiiii
                                                                  silt & I	1
                                                                   day I	1
                      W<     Island
               STURGEON >*         '
Figure 1.  Geologic  map of the low-'iying  Fraser  River Delta region of  heavily
populated Greater  Vancouver,  B.C.  Map shows  the location of dykes to  prevent
flooding of  deltaic  islands.   Broken  line marks  seaward limit  of the  delta
foreshore.  Arrows indicate direction of present advance or retreat of the delta
front, solid bars  denote  no change (R.E.  Thomson, personal communication).

North America
             1.0 -
                             HALIFAX TIDE GAUGE

Figure 2.  Sea level at Halifax, Nova Scotia is already rising  at  the  rate of
0.3 meters per  century.   This  is  thought  to be post-glacial adjustment,  the
greenhouse effect could greatly accelerate  the  trend.

Coastal Infrastructure

     With a rise in sea  level, coastal infrastructure related to human settlement
and industrial development on all coasts will be subjected to some  level  of
increased flooding.  In some cases, this risk will  be  new;  in others,  existing
flood  risks  will  be  exacerbated  by  increased  water  levels.     Coastal
infrastructure so affected may be grouped  into three general categories, namely:

         existing  permanent  structures that would suffer loss or damage solely
         attributable  to a  rise in  sea level.   Replacement or preventive
         strategies,   including   resettlement,   would   require   major   new
         expenditures.   However, depending on  the  magnitude  of  the  potential
         loss  or damage, investment in adaptive  options may be unavoidable. The
         loss of valuable waterfront land would also  fall into  this category, but
         it might  be offset  by reclamation/landfill  projects.

         existing  nonpermanent structures with  finite  life  expectancies,  which
         would normally need to be replaced within the  next 50-75 years anyway.
         With  careful planning,  the incremental  cost of taking  sea  level  rise
         into  account when  structures are replaced  may be negligible  in  these

        new or planned  infrastructures.  The opportunity  exists now to design
         such  structures to avoid or minimize  the impact of sea level rise, also
         at minimal cost.

     In  short,  advance planning  taking sea level  rise  into  account  before
construction  is   the  most  intelligent  and  cost-effective  approach  to  the


development of new coastal  infrastructure.   Based  on  the studies to date, the
cost of replacing or modifying coastal  infrastructures  in Canada  in response to
sea level  rise  could be in the range  of  U.S.  $3-4 billion or more.   A large
fraction of  this cost could  be avoided  by incorporating sea  level  rise into
routine maintenance and reconstruction costs.

Homes, Buildings, and Roads

     In most coastal cities,  a number  of  waterfront  properties and structures
will be subject to flooding from a one-meter rise in sea level.  Higher levels
will increase the risks posed by surface waves, tides, ice jams,  storm surges,
river runoff, and sea ice.   Accurate  risk  assessment will require detailed data
compilation and flood zone mapping at the local level.

     The mitigative  options  range  from permanent  floodproofing  of individual
structures frequently  subjected  to flooding to  temporary  protective measures
for areas  subject to  infrequent flooding.   Where there are extensive lowlands
and the value of the affected infrastructure justifies it, a  system of protective
dikes may  be created.   In  the residential  area of Richmond,  British Columbia,
south of Vancouver, which constitutes high-price real  estate located on a delta,
a diking system  already exists.  However,  it would need to be topped off to allow
for higher sea  levels,  storm surges, and waves.   Further  new  diking would be
needed if flooding threatens other farmlands within the river valley.  In the case
of much less valuable property, such as the Village of Tuktoyaktuk (comprising
Inuit homes,  oil  company exploration  shorebases,  and an airport)  located on the
shores of  the Beaufort Sea  and Arctic  Ocean,  it may  be more  cost-effective to
actually move the location  of the  town, or  at  least  the flood-prone sections,
to higher ground.  Fortunately for  Canada, few  situations will actually require
large-scale human resettlement.

     Finally,  new development on  the waterfronts of Canada's  major cities (for
residential,  commercial,  industrial,  transportation, and recreational purposes)
continues to draw considerable business  investment, simply because  the waterfront
is one of the most  desirable places to  be.  Property zoning, construction codes
and standards, and coastal  zone  planning processes need to  take into account
the explicit possibilities of sea level rise.

Municipal Sewers and Water Supplies

     A rise  in  sea  level  will  affect the  operation of  sewer  outfalls.   In
addition, there will  be flooding of existing storm and sanitary sewers located
near the water, which will  result  in either  corrosion  of the  sewer  pipes or a
backing up  of the sewer systems resulting from inhibited outflows from the higher
sea levels  at the outfall to the sea.   Such flooding will  in turn cause property
damage and  create a health risk, including possible contamination of the drinking
water  system.    In  light of  the  overriding public  health considerations,  a
modification of the affected sewage and water supply systems is inevitable.  In
many  communities,  new sewers and sewage treatment systems are being planned at
a cost of  billions of dollars.  To protect  those investments,  it is essential
to design now for higher sea levels in the future.


North America

Ports, Small-Craft Harbors, Breakwaters, and Fish Processing Plants

     By their very nature, such facilities need to be located near the water's
edge.  In Atlantic Canada  alone, there are over 1,000  small-craft  harbors, over
100 federal government wharves, 13 ferry terminals, 21 marine service centers,
and over 500 fish-processing plants.

     The routine maintenance and replacement of wharves probably could be planned
to take  into account higher  sea  level.   Wharves  will  definitely need  to be
raised.  Old Federal wharves,  for  example,  are only  1 meter above normal high
tides, but newer wharves are meters higher.   Fish plants would have to be moved
further inland or somehow modified  to keep the  work areas dry.  For small-craft
harbors,  a  rising sea would  (at  least slightly) reduce  maintenance  dredging

     On the other  hand, changes in currents, circulation, wave and ice patterns,
river deposition,  and the resulting changes  in  shoreline erosion patterns could
more than offset such savings.  Site-specific assessments and engineering studies
would be needed.  Not only might breakwaters have to  be raised to afford better
storm protection  from higher  seas,  but their location and configuration might

need to be changed to adapt to new wave refraction patterns and changes in the
way rivers deposit sediment.

Roads, Bridges  and Causeways

     Canada has an extensive  network  of  roads, small bridges,  and  causeways
throughout its coastal  region.  Many of these structures would be vulnerable to
a one-meter  sea level rise.   The  corrective measures would include relocating
or raising roads,  reinforcing and  raising  causeways,  and raising bridges -- all
at a cost significantly greater than normal maintenance costs.  Some major new
causeways are at the  planning  stage -- e.g, the causeway to  Prince Edward Island
-- but proper planning can allow for higher sea level  and changing ice regimes.


     Coastal erosion is a  problem  in many parts of Canada, especially  on the
east coast (Figure 3).   In some cases, shores are retreating as  much as 5 meters
each  year.  Sea level  rise  is generally expected to aggravate  the  problem.
However, the actual response of vulnerable shorelines will also depend on changes
to wind  and wave  patterns,  currents,  the geology and geomorphology,  the ice
regime, local land subsidence, and  sediment supply limitations.  Our ability to
predict  the  timing and  magnitude  of  changes to erosion  patterns will require
further  research  on a   site-specific  basis.    Realistically,  however,  the
implementation  of shoreline  protection  measures  will  only  be  economically
feasible  for  those  areas  where   the  value  of the  shoreline  investment is
sufficiently high, such as residential  and recreational developments, harbors,
power plants,  and  other infrastructure.

Figure 3.  Accelerated erosion can be  expected  in  places  where an increase in
mean  sea  level  would allow  wave-induced  erosion to attack  vulnerable cliffs
instead of dissipating on the beach,  as in this area at the head of the Bay of

Tidal Power

     One of the  more interesting  coastal development concepts in Canada is that
of tidal power  in the Bay of Fundy, where  the  tidal  range is as much as 10-12
meters in  some  locations.   From  numerical  models,  it  has  been calculated that
an increase of 1 meter in sea level at  the  ocean  entrance (Georges Bank) would
increase the tidal range at  the head of the bay  by  about 1.7% -- that is, by 20
centimeters.  Therefore,  the height of  the  tidal  power  barrage would need to be
raised by  about 1.2 meters.   Fortunately, the  increase  in tidal  range also
results in greater power output,  so that if development proceeds, the increased
cost of engineering and construction  will  be roughly balanced by the increased
revenues from power generation.


     The question of impacts  in  our estuaries  has  not  generally been resolved
and requires further research and site-specific  studies.   In general, one would
expect a rise in sea level to extend  partway upstream,  which would raise water
levels and salinities.  However, water levels will  also be directly controlled
by the extent of river outflows and ice cover.   Outflows will  vary from one part
of the country  to another and require  accurate predictions of temperature and

     In the St.  Lawrence River,  a  related  concern  is  the  expected lowering of
water levels in  the  Lower Great Lakes  by 30-80 centimeters, which would decrease
the outflow of the St. Lawrence River by 20%.   This, in turn, would not likely


North America

decrease water  levels in the  river.   The  net result of  these complexities,
including crustal movements, is considerable  uncertainty in the expected rise
or fall of  sea  level  in  our estuaries, and it is too  soon  to design adaptive
strategies. Much more basic and site-specific hydraulic research  needs  to be
conducted before we even know what conditions we need to adapt to.  (Note: The
drop in lake levels  is independent of sea level  rise,  and is generally, expected
to result from increased evaporation at higher temperatures).

Agricultural Lowlands

     A small percentage  of  Canada's agricultural production  takes place near
the ocean shoreline, primarily in  the  Fraser River delta and in low-lying lands
on the east coast.  Many of these  areas  are  already  diked,  and they also have
"aboiteaux," which are essentially  tidal gates that  allow water to drain from
these lands during low tide.  The solution to combat  sea level rise will  be to
gradually increase  the height  and extent of these structures.   Moreover,  new
dikes and weirs  may need to be built  along  the  shores of the  Fraser  and St.
Lawrence Rivers as rises in sea level  extend farther  upstream.

Marshes, Wetlands,  and Wildlife Habitat

     The key areas  that may be affected  are easy to identify  and  are  located
mainly in the major estuaries  and  deltas  (the  Fraser,  St.  Lawrence, MacKenzie
Rivers) and low-lying lands along the southern shores of Hudson Bay and on the
east coast.  However,  the impacts are not so easy to  predict.

     No doubt,  a sea  level  rise will  inundate  parts of these  habitats.   But
where topographic gradients  permit, and if sea level changes slowly enough, these
productive  systems  will  hopefully  reestablish  themselves  farther  up  the
shoreline,  and various biological species  and their food  supplies will recolonize
or adapt to their new surroundings.  It is also possible that such habitat may
not be reestablished.   For  large remote  areas, such  as Hudson  Bay, it  is very
likely that no adaptive  options are practical, except to allow  nature  to run
its course.  For less remote  areas, critical habitat might be replaced by manmade
development of new habitat at nearby locations, but  at  considerable effort and

     For some fish  and other species  of economic  importance, new habitat is
already being created  as part of a Fish Habitat Management Policy, which strives
to achieve  no net  loss of natural  habitat.  On the  west  coast of  Canada,
significant amounts  of new habitat  for  salmon have been created by planting eel
grass  in  several major  salmon estuaries.  Further   habitat  development  is  a
practical  means  of mitigating losses of salmon and trout habitat from sea level
rise in estuaries and  rivers.

     Economic  approaches  also  exist  to  replace  lost  production  of  certain
economically valuable fish  species that  spawn or grow  in  estuaries and  the
nearshore.    Salmon  are  being  produced  on  a  large  scale through artificial
enhancement, in  which eggs  from wild  fish  are recovered during  the  spawning
season and  grown in temperature-controlled  hatcheries  to an  appropriate size



before being released to the  sea.   This  approach  does not resolve the habitat
problem per se,  but  it does contribute to  sustainable development and economics.

     Another solution to  the economic problem is commercial  aquaculture.  In
Canada, a considerable aquaculture industry  has developed over the past decade,
mainly for salmon,  oysters, and mussels.  The  industry's  value has grown from
$13 million in  1982 to  $100 million in 1988, mainly  on the Pacific coast, and
further major expansion, especially to the east coast, is projected.  Clearly,
there  is  an economic  opportunity  here that can also  assist  in mitigating the
effects of rising sea level.

     Finally,  it must be noted that the  key climate  issue facing fisheries in
Canada is not sea  level  rise, but the changes in water temperatures, circulation
patterns, wind-induced  upwelling,  and other factors that will   determine the
future distribution,  recruitment,  and  production of fish.  This    has  major
implications for national  and  international  resource management  strategies and
agreements, fishing industrial  strategies, and  regional    economics.    (See
Everett,  Volume 1, for  additional  discussion of response strategies to protect


     From a coastal  zone  management  point  of  view,  a considerable  degree of
skepticism exists in Canada regarding the risk of sea level rise over the next
few  decades  and  beyond.    It  must  be  recognized  that  while  research  and
understanding of climate change takes place at national  and international levels,
a large part of  the  decision making to mitigate  local and regional effects takes
place at the local or regional level of government.  At what stage of research
and assessment will  there be sufficient knowledge and understanding to encourage
or persuade natural  resource managers and local officials to actually allow for
higher sea levels  in  planning for  habitat  management  and  protection;  for the
owners of real  estate and infrastructure in the coastal zone to actually spend
money  to floodproof  existing  buildings or  to   invest  in  diking  and  other
protective measures,  or to make  the increased investment in  planned  coastal
works needed to avoid future flooding, or even to ensure that rising sea level
is taken  into account in existing coastal planning and decision making processes?
Whatever that point  of credibility may be, it is clear that we  are  still far from
reaching that point.

     Where,  then,  do we  go  from here? I  believe that the following actions are

         Continue   research  on  global   climate   change   to   reduce  current
         uncertainties in the prediction of sea  level rise resulting from global

         Encourage further  research  and monitoring related to sea level  change,
         which must include the contribution  of vertical movements  of the Earth's

North America

         crust  and groundwater depletion to relative sea level  change  as well as
         global  warming  effects.

         Develop  regional   models  for   climate   change,  and   carry   out
         multidisciplinary  site-specific studies that integrate all the factors
         that  influence net changes to  water levels in  estuarine and coastal
         areas,  including interactions  among precipitation and runoff,  tides,  ice
         cover,  crustal  movements,  erosion,  sedimentation, storm surges,   and

        Improve the scientific understanding of marine  coastal  ecosystems in
         order  to conduct ecological  impact  assessments  related  to rising  sea

         Develop detailed inventories  and mapping of coastal infrastructure  and
         natural  resources in areas potentially affected by changes in  sea level,
         in  order to facilitate  improved impact assessments.

         Continue research into coastal geomorphology and  sedimentology in order
         to  understand  coastal  erosion  processes,   to  predict the  impacts of
         higher sea  levels,  and  to develop adaptive  strategies.

         Encourage multidisciplinary impacts  research related  to  sea  level.

         Encourage the  innovation  and  development of adaptive  options.

         Facilitate  the  public dissemination  of  information and research results
         relating to sea level rise.

         Encourage   those  involved  with  coastal   zone management,   building
         standards/codes, property zoning, and sustainable development planning
         to  take into account the  future possibilities for rising sea levels.
         Development of flood-prone  lands  must  be  discouraged,  by  legal
         prohibition if  necessary.


Anon.  1989.  The full range of responses to anticipated  climatic change.  United
Nations Environment Program and Beijer Institute,  April.

Forbes, L.B.,  R.B. Taylor,  and J.  Shaw.  1989. Shorelines and rising  sea levels
in eastern Canada,"  EPISODES,  Vol. 12, No.  1, p.  23-28.

Lane, P. et  al.   1988.   Preliminary study of  the possible  impacts of a one-meter
rise in sea level at Charlottetown, Prince Edward Island.  Climate Change Digest,
Report No. CCD 88-02, Environment Canada,  Ottawa,  Canada.

Martec Limited.  1987.   Effects of a one-meter  rise in mean sea level at Saint
John, New Brunswick and the lower reaches  of  the  Saint John River.  Climate



Change Digest, Report No. CCD 87-04, Environment Canada, Ottawa, Canada.

Sanderson, M.  1987.  Implications of climatic change for navigation and power
generation in the  Great'Lakes.   Climate Change Digest,  Report  No.  CCD 87-03,
Environment Canada, Ottawa, Canada.

Scott, D.B.,  and D.A. Greenberg.   1983.   Relative  sea level  rise  and tidal
development  in  the Fundy Tidal  System.   Canadian Journal of Earth  Sciences,

Smith, J.V.   1989.  Possible impacts of mean sea level  rise scenarios on downtown
Vancouver. Unpublished manuscript prepared for Atmospheric Environment Service,
University of Waterloo,  Ontario, Canada.

Stokoe, P.   1988.   Socioeconomic  assessment of  the physical  and  ecological
impacts of climate change on the  marine environment  of  the Atlantic  region of
Canada -  Phase  1.   Climate Change Digest,  Report No.  CCD 88-07,  Environment
Canada, Ottawa,  Canada.


                       MARIO ARTURO ORTIZ  PEREZ
                            CARMEN VALVERDE
                         Institute  de Geografia
               Universidad Nacional Autonoma  de Mexico
                          Mexico City,  Mexico

                            NORBERT P.  PSUTY
             Center for  Coastal & Environmental  Studies
            Rutgers - The  State University of New Jersey
                       New Brunswick,  New Jersey

                              LUIS M. MITRE
                         Institute de  Geologia
               Universidad Nacional Autonoma  de Mexico
                          Mexico City,  Mexico

     Mexico's Gulf of Mexico coast is largely lowland subject to a large range
of marine  influences.  Of six large lowland  areas that are  subject to relative
widespread flooding, four are within deltaic systems.

     The coastal  zone has been undergoing considerable change as a result of port
development  related to the extraction  of  oil and to the concentration  of oil
refineries and  petrochemical plants.  This area has  also undergone a  great
expansion  of commercial  agriculture,  cattle ranching,  and high-cost  tourist

     There are,  at present, many conflicts  between the development interests and
the  local  economies  based  on  the  coastal  resources.    The intensity  of
exploitation is  currently causing serious deterioration of the environment, which
is produced  by  a combination of the  cultural  processes  superimposed on  the
natural changes.  The losses of marshlands, mangroves, and other aspects of the
coastal aquatic system are problems that need to be addressed.  Although attempts
have been  made to control some of the changes by constructing coastal protection
devices,  these  "solutions" have  been neither well-planned  nor successful.   An
awareness  of the dynamics  of the coastal  system and the  changes  driven  by  a
rising sea level must be introduced into the decisionmaking process.


North America


     Approximately two million Mexicans live within five meters above sea level.
Although a one-meter rise would inundate only a fraction of the nation's coastal
zone,  it  would  threaten some of  the most  valuable  land,  including tourist
resorts, port  facilities,  and  the wetlands that  support an  important fishing

     The intent  of  this  paper  is to summarize the present state of knowledge
concerning  the   physiographic   information,   the  wetland  areas,   and  the
socioeconomic  aspects  of the Mexican Gulf  Coast  and  to identify  some  of the
impacts to the system as a result of a future sea level rise.


Physical Effects

     Sea level  rise  particularly threatens the barrier  islands along the Gulf of
Mexico; as  sea  level  rises,  they will  gradually  narrow  and some will  shift
inland.  The islands in front of the southern portion  of the  Laguna Madre will
certainly shift  landward,  and additional  inlets  are  likely to  form,  further
segmenting these islands.    On  the other  hand,  the barrier in front  of the
Tamiahua Lagoon  will narrow  at first, although it  will eventually break up as

     The  high,  dune-lined  barrier  islands  near Veracruz,   Alvarado,  and
Coatzacoalcos have sufficient size and mass to resist  erosion,  at least in the
early years.   There will  be  some loss of sediment and there will  be  a slight
shift of the beach  into the dune zone, but the effects will  be  limited.   Along
the Tabasco-Campeche barrier  system, the effects will vary:  In western Tabasco,
the barriers in front of most of the smaller lagoons will be removed by overwash
and breaching,  creating  a very  indented  shoreline.   The  area  from  Tupilco,
Tabasco, to Champoton,  Campeche,  is very low but very wide.  Along this segment,
the coast will  erode at a very rapid rate as sea level  reaches to higher levels
and removes sediment from the low-lying beach ridges.  The oil port  of Dos Bocas
will be increasingly exposed to storm effects and breaching of  the jetties and
shore protection structures.

     The very narrow barrier along the Yucatan Peninsula will diminish greatly
in size and probably break  up.  The salt-evaporation ponds at Progresso will be
threatened as they are  initially  overtopped by inundation with higher sea level
and then erosion as they become exposed to wave attack. The  barrier island at
Cancun will  become every narrower and more liable to storm  damage as sea level
rises, thus threatening all existing and future infrastructure.

     Mexico's   wetlands  would  also  be  vulnerable to  a rise   in  sea  level,
especially given the impacts of  economic development.   Their inundation would
normally be  balanced  by an upward  growth  as  organic and  inorganic  matter
accumulates to a new level.   The problem  of  sea level rise is  compounded in


                                                                 Ortiz, et a7.

Mexico because nearly all  of the major  rivers leading to the vast wetland areas
are dammed and the  sediment  supply has been attenuated for decades.  The product
of the sea level rise  and a decreasing sediment  supply  will  lead to a loss of
wetland area and a  loss of primary productivity of the wetlands, the estuaries,
and the adjacent nearshore areas.  This could lead to serious deterioration of
the  local  fisheries  industries,  independent  of  problems  of  pollution  and

     The wetlands of  Laguna Madre and the Tamiahua Lagoon have already shown the
effects of a  limited  sediment supply.  Their bordering wetlands  are very narrow.
The Alvarado Lagoon and the  Papaloapan  lowlands will show a considerable change
both as a result  of the higher water  level and the severe  loss of sediment supply
coming into the estuary.

     The Grijalva lowlands will be the most seriously affected because it is the
largest wetland  area in Mexico  and  because of local  subsidence  and  sediment
starvation associated with the Malpaso Dam.  Wetlands are already migrating onto
the slightly  higher  coastal  beach  ridges and sand  dune topography, while the
bodies of open water are increasing  and the  shoreline is migration inland.  The
new population centers there and the petroleum industry will be affected as the
water table rises and it becomes more difficult to drain the surface water off
the land and lead the sewage away.

Socioeconomic Implications

     Port activity  could be  affected by the  sea level rise,  especially in areas
where the  infrastructure  is essentially at beach level, such  as at Campeche,
Ciudad del  Carmen,  Frontera, Dos Bocas,  and parts  of  Coatzacoalcos and Veracruz.
In Carmen, Frontera, and Dos Bocas,  there is no higher  ground to accommodate a
landward retreat.  The  landscape is  only  a  few meters above  sea level  and any
increase will expose these sites to greater storm damage.

     Much of  the lowland is  used  for  some type of economic  activity.   Oil
exploration is certainly a common use throughout much of the coastal plain, and
it is especially  prevalent in the Tabasco lowlands.  In addition, cattle pasture,
coconut  plantations,  cacao,  maize,  sugarcane,   lumbering,  and  fishing  are
important economic pursuits.  With  the  exception  of fishing, all  of the other
economic activities will be  adversely affected by a  higher sea level because of
the changing salinities and water table.  Whereas the entire area will  not be
affected uniformly, the net  effect will  be a loss of surface area where each of
these economic activities  can be practiced.  The petroleum industry will be able
to conduct its exploration phase despite sea level rise.   However, some of the
stationary infrastructure may  be negatively affected as shoreline  erosion or
higher water levels begin to encroach upon these structures.


     One can  reasonably  expect that revenue-producing activities such as tourist
beaches, ports,  and  petroleum activities will  be  protected with  traditional
coastal engineering measures.  The casualties in  this process will  almost


North America

certainly be the environment and people pursuing traditional  activities who lack
the necessary resources to hold back the sea.

     The coastal environment in Mexico is currently being exploited in manners
likely to have an adverse impact in the long run.  If we are unable to adequately
address current environmental  problems, how can we prepare for consequences of
a rise in sea level that is still decades away?

     Nevertheless,  Mexico does have institutions that are capable of planning for
the future, provided  that  the  actions  do not substantially  undermine economic
growth.  In this regard, it seems wise to direct future coastal development to
areas that are at least three meters above sea level; not only would this prevent
future environmental impacts,  but it would leave these  areas less vulnerable to
flooding even  in the  short term.   Similarly,  along the ocean coasts,  tourist
facilities  should   be  set  back  from  the  shore;   this would  make them  less
vulnerable to hurricanes and would enable the beach to survive accelerated sea
level rise.

     But perhaps the most  important  first step  in  planning  for sea level  rise
would  be  increased  awareness  on  the  part  of  the  public   in  general  and
governmental officials in particular.  Information transfer is a slow process.
This is an area where researchers and universities can play an important role,
rather than being outside observers and critics  of governmental processes.  The
scientists and economists  in Mexico need to  begin  discussing  the implications
of global  climate  change,  so  that  we  can  better  inform the  policy  makers  of
possible responses.

     We note in particular that the Sea Grant  College programs of California and
Texas are interested in collaboration with Mexican  scientists.  We strongly urge
these organizations to collaborate with the relevant Mexican Universities on the
issue of sea level  rise, with the  goal of a  bilateral  conference  on  sea level
rise similar to the Miami conference but  focused on the common coastal  problems
facing states on either side of the U.S./Mexican border.


Coastal Geomorphology

     The Mexican  coast on the Gulf of Mexico has  a length of approximately 2,500
km.  The  coastal  plain has a width varying from 30 to 150 km.  The coastal  relief
generally is even and  low,  being  traversed by more than 25 important rivers and
incorporating 23 coastal lagoons of  very different sizes.   The coastal  inlets
are  very important owing  to  the  different  transitions  between the  barrier
islands, river mouths, and deltas, linking floodplains,  lagoons, marshes, swamps,
and mangroves.

     The rocky coasts appear in  short  sections and are of  low  altitude;  some
are composed  of  compact volcanic  rocks  forming isolated promontories  on  the
general coastal  outline.  On the Caribbean margin,  the coast is rectilinear and


                                                                 Ortiz, et al.

rocky with short sections  of  indented  configuration.   Escarpments are low and
formed  in  calcareous rocks incorporating  a narrow abrasion  and accumulation
platform, isolated from the open sea by a coral barrier.

     The predominant  types of coast are  sandy beaches (1,629 km),  followed by the
swampy  coast  and marshes  (389  km), very  important  around the  estuaries and
lagoons; the rocky coast has a length of 382 km.


     The regional climatic  characteristics  of the Mexican Gulf  Coast are the
dominant pluviometric system  and  the yearly temperature distribution (Garcia,
1989).  Garcia divides these elements into three broad zones that from north to
south are as follows:

       The Tamaulipas northern coast,  which is hot and arid,  characterized by
        temperatures higher than 18C during  all the year, with  a yearly rainfall
        of  less  than  800 km.   Seasonally,   it  has  an  extreme climate, with  a
        yearly thermal range of more than 14C.   During the winter it receives
        cold  wind masses and  during summer torrential  rains associated  with
        cyclones or tropical storms.

       The central part of the littoral is  subhumid toward the north and humid
        at the south,  with  an  average yearly temperature that  varies from 22C
        to 26C and a yearly rainfall between 1,000 and  1,500 mm, increasing to
        the south.  During  the winter the coast receives north winds, that is,
        cold  wind  masses,  and during autumn,  the easterly tropical  waves are
        common.  The  rest of the year the trade winds are dominant.

       The southeast  section comprises the  complete Yucatan Peninsula.  It has
        a circulation system similar to the above, with the  exception  of the
        temporary stationary high  pressure  cell  over the south-central section
        of  the  gulf.   The  high pressure cell  is  responsible  for a  series of
        climatic zones that vary from a dry  semi arid condition at the northwest
        end of the peninsula to a  subhumid climate toward the  south and
        southwest interior.

     The gulf is a favorable area for tropical cyclones and their accompanying
floods and  storm tides (Jauregui,  1967).  Almost 35% of the cyclones originating
in the Caribbean Sea  touch or cross the  Mexican coasts. Winters contribute storm
waves caused by the north winds, in addition to the  frontal rains and orographic
rainfall created when the humid air masses  collide  with  the slope of the Sierra

Waves and Currents

     Three  types  of   wave  regimes  are  found at  the  Gulf of Mexico  and the
Caribbean coast (Lankford,  1977):

       waves and storm surge  associated with the tropical cyclones;


North America

      waves and storm surge associated with the movement of polar wind masses
       known in Mexico as north winds (Nortes); and

      waves and wind surge  that  is  generated  within  the limited fetch of the
       gulf basin.

     The dominant winds  show a preference for directions  from  the northeast,
east, and southeast quadrants.  The wind waves typically have short periods of
between 5 and 7 seconds,  and  the average heights are of 2.3,  2.3,  and 1.4 m from
the northwest,  north,  and northeast,  respectively  (Lankford, 1977).  In general
terms they can  be considered  as intermediate to low energy waves,  except for the
north wind and hurricane  situations, where waves  of more than 4.5 m have been

     The hurricanes occur in the summer, causing intense storms.  The cyclonic
paths  show  a  preference  in  their course  for the  Yucatan Peninsula  and  its
platform, crossing it, and more frequently approaching the northwest coast than
the southwest coast.

     The Nortes develop  between October  and February.  Each year between 15 and
20 Norte events occur, each  one with  a duration of 1 to 5 days.   It is frequent
that they exceed 100 km/hr,  creating storm tides that  inundate lowlands,  erode
the shores,  and transfer sediment in numerous directions.  There is a movement
of sands in  the dune fields, with an orientation from north to south, prograding
the coastal  lagoons to the lee.

Cultural and Economic Features


     The coastal zone of the  Gulf of  Mexico is  shared  by six  states of  the
Federation:   Tamaulipas, Veracruz, Tabasco, Campeche, Yucatan, and Quintana Roo,
with a total  of 57 municipalities which together in 1980 had  a population of 2.8
million, representing the 4.1%  of the total population  of  the country (Table 1).

     Even though the Gulf of Mexico coastal  zone has a long tradition of human
settlement,  at present it does not have a dense population.  In  recent decades
there is a slight tendency toward  an  increasing  population,  especially in  the
urban areas.  In the year 2000,  it is estimated that the coastal zone will record
a population of 4.5 million inhabitants, that is,  4.7% of the total population
of the country.

Distribution of Human Settlements

     Of the 2.8 million  coastal inhabitants  in 1980,  70% lived  at an altitude
between 1 m and 5 m, mainly along the coast or at river borders very near their
mouths.  About 60% of the coastal  population reside in cities (Table 2);  44.9%
live in cities with more than 100,000 inhabitants.

                                                                 Ortiz, et al.

Table 1.  Total Population of Mexico and the Gulf of Mexico Coastal States and
          of the Coastal Zone, 1960-2000
    Area                1960          1970      1980         1990      2000
Country                34,923,129  48,377,363 66,846,833  78,140,006 1,802,174
Coastal States          5,080,858   7,138,668 10,090,396  1,244,617 14,950,947
% Total Country             14.55       14.76      15.09       15.93     16.29
Coastal Zone            1,236,269   1,864,189  2,792,613  3,526,055 4,303,529
% Total Country              3.54        3.85       4.18        4.51      4.69
% Total Coastal States      24.33       26.11      27.68       28.33     28.78

Source:Censos Generales de Poblacion (1960, 1970, 1980).
Table 2.  Distribution  of the Coastal Zone Population by Size of the Settlement,
          1980 (Size of the settlement by number of inhabitants)

                    1-999    1,000-   15,000-   20,000-   more than     Total
                            14,999    19,999    99,999     100,000
No. of villages
Total Population
Source:  General Population Census (1980).


     In  general, all  the states  that  constitute the  gulf coastal  zone have
important cities (Table 3).  There are other smaller  cities  that during the last
decades have obtained great importance, registering a high rate of demographic
growth, such as Ciudad del Carmen in Campeche and Cancun in Quintana Roo.

     Most  of  the cities  with  more  than  15,000  inhabitants perform  harbor
functions; included here are the largest with the exception of Matamoros.

Port Facilities

     The region  has 56 ports, of which 17 are  sea  ports  and  the rest are fluvial
ports.  Major ports  are located in the  States of Tamaulipas, Veracruz, Tabasco,

North America

Table 3.  Population of the Cities With More Than 15,000 Inhabitants, 1960-2000
Tamp i co
Gtz. Zamora
Source: General Population Census (1950, 1960, 1970,  1980).
alt  was not possible to make a projection of the Cancun population, because it
 is  of recent creation  and has no population register for the period 1950-1970.
and on the coast of the Yucatan Peninsula.  The gulf coastal  zone is important
because of the petroleum industry,  both  in production as well as in processing.
From the coastal zone of Tamaulipas, Veracruz, Tabasco, and Campeche is extracted
most of the Mexican oil.  In 1985 the zone had 370 fields  (S.P.P. 1986, p. 88-
110).  The processing industry  is represented by petrochemical refineries.  The
most  important petrochemical  complex  is  Coatzacoalcos-Pajaritos-Minatitlan-
Cosoleacaque-Cangrejera; it is  primarily located along the  lower Coatzacoalcos
River.   The  complex has 33 petrochemical plants:   12 in Cosoleacaque,  11  in
Minatitlan, 13 in Pajaritos, and 21  in  Cangrejera.   It also  has a refinery in
Minatitlan, with a capacity of 258 thousand barrels per day.

     In 1985, this complex,  together with the one at Ciudad Madero, also located
in the  gulf coastal  zone,  had the  highest  production in  the country.   The
production obtained was 968 million barrels of crude oil  and 1,186,667 million
cubic feet of  natural  gas  (S.P.P.  1986, p.47), representing 98.1%  and 90.2%,
respectively,  of  the  total  production  in  the   country.    With  regard  to
petrochemicals, in 1984 the production  of refined  oil was  200  million barrels
and petrochemicals amounted to  8.5 million metric  tons;  that is 41% and 74% of
the yield in the country.

     Equally important is the oil-line and gas-line net in  the State of Tabasco
that starts at the Sonda de Campeche  with a terminal  at the port of Dos Bocas.


                                                                 Ortiz, et a/.

Also, Campeche has the majority of maritime production platforms in the Gulf of
Mexico, with a total of 48 (Ecodevelopment,  1988).

     Recently  the  first  nuclear  electric  plant  at Laguna  Verde started  to
function.  It is  located on the Veracruz coast 70 km northeast of Veracruz.  The
plant has two units, each one with a capacity of 654,000 kilowatts.

     Even  though  the gulf coastal  zone  and  the Mexican Caribbean  have had  an
uneven  touristic  development,  it  is  important  to point  out the  touristic
installations exist in some points  of this  region.   Located in the Caribbean,
Cancun  is the  principal  touristic node.  In  only one decade  it  has  risen  to
become the most important tourist  site in the country.  Its development has been
totally planned.   It was principally created  to satisfy an international demand.
In 1988 it was able to offer lodging in 9,520 rooms.

     Veracruz and Cozumel  are also considered to  be important touristic centers.
In 1988 they were  able to offer  4,400 and 2,320 rooms  respectively.   Veracruz
covers principally the demand for national  tourism, while Cozumel  is  important
for  international tourism.

     The  ports and installations  mentioned  having the  greatest   exposure  to
effects caused by the sea level increase are Tampico,  Alvarado, Coatzacoalcos,
Dos  Bocas, Frontera, and Ciudad  del  Carmen.   Each has  an altitude that varies
between 0 and 3 meters.

    At the coastal zone,  the combination of different elements of the hydrologic
cycle creates two great natural systems:  (1) the coastal lands system and (2)
the coastal waters system (Toledo, 1984); both are highly productive.

Use of the Land of the Coastal System

    The use  of  the  land  (Table 4)  of the first mentioned systems,  the coastal
lands, can also be divided in  two:   (1)  one of  natural origin and (2) the other
introduced by man.

    In the Tamaulipas coastal  strip, dry shrub vegetation is dominant.  Forest
cover is located  in well-defined  areas,  presenting  some variants  depending of
the rainfall requirements.  A  small  portion  at the  northwest  and  north of the
Yucatan Peninsula completely lacks vegetation.

    Among the land uses introduced by man, one  is extensive cattle raising that
takes great advantage of the natural pasture characteristic of the zones.  New
pastures that have technically modified  some  ecosystems  as the forest have also
been introduced.  The  use of the land for natural  and induced pasture covers the
largest surface area (25%) of the coastal zone.  Most of the cattle production
in the zone is destined for the internal  market, principally  in the central part
of the country.


North America

      Table  4.   Use  of the  Land  in  the Coastal Zone of the Gulf  of  Mexico
  Use of the Land
      Surface in km2

Partial            Total

Partial   Total
Pasture ground

Bush                       6257
  Tamaulipas Bush           375
  Mesquite                 1278
  Rosettophyle Bush        1809
  Cacicuale Bush           2795

  Low Perennifoil           979
  High Subperennifoil      7335
  Medium Subperennifoil    1118
  Low Subperennifoil       1558



Tular and popal





Without irrigation
4542 9.3
    Of less  importance  is  the use of the agricultural land  in  its  two forms,
natural  and irrigated.  For the latter, the most  important  zone is  located at
the north of the coastal region (Tamaulipas)  near the U.S.  border, principally
dedicated to  the  cultivation of  cereals.   In non-irrigated  agriculture,  the
commercial  monocultivation  plantings   (sugarcane  and  bananas)  are  located
principally in Veracruz and Tabasco.

Use of the Coastal Waters System

    The water system  is one of  the  most important  systems  in the coastal  zone
for its  fragility as  well  as for its  ecologic conditions,  and  because  it is
highly productive.  It can  be  divided into two subsystems, both intimately tied

                                                                 Ortiz, et al.

through physiographic and  ecologic  processes  in  a way that --  on  one hand --
there is the vegetation typical of the system (mangrove,  Tular, and Popal) and
--on the other hand -- there are the waters.

    The mangrove is principally limited at the border of the coastal lagoons and
in the mouths of the rivers.  The most important associations are located in the
Tabasco and  Campeche  littorals.  The red  mangrove is characteristic of  this
community, reaching heights up to 25 meters; it is used for marine construction
and in the manufacture of charcoal (Ecodevelopment Center, 1988).

    The Popal,  or  marsh,  consists of an  association of hydrophytes,  including
Thalia, Cyperus, Colathea.  and Heliconia.  Very often,  it  is found together with
tulares.  The greatest extension  of this type of vegetation  is located at the
south of Veracruz and in Tabasco.  Commonly it is burned during the dry season
to take advantage of the land for cultivation.

Economic Importance of the Coastal Zone

    The  Gulf of  Mexico  coastal  zone has  played  an important  part  in  the
development  of  the country.   At the beginning  of the  20th  century,  it was
distinguished for  plantation  agriculture (sugarcane,  banana,  and  sisal, among
others).    Later,   it  acquired  importance  for  commercial  cattle  raising,
principally for the internal markets.  During the  last  decades, the oil industry
has become the most relevant  economic activity.   It is important  to  point out
that the coastal states (Tamaulipas, Veracruz, Tabasco, Campeche,  Yucatan, and
Quintana Roo) contribute 14.7% of the gross  internal  product of the country, and
the coastal zone contributes 3.9%.

    At  present, plantation  agriculture  is still  the most  important  in the
coastal zone (INEGI, 1985).  The region contributes 47.3% of the sugar production
in the country.  Of importance is the irrigation agriculture, especially in the
coastal plain of the  State of Tamaulipas that produced  41.5%  of  the national
sorghum that year.

    Cattle raising has been acquiring great  importance, principally the breeding
of bovine cattle.   The region  had 26.4% of the national production of this type
of cattle  in  1983.  But,  undoubtedly, the  oil  industry has  distinguished this
region for  its  crude  production as  well  as  for  petrochemicals  (see industrial


    The  Gulf of Mexico  and the  Caribbean  coastal  zone  with  its 2805  km of
coastline, its 771,500 km2 of exclusive  economic  zone, and a broad continental
shelf, represent a significant fishing zone, even though  not the most important
in the country.  Outstanding within the region are the Campeche sound and some
tropical fisheries.

Worth America

    Fishing in the region,  even though limited principally to the littoral zone,
including the  coastal  lagoon  systems,  is also carried out in  the shelf.   The
State of Campeche has  excelled in  this  type  of fishing.   As  a whole, the zone
had a 1983 production of 275,493 tons (INEGI, 1985).

    When  studying the  fisheries  of the  region,  great differences  are noted
between the Gulf of Mexico  and the Caribbean.   The first presents a sustained
production, carried out principally  on  the continental platform.   In 1983,  it
registered a value of production of 3,842,141  million pesos.  The most important
species captured are shrimp,  oyster, clam, crab,  sea fish, mullet,  and snook.
In the Caribbean zone, even though the fishing activity is  not so important, some
fisheries have developed that  have economic importance (snail and lobster).  The
value of the fishing production of the zone represented in  1983  a value of 7576.5
million pesos.  Among  the  fisheries  of  the region,  the most  important are the


    Shrimp represent  a great economic  value,  and a considerable part  of the
production is exported. Shrimp from the Gulf of Mexico have a benthic habitat;
they are distributed from  the littoral  lagoons up to 200 meters  depth  on the
continental platform   (Ecodevelopment,  1988).   According  to the  catch figures
for 1985,  the Gulf of Mexico littoral contributed 25,149 tons,  which represented
33.8% of  the  national  production  (Secretaria de  Pesca,  1977).   In  1984,  100
shrimp cooperatives were registered, with bigger vessels destined to catch shrimp
in  the  open sea.   Seventy-nine  cooperatives  shrimped  in  the estuaries  and
lagoons.  The former reported 76.9% of the shrimp production and the latter 23.1%
(op.cit.). Most of the estuary shrimp are obtained at Laguna Madre and Tamiahua
Lagoon (97.2%).


    The oyster resource commercially exploited  in  the Gulf of Mexico's littoral
is principally the sand bank oyster or  American oyster (Crassostrea virqinica)
and, of less importance, the mangle oyster (Crassostrea rhizophora).

    The oyster fisheries that have  developed in the  Gulf of Mexico's littoral
are the most important  in the country; 96% of the national  production originates
from them.  The principal oyster fisheries are located in  the  following coastal
lagoons:  Laguna Madre, Laguna de Pueblo Viejo, Tamiahua, Lagunas Carmen and
Machona, and Laguna  de  Terminos.

    In the Gulf of Mexico, 52 cooperative societies exploit the oyster, but only
11 of them register 80% of the total production.  Together, the 52  cooperatives
employ approximately 15,000 fishermen.

                                                                 Ortiz, et al.


Social Context

    The developing countries present numerous  problems, which in some instances
become more  serious  because of the inadequate handling of  the resources they
have.  A clear example of this situation are the Mexican shores of the Gulf of
Mexico and the Caribbean.

    Recently, the  region has registered a remarkable economic growth.   Going
from  an  almost  isolated rural  region,  commercial  cattle  raising,  tropical
plantations, the petroleum activity, and tourism have dramatically altered the

    One  can question whether  these changes  have  been for the better.   The
development of the region  has  often proceeded as if the  only  objective is to
maximize current revenues without regard for  the future.  The  economic growth
of the region has had high social and environmental  costs.  Toledo (1984), for
example, argues  that petroleum exploitation is responsible for a substantial
degradation  of  the  environment.   Similarly,  the  extensive growth  of cattle
raising and agriculture has been at the expense of the natural  vegetation.

    Even though the area has registered an  accelerated economic growth, much of
the population  receives no  benefit;  many  people  are economically  marginal,
performing economic activities  in the traditional way, in large  part because the
people inhabiting the coastal regions  are not  trained to compete within the new
labor markets.  Yet the introduction of the new economical activities has greatly
altered their standard of living.

    Another  aspect that characterizes the urban development of the  region is
the spontaneous  settlements, principally  inhabited  by  people  left  behind by
economic  development.   Nolasco  (1979)  estimates  that  for  the year  1990,
Coatzacoalcos and Minatitlan will have  a  "marginal"  population of 182,488 and
123,931  inhabitants, respectively,  representing 86%  and  73%  of   the  total
population.   This   enormous  population  is  not  only marginal   socially  and
economically within  the urban space,  but  it  is spatially  relegated to those
places with the most adverse physical  conditions for urbanization, potentially
the most exposed to the negative effects of sea level rise.

Environmental Regulation

    Given  the threat to coastal  environments, Mexico has  taken some  measures
-- but because they  were started too  late,  they  have a  corrective more than a
preventive character.

    One  of  the  first  actions  was  the  Federal  Law to  Prevent and  Control
Environmental Pollution,  issued in  1971.    For the first  time, the  Mexican
Legislature  considered  the   importance   of   controlling  the  environmental
deterioration and created offices to enforce environmental laws.

North America

    However,  it was  not  until  1980  that  important  steps  were taken to protect,
the environment.   In  1981, the Public Works Law was  issued, which required those
planning the construction of buildings to consider the environmental impact.

    In  1982,  the Federal Protection of the Environment Law entered into effect
and with it important advances were obtained,  even though  the  scope was confined
to controlling air and water pollution.   In  1988,  the General  Law of Ecologic
Balance and Environmental Protection brought  remarkable changes in how Mexican
institutions  conceptualized  problem.   Under  this  law,  regulations  have  been
developed  that  focus   on   the   entire   ecology,   considering  conservation,
restoration, and improvement of the environment, as well  as  on the protection
of natural  areas,  flora,  and  fauna (wild and aquatic).   Also,  the new law refers
to the reasonable utilization of the natural elements, encouraging estimates of
the economic benefits of protecting ecosystems  and preventing  air,  water,  and
soil pollution.

    This   law  defines  "environmental   impact"  to  include  environmental
modification caused by human  or natural action.  Thus  it would appear to require
consideration of  sea  level rise due both to natural factors and to the greenhouse
effect.  Currently,  implementation  has  centered only on  the impacts  of human
activities.    Even  under  this   more  restrictive  interpretation,  however,
considering  sea  level rise  appears  to be required,  since  the  environmental
implications  of  new  projects  will  be different  if  sea level  rises.    The
Secretaria de  Desarrollo Urbano  y Ecologia  (SEDUE)-Urban  Development Ecology
Department is currently in charge of evaluating the environmental  pollution.

    At  this  point, one might ask  who  makes the decisions in  the management of
the Mexican  littoral  zone.   In accordance with Merino and Sorensen  (1988), a
great number  of jurisdictions  and powers on  the littoral  are  identified,  but
unfortunately there is no integrating program for the coast.

    Table  5  shows  the many agencies involved  in coastal  zone  management;  the
vast majority  of