DRAFT
      THE CONTROL OF POLLUTION FROM
         CONSTRUCTION ACTIVITIES
CAUSING CHANGES IN THE CIRCULATION OF WTEP
                       Office of Mater Proqram Operations
                       uater Duality and Non-Point
                         Source Control Division
                       Toon 1035, Fast Tower
                       Auaust 2, 1973
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                        CONTENTS
Introduction                                      1

Guidance for Identification
 and Evaluation of the Effects of
 Channelization                                   5

Methods, Processes, and Procedures  to
 Control Pollution Resulting from Channel
 Modification Projects                            46

Guidance for the Identification and
 Evaluation of the Effects of
 Reservoirs                                      66

Methods, Processes, and Procedures  to
 Control Pollution from the Impoundment
 of Water                                       116

Guidance for the Identification and
 Evaluation of the Effects of Urbanization        145

Processes, Procedures, and Methods  to
 Control Pollution Resulting from
 Urbanization                                   161

Guidance for the Identification and
 Evaluation of the Effects of Dredging            167
                    DRAFT

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                          DRAFT
                         INTRODUCTION
      This report will discuss processes,  procedures and       11



  methods  to control pollution resulting from changes in the



 imovement, flow or circulation of any navigable  waters or      12



  ground waters caused by construction activities in or in      13
 »


  conjunction with a stream channel which includes             14



  construction of dams, levees, channels or flow  diversion      15



  facilities.  This report is mandated in Section              16



  304 (e) (1)6(2) part (F) of PL 92-500.                         17







      The initial step in such a study is  to endeavor to       19



  determine exactly what the congress intended to accomplished  20



  by this  Section of the Federal Water Pollution  Control Act    21



  Amendments of 1972.  Examination of the Senate  Committee on   23



  Public Works Report which accompanied S.  2770 and the Report  2H



  of committee on Public works of the U.S.  House  of             25



  Representatives which accompanied H.R. 11896 was made to      26



  make this determination in conjunction with the specific      27
I      "*


  language contained in the law as finally  passed (P.L. 92-     28



  500).



 A

i


      The information, gu,
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                        DRAFT
of hydrographic modification work,..." (p.49).  The term      33


water quality is defined by the Committee as "...to refer to  34


the biological, chemical and physical parameters of aquatic   35


ecosystems,  and is  intended to include reference to key                     f


species,  natural temperature and current flow patterns,..."   36
                                                                          ,«

Jp.51).   Thus,  changes  in flow patterns through channel       38              *


modification which  must be identified and if possible,        39


methods  to reverse  or alleviate damages described.   Another   41


problem  cited by the committee is the effects of H...the                      •


temporary or permanent  obstruction or diversion of  fresh      42


water flows  in the  construction of a dam or other facility,   43


which may also cause salt water intrusion from estuaries"     44              9


(p.54).






     The descriptions in the House of Representatives        46              ^


Committee were not  as expansive as the senate Committee's     47


discussion for this section.  The report directs the         49


Administrator to be "...diligent in gathering and


distribution of the guidelines for the identification and     50


the information or  processes, procedures, and methods for     51


control  of pollution from such non-point sources             52            A


as...natural and manmade changes in the normal flow of        53
                                                                           *

surface and ground  waters."
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                           DRAFT
       With these comments in mind,  the  specific language of    55



   the bill i_s clarified.  The pertinent  part of the Act reads   57



   as follows:  sec 30U(e)
            Administrator. . .shall  issue. ..within one            59
 •


       year. . .information including  (1)  guidelines for          60



       identifying and evaluating  the  nature and extent of      61



       non-ooint sources of  pollutants,  and  (2) processes,      62



1       procedures, and methods to  control pollution resulting   63



       from--... (F)  changes  in the movement, flow or            64



       circulation of any navigable  waters or ground waters,    65



i       including changes caused by the construction of dams,    66



       levees, channels, causeways,  or flow diversion           67



       facilities. "



i



       Part.  (1) calls for guidelines for identification and     69



   evaluation;  this does not  reguire  EPA  to identify and         70



   evaluate rather only to provide  yardsticks for such.  Part    72



   (2) reguires identification of available processes,



   procedures and methods for relieving or ameliorating the      73



•  pollution resulting from changes in  flow induced by stream    7U



   bed modification.   It does not reguire evaluation of these   76
 4


   methods, only identification.                                77
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     Basically the assigned task is to develop informational   79



guidelines for evaluating  the pollution caused by flow and     80



circulation changes through stream bed modifications; and to   81



describe  known processes to control pollution resulting from   82



such changes.  Although not mandated in the  legislation,  the   84



pollution problems themselves must also be identified and     86



highlighted in order for the mandated requirements to be



meaningful.  This is not to say evaluated, but only           88



identified.
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               Guidance for the Identification                 93
               and Evaluation of Channelization                9U
                         Introduction                          99
*

       This discussion will be limited  to aspects of            102
  channelization where actual in-channel modifications occur.    103
  consideration of other aspects  of  channelization will be      105
  covered  under senarate headings such  as reservoirs.           106


       The type of channel envisaged in this discussion is the   108
  relatively small stream which frequently floods either urban   110
  or rural areas causing significant damage.  Also included     111
  are those drainage projects used to render low-lying
  wetlands usable for agriculture or construction of suburban    112
  developments.

               Cur r ent_Government al,_I nvol ve ment                116


       The initial step in identifying  and subsequently         119
  evaluating channelization projects is to determine those      120
  governmental agencies, grivate  groups and individuals         122
                             DRAFT

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involved in desiqninq and constructing projects,  Zor          124



Federal Agencies the list is quite short, perhaps even



shorter for State Aoencies hut conceivably quite extensive     125



for local aqroups and individuals constructing such            126



projects.








     The Federal Aqencies principally concerned with           128



channelization projects on a whole basin scale or major        129



portions of basins are the Soil Conservation Service of the    130



Department of Aqriculture, U.S. Army Corps of Engineers of     131



the Defense Department, the Bureau of Reclamation of the       132



Interior Department and the Tennessee Valley Authority.        133



Other Agencies may be indirectly involved in smaller           134



projects because drainage or flood protection may be           135



included as part of a project.  These Agencies would include   137



the Federal Housing Administration in the Department of        138



Housing and Urban Development, Veterans Administration and     139



Federal Highway Administration of the Department of            140



Transportation.  These smaller incidental projects will not    141



be discussed in this section.                                  142








     Contacts with the major Federal Construction Agencies     144



should yield listings of projects completed, under planning    145

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   and/or  design  and  those  being requested by various  local       146

   governments  or private interest groups.   Such contacts would  148

   provide the  major  projects in a given  state or planning       149

   area.

   *

        state and local  agencies involved in channelization       151

   projects are more  difficult to identify in this type of       152

   report  bocause of  the various names  of such organizations     153

   used  from State to State and locality  to locality.   Often     154

   these Agencies will be identified  in project reports          155

   prepared by  the Federal  Agencies as  participants in a given   156

*  project. Organization names frequently used include a State  157

   Soil  and Water conservation Committee, Soil Conservation       159

   Districts, Conservancy District, Flood Control District or    160

•  Irrigation District.   These organizations provide local       161

   support and  frequently partial funding of projects             162

   constructed  under  the auspices of  a  federal grogram.          163

4)       State and local  governments frequently are directly       164

   involved in  the financing of projects  either on a partial     165

   basis conjunctively with Federal Agencies or totally for       166
  t
£  Federally ineligible  projects.                                 167

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     Privately constructed projects  are even  more  difficult    169



to identify.   Usually,  these projects are  small  and  limited    170



to an individual's or at most a few  individual's property.     171



These projects would generally be  for drainage purposes  to     172



make land usable for agriculture or  housing developments.      173



However, the  effects of such projects may  cause  significant    174



water quantity and quality changes in a given area.  These     176



projects may  be identified by examination  of  Department  of



Agriculture aerial photographs, examination of construction    178



permits issued, examination of recently constructed  housing    179



subdivisions  or contact with large housing or heavy            180



equipment contractors in a local area.






                     Current_Practices                        184






     Current  practices can generally be subdivided into        188



those principally flood control oriented or those


principally drainage oriented.  In combined projects,  design   191



is frequently controlled by flood  control  requirements.        192



Several alternatives are generally available  to  accomplish     194



the goals of  a given project.  Current practice  is generally   195



to use the method with the highest benefit-cost  ratio  unless   196
                  _


some compelling reason overrides the economic justification.   197
                             DP"4 & F*TP
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CLEARING AND SNAGGING                                        200




     Clearing and snaqqinq operations may be used as an       202
<
independent technique for increasing channel hydraulic        203

capacity or it may in essence  be  a  maintenance technique for  205


maintaininq a previously imoroved channel.  The basic         207


operation is the removal cf obstructions from the channel

which may impede flow directly, increase hydraulic friction,  208


or present obstructions which  accumulate debris carried by    209

the stream during hiqh water conditions and reduce the        210


available area of flow.




     Clearing and snaaqing operations are frequently used     212


following high water to remove accumulated debris, logs,      213


rocks,  etc.  and restore the hydraulic capacity of the        21U

channel.  Equipment used consists of bulldozers and front     215

loaders to ghysically remove the  obstructions.                216




     Although the least expensive means for increasinq the    218

hydraulic capacity,  clearinq and  snagqing is also the least   219

effective.  Only modest improvements can be anticipated and   221


these frequently short lived.  In certain types of basins     222
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                            10
channel obstructions re-occur within relatively  short spans   223



of time.







CHANNEL EXCAVATIONS                                          226







     Channel  excavating is principally of two types.  In      229



many cases the  existing channel is enlarged and  reshaped to   230



increase  hydraulic capacity.  In other cases the existing     232



channel is abandoned with a new channel being excavated.      233



New channel construction has also frequently been used for    234



irrigation canals where no previous channel existed.  In      236



these irrigation channels, design is more precise because     237



flow rates are  predetermined and not subject to  the whims of  238



nature.







     The  design configuration and construction of the         240



channel excavations depends on the purpose and setting of     241



the new channel.  In urban areas where land values are high   242



and flood damage losses high, channels are frequently         243



designed  with a rectangular configuration and are concrete    244



lined to  achieve maximum hydraulic efficiency and require a   245



minimum of right-of-way.  .In rural settings channels may be   246



designed  wider  with a trapezodal shape.  Side slopes are      247
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                               11
  determined  by  soil  stability or by the final coverinq used    2U7



  such as grass  or rip-rap.  In situations where channel        249



  straightening  has resulted in excessively steep hydraulic     250

 <
  slopes with resulting excessively high water velocities



  which erode the channel bottom or side slopes, drop           251



  structures  are used to dissipate energy at frequent points    252



  along the channel.







      The method selected for excavation varies with the       25 U



  project size,  whether "wet" or "dry" techniques are possible  255



  and the method of disposing of the spoil.  In dry situations  257



  conventional drag lines, power shovels or front end loaders   258



  are used; in wet situations generally some method of



  dredging is employed.  The dredging method used also depends  260



  on the material to  be dredged.







  CHANNEL REALIGNMENT                                           263







      The purpose of channel realignment is principally to     265



  eliminate the  meandering of the stream over the flood plain.  266



 "Such meanders  frequently result in instabilities which cause  268
i


  shifting of the channel and poor hydraulic efficiency.  By    270
 «


  realigning  the channel into a straighter and therefore
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                             12
shorter length,  costs of  a channel  improvement may be         271



reduced.







     Restraints  on realignment  are  existing roads and         273



bridges and the  existence of  available land for right of      274



way.  Channel realignment is  complicated by the problem of    275



excavated material disposal and the abandonment of the fish   276



and wildlife habitat available  in the old channel.            277



Frequently, these "oxbows" are  maintained with sufficient     278



flow or backwater to maintain the habitat.                    279







FLOODWAYS                                                    282







     Floodways are channels which are constructed to convey   285



floodwaters around a protected  area.  These channels may be   286



constructed in lieu of modification of the existing channel   288



or in conjunction with channel  hydraulic improvements.







     Such channels are constructed  to be dry until the water  290



stage in the stream reaches a predetermined level and then    291



to convey  (in conjunction with  the  existing channel) flows    293



greater than this amount.  When flood flows recede, water is  294



diverted from the floodway back into the principal channel.   295

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      Floodways are generally shorter than the natural         297
 channel and have greater hydraulic efficiency.  Flood stages  299
 up-and-downstream may be affected by such a project.
<

      Since floodways are normally dry, they may be used for   301
 other purposes such as pasture or as parkland.  Maintence is  303
 required to remove new growths of trees and brush and to
 maintain grass cover to minimize erosion during flood         304
 periods.


      This type of flood control project requires more land    306
 then a channel modification project and is therefore more     307
 expensive.  Maintenance costs are also high especially if     308
 non-permanent overflow devices are used such as a narrow      309
 earthen levee which must be replaced following each period    310
 of high water.


      The principal benefits as related to water quality are   312
 the non-destruction of the nataral fish and wildlife habitat  314
 and aesthetically by maintaining the natural appearance of    315
*the stream.

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                        iv«i
RESERVOIRS                                                   318








     The type of  reservoir considered in this discussion of   320



channelization is basically a retarding basin.  These basins  322



contain a dam with an  unqated outlet which discharges water



proportional to the height of water stored in the reservoir.  32U








     The purpose  of these structures to hold large volumes    326



of storm water initially with a subsequent gradual release    327



when the channel  capacity exists to pass the flow.  The       329



hydrograph thus reflects a reduced stage and is lengthened    330



time-wise consequently reducing flooding downstream.








     Consideration of  such structures as part of a project    332



is influenced by  actual construction costs, land acquisition  333



costs and the existence of acceptable terrain.                334
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                               15
I



   DRAINAGE DITCHES                                              337




       Drainage ditches, although included in a channelization  339

 «
   scheme as part of the justification, seldom dictate channel    341


   capacity.  Channel capacity normally is dictated by flood     342


1   flow conditions.  Drainage ditches usually involve deepening  343


   natural channels or in constructing new ditches where none     344


   previously existed.

I


       The major effect on the hydrology is to lower the water  346


   table and perhaps reduce dry weather stream flows in the       347


   main channel if ditching is sufficiently extensive,   some     349


   increase in main channel peak flows may occur as a result of  350


   better interception of surface run-off and more efficient


   hydraulic conveyance than previously existed.                 351




       Depletion of ground waters and subseguent reduction  of    353


   stream flows can adversely affect water guality in both the    355


   surface and subsurface.  in addition to adverse effects on     356


   fish and wildlife habitat,  there is decreases dilution water  357


* and higher water temperatures.
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                             16
                    Sources_Qf Pollution                      361







     Following stabilization after the various                364



channelization schemes, both direct and indirect sources of   365



pollution are identifiable.  Realizing that the main purpose  367



of channelization projects is either to increase hydraulic    368



capacity to convey flood waters thus protecting adjacent      369



property; or to provide drainage of land to increase its      370



economic usefulness, the attributes in terms of               371



environmental pollution are readily apparent.







SCOUR FROM BOTTOM AND BANKS                                   374








     In order to enhance the hydraulic efficiency of          376



channels by excavation, realignment or even clearing and      377



snagging, the channel roughness is reduced.  Such a           380



reduction in roughness decreases friction losses and thereby  381



increases the velocity of flow.  Increased flow velocities    382



may exceed the stability velocities of the bottom or bank     383



materials and cause erosion or scour.  This in turn degrades  38U



the channel and furnishes sediment for stream transport,      395

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                             */ -   ,j ^   i3
                            • •-  -i ?• ;,  g



                              17






 destroys natural habitats and detracts from the aesthetics    386



 of the stream.






      Perhaps the worst offender in this regard is channel     388



_jstraightening and realignment.   This process reduces channel  390



 lengths but not the decrease in elevation over which the      391



 water is lowered in traversing a stream section.  The net     393



 result is a substantial increase in the stream gradient with  394



 resulting substantial increases in stream velocities.         395



 Without extensive control measures for stabilization or the   397



 use in-channel drop structures, channel degradation can be    398



 extensive.






 INCREASE USE OF FLOOD PROTECTED AND DRAINED LAND              401







      Following the implementation of both flood control and   403



 drainage projects, extensive amounts of land become           404



 available for higher economic production.  Land formerly      407



 used for pasture or low return agricultural crops can be



 converted to high yield agricultural crops.  Within           409



 municipal areas, property values are increased and uses with



 more economic return can be developed.  With such economic    411



 gains generally there follows environmental degradation.

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                             18
     Enhanced agricultural uses  is  accompained  by  increased   413



fertilizer, herbicide and pesticide use  and  by  increased      414



.land tillage which increases erosional soil  losses.  The by-  416



products of this agricultural use drains to  the stream and    417



causes various amounts and kinds of water quality



impairment.
     Channelization projects which provide  flood  protection   420



within urban areas frequently include the provision of lined  421



channels.  The effects on the water environment of these      423



channels is both the destruction of fish and  wildlife         424



habitat and to destroy aesthetic gualities.                   425








GROUND WATER DEPLETION                                       428








     Provision of protection against overbank flooding by     430



various channel modification schemes and the  provisions of    431



drainage channels through wetland areas both  contribute to    433



the deterioration of ground water quality and the reduction   434



in ground water quantity.
                          m. AFT

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                               19
       Many  flood  plain  aquifers  receive  recharqe during         436



  overbank flooding  periods.   Such recharqe  provides in          438



  addition to  the  quantity  of  available qround water,  low        439

«

  mineral content  water  which  serves  to dilute mineral



  concentrations in  existing ground waters.  Removal of this     441



  recharqe will thus result in both reduced  quantity and



  quality of these qround waters.                                442







       Additionally,  since  qround waters  frequently furnish      445



  the dry weather  base flow of many streams, the effects of      446



  the removal  of recharqe and  resultinq lowered water  table is   447



  to reduce this base flow.  The  annual hydroqraph of  a stream   448



  may become more  extreme between wet and dry weather  periods    449



  of the year  if the  channelization project  is sufficiently



  extensive.







       Drainage ditches  also lower water  tables substantially    451



  and reduce the base flow  of  streams which  is provided by       452



  qround water infiltration.   Since swampy or wet areas which    454



  are in hydraulic contact  with the qround water are             455



  frequently drained and converted to other  uses, this



  reservioir of water is also  made unavailable for providing     456
-<


  infiltration to  streams.

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ELIMINATION OF FISH AND WILDLIFE HABITAT AND AESTHETIC        459

QUALITIES




     The various channelization practices have varying        461

effects on fish and wildlife habitats.  In general, the more  463

extensive the modification structurally the more damage that  465

is caused to habitat areas.  For example, concrete lining of  466

channels eliminates habitat areas for practical purposes      467

whereas at the other extreme, clearing and snagging may not   468

have a detectable effect.  The effects of the project can     469

only be determined by the use of before and after surveys     470

designed to detect both drastic and subtle changes.           471




     Aesthetic values for streams depends a great deal on     473

the beholder.  swamp habitats may be quite disagreeable to a  474

non-naturalist whereas parkland or pasture beside an          475

improved channel may appear quite pleasing.  To this extent   477

aesthetics may be somewhat acquired in conjunction with       478

strictly innate appreciation.  Perhaps aesthetics is the      479

most difficult environmental factor to quantify and may       480

require the opinion of a representative cross section of the  481

population before classification of a project is acceptable.  482

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                                 f
                              21
                           o f _Poi l.u t ant s                       186
      Depending on the location of a project, perhaps almost   U89
^
 any conceivable pollutant could be introduced by a            490

 channelization project.  This discussion will be limited to   193

 the common pollutants both contributed directly and           U91


 indirectly.  Such pollutants are the common denominators to   195

 be anticipated from the majority of projects.                 196




 gIRECT EFFECTS                                                199




 Sediment                                                      501




      Sediment is perhaps the most ubiquitous of all           503

 pollutants associated with channelization.  The most          505

 pronounced effect on sediment occurrence and concentration


 is during the construction phase of the project.  With bare   508

 soil banks and a non-stabilized channel, the natural stream   509

 flow itself and any rain that occurs flushes sediment into    510

 the stream discoloring the water and making it turbid and     511

'non-transparent.  Following stabilization however, the        512


 stream frequently remains more turbid than before the         513

 project was constructed

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                             22
     Every stream has an ability to naturally transmit        515



certain amounts of sediment.  The amount transmitted is       517



termed bedload and is a definable stream characteristic.      518



When channel hydraulic characteristics are changed by         519



constraininq the channel to a fixed location, by



realignment, or by other ireans, the velocity of water flow    520



in increased and consequently the ability to transmit         521



sediment is likewise increased.







     The effects of increased sediment or water quality are   523



to reduce light penetration, to blanket fish spawning areas,  524



to blanket and suffocate aquatic insect larvae used by fish   525



as J-ood, to create shoaling and instabilities in the channel  526



itself, and to cause problems with sedimentation in           527



unimproved channel sections downstream from the project       528



section,  ^n addition to these problems which directly        529



affect water quality instream, increased costs are realized   530



by water users including water suppliers and irrigators,      531



Additionally, aesthetic quality is reduced to a substantial   532



degree.

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                               23
  Jhermal                                                       535







       The design of channelization projects in terms of flood  537



* prevention requires increased channel dimensions.   Because    539



  of enlarged channels, the dry weather flow is directed near   511



  the center of the channel and is thus exposed to solar        542



  radiation which heats the water.  Previously in the natural   543



  channel, the presence of trees along the banks provided       544



  shade and helped moderate stream temperatures.  The purpose   545



  of channelization being to increase the hydraulic efficiency



  of the channel, those trees are removed as they impede flows  546



  during high water.                                            547







       In addition to reducing temperatures during daylight     549



  hours, the insulating effect of these trees is removed and    550



  night time temperatures are reduced to a greater extent than  551



  previously.  Thus, a greater diel variation in temperature    552



  can result from a channelization project.                     553







       The effects on fish and aguatic life are caused by both  555



* the absolute temperature itself and the temperature           556



  variation.  Both increased maximum temperatures and           557



  increased variation can have detrimental effects on fish and  558

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aquatic life during various stages of their life cycle.       559



Specie selection, availability of food, attendant life cycle  560



chemistry and water quality changes are all phenomene that    562



are temperature affected.







     Water quality is affected by the increased respiration   56<»



rates caused by increased temperatures so that dissolved      565



oxygen is removed more rapidly by bacterial oxidation of      566



soluble and suspended organic materials.  This problem is   / 568



compounded by reduced oxygen solubility at higher



temperatures so that a resultinq decline in stream dissolved  569



oxygen concentrations results.  Decreased dissolved oxygen    571



concentrations decreases water quality and stresses aquatic   572



life dependent on this constituent.







Movement of Pollution Effects Downstream                      575







     Because one result of channel improvement projects is    578



to improve hydraulic conveyance of channels, frequently       579



velocities of flow are increased.  Jn channel relocation or   582



realignment projects where channel lengths are substantially  583



reduced, the effect of increased velocity can be pronounced.  58U



Jhe effects of increased velocities on surface water quality  585
                             s ,;> A r
                              ''

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                              25
 is to move the effects of pollutants which are time           586

 dependant downstream.  Discharges of organic wastes or        587

 drainage of natural organics from swampy areas along the      588
•V
 stream, both of which are bacterially degraded and oxidized   589

, in the course of moving downstream, move much farther in      590

 distance for the equivalent period of time required for

 completion of the reaction.  Thus the effects of reduced      592

 dissolved oxygen levels extends farther downstream than       593

 previously.




      increased water velocities also are capable of           595

 transporting increased sediment loads which are deposited in  596

 non-channelized areas downstream.  Such deposition effects    598

 tend to migrate upstream clogging channels and defeating the  599

 channelization improvement unless removed during maintenance  600

 operations.




      In addition to simply transporting more sediment,        602

 increased velocities make streams more aggressive in eroding  603

 channels and stream banks which destroys much of they         604
A
 usefulness of the stream for other purposes.                  605




 Fish and wildlife Habitat Alteration                          607

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                             26
     Almost any modification of a channel alters the          609



existing habitat for fish and wildlife.  Not all such         612



changes are detrimental however, provision of water storage   613



for example may provide increased habitat areas but perhaps   614



for a different than pre-project biological assemblage.







     Most in-channel modifications do remove obstructions     616



that are used by fish for protection from predators, for      618



fish food habitats and for backwater breeding areas.



Removal of trees and brush along stream banks removes         619



protective cover and food sources for various water related   620



wildlife.







     Many of these effects can be mitigated by incorporating  622



proper factors into project design.  For example,             621



maintenance of water in cut-off oxbows helps retain           625



available fish and wildlife habitats.







                      INDIRECT EFFECTS                        628







                 Destruction of Aesthetics                    630
                                  *A

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                              27
      Channelization projects have frequently been criticized  633


 for the destruction of aesthetic values of natural streams.    634


 The creation of geometrical shaped channels with highway-     636

f
 type alignment is not conducive to aesthetic appreciation by  637


.naturalists or the general public.   It is possible to         639


 mitigate much of the aesthetic destruction by use of proper    610


 design techniques.  For example, those techniques which only  611


 alter one stream bank or which provide a replanting program    612


 similar to that existing £rior to construction can be used.    613


 Other similar measures can be included to minimize the        615


 reduction of aesthetic values.





      It should be mentioned also that aesthetic values can    617


 be enhanced for many people by various channelization-        618


 related projects.  In many instances public accessibility to  619


 water courses is improved and parks or other recrection       650


 facilities can be incorporated into the right of way          651


 acquired for the project.




      In-stream techniques can also be applied to maintain     653
»
 fish and wildlife habitat.  Construction of pool and riffle    655


 areas is one technique available.   Use of more natural        656

-------
                             28
alignment, and other design features are available to project  657



planners.








Hydrology                                                     660







     Considering the major function of channelization         662



projects as either flood control or drainage or a             663



combination of both, many of the effects on basin hydrology   665



can be anticipated.  The major effect of these changes is to  666



increase the hydraulic capacity of the principal channel and  667



the smaller channels which drain into the principal channel.  668



The effect of this change is to move water more rapidly       669



through the channel.  Downstream from the channelization      671



project these increased flows may cause increased flooding.   672







     Drainage projects may aggravate this problem by          674



allowing higher valued operations on the drained land.  If    676



the higher valued use is urbanization, then the paved areas



including roof areas drain water to storm drains which        677



convey water to the water course even more quickly and        678



increase peak flow rates and subsequent flooding.             679

-------
                           J^AFT
                              29
      Drainage facilities also tend  to  lower the water table   681


 during wet periods of the year and  deprive streams of the     682


 critical base flow required during  dry weather periods of     683

t
 the year.  Lowering of the water table is not always          684


 detrimental for all purposes as this technique has been used  686


 to control ghreatophyles Jthose plants whose roots extend     688


 into the saturated zone)  by drawing the water table below     689


 the root zone.  This technique has  reduced transpiration      690


 losses from these plants providing  more irrigation water      691


 flow existing projects,   wildlife habitat near these stream   692


 beds has suffered however.                                   693

-------
                           i •. ,ff,,j *•   yt
                         ,.c>. ' d k / i :i  m



                             30








               Methods  of Pollutant Transport                 697








     The methods of pollutant  transport  in channelized        700



stream basins are essentially  the  same as in the unaltered    701



stream basin.  certain  transport mechanisms are either        703



increased or decreased  by the  effects of the alteration.      704








BEDLOAD                                                      706








     As indicated previously,  bedload is the amount of        708



sediment characteristically carried by a particular water     709



course.  it is related  to several  factors but principally     710



the hydraulic characteristics  of the stream and the soil and  711




geologic characteristics  of the stream channel and drainage   712



basin.








     The effects on bedload of a channelization project is    714



generally to cause an increased amount.  .Improved hydraulic   716



conveyance produces increased  water velocities and enhanced   717



sediment transnort capability.  If the streambed is           718



improperly stabilized following construction, this increase   719




can be dramatic.  Even  though  proper stabilization            720



techniques are used, concentration of sediment generally      721
                            DRAFT

-------
                               31
  increase except in the special case of complete channel       722
  lining with concrete or other paving materials.  Downstream   723
,  from the channelization section, these materials can settle   724
 , and fill the channel with excess materials destroying
  hydraulic efficiency and biological life.                     725
 «

       Indirect effects of channelization are to enhance land   727
  for higher economic uses such as increased agricultural       728
  production or urban and commercial development of some type.  729
  Many of the pollutants generated by these increased uses      730
  become adsorbed with soil grains.  Such organics as           732
  herbicides and pesticides are particularly susceptible to     733
  such adsorption.  When these soil particles are flushed into  73U
  the stream, the adsorbed materials are likewise carried       735
  along for later deposition downstream.  Following such        736
  deposition, these materials can enter the life cycle of the   737
  stream and through biological concentration mechanisms cause  738
  significant ecological desturbances.


       Increased bedload can be visible as increased turbidity  740
  or opaqueness of the stream water.  Such turbidity can be     7U2
  dangerous by obstructing swimmers view of hazardous           743
 ' obstructions.  The principal effect is to decrease the        7UU

-------
                             32
aesthetic value of a stream.  On larger streams used for      745



water supply purposes, increased turbidity causes increased   746



treatment costs for potable or industrial water users.        747







     Bedload increased can therefore cause problems with      749



excess channel scour and downstream deposition; adsorbed      751



pollutant transport; and direct detrimental effects to water  752



suppliers and stream aesthetic values.








DIRECT DRAINAGE                                               755







     The increased uses of land adjacent to streams           757



following the provision of flood protection and drained       759



arable land provide sources of pollution which directly



drain into the water course.  Many of the pollutants arise    762



as the normal product of urbanization or farming practices.   763



Others arise because of the removal of natural mechanisms     764



which trap contaminants directly or provide detention time    765



for the adverse effects to decay to acceptable levels.        766







     The effects of urbanization include many direct          768



discharges to the surface waters and to ground waters which   769



discharges contain pollutants that upset stream ecology.      770

-------
                              33
  Urbanized areas  contain extensive paved areas which are       771



  serviced by storm  sewers  which discharge pollutant laden      772



  run-off  directly into near-by water courses.  Pollutants      77U



„ including inorganic  fertilizer nutrients, petroleum



  products,  rubber,  animal  feces and sediment are discharged    776



' without  treatment.   J.f the area is serviced by sanitary       777



  sewers,  this effluent is  discahrged with substantial          778



  pollutants even  though treatment is provided.  If not         780



  sewered,  septic  tanks are used which can pollute ground



  waters with pollutants including nitrates and sulfates in     781



  properly operating systems; organics, and unoxidized          782



  nitrogen and sulfur  compounds in improperly operating         783



  systems;  and synthetic organics such as pesticides in either  784



  system.   These comoounds  pollute the ground water and if not  785



  intercepted by a well or  diverted to a deeper aquifer may     786



  infiltrate along with the ground water into surface waters.   788



  Since dry weather  stream  flows essentially reflect the        789



  guality  of infiltrating ground waters, the stream water       790



  quality  may be substantially impaired.                        791







       With time,  many pollutants are degraded into innocuous   793



  substances.   Nature  provides detention time in natural        795



* blackwaters and  in ^sluggish meandering streams.  Pollutants   797
                            DRAFT

-------
                             3U
in solid form or which naturally  flocculate and settle are    798



assimilated and destroyed in  bottom  sediments by biological   799



life forms.  Nutrients are chemically removed either as       800



insoluble salts or by conversion  to  qaseous forms which       801



evolve to the atmosphere.   Following channelization and       802



drainage projects these natural places of detention are by-   803



passed or removed which has the effect of increasing          804



pollutant concentrations in the flowing waters.  The effects  806



of these pollutants are then  transferred downstream



decreasing water quality while in passage.                    807








SOLAR INSOLATION                                             810







     The light provided by the sun provides the energy for    812



the biology of natural waters.  The  so called "food web"      814



begins with primary production by algae which are capable of  816



photosynthetic production, up through the consumer species    817



including aquatic insects and fish.  Too little solar         819



insolation produces too few algae, little primary



groduction, and a sparse fishery. Too much sunlight heats    820



the water, jgrovides a competitive advantage for undesirable   821



biological species and an unsatifactory fishery.  The         823
                           DRAFT

-------
                             35
effects of solar insolation  are  both on water quality and on  823



the biological response and  effects on that water quality.    824







     In many streams light penetration extends essentially    826



to the stream bottom and is  necessary for the maintenance of  827



a healthy biological condition.  The existence of such light  828



provides for attached algae  which  provide both food and       829



oxygen for animal life.   In  streams characterized by pools    830



and riffle areas, these productive areas are interspersed     831



along the stream.  in deeper streams productive areas are     832



near the edge of the stream  extending outward until the       833



incident light is extinguished to  less than usable levels.    834



Following channelization,  the stream channels are frequently  835



deeper reducing light penetration  from former levels and      837



higher velocities occur which scour attached algae or



inundate such areas with sediment.  Thus the former habitat   839



is altered and a different biological assemblage develops.    840



Frequently,  the new assemblage is  composed of less desirable  842



species than previously.
     Thermal effects  become  evident  because shading trees



and brush are removed allowing  both  more time of exposure     846



and increased surface area of exposure to sunlight.
                           DRAFT

-------
                             36
Coldwater species of fish can not  tolerate  the elevated       8U7
water temperatures and are replaced  by  warm water species.    848
Thus, the direct effect of increased solar  radiation          849
indirectly changes the stream fishery.                        850

                  Magnitude and Variation                     854

     Available statistics for defining  the  national           857
magnitude and variation of channelization projects indicates  858
that perhaps 200,000 miles of waterways have  been altered  in  860
the last 150 years in the United States.  Since the           862
initiation of Federal projects in  the early 1910 «s planning
f^or and development of about 34,240  miles of  waterways in     863
1,630 projects have been initiated under the  federally-       864
assisted local protection and small  project programs of the   865
U.S. Army Corps of Engineers and watershed  programs of the    866
soil Conservation service.  Additional  projects have been     868
initiated by the Bureau of Reclamation, the Tennessee Valley  869
Authority and other Federal, State and  local  Agencies,        870

     The Corps of Engineers have assisted in  889 projects  of  872
which 47 percent involve channelization and 53 percent        873
involve levees.  Of these projects 6,180 miles  (56%) are      874
                            DRAFT

-------
                               37


*

   completed, 3,896 miles (35%)  are under construction and       875

   1,001  miles  (9%) are planned.  The median size for these      876

   projects  is about U miles with two thirds under 5 miles and    877

   80  percent less than 10 miles.
                                                               879
        "Report on Channel Modifications'* by A.D. Little,  Inc.   882
        submitted to the council on Environmental Quality,  U.S.  884
        Gov. Printing Office,  Washington, D. C. (March,  1973)
                              DRAFT

-------
                             38
     The Soil Conservation Service assisted in 558 projects   887
of which virtually all involved channelization.  Of these     889
projects 4,209 miles  (25%) were completed by 1971 and ^2,426  890
miles  (75%) still remaining to be completed.  The median      892
size of the projects is about 18 miles with 38.7 percent
JLess than 10 miles and 24 percent less than 5 miles.          893

PROJECT DESCRIPTIONS IN COUNCIL ON ENVIRONMENTAL QUALITY      896
REPORT

     The Council on Environmental Quality's sponsored report  898
previously referenced discusses 42 different projects of 4    899
different Federal Agencies.  To quote that reports'           902
description of the environmental settings of the projects,    903
          range was from virtually untouched, natural         905
     conditions to totally altered surroundings.  The 42      907
     projects encompassed dense swamp forests and mixed hill  908
     country and flood plains of the Southeast, intensively
     used citrus, sugarcane and cattle-raising leands of the  909
     flat Florida interior, the totally urbanized bedrock     910
     slopes of the Northeast, the deep-soiled featureless     911
     Mississippi details agricultural empire, the rolling     912

-------
                        39
prairie farm and woodlot country  of  the Midwest,         913



totally industrialized Detroit, the  semi-arid and        91U



treeless northern Great Plains, and  an arid Valley in



the southwest.                                           915







The soils ranged from liqht  organic  mucklands to heavy   917



clay ^spung", with pure sand,  gravel, boulders and       918



clayes-silt in other places.   The vegetation was         920



luxuriant to poor grass.  Precipitation was a well-      921



distributed 70 inches annually to an intermittent 16     922



inches annually.  The stream flow was swift and          923



sluggish, pure and unbelievably contaminated.            924



Streambeds and channels were bankfull with flood flows   926



and bone dry with blowing sand.   Fish and wildlife       927



resources were plentiful,  diverse and non-existent.



Adjacent lands were canopied forest, high-valued         928



specialty truck gardens, grain farms, fish farms,        929



vineyards, fruit and nut groves,  pasture, idle           930



brushland, marshes, factories, shopping centers and



railroads.  There were surrounding areas of arresting    932



scenic beauty and depressing ugliness."                  933
                      DRAFT

-------
                             40
     Each project was analyzed amonq othej: things for the
     """                                   I
                                         !
basis of project formulation, physical effects of the
                                         \
completed project and the bioloqical effects on the aquatic
                                         \ ;
and terrestrial systems.  The report presets an excellent

format for those evaluatinq additional projects.
ENVIRONMENTAL ASSESSMENT REPORTS
     Since the enactment of the National Env conmental

Policy Act of 1969  (P.L. 91-190) each Federa

participatinq in a  proposed channelization pi

siqnificantly affects the quality of the hume

must prepart an environmental imoact statemen
Aqency

ject that

 environment

   These
statements must assess for the project: jTitli 42 U.S.C.,

Sec. 4332)
936

937

938

939

940



943




945

947

949




951

952
     11 (i) the environmental impact of the propped action     955

                                               \
                                                )
     _Cii) any adverse environmental effects whi<\ cannot be   958
                                                 \
          avoided should the proposal be
     (iii) alternatives to the proposed action
                960

-------
                             U1
     _[iv) the relationship between local short-term uses of   962



          man's environment and the maintenance and           963



          enhancement of long term productivity, and          964







     Jv)  any irreversible and irretrievable commitments of   966



          resources which would be involved in the proposed   967



          action should it be implemented.11                   968







     In accordance with NEPA all Proposed Projects            970



significantly affecting the environment have such reports     971



prepared which initially are made available for review and    972



comment.  Final reports incorporating comments of reviewers   973



are submitted to CEQ and are available upon request from the  97U



preparing Federal Agency.                                     975








     The environmental effects of a project are               977



comprehensively covered in these reports.  Whether or not     979



the Agency is able to mitigate the adverse effects            980



identified in the environmental assessment, discussion of     981



these effects is included.  For most projects these           982



assessments are invaluable in evaluating a project.           983

-------
                             42
     It should also be pointed out that several states have   986
also enacted statutes patterned after NEPA which require an   987
environmental impact statement before the expenditure of      988
state funds or in some cases before permits are issued to     989
private interests for project construction.

-------
                               " .'-'BV


                                 43
                                    Methods                       994
         Methods to predict the effects of channelzation          997

    projects will not be directly presented in this report as a   999

    tremendous volume of literature exists discussing such        1001

  «  effects,  several sources of information will be mentioned    1002
•
    as convenient and comprehensive starting places for project   1003

    evaluation including the mitigation as much as possible of    1005

    the inevitable adverse effects.

•


         The previously mentioned CEQ Report on channel           1007

    Modifications presents the results of extensive biological    1008

    investigations conducted by the Philadelphia Academy of       1009

    Natural scieces.  Chapter 5 of Volume I of this report        1010

    entitled, ^Effects of Channel Modifications on Fish and       1011

*   Wildlife Resources, Habitat, Species Diversity, and           1012

    Productivity" directly addresses the biological effects       1013

    observed in 21 channelization projects analyzed.  The same    10 1U

•   or similar effects therefore are to be anticipated in other   1015

    projects under comparable conditions.  Discussion includes    1017

    the effects of channelization projects which cause erosion,   1018

ft   consequent sediment accumulations and unstable stream beds,   1019

  - remove solid substrates, or decrease light penetration which  1021

-------
                             44
may affect the biological population by disturbing the



number of species, the populations of each, or the



productivity of the stream.
1022



1023
     Methods to predict the effects of channelization         1025



projects are in included in a volume produced by the Soil     1026



Conservation Service entitled, ^Planning and Design of Open   1028



Channels." *This document comprehensively presents available  1029



information on channel design including anticipated flows;    1030



location, alignment and hydraulic design; and stability       1031



design.  A recently added chapter 7(1971) includes            1033



environmental considerations.  The technical methodology      1034



presented in this document is sufficient to predict the       1035



effects of the hydraulic changes caused by a channelization   1036



project including any increases in sediment transport.  *     1038



U.S. Dept. of Agriculture, Soil conservation Service,



^Planning and Design of Open Channels", Technical Release     1040



No. 25. December 15, 1964  (Rev. March, 1973) .







     increases in the Stream temperature and the diel         1042



variation are not so readily predicted.  The calculations     1044



can only be made by estimating the amount of protective       1045



shade removed, changes in depth and changes in channel
                           K AH .
                           '•*'? '4 *.,

-------
jLength in conjunction with tables of solar insolation         1046



values.  Such calculations will probably only yield           1047



approximate semi-quantitutive amounts of change.              1048







     The best technique is the field survey of a nearby       1050



stream which has undergone the changes projected for the      1052



stream of interest.  Comparisons of this type of information  1053



establish a more rational basis for predicting the various    1054



physical, chemical and biological changes to be anticipated.  1055



In the absence of such a situation, predictive techniques     1056



from the sources suggested above and in the compenion report  1058



on Methods, Processes and Procedures to Control pollution     1059



resulting from channelization projects must be utlized.

-------
                        Bibliography                          3


!_.   A.D.Little, Inc., "Report on Channel Modifications,"     7
     submitted to the Council on Environmental Quality, U.S.  9
     Government Printing Office, Washington, D.C.   (March",    ]0
     1973).

£.   Anon., "Planning and Design of Open Channels,"           ]2
     Technical Release No.25, U.S. Department of              ]3
     Agriculture, Soil Conservation Service  (December, 1964,  ]4
     Revised March, 1973).

3_.   Anon., National Engineering Handbook, Section 16,        ]6
     Drainage, Chapter 6.  Open Ditches for Agricultural      ]7
     Drainage, U.S. Department of Agriculture, Soil           ]8
     Conservation Service (February, 1959).                   ]9

£.   Todd, O.K., Ground Water Hydrology, John Wiley £ Sons,   22
     Inc., New York (1959~n

5_.   Anon., Water Quality Criteria, Report of the National    25
     Technical Advisory Committee to the Secretary of the     26
     Interior, Section 1, Recreation and Aesthetics, Federal  27
     Water Pollution Control Administration  (April, l9"68).

6_.   Dewiest, R.J.M., "Replenishment of Aquifers Intersected  30
     by Streams, Jour, of the Hydraulics DivisionT A.S.C.E,,  3]
     No. HY6, (November, 1963).

T_*   Anon., "Sedimentation Transportation Mechanics: G.       33
     Fundamentals of Sediment Transportation," A.S.C.E.       34
     Task Committee on Preparation of Sedimentation Manual,   35
     Committee on Sedimentation, Journal of the Hydraulics    36
     Division, A.S.C.E., No. HY12  (December, 1971).           37

£.   Mackenthun, K.M., The Practice of Water Pollution        39
     Biology, U.S. Department of the~Tnterior, Federal Water  4]
     Pollution Control Administration  (1969).          "~

-------
                             U6
   Methods, Processes and Procedures to Control Pollution      1066



        Resulting from Channel Modification Projects           1067








     Discussion under channelization will be limited to        1070



thosp cl^siqn changes in the actual channel modification        1071



project that can be incorporated to enhance and mitigate       1072



undesirable by-products.  Additionally, attention will be      107S



directed to consideration of alternatives to channel           1076



modification such as flood plain zoning regulations.           1077



Discussion of other structural alternatives including          1078



upstream storage reservoirs are covered under separate         1079



headings.                                                      1080








Design^Modifications to Minimize Adverse channelization        1083



Impacts                                                        1084








CHANNEL ALIGNMENT                                              1086







     Channel improvement projects generally are designed to    1088



follow existing stream alignment with the exception of         1090



situations where stability or cost factors force an            1092



alternative course.   In stream sections passing through        1093



highly erodable soils for example, an alternative course may   1094

-------
 be desirable if an alignment through more stable soils        1095

 exists.   Relocation also may be desirable to avoid passage    1096

 through  valuable Rowland areas which serve as fish and        1097
r
 wildlife habitats.



      In  constructed channels the alignment generally should   1100

 follow a natural pattern which should consider the type of    1101

 existing stream, the required hydraulic capacity and

 comparison with up-and downstream sections of the particular  1102

 water course or nearby water courses.  Use of such design     110U

 technigues avoids the unnatural appearance of a modified      1105

 channel  thus improving aesthethic appeal and in many cases

 may aid  stability by not changing the channel gradient        1106

 excessively.                                                   1107




      Special features along the stream should be protected    1109

 to enhance aesthetic appeal.   By proper design of channel     1111

 alignment the existence of particularly striking features     1112

 can be preserved and perhaps enhanced which adds to the       1113

 public appreciation of the projects.   Design should           111U

 incorporate provisions to protect these features including

 special  stream and streambank stabilizing measures, land      1115
*"""

 treatment methods and grade adjustments.                       1116

-------
                             48
CHANNEL CAPACITY                                              1119




     Channelized streams should convey water discharges       1121


ranging from base flow to the design flood flow without       1122


damage to either the channel itself or the associated fish    112U


and wildlife resources.  The low flow channel cross section   1125


should approach the natural stream condition.  The bottom     1127


width and side slopes can be designed to simulate the


natural channel so that it will blend with up and downstream  1128


sections of the natural channel and avoid a monotonous        1129


appearance.  At bends, the channel side slope can be          1130


steepened on the outside of the channel bend and flattened    1131


on the inside of the bend to simulate natural water ways.     1132
                                      ~                     *

Use of naturally occurring rocks and boulders can be placed   1133


at selected goints for aesthatic appeal, energy dissipation   113U


and fish habitat development.  The bottom width of the        1136


channel can be varied in conjunction with the channel slope   1137


to develop pool and riffle areas to aid fish and wildlife     1138


yet maintain hydraulic capacity,  inclusion of these devices  1139


however reguires carefull attention of the designer, on site  1110


inspection personnel and especially the contractor.

-------
                              49
 CHANNEL GRADE                                                 1143




      Within the topographic constraints of a given project,    1145

i
 the channel gradient can be varied between stream reaches to  1146


 achieve naturally appearing pool and riffle areas, cascades    1148


 or other such features.   To accomodate the existence of       1150


 highly erosive soils in  certain reaches,  gradients can be     1151


 flattened and conversely,  in erosion resistant soils


 gradients can be steepened, all within the natural            1152


 topographic constraints  of channel elevations at the          1153


 beginning and end of channel sections.   Use of such grade     1154


 variations not only enhances aesthetic appeal but increases


 protection against meander development, increases channel     1155


 stability and thereby minimizes sediment from channel and     1156


 bank erosion.




      Adjustment of the channel  gradient to develop pool and    1158

 riffle areas can also provide increased atmospheric           1159

 recreation capacity in the stream.   Reaeration increases      1160


 with increased velocity  and decreasing stream depth.  Riffle  1162

'areas additionally provide increased turbulence which also


 tends to increase reaeration.  The increased dissolved        1164


 oxygen supplied by the increased reaeration improves the      1165

-------
                             50
habitat for fish and aquatic life.  £t also provides          1166



additional capacity to satisfy the demands exerted for the    1167



oxidation of naturally occurring or man-contributed organic   1168



material before damage to aquatic life occurs.                1169







SPOIL PLACEMENT                                               1172







     The on-site placement of excavated spoil material        1171



should be accomplished so as to minimize the amount of        1175



clearing required or other land disturbing activities.        1176



Spoil should be nlaced in such a fashion so as to minimize    1178



the potential for the erosion of the material back into the   1179



stream.  Placement of spoil should also be made so as to      1180



minimize the adverse effects on wildlife habitats and may be  1181



concentrated at selected locations along the stream section   1182



to accomplish this goal.  Through proper re-vegetation and    1183



planning the spoil amy be used to create scenic overlooks     1184



and other contrasting features which may enhance the          1185



aesthetic appeal of a project and avoid the monotony of       1186



continuous spoil banks beside the stream.                     1187








     The amount of spoil can also be minimized by the use of  1190



one-sided or single stream bank construction where
                               '\ -•• r

-------
                              51
 appropriate.   Other spoil  reducing  measures can be included   1192


 by the use  of  non-structural  alternatives totally or          1193


 partically  in  lieu of actual  channel  modification.

«




 STRUCTURAL  MEASURES                                           1196






      Structural  measures can  be included  in a  channel          1198


 modification groject to alleviate problems of  excessive       1199


 grade to maintain  stability.   Structural  measures can  also    1202


 be applied  to  side stream  entry points  to control the          1203


 introduction of  sediment,  debris or other pollutants or       120U


 effects.






      For channels  with excessive slopes which  would           1207


 otherwise erode  producing  sediment, typical structures


 include drop structures, chutes,  steepened rock armored       1208


 sections and cascade structures.  Each  of these structural    1209


 modifications  provides resistance to  high velocity flows  and  1210


 allows the  use of  stable,  moderate  gradients upstream  and     1211


 downstream.






      For channels  with sufficiently flat  gradients so  that    1213
*

 channel and bank stability are not  problems, designs can  be   1214

-------
                             52
incorporated usinq the pond, riffle and pool sequence.  The   1216



inclusion of ponding provides sufficient excess elevation



that succeeding oool and riffles can be maintained.  Besides  1218



protecting fish habitat, aesthetic appeal is increased.
     Side channel structures include pipe drops, iined        1221



chutes and drop spillways.  These structures can be used in   1222



conjunction with sediment basins and debris traps to retard   1223



the input of these materials into the main channel.  The      1224



principal purpose of these structures is to prevent the loss



of vegetation from stream banks at the point of entry,        1225



slumping of the main channel bank or the cutting of a deeper  1226



tributary channel all of which produce sediment into the      1227



main channel and reduce channel stability.             •

-------
                             53
VEGETATION                                                    1230








     The early re-establishment of vegetative covers          1232



following in-channel modifications is most important to       1233



prevent extensive erosion and damage to the hydraulically     1234




improved channel.  The selection of the plantings should      1235



incorporate both an initially quick growth to stabilize the   1236



bank and the subsequent development of a cover which will     1237



blend or simulate the natural cover.








     Use of proper erosion resistant cover will keep          1239



sediment concentrations and adverse water quality impacts to  1240



a minimum.  Proper trees and bushes will enhance biological   1241



productivity within the stream itself and the associated      12U2



wildlife.  Shade provides against excessive solar insolation  1213



which helps maintain maximum temperatures within allowable    1244



tolerances and insulate against excessive diel thermal        1245



variations.








     Use of aguired right of way for parks, hiking paths or   1248



the provision of access for fishing is also enhanced



aethetically for public use by the use of suitable            1249



revegetation practices.

-------
                             514
EFFECTS ON GROUND WATER
1252
     Any channel modification will tend to alter the natural  1255



circulation of the ground water.  Natural recharge to the     1256



ground water may be increased or decreased depending upon     1258



location, depth, and other characteristics of the new



channel.  Thorough investigation of possible effects upon     1259



both quantity and quality of ground water should be made      1260



before undertaking a channelization project.








     An important distinction in terms of their effect on     1262



ground water Duality is whether channels are lined or         1263



unlined.  A lined channel, constructed of an impermeable      1264



material such as concrete, grevents in many reaches the       1265



natural recharge of streamflow to ground water.  The water    1266



table may be lowered, and ground water circulation and



dilution reduced, so that quality is impared.                 1267
     To control this situation water needs to be



artificially recharged to the ground water.  This can be



done by installation of ditches or basins for artificial
1269



1270



1271
recharge in the vicinity of the lined channel.  High-quality



water diverted from the stream or derived from some other     1272

-------
                             55
source and released into these structures would infiltrate    1273



to the qroundwater and thus compensate for the loss of        1274



natural streambed recharge.  This is extensively practiced    1275



in California.







     In unlined channels, a primary effect is that produced   1277



by changing the water table elevation.  If a channel is       1278



dredged in an area where the water table is close to the      1279



ground surface, the new channel acts as a drain and lowers    1280



the water table.  If the groundwater body is underlain by



saline water, the reduction in freshwater head would cause    1281



the saline water to rise and pollute the fresh groundwater.   1282








     Methods to control this effect include:                  1285







          ^Install pumping wells in the underlying saline      1287



     water.  Removal of a portion of the saline water by      1288



     pumping will counteract its upward movement and protect  1290



     the overlying freshwater.  Means for the disposal of     1291



     the saline water must be provided, as by evaporation



     from lined basins, disposal to the ocean, or desalting   1292



     and use.
                                . r i

-------
                             56
          Line the channel with an impermeable material.       1294



          This will p_revent dewatering of the upper portion   1295



          of the aquifer and hence maintain the original       1296



          natural conditions of groundwater quality.   some    1297



          drainage to prevent uplift of the channel lining



          would be necessary.                                 1298







     There may be some loss in streambed recharge even with   1300



unlined channels of the hydraulic characteristics are         1301



improved and the gradient steepened, resulting in higher       1302



velocities.  The effects on groundwater quality are the same  1303



as for lined channels.  Artificial recharge can be used to



compensate for the loss.                                      130U








     Unlined channels may allow polluted water to enter the   1306



groundwater if the groundwater is below the bottom of the     1307



channel and if there is no impermeable layer above the        1308



groundwater body.







     Jn some coastal areas (e.g., Florida and California)     1310



natural channels have been deepened or new channels           1311



excavated.  These have sometimes cut deeply into or through   1312



the underlying clay formation which originally acted as a     1313

-------
 natural barrier and prevented the downward movement of        1314


 saline water into the underlying freshwater aquifers.


 Serious groundwater pollution has resulted, as from the Los   1315


 Gerritos Creek Flood channel near Seal Beach,  California.      1316


 Such channels should be located, designed, and constructed    1317


 with care so that the natural barriers to saline water        1318


 intrusion will not be impaired.   If this is not possible,      1319


 the channels should be lined withal.   In some  flood control   1320


 channels it may be possible to install inflatable rubber      1321


 dams to prevent the movement of  saline water from the  sea  or


 bay into the channel.                                         1322
     Structural  Alternatives  to In-Channel Modifications       1327






      In many  cases  in-channel modifications can be  reduced    1330


 substantially or avoided  altogether by the use of various     1331


 alternative schemes involving construction of off-stream      1333


 facilities.   Such facilities as levees,  floodways,  retarding  1334


 basins  and  land treatment can be incorporated into  projects   1335


"to  avoid actual channel modification.   The construction of    1336


 these alternatives  themselves potentially contribute  to       1337


 water quality degradation.
                             -^  <*, r- r
                             •;  '  \ »-"' P
                             :••/!'  ,  h

-------
                             58
Levges                                                        1340








     Levees are generally low structures located along the    1342



edges of surface water bodies such as rivers, reservoirs,     1343



lakes, and the sea to prevent inundation of land behind the   1345



levees during periods of high water levels resulting from     1346



floods, storms, or tides.  Levees may be constructed to form  1347



a controlled channel.  A floodwall ^erves the same purpose    1348



as a levee but is constructed of concrete or masonry to save  1349



on right-of-way acguisition.  Only in rare instances do       1350



levees or floodwalls have a subsurface vertical extent



sufficient to form a barrier to groundwater flow.             1351








     In coastal areas levees prevent the flooding of land by  1353



seawater.  As a result, the quality of groundwater in the     1354



aguifers behind these levees is protected.  The principal     1355



harmful effect of levees on groundwater quality occurs in     1356



floodplains of rivers.  The mineral quality of most           1357



floodwaters, neglecting their susgended sediment, is higher   1358



than that of groundwater.  During periodic inundations of     1359



floodplains, some of the water infiltrates to the             1360



groundwater and acts to improve its quality by dilution.



Where levees prevent this action and thus reduce the natural  1361

-------
                             59
recharge, the mineral quality of the qroundwater will tend    1362



to deteriorate with time.                                     1363







     To counteract this effect which tends to degrade ground  1365



water, two possibilities deserve consideration.  One would    1366



be to pump groundwater from the aguifer behind the levee so   1367



as to increase the circulation of groundwater and to remove   1368



accumulations of salinity.  The other approach would be to    1369



divert fresh water to the land behind the levee.  By          1370



overirrigation or other means of artificial recharge with     1371



water of a quality equal to or better than that of the



existing recharge, a dilution of the groundwater similar to   1372



that produced by natural floodwaters could be maintained.     1373







     The effect on surface water quality of levees located    1375



along a channel is principally the encouragement of erosion   1376



and channel scour during high water periods which contribute  1377



sediment and increase water turbidity.   Since the stream is   1378



confined by the levee to a smaller than natural flood         1379



channel, water velocities are increased above natural         1380



conditions causing channel scour to occur.  The increased     1381



scour can subject underlying less resistant geological



formation to attack and perhaps even breech aquitards         1382

-------
                              & FT
                                t.
-------
                             61
flowing in a bypass channel and infiltrating into the ground



would tend to improve the local groundwater quality.          1405
     Because of the negligible effect in degrading            1(407



groundwater quality, no specific control measures are sugged  1408



to prevent pollution of this resource.                        1409







     The effect on surface water quality depends on channel   1411



stability measures incorporated into the design of the        1412



floodway and the maintenance provided.  Incorporation of      1413



proper replanting, rip-rapping of channel bends prevent the   1414



scour of sediment during high flow periods.  Insufficient     1415



maintenace can lead to substantial quantities of sediment     1416



and debris which decreases water guality downstream.          1417
Retarding Basins
1420
     These basins ar«? constructed on tributary streams and     1422



in the main stream.  By regulating the hydrograph              1423



downstream, flood stages are reduced and damages due to        1425



flooding consequently reduced.

-------
                             62
     Water quality is generally unaffected by these basins    1427



during low flow conditions as the water passes through        1428



essentially unaffected.  During the high runoff periods, the  1429



basins help reduce sediment concentrations and trap debris.   1430



If accumulated sediment and debris are not removed during     1431



maintenance operations subsequently, sediment storage will    1432



be filled and any additional quantities will be transported   1433



downstream.







     Proper stabilization and planting programs will avoid    1436



erosion and subsequent input of sediment directly into the



basin and prevent caving and slumping of the inundated areas  1437



during high water.                                            1438








frand Treatment Measures                                       1441







     Land treatment measures include proper farm cultivation  1443



techniques and use of vegetation in the drainage basin.       1444



These measures are effective in reducing sediment bearing     1446



runoff and extending the time for runoff itself during light  1447



and moderate rainfall p.eri°ds but are not particularly        1448



effective during heavy rains that lead to flooding.           1449

-------
                             63
Basically these measures are beneficial and do not require    1450



abatement measures.
       Non-Structural Alternatiyes^to Channglization          1455







     The principal purpose of channelization projects is to   1458



reduce the damage caused by periodic flooding.  Thus far in   1459



this report, the physical methods to mitigate the water       1461



quality degradation that occurs because of such channel       1462



modification have been discussed.  One alternative to a       1463



physical solution to prevent damage from flooding is to       1464



delineate areas subject to flooding and prohibit uses of      1465



these areas that are damaged by floods.  Such non-structural  1466



alternatives can eliminate the jaollution effects directly     1467



attributable to channel modification and if properly planned  1468



and enforced can eliminate pollution effects that would       1469



otherwise occur when the project design flood is exceeded     1470



and flooding occurs.








     The CEQ Report previously referenced summarizes these    1472



approaches as follows:                                        1473

-------
                             64
         -structural adjustments take many forms.  The three   1175



major measures are regulatory,                                 1476



technical/administrative/policy, and economic/financial        1477



measures.  Powers, programs and incentives are available for   1478



each.  Regulatory measures combine State encroachment



statutes, local rural and urban zoning ordinances,             1479



subdivision regulations, building and housing codes, and       1480



open space regulations.  Technical/administrative/policy       1481



measures combine flood proofing, temporary (preplanned) and    1482



permanent evacuation, flood forecasting and warning systems,   1483



alternative uses of protective works, lending policies,        1484



local facilities development jjolicies, urban renewal, and      1485



relief and rehabilitation policies and programs.               1486



Economic/financial measures combine flood-risk insurance,      1487



tax adjustments, rights, easements, dedications,               1488



reservations and public or private acquisitions."
     In practice, a combination of structural and non-        1490



structural approach is taken to flood damage reduction.  For  1491



any given situation, the effects of the                       1492



alternatives on water quality ^hould be calculated and        1493



considered in the overall project evaluation.                 1494

-------
                        Bibliography      •••-^J -c.^ L           3


]L.   A.D.  Little, Inc., "Report on Channel Modifications,"    7
     submitted to the Council on Environmental Quality, U.S.  9
     Government Printing Office, Washington, D.C. (March,
     1973).

2_.   Anon., "Planning and Design of Open Channels,"           ]]
     Technical Release No. 25, Chapter 7, Environmental       ]2
     Considerations :Ln Channel Design, Installation and       ] 3
     Maintenance, U.S*. Department of Agriculture, Soil        ]4
     Conservation Service (October, 1971).

3_.   Anon., Water Quality Criteria, Report of the National    ]6
     Technical Advisory Committee to the Secretary of the     ]7
     Interior, Federal Water Pollution Control                ]8
     Administration (April,  1968).                            ]9

-------
                             66
            Guidance for the Identification and               1502



                  Evaluation of Reservoirs                    1503
                        Introduction                          1506
     This discussion of reservoirs will describe the effects  1510



on water Duality of both storage reservoirs and run-of-the-   1511



river or main stream impoundments.  In addition to            1513



distinguishing between these two classes of reservoirs, the   1514



principal differences between lakes and reservoirs should     1515



also be mentioned.







     Essentially a reservoir may be considered as the         1517



upstream half of a natural lake with the dam providing the    1518



artificial separation.  Since both lakes and reservoirs are   1519



physically similar many of the characteristics of lakes are   1520



reproduced in reservoirs.   There are two significant          1521



differences however which produce differences in water        1522



quality in downstream discharges.

-------
                             67
     The first difference involves facilities for             1524



controlling the rate of discharge.  Downstream flows may be   1525



reduced to less than natural and in fact, in certain type     1526



operations may be reduced to zero for significant periods     1527



during the daily operating cycle.                             1528








     The second difference is the depth from which reservoir  1530



discharges are withdrawn when compared with the surface       1531



discharges from lakes.  Natural lake discharges are           1532



generally surface waters which are aerobic and therefore      1533



have been subjected to the normal aerobic processes of        1534



natural purification.  Reservoir discharges are frequently    1535



withdrawn from deep within the reservoir.  If the reservoir   1536



is stratified, this water may be anaerobic and contain        1537



undesirable minerals resulting in decreased water quality.    1538







     Run-of-the-river impoundments are located on main        1540



stream rivers and are characterized by relatively low head    1541



dams with impounded waters not extending far from the         1542



natural channel and water detention times of a few days.      1543



water velocities are appreciable and in a positive            1544



downstream direction.  Passage of water through the           1545



reservoir is by displacement without significant vertical

-------
                             68
stratification other than that caused by daily surface        1546



warming by the sun.   These impoundments are constructed       1547



principally to deepen rivers for navigation in canalization   1548



projects or to provide re-regulation downstream from peaking  1549



power operated storage reservoirs.








     Storage reservoirs are generally located on tributary    1551



streams and are characterized as being relatively deep with   1552



the water surface extending far beyond the natural river      1553



channel.  These reservoirs have large storage capacity in     1554



relation to the drainage area and generally have several      1555



months detention time.  Because of the operation of these     1556



reservoirs passage of water through the reservoir may be      1557



discontinuous and subject the reservoir to large differences  1558



in water level on a seasonal basis.  Because of the large     1559



lake level fluctuation, past designs have placed outlets



deep in the reservoir.  These reservoirs are characterized    1560



by stratification aenerally of the classic three layer        1561



system.  Primary uses of storage reservoirs include flood     1562



storage, hydro power production and water supply storage.     1563



Recreational use is an important secondary use on many        1564



storage reservoirs.

-------
                             69
              Current Governmental Involvement                1569








     Several Federal Agencies are involved in the             1572



construction of storage and main stream impoundments.  As     1573



the Agency responsible for navigation on the nation's inland  1575



waters, the Corps of Engineers is responsible for             1576



constructing both types of reservoirs.  The Tennessee Valley  1577



Authority which was initially authorized to construct



storage reservoirs to control flooding, has additionally      1578



constructed low head impoundments to facilitate navigation.   1579



The Bureau of Reclamation has constructed storage             1580



impoundments to provide water for the irrigation projects in  1581



the western States.  The Federal Power Commission is          1582



responsible for approving private development of hydropower



and is involved in the approval of reservoir construction     1583



for this nurpose.  information on reservoir projects for      1584



hydropower production of a regional nature is also available  1585



from other U. S. Department of Interior Agencies including    1586



the Bonneville Power Administration, Alaska Power Admini-



stration, Southeastern Power Administration and the           1587



Southwestern Power Administration.  The Department of         1588



Housing and Urban Development has information on reservoirs   1589



constructed in housing projects in which they have an         1590

-------
                             70
interest.  State and local governmental agencies are also     1590



involved in reservoir construction.  Such developments may    1591



include recreation reservoirs and public water supply         1592



reservoirs.  The name of the appropriate State and local      1593



agency varies from State to State and therefore must be       1594




determined for each particular situation.








     Private development of small impoundments has become     1596



commonplace.  Private developers construct suburban housing   1597



developments and recreational weekend communities             1598



surrounding man-constructed impoundments.  Private



development of small lakes has also occurred in conjunction   1599



with campgrounds, recreational parks and even pay fishing     1600



lakes.  A survey of the governmental sources will delineate   1601



the large projects and most of the significant smaller        1602



projects.  Other projects may require an examination of       1603



local construction permit files or consultation with local



planning commissions.                                         160U

-------
                             71
                             Pr act i ces                        1609
     Current planning and justification for large reservoirs  1612



involving the Federal Government are generally based on       1613



multipurpose use.  The principal multipurpose uses included   1615



are flood control, nydropower production, navigation,         1616'



recreation, irrigation water supply, public water supply,     1617



low flow augmentation for water quality or other special      1618



purposes, and fish and wildlife propagation.  State and



local projects are generally multipurpose also with the       1619



exception that some water supply imnoundments are reserved    1620



solely for that purpose.








FLOOD CONTROL                                                 1623








     Extensive use of reservoirs whose initial justification  1625



was for flood control have been constructed by the Corps of   1626



Engineers and the Tennessee Valley Authority.  The basic      1629



theory of operation is to reduce storage quantities to a      1630



minimum level prior to the normally wet seasons of the year.  1631



During the wet season, outlet flows are kept to a minimum



while excess tributary drainage is stored.  Following the     1632



wet periods the reservoirs are filled to near maximum         1633

-------
                             72
storage levels.  The available storage is then used to         1634



maintain normal or increased stream flows, produce             1635



hydropower when passing through the dam, and provide re-



creational opportunities on the reservoir itself.  During      1636



the drier periods of the year the level is gradually lowered   1637



to reach the minimum as the next wet period arrives.           1638








POWER PRODUCTION                                               1641








     Water storage for hydropower production is cne of the     1643



oldest uses of reservoirs.  Many small reservoirs have been    1644



constructed to furnish energy to individual mills or small     1646



communities.  Current developments are rarely designed for     1647



singe purpose hydroelectric power production but. <-he feature   1648



is primary at many reservoir sites.








     Hydroelectric power production is generally used to       1650



meet peak daily loads in conjunction with a steam-electric     1651



facility supolying the base electric nower reguirements.       1652



The steam-electric facilities operate continuously while the   1653



hydroelectric power is produced for 4-8 hours to meet peak     1654



demands for air conditioning, home and industrial electric     1655



consumption demands.   Such neaking power operations are the    1656

-------
                             73
standard operating scheme for many areas including the



Tennessee Valley Authority.
1657
     Some storage reservoirs were constructed sufficiently    1659



large in comparison with power demands to allow continuous    1660



power production operations by adjusting water turbine        1661



operations to conform to the applied load.  This type         1662



operations is generally inefficient with greater economies    1663



achieved by using steam generated power for the base load     1664



and meeting peaks by hydroelectric power.
     Many of the main stream run-of-the-river impoundments    1666



also have gower generating facilities.  Since the operation   1667



of these reservoirs is freguently for maintenance of a        1668



specific pool elevation, peaking power with its inherent      1669



rapid pool stage fluctuations is not possible.  Power         1670



production is therefore limited by the incoming river flow    1671



and must be marketed on that basis.

-------
   NAVIGATION                                                    167U
t



        Development of navigation on the nation's inland         1676


 .  waterways is a major use of run-of-the-river impoundments.     1677


   Such dams are serially located alonq a stream with the pool    1679


   of the downstream reservoir terminating at the toe of the     1680


   next uostream dam.   Navigation locks are provided at each     1681


   dam to raise and lower river traffic.  The use of such        1682


   canalization techniques have been applied on the Ohio River    1683


   and the Upper Mississippi River to name two examples.         168U




        The dams are operated to maintain controlled pool        1686


   elevations for the  convenience of commercial barge traffic.    1687


   Flow at each dam is adjusted by use of weirs,  by flow         1688


   through electric generating turbines, and by the number of     1689


   lockages to maintain the specified pool elevation.            1690




   WATER SUPPLY STORAGE                                          1693




        Water supply storage includes small reservoirs for       1695


 .  public water supply arid industrial water supply and large     1696


   reservoirs for irrigation water.   Domestic and industrial     1698


   water supply reservoirs are frequently small when compared     1699

-------
                             75
with other types of storaqe reservoirs.  These impoundments   1700



are constructed to provide sufficient Quantities of water to  1701



augment the incoming stream flows during low flow periods.    1702



Sufficient detention time is generally provided to allow      1703



natural purification processes such as biochemical oxidation



of organics and sedimentation of particulate matters to       170U



enhance the water quality and reduce water treatment costs.   1705








     Storage of water for irrigation use is responsible for   1707



most of the agriculture in the western States.  Large         1708



impoundments, exemplified by the reservoirs on the Colorado   1709



River, store water from snow melt and winter rains and        1710



provide irrigation water during the growing season.  Huge     1711



complexes of irrigated farms have developed to make use of    1712



the water which is diverted from these reservoirs.
MULTI-PUPPCSE RESERVCIPS
1715
     Only infrequently are truly single purpose reservoirs    1717



constructed under conditions presently existina.  Most        1718



reservoirs include many uses although one use may             1720



predominate.

-------
                             76
     Flood control reservoirs can combine power production,   1722



water supply storage and recreational benefits although the   1723



operating rules would be mandated by the flood control        172U



purpose.  The Tennessee Valley Authority storage reservoirs   1725



generally operate on this scheme.  Reservoirs designed with   1726



peaking power as a principal output may be hazardous for      1727



recreational use because of rapidly fluctuating water         1728



levels.  However, these reservoirs may provide flood



protection and water supply benefits in addition to hydro-    1729



power generation.







     Other combinations of multi-purpose uses are             1731



discernable.  Modern planning incorporates all such multiple  1732



uses to calculate the benefits accruing from a proposed       1733



project.  Costs are likewise allocated to various projected   1734



uses.  The final benefit-cost ratio reflects to total value   1735



of the project as against the cost of construction.           1736

-------
                             77
                    Sources of Pollution
1741
     The construction of reservoirs of all types produces     1744



direct and indirect changes on water quality of the           1745



inflowing water.  Direct changes include the physical,        1747



biological and chemical changes that occur during storage     1748



and because of the changed environment from a moving stream   1749



to a quiescent lake.  indirect effects include waterhsed      1750



development which contribute pollutants and nutrients which



ultimately degrade water quality in the impoundment.  Many    1751



of the direct changes that occur are also either magnified    1752



or mitigated by the changed encironment from straam to        1753



reservoirs.
BASIC RESERVOIR MECHANICS
1756
     The deleterious effects on water quality caused by the   1758



construction of a reservoir or by a series of reservoirs in   1760



a canalization project can best be understood after an        1761



elementary understanding is acquired of basic reservoir       1762



hydraulics.

-------
                               78
       Storage reservoirs in temperate climates frequently       1764



  become stratified during the summer and winter with periods    1765



  of non-stratification during the spring and fall.  The         1766



  formation of stable stratification depends on the density of   1767



  water.  The density of water changes with varied               1768



  temperatures reaching a maximum of 4 degrees Celsius and



  decreasing with either an increase or decrease in              1769



  temperature from that point.







       The classic stratification pattern for summer has a       1771



  surface layer, the epilimnion, which is well mixed by wind     1772



  and wave action.  Beneath the epilimnion is a narrow zone of   1773



  rapid temperature decline called the thermocline or            1774



  mesolimnion, which is characterized by a temperature change    1775



  of more than 1 degree Celsius ger meter.  The lowest zone,     1776



  the hypolimnion, is effectively shut-off from atmospheric      1777



  reaeration, has only a small temperature gradient and is       1778



  generally stable.







       The winter stratification of storage reservoirs is        1780



"  characterized by either ice or water of temperature less       1781



  than 4 degrees Celsius floating on water of 4 degrees          1782



  Celsius which then extends to the bottom of the reservoir.

-------
                             79
The hypolimnion is again stabile and is effectively removed   1783



from atmospheric reaeration.  Because of low temperatures     178U



however biological activity is low and water quality may not  1785



be substantially impaired during the winter stratification.   1786







     The point of discharge in most storage reservoirs is     1788



near the bottom so that releases can continue to occur when   1789



the water level is low in the reservoir.  Thus, hypolimnetic  1790



water is generally released.  If anaerobic, this water may    1791



be initially of poor quality because of no dissolved oxygen,  1792



concentrations of odorous sulfur compounds and                1793



concentrations of soluble metals.  The quality of the         1794



discharged water is therefore greatly affected by the



dissolved oxygen concentration in the hypolimnion if          1795



withdrawal is effected from this water mass.                  1796
     If the dam is constructed so -that water can be           1798



withdrawn from the different depths, stratification allows    1799



the selective withdrawal of water of better quality.  This    1800



is accomplished through the phenomena of stratified flow to   1801



accomplish selective withdrawal.

-------
                                              WATER  SURFACE.
Figure 1  —  Representative profile  shoxing lummer  (notification  in a  typical storage  reser-
                                      voir  (Ref. 3)
                  DAM
                                                             WATER SURFACE
                                  INFLOW  TEMPERATURE  NORMAL
              fig0fe 2	Summer strotifk'jtion in man stream reservoirs (Re<. 3).

-------
                                          Inflow
                                                     i  .  I
              Length
0   10   20  30
Temperature, °C
Figure 7 — Storoge retervoir — winter stratification.
                                rfe

-------
       The thermal stratification of storage reservoirs is      1809



  governed by a heat balance taking into account solar          1810



  radiation,  surface losses by evaooration and conduction, and  1911




•  the input and outputs of heat by inflows and outflows.   The   1812



  thermal stratification effects discussed has a dominant       1813



  influence on internal flow patterns in the reservoir and      1814




  greatly affects outflow water quality.








       Main stream reservoirs may exhibit a gradual             1816



  temoerature gradient with temperatures decreasing from top    1817



  to bottom.   This gradient is caused by the absorption of the  1818



  sun's energy in the uoper water layers and the existence of   1819



  insufficient downstream velocity or wind induced mixina to    1820




  insure complete vertical uniformity.  If the stratification   1821



  is stable enough to continue overnight or exist for several   1822



  consecutive days, water guality in the lower layers may be    1823



  adversely affected by declining dissolved oxygen levels.      182U



  Downstream quality may be affected depending on method and    1825



  location of outlet works.








.       To summarize, thermal stratification of reservoirs       1827



  occurs in both those designed for long term storage or in     1828



  main stream reservoirs.  The effect is to reduce vertical     1829

-------
                             82
circulation and the transport of dissolved oxygen to lower    1830



layers in the impoundment.  Without some means to discharge   1831



waters from other than the hypolimnion, downstream water      1832



quality may be impaired.








WATER QUALITY CHANGES WITHIN RESERVOIRS                       1835








CHEMICAL - PHYSICAL                                           1837








     The annual cycle of storage impoundments in temperate    1839




climates consists of the winter and summer periods of         1840



stratification which are separated by periods of essentially  1842




uniform temperature distributions from top to bottom of the   1843




reservoir during which the waters freely mix.  The periods    1844



of mixing are called the spring and fall turnovers.  During   1845



the turnover periods soluble material entrapped in the hy-



jDolimnion which was derived from material either settled      1846



from the epilimnion or was leached from the bottom muds is    1847



returned to the biologically active near surface region.      1848



Such materials consist of the inorganic nutrients nitrogen    1849




and phosphorus, reduced heavy metals such as iron and         1850



manganese, and unoxidized organic material.  The nutrients    1851



become available to support renewed primary production.       1852

-------
                             83
This period frequently coincides with the typical fall and    1853



spring plankton blooms observed in many reservoirs.








     Durina the turnover periods dissolved oxygen             1855



concentrations are uniform throughout the depth of the        1856



reservoir.  As the reservoir warms following the spring       1857



overturn and stratification is created, the supply of oxygen  1858



to the hypolimnion from atmospheric reaeration is



terminated.  As the summer progresses dissolved organic       1859



material in the hypolimnion including that present initially  1860



and which is supplemented by material settling from the       1861



epilimnion, exert oxygen demands as bacteria oxidize these    1862



materials.  If the organic content is insufficient to



exhaust available dissolved oxygen concentrations then        1863



waters withdrawn from the hypolimnion have improved quality   1864



based on organic concentration.  However, if the organic      1865



content is sufficient to exhaust dissolved oxygen             1866



concentrations then anaerobic conditions become established   1867



and water quality is seriously degraded.







     Compounds which are chemically stable and insoluble      1869



under aerobic conditions become soluble and enter solution    1870



under anaerobic conditions.  This condition leads to the      1871

-------
leaching of materials from the bottom muds.  The bottom muds  1872



have an oxidized surface layer during aerobic conditions      1873



which prevents leaching of underlying anaerobic products.     1874



Under anaerobic conditions this oxidized zone is eliminated   1875



and compounds are readily leached.  Increases in ferrous,



ammonious, manganeous, silica, phosphate and sulfide ions     1876



have been observed in oxygen depleted waters in contact with  1877



bottom muds.  .Increases in soluble organic compounds have     1878



also been reported.








     Since many storage reservoirs withdraw water for         1880



release from near the reservoir bottom, the quality of this   1881



water may be much poorer than occurred in the preimpoundment  1882



stream.  Low dissolved oxygen concentrations, the presence    1883



of reduced metallic compounds and the presence of odorous     188U



organic compounds are evidence of such deterioration.         1885
     Main stream reservoirs as a general rule dc not become   1887



stratified for extended periods of time.  Depending on the    1888



dissolved oxygen concentration gradient (if one exists)       1889



however similar leaching from the bottom muds may occur as    1890



that in storage reservoirs.  Without stratification and       1891



assuming mixing from top to bottom, the water discharged      1892

-------
                             85
does not represent a particular zone and thus the depth of    1893



withdrawal is not critical to wat^r quality.








BIOLOGICAL                                                    1896








     In addition to various other classification schemes      1898



used for aquatic biological systems are the differentiation   1899




between lentic and lotic communities.  Those biological       1901



communities adapted to the moving water stream system are     1902



termed lotic; those adapted to still water or lake            1903



environments are termed lentic.








     In the process of converting a stream into a reservoir   1905



the biological community must adapt from lotic to lentic.     1906



The entire system may change significantly in storage         1907



reservoirs whereas only minor changes may occur in main       1908



stream reservoirs depending on prior conditions.              1909



Anticipated changes include plankton, rooted aquatic plants,  1910



aquatic invertebrates, and fishery speciation.

-------
                             86
SITE PREPARATION
1914
     A critical process to the future water quality of an     1916



impoundment is the preparation of the area to be flooded.     1917



Older impoundments for power production frequently performed  1919



little if any site preparation but simply flooded an area.    1920



Such reservoirs are typified by highly colored waters and     1921



low dissolved oxygen concentrations.  Current practice        1922



usually provides clearing at least from the minimum pool      1923



elevation to several feet above the maximum flood gool        192U



elevation.  Organic deposits such as peat boggs are



generally either removed or covered with sufficient material  1925



to effect a seal.  The remaining brush and shrubbery below    1926



the minimum pool level if left to decay will produce          1927



undesirable color, provide organic material which             1928



subsequently depletes dissolved oxygen, and provides



nutrient and growth factors which supports plankton growth.   1929

-------
                             87
RELEASED WATER                                                1933








     The water quality downstream from a reservoir is         1935



obviously affected by the design and operations of that       1936



reservoir.  If lower guality water is discharged than         1938



previously existed before the reservoir then the effect is    1939



the same as caused by a pollution source.








     Additionally, the discharge may be of a temperature      1941



unnatural for natural biological systems.  This occurs        1942



frequently during the summer because the hypolimnetic water   1943




released reflects the cooler water stored during the high     1944




flow winter-early spring seasons.  Such low temperature       1945



discharges interfere with natural fish spawning cycles as     1946



well as the existence and reproduction of invertebrates and   1947



other low life forms.








     The effects on downstream water users from the effects   1949



of impoundments include increased treatment costs at points   1950



of withdrawal for water supply use.  Taste and odor, color,   1951



iron and managanese concentrations all may be increased       1952



above previous stream concentrations and require treatment    1953



for removal.  Increased nutrients, principally phosphorus

-------
                             88
and ammonia-nitroqen may be present In increased amounts if   1954



the reservoir hypolimnion was anaerobic.  These nutrients     1955



can stimulate rooted aquatic plant qrowth as well as          1956



plankton in downstream reaches.  Plankton in nuisance         1957



amounts can produce water treatment problems by contributinq  1958



taste and odor to water and by interferinq with filtration    1959



processes.  Both plankton and rooted aquatics reduce the



aesthetic quality of water, reduce recreational aopeal and    1960



pose subsequent oxygen demands on the stream^ dissolved      1961



oxyqen resources.
EFFECTS ON GROUND WATER
     The most important effect of a dam on qroundwater        1966



quality occurs where the foundation of the structure          1967



provides a substantial or complete cutoff of qroundwater      1969



flow in an aquifer.  For example, Prado Dam on the Santa Ana  1970



River in southern California, is located at the uoper end of  1972



a narrow, V-shaped canyon which forms the natural outlet for  1973



both surface and aroundwaters from the Upper Santa Ana



Valley, an extensively developed reqion.  The cutoff wall     1974



extends to bedrock and blocks subsurface flow out of the      1975



upstream qroundwater basins.  Such a stoppaqe reduces the     1976

-------
                             89
hydraulic gradient of the groundwater upstream of the dam.    1977



This causes an increased accumulation of 2°Hutants i-n fc^e    1978



groundwater, because of slower movement or complete



stoppage; the natural disposal of salinity from the basin or  1979



aquifer is reduced or eliminated.  Under these circumstances  1980



the resulting accumulation of salts from natural or man-made  1981



sources, such as irrigation return flows, could markedly      1982



increase the groundwater salinity.                            1983








     A second and related effect is due to the higher water   1985



table created back of a dam.  This brings the groundwater     1986



closer to the ground surface where the opportunity for        1987



pollution from agricultural and septic system sources, for    1988



example, may be increased.  Marshy areas, swamps, and pools   1989



may be created; evapotranspiration losses then concentrate    1990



salinity in the groundwater.  There may also be adverse       1991



effects on surface-water quality.







     Even in situations where the dam and its foundations do  1993



not substantially alter the total groundwater flow through    1994



the underlying aquifers, the localized effects on             1995



groundwater levels and on the original pattern of             1996

-------
                             90
qroundwater flow may have significant adverse impacts on      1997



groundwater quality.








     ™he reservoir created by the dam may have somewhat       1999



similar effects on the groundwater of the area.  If water is  2000



stored in the reservoir for significant periods of time, the  2001



effects may be more pronounced than those resulting from the  2002



dam itself.  Seepage losses from the reservoir also           2003



contribute to the groundwater.  .If the quality of the water   2004



in the reservoir is better than that of the groundwater,      2005



improvement in groundwater quality results.  Conversely,      2006



seepage losses from a reservoir storing poorer quality water  2007



(e.g., reclaimed water)  degrade the groundwater.







WATERSHED DEVELOPMENT                                         2010







     In certain areas development of land areas tributary to  2012



reservoirs may constitute major sources of pollution and      2013



nutrient fertilization.  On small reservoirs constructed in   2015



conjunction with suburban housing developments direct         2016



drainage from streets and lawns constitutes the primary       2017



cause of water quality degradation.  On large reservoirs      2018



increases in upstream tributary population and development    2019

-------
                             91
on the periphery of the lake shore must be considered in      2020



projecting water quality although these sources may not be



of immediate concern.                                         2021







     Suburban development surrounding a small reservoir can   2023



deteriorate water quality by direct wastes disposal through   2024



the use of package sewage treatment plants not providing      2025



nutrient removal, discharges from watercraft, run-off from    2026



yards and streets and by polluted groundwater where septic    2027



tanks are used.  Contamination in the feeding stream          2028



upstream from the reservoir intensifies the pollution         2029



problem.








     Larger reservoirs are also adversely affected by the     2031



direct sources described above but because of the volume of   2032



dilution available, these effects may not be noticeable.      2033



Large direct discharges from industries or municipalities     203<4



however can seriously degrade water quality unless adequate   2035



treatment is provided these sources.  Nutrient                2036



concentrations from upstream point and non-point sources may  2037



accelerate eutrophication processes causing algal blooms and  2038



subsequent dissolved oxygen problems.

-------
                             92
     In order to estimate future water quality rationally,    2040



mass balances of waste and nutrient sources are required to   2041



determine accumulations and future increased constituent      2042



concentrations and the corresponding development of water     2043



quality deteriorating conditions.                             2044








CHANNEL MAINTENANCE                                           2047








     Frequently, since one of the principal reasons for the   2049



main stream reservoir is to maintain minimum depths for       2050



navigational use, channel maintenance is a key feature to     2052



maintaining the system.  Such maintenance qenerally consists  2053



of some method of dredging but may include channel bank       2054



maintenance where affected by wave action or propeller wash.  2055



Water quality is affected by the dredging operation itself,   2056



the total extent is determined by the spoil disposal method   2057



employed.








     The dredging itself resusoends silt and other fine       2059



grained material which increases- turbidity.  These materials  2060



later settle blanketing downstream sections of the            2061



impoundment.  Adsorbed materials, such as organic coumpounds  2062



and nutrients, which travel with these siltaceous materials,  2063

-------
                             93
may be released to the aquatic phase either stimulatinq or    2064



inhibiting bioloqical life.








NAVIGATION RELATED SPILLS                                     2067








     Any stream which is maintained for navigation is         2069



subject to accidental spills of carqo and fuel while in       2070



transit plus the possibility of catastrophic accidental       2072




spills from shore facilities.  These potential pollution      2073



sources are unpredictable as to time of occurence but can be  2074



expected from time to time.  The effects of these spills can  2075



be disruptive to other water uses and disastrous to aquatic   2076



life.








REDUCTION IN WASTE ASSIMILATIVE CAPACITY                      2079








     Waste assimilative capacity has traditionally been       2081



based on the dissolved oxygen requirements necessary to       2082



maintain fish and aquatic life.  The calculation of the       208U



dissolved oxygen concentration profile downstream from a      2085



waste source essentially is a balance between the amount of   2086



oxygen required to oxidize organic material and the amount    2087



of oxygen supplied by atmospheric reaeration.  Reaeration is  2088

-------
increased by an increase in water velocity and decreased by   2089



an increase in water depth.  A reservoir both decreases



velocity and increases depth and therefore reduces            2090



reaeration by both factors.                                   2091








     The decreased water velocity also provides for           2093



sedimentation of particulate material in waste discharges     209U



usually near the outfall.  This material intensifies oxygen   2095



demands near the outfall and reduces oxygen levels even more  2096



rapidly.








     The biochemical oxidation of organic material is         2098



generally assumed as a function of time.  By reducing the     2099



water velocity the distance over which this demand is         2100



exerted is reduced.







     The net effect of the reservoir is to reduce the         2102



distance over which dissolved oxygen concentrations are       2103



reduced  below acceptable levels but to greatly intensify     2104



the amount of depletion that occurs with that reach.  For     2105



dischargers, this means increased waste treatment.            2106

-------
                             95
     For main stream reservoirs the effects on dissolved      2108



oxyqen resources are readily calculable using standard        2109



techniques; for storage reservoirs the hydraulics are         2110



complicated and variable and such changes are predicted with  2111



great difficulty and little precision.                        2112







                    Types of Pollutants                       2116








     Water quality changes which are related to reservoirs    2119



are of concern within the reservoir itself and in the         2120



downstream reaches receiving discharges from the reservoir.   2121



The water quality at the surface is of importance for         2123



recreational, biological and aesthetic purposes; that in the  2124



hypolimnion affects water quality of released water for       2125



downstream uses.  At times of non-stratification the          2126



existing quality affects all uses and establishes the mixing



of materials which will determine water quality in both       2127



zones following re-establishment of stratification.           2128







     Reference is here made to a report entitled "Measures    2131



For the Restoration and Enhancement of Quality of Freshwater  2132



Lakes" which was prepared to comely with section 301 (i)  of    2133



P.L.92-500.  The Appendix to this report covers the source    213U

-------
                             96
of pollutants more thoroughly than here.  For more detail     2135



the report should be obtained.








BIOLOGICAL FACTORS                                            2138



     The biological life in the epilimnion indicates many     2140



water Duality changes in both this zone and in the            2141



hypolimnion.  Bacteria, plankton, rooted aquatic plants,      2143



invertebrates and fish all contribute and react to these      2144



water quality changes.








     The plankton as primary producers in the system use      2146



available inorganic nutrients in developing and sustaining    2147



their populations.  increases in nutrients provide material   2148



for increased plankton numbers.  The major nutrients          2149



required include inorganic nitrogen, carbon and phosphorus.   2150



So-called minor nutrients and growth factors may also be      2151



reguired.  Plankton populations generally are related to      2152



nutrient concentrations assuming adequate light and the       2153



absence of toxic materials.








     The population of plankton in relation to other factors  2155



is used as indicators in the estimation of the eutrophic      2156



condition of a body of water.  Dense populations are          2157

-------
                             97
indicative of eutrophic waters while sparse populations are   2158



indicative of oligotrophic waters.  The concept of eutrophy   2159



however is not strictly applicable to reservoirs as to age    2160



but is more indicative of aesthetics and water quality as     2161



affected by plankton populations.







     Dense plankton populations directly effect the chemical  2163



guality of water.  During daylight hours these algae remove   2164



carbon dioxide from solution which causes increases in pH;    2165



and by photosynthetically producing dissolved oxygen in       2166



quantities that frequently exceed the water solubility of     2167



this element.  At night carbon dioxide is released by         2168



respiration which reduces pH and depletes dissolved oxygen    2169



concentrations below values that would otherwise occur.       2170



These diel fluctuations in pH and dissolved oxygen can have   2171



detrimental effects on other biological life.  For example,   2172



in extreme situations dissolved oxygen levels may approach    2173



zero at night because of plankton respiration.







     Upon the death of these algae so-called "algae rains"    2175



occur as the remains settle into the hypolimnion.  Bacterial  2176



decay exerts a demand on the hypolymnion oxygen resources     2177



which may ultimately cause total dissolves oxygen depletion.  2178

-------
                             98
     Rooted aquatic plants along the shoreline of the         2180



impoundment detract from aesthetic qualities, reduce          2181



recreational opportunity for swimming or other water contact  2182



sports, provide protection for insect development which may   2183



pose a health hazard, and become a liability on the           218U



reservoirs oxygen resources when death occurs.  These plants  2185



require stable water levels and clear water allowing light    2186



penetration in order to become established.








     The higher organisms in the biological chain feed        2188



directly on plankton, their detrital remains in the bottom    2189



muds, or on those organisms that do.  The population of       2190



these higher organisms depends on the productivity of the     2191



plankton.  Detrimental effects on these organisms, which      2192



include fish, are caused by dissolved oxygen depletion, pH    2193



changes, or olankton-produced toxins.  These effects occur    2194



through the plankton activity.








     Microbiological factors must also be considered.         2196




Tributary drainage, waste treatment plant discharges and      2197



direct water craft discharges potentially contribute disease  2198



causing oraanisms.  For recreational use bacteriological      2199



guality must be maintained so that disease transmission from  2200

-------
                             99
fecal discharges is minimized.  Monitoring by using the       2201



fecal coliform test is the standard technique for             2202



determining the sanitary microbiological guality of           2203



reservoir waters.








AESTHETIC FACTORS                                             2206



     Aesthetic appeal of an area can be enhanced or degraded  2208



by reservoir design and operation.  Ignoring shoreline        2209



development and concentrating on water quality aspects the    2211



most important factors are the control of aquatic plants;     2212



maintenance of dissolved oxygen, color, turbidity and other   2213



chemical constituent concentrations in the range conducive    221U




to desirable fish and aquatic life development and            2215



maintenance; and maintaining lake levels sufficiently high    2216



during the recreation season to safely allow reservoir        2217



recreational use.  A balance of these factors aid in the      2218



enjoyment of the water resource.








CHEMICAL FACTORS                                              2221



     Maintenance of the water quality in a reservoir for      2223



multiple uses requires control of the water chemistry,        222U



inputs of point and non-ooint waste materials and any toxic   2225



materials.  Common measures of chemical water quality         2227

-------
                            100
include dissolved oxyqen, color, pH, various inorganic        2228



salts, metals, nutrients and organic compounds including      2229



pesticides and herbicides.  Specific levels for these         2230



materials are contained in the various State Water Quality



Standards.  Discussion of these materials with recommended    2231



levels are also available in a book entitled "Water Quality   2232



Criteria" published by the Environmental Protection Agency.   2233
     Chemical factors are important for maintaining the



usefulness of the reservoir for recreational use, water



suoply use, maintenance of fish and aquatic life and for



preserving downstream water uses.
2235



2236



2237
PHYSICAL FACTORS                                              2240



     The physical factors of water quality include            2242



determinations such as temperature and turbidity which        2243



affect the usefulness of v>ater and mediate other chemical     2245



and biological reactions.
     Temperature affects the rate of physical, chemical and   2247



biological reactions.  In terms of reservoir hydraulics,      2248



temperature related density changes in water causes the       2249



development of the stable summer stratification with its      2250

-------
                            101
pronounced affect on water Quality.  Chemically, th^          2251



solubility of gases with dissolved oxygen principally being   2252



of interest; the solubility of chemical compounds is          2253



affected; and the reactiveness of certain constituents all



are affected by water temperature.  Biologically, reaction    225U



rates roughly double for every 10 degree Celsius increase in  2255



temperature as well as regulating reproductive mechanisms     2256



and life itself.  Temperature is obviously most important     2257



consideration in reservoir water quality evaluations.         2253








     Turbidity is a measure of the reduction in incident      2260



light penetration caused by suspended particulate matter.     2261



As a aeneric term i.t includes measurements such as suspended  2262




solids and secchi disc in addition to a turbidimetric         2263



measurement.  The suspended matter in epilemnetic waters may  2264



be plankton while in hypolimnectic waters it may be sediment



clays or silts.  In surface waters turbidity is used as a     2265



factor in determining the depth of light penetration in       2266



determining the so-called euphotic zone or zone of            2267



photosynthetic activity.  In water supply uses of various     2268



types it is a factor in treatment costs.  In reservoir



hydraulics a turbid inflow may be more dense than certain     2269




existing layers and produce a phenomenon known as an inter    2270

-------
                            102
flow which would insert a layer between existing water        2271



layers and subsequently affect discharged water quality.       2272



Turbidity is both an economic and quality parameter to be     2273



excluded in Reservoir water quality.
                       of_ Pollutant Transport                 2277
     The basic hydraulics of both storage reservoirs and      2280



main stream reservoirs has been previously discussed.  The    2281



movement of soluble p_ollutants through a reservoir simulates  2283




the hydraulic movement.  Particulate pollutants, if organic,  2284



may be biologically solublized; inorganic materials may be    2285



indefinitely held up by being incorporated into the           2286



reservoir sediments.  other factors such as solar insolation  2287



and the reservoir operating schedule influence water quality



in the reservoir itself and the stream downstream from the    2288



reservoir.








     Pollutant transport in a stream is generally quite       2290



simple as the pollutant travels at the same rate as the       2291



water itself.  This generalization has exceptions as for      2292



example sediment bed load which varies with respect to the    2293



water velocity and temperature.  This same essential

-------
                               103
   transport process occurs in main stream impoundments where    229U



   velocities are typically discernable and sufficient to        2295



   maintain particulate matter in suspension.  Stratified        2296



   storage reservoirs in contrast have extemely ecomplex         2297



   hydraualics.  Density effects, surface mixing caused by       2298



   winds and the level of water release all bear on pollutant



   residence time.                                               2299
   TRANSPORT INTO THE STORAGE RESERVOIR                          2302



        Discharges directly into reservoirs which includes       2304



   direct runoff, tributary streams or waste streams are         2305



   segregated in the reservoir by their density.  Beginning in   2306



   the spring as discharges typically become progressively       2308



   warmer and less dense, the flows form layers above the



   existing cooler waters.  Toward fall when inputs become       2309



   cooler and therefore more dense than stored water the inputs  2310



   may form interflows between existing layers.  Waste           2311



   discharges would also tend to be density segregated which in  2312



   that case may include ionic density effects in addition to



   thermally caused density effects.  Thus the location of an    2313



   incoming pollutant depends on the existing density regime in  2314



*   the reservoir and the density of the water tranporting the    2315



   pollutant.

-------
                            10U
TRANSPORT WITHIN THE STORAGE RESERVOIR                        2318



     The princiapl controlling factor on water release is     2320



the location of the outlet.  Normally, the water discharged   2321



is the densest existing layer above the outlet structure.     2323



In storage reservoirs with fixed deep outlets progressively   2324



less dense water is released during the summer stratified     2325



period which approximates the time of entry into the




reservoir.  This progressive release may be interrupted by    2326



the occasional passage into and through of more dense         2327




sediment-laden storm water or some other density anomaly.     2328



As the fall season approaches, but before the fall overturn,  2329



cooler tributary inflows may also flow beneath existing



storage and pass through the reservoir ahead of existing      2330



storage.  Soluble pollutants which are stable  (eg salts)      2331



would be transported in a similar fashion.                    2332
     Particulate pollutants if off sufficient size, tend to   233t



settle toward the reservoir bottom.  These materials settle   2335



at different rates depending on a myriad of factors but may   2336



finally reach the bottom or be retained by buoyant forces     2337



occurring in more dense water layers.  Thus a density



segregation of particulate matter also occurs.  Particulate   2338



pollutants that reach the bottom may be essentially           2339

-------
                            105
permanently removed while those trapped in lower lying        2340



denser flows may pass through the reservoir more rapidly      2341



than the initial transporting water.







     Many organic pollutants are biologically degradable and  2343



during the storage provided in the reservoir are destroyed.   2344



These may be either soluble or particulate in form but are    2345



amenable to biological attack.  These materials are           2346



therefore not transported out of the reservoir but are        2347



decayed.







TRANSPORT OUT OF THE STORAGE RESERVOIR                        2350



     Older dams frequently were designed and constructed      2352



with low level outlets only.  Newer designs incorporate       2353



multiple outlets so that water from various levels within     2355



the reservoir can be released.  Because of density effects,   2356



the water withdrawn will principally be from the densest      2357



layer above the outlet level.  With a^multiple outlet         2358



system, water of the best available quality can be withdrawn



to protect downstream uses.  This is especially important     2359



during the late summer period when normal hypolinion          2360



releases contain the worst water quality of the year in       2361



terms of dissolved oxygen, nutrients, metals and odorous      2362

-------
                            106
compounds.  Release of aerated epilimnion waters avoids this  2363



problem to the maximum available extent.







     hypolimnetic releases during late summer may release     2365



materials that settled to the bottom and became biologically  2366



solubilized or those chemically precipitated with subsequent  2367



settling to the bottom which become resolubilized under the   2368



low oxygen conditions near the reservoir bottom.  Examples    2369



include detritus of plaaktonic origin which decay and         2370



metallic phosphates which become soluble under anaerobic      2371



conditions.  Thus hypolimnetic releases contain the non-re-



active dissolved materials contained when the water entered   2372



the reservoir plus those products initially removed  but      2373



resolubilized.
     Epilimnetic releases contain the active biological life  2375



in this zone plus the existing surface water quality as       2376



affected by those biological processes and other physical     2377



processes.  These waters are generally characterized by high  2378



quality water including substantial concentrations of         2379



dissolved oxygen.

-------
                                   107
                      § and Variation of Pollutant Effects          2384
           Water quality transformation for reservoirs as compared  2387

      with the preimpoundment streams have been prepared on         2388

      several basins under the auspices of the constructing         2390
•
      agency.  For main stream reservoirs one series is available   2391

      for the Ohio River which includes changes observed following  2392

      the initial installation of low head impoundments.

      subsequently many of the low head impoundments have been      2393

      replaced by higher head impoundments for which pre-and post-  2394

      water quality investigations have been conducted.  (See       2395

      bibliography for references)



           Similar studies are available from the Tennessee Valley  2397

*     Authority for both main stream and storage impoundments.      2398

      Monitoring information for each operating year for various    2399

      water quality parameters are also available in addition to    2400

•    special studies performed during the year.



           The Bureau of Reclamation Reservoirs also have water     2402

ft    quality studies available for their reservoirs.  Such         2403

      studies are required for determining the quality of           2404

-------
                            108
irrigation water in addition to monitoring ^for recreational   2405
and other uses.
     State and local controlled reservoirs whether for
recreation or water supply purposes, monitor the water
quality to meet public health requirements.  These
2407
2408
2409
measurements are available in annual State monitoring system  2410
reports or local water supply annual reports.

     In addition to these governmental sources of guality     2412
information, engineering and biological literature is         2413
replete with special water quality studies of reservoirs.     2414
Examples are included in the bibliography to this section.    2415
                                       Methods
2420
     The prediction of water quality in reservoirs has been   2423
performed by several methods.  Included among the various     2424
techniques are empirical techniques, hydraulic model          2426
studies, and mathematical model studies.  All of these  .      2427
techniques require field data for verification QT             2428
calibration.  Such surveys include chemical, biological and

-------
                           109





physical studies to ascertain existing water quality and      2429



establish baseline conditions.                                2430







EMPIRICAL TECHNIQUES                                          2433



     Empirical methods are generally developed specifically   2435



for one reservoir and include analyses of data recorded for   2436



a number of seasons or years.  Although simpler analyses are  2438



used, statistical correlations are developed between input    2439



water quality variables, reservoir water quality and output   2440



water quality.  Operating rules for the reservoir can be      244]



modified based on such analyses to maximize one set of        2442



parameters as opposed to another.








     Simpler techniques than statistical methods would be     2444



simple graphs with trend line development.  Obvious problems  2445



with such methods includes: the applicability to only one     2447



site, predictive ability only in range used for development,  2448



no mechanism to correct for changes in physical conditions,   2449



lack of fundamental understanding in reservoir mechanics,



and extended record required for development.                 2450







     The principle advantages are the relatively inexpensive  2452



development cost and simplicity in use.  Depending on         2453

-------
                            110
precision required such techniques may be adequate for many   2452



purposes.







HYDRAULIC MODELS                                              2455



     Hydraulic models range in scope from simple laboratory   2457



scale aquariums to multidam basin models coverinq several     2458



acres.  These models are used to verify dam desiqns for       2460



hydraulic properties, effects on reservoir stratification of  2461



these desiqns, or entire river conditions for various flow    2462



reqimes.







     Data from the models are collected by usinq various      2464



tracer and staqe-velocity measurement techniques.  The data   2465



is then fitted to a mathematical formulation for              2466



incorporation into a particular desiqn.  These data are also  2467



valuable for evaluatinq mathematical models as some water     2468



quality parameters can be empirically or theoretically        2469



scaled from model to prototype.
MATHEMATICAL MODELS                                           2472



     Mathematical models are used for many purposes in        2474



reservoir desiqn and operation.  The hydroloqy of an entire   2476



basin may be modeled to aid in sizinq and locatinq the        2477

-------
                            111
optimum number of reservoirs or the amount of water storage   2478

required to meet certain objectives.  Internal reservoir      2479

hydraulics and mixing have also been simulated by

mathematical models frequently as a first step in predicting  2480

the distribution of pollutants in the reservoir or to         2481
     (r
predict the discharge sequence of stored water with a given   2482

water quality for each stratified layer.  Recent attempts     2483

have been made at ecological modeling.  These models begin    2484

with material inputs from which plankton and fish

populations are ultimately predicted.  Hydraulic              2485

simulations, water guality constituent distributions,         2486

phytoplankton production, zooplankton controls on             2487

phytoplankton populations, and fish populations are all       2488

incorporated in such models.




     The basis for the water quality and ecological models    2490

is a basic understanding and prediction of the thermal        2491

stratification process in reservoirs.  Recent research        2492

efforts have extended knowledge of the stratification         2493

process to the extent that reasonable predictions of the      2494

internal temperature distributions can be made.  Using the

system hydraulics as the basic transport process, the         2495

chemical, physical and biological reactions are imposed       2496

-------
                            112
using the laws of conservation of mass and from general       2497



kinetic principles.  Equations are constructed for each       2498



constituent with the entire set of equations subsequently     2499



being solved using numerical techniques with the aid of the   2500



digital computer.  The model outputs include the important



water quality characteristics for water quality models and    2501



additionally populations cf principal biotic species in       2502



ecologic models.







     The predicted concentrations and biological populations  2504



from the models generally follow the observed trends of the   2505



data used fpr verification with numerical values being        2506



representative of actual.  For most management decisions      2507



concerning reservoirs the results offer adequate accuracy     2508



and a valuable tool for evaluating alternative waste          2509



treatment schemes including input locations, operating rules



jjor the reservoir to maximize water quality, and the          2510



projected water quality for various uses.                     2511







WATER QUALITY SURVEYS                                         2514



     The use of any statistical or modeling technique         2516



requires adequate information for verification and            2517



development.  The usefulness of the various models depends    2519

-------
                            113
on the accuracy of the predictions made which can only be     2520



verified by field observations.  The basis for the validity   2521



of predictive techniques requires the performance of          2522



intensive water quality surveys auqmented by routine



monitoring.  Key parameters of water quality require          2523



delineation both temporally and spatially within a reservoir  252U



as well as in the inflows and the outflow.  These data        2525



provide information for compliance with water quality         2526



standards in addition ro providing data for future            2527



improvements in analytical and modeling technology.
                                  \ rV
                                  \ r

-------
                        Bibliography


1.   Water Resources Engineers,  Inc.,  "Mathematical Models
     for the Prediction of Thermal Energy Changes in
     Impoundments," Water Poll.  Contr.  Res.  Series 16130EXT
     12/69 Environmental Protection Agency (December,  1969).

2.   Markofsky, M. and D.R.F.  Harleman, "A Predictive  Model
     for Thermal Stratification  and Water Quality in
     Reservoirs," Water Poll.Contr.Res. Series,  1630DSH
     01/71 Environmental Protection Agency (January, 1971).

3.   Markofsky, M. and D.R.F.  Harleman, "Prediction of Water
     Quality in Stratified Reservoirs," Jour,  of the
     Hydr.Division, A.S.C.E.,  Vol. 99,  No. HY5,  pp 729-745
     (May, 1973).

4.   Anon., Hydraulic Models,  Manual of Engineering Practice
     No. 25, American Society of Civil Engineers.

5.   Imberger, J. and H.B. Fischer, "Selective Withdrawal
     from a Stratified Reservoir" Water Poll.Contr.Res.
     Series, 1540EJZ 12/70, Environmental Protection Agency
     (December, 1970).

6.   Chen, C.W. and G.T. Orlob,  "Ecologic Simulation for
     Aquatic Environments," Office of Water Resources
     Research, U.S. Department of the Interior (December,
     1972).

7.   Di Toro, D.M., D.J. O'Connor and R.V. Thomann, "A
     Dynamic Model of Phytoplankton Populations in Natural
     Waters," presented at a course, Advanced Topics iri
     Mathematical Modeling of Natural Systems, Manhattan
     College, Bronx, New York" (1971) .

8.   Guarraia, L.J. and R.K. Ballentine, "Influences of
     Microbial Populations on Aquatic Nutrient Cycles and
     Some Engineering Aspects, "Technical Studies Report TS-
     00-72-06, Environmental Protection Agency, Washington,
     D.C.  (May, 1972).

9.   McCaw, W.J., III, "Water Quality of Montgomery County
     Streams and Sewage Treatment Plant Effluents; December,
     1969-January, 1973," Montgomery County, Maryland, Dept.
     of Environmental Protection, Division of Resource
     Protection  (June, 1973).

-------
                                  /'=»


      10.  Anon., "TVA Activities Related to Study and Control of
           Eutrophication in the Tennessee Valley," Papers
           Discussed at Meeting of the Joint Industry/Government
)          Task Force on Eutrophication, National Fertilizer
           Development Center, Muscle Shoals, Ala. (April 29-30,
           1970).

      11.  Brooks, N.H. and R.C.Y. Koh, "Selective Withdrawal from
           Density-Stratified Reservoirs," Jour, of the Hydraulics
§          Division, A.S.C.E., No. HY4(July, 1969).

      12.  Mackenthun, K.M., The Practice of Water Pollution
           Biology, United States Department of the Interior,
           Federal Water Pollution Control Administration,
           Washington, D.C. (1969).

      13.  Vanderhood, R.A., "Changes in Waste Assimilation
           Capacity Resulting from Streamflow Regulation" in
           Symposium on Streamflow Regulation for Quality Control,
           999-WP-30, DHEW, Public Health Service (June, 1965).

^    14.  Churchill, M.A. and W.R. Nicholas, "Effects of
           Impoundments on Water Quality," Journal of the Sanitary
           Engineering Division, A.S.C.E., No.SAG (December,
           1967).

      15.  Kittrell, R.W., "Thermal Stratification in Reservoirs"
           ill Symposium on Streamflow Regulation for Quality
           Control, 999-WP"-30, DHEW, Public Healtn""Service  (June,
           1965) .

      16.  Anon., Water Quality Criteria, Report of the National
           Technical Advisory Committee to the Secretary of the
           interior, Federal Water Pollution Control
 •         Administration  (April, 1968).

      17.  Anon., "A Study of the Pollution and Natural
           Purification of the Ohio River" Public Health Bulletin
           No. 143, U.S. Public Health Service (July, 1924).

 ^    18.  Anon., "Ohio River: Markland Pool, "Investigation by
           the Federal Water Pollution Control Administration
           During 1957, 1960 and 1963  (Pre and Post Impoundment,
           Compiled and Presented by Ohio River Division, U.S.
           Army Corps of Engineers (June, 1968).

-------
   Methods, Processes and Procedures to Control Pollution

          Resulting From the Impoundment of Water
     The principal water quality changes that occur by
transforming a flowing stream into a reservoir are the
obvious ones related to the reduced water velocity and
extended detention time and those changes affected by
thermal stratification of the stored waters.

     Reduced water velocity enhances sedimentation of
inorganic suspended material and tends to increase water
clarity.  Such quiescent conditions in conjunction with
increased light penetration and sufficient nutrient
materials are ideal for the production of aquatic plants.
Under certain conditions this may lead to phytoplankton
production while in others rooted aquatic or floating
aquatic plants may develop.  Such production ultimately may
produce organic materials for decomposition in the

-------
                            117
hypolimnetic waters or bottom muds followinq the death of     2569



such organisms.







     Thermal stratification, especially the classical three   2571



layer system typical of summer conditions, creates an         2572



effective trap in the hypolimnion  (lower layer) for material  2573



initially there at the time of stratification or accumulated  2574



there by sedimentation or other processes.  If sufficient     2575



organic material accumulates in the hypolimnion, dissolved    2576



oxygen may be totally depleted creating anaerobic             2577



conditions.  Such conditions eliminate desirable biological   2578



life, produce reduced compounds which contribute taste and    2579



odor to water and presents conditions conducive to re-



solubilization of many chemical compounds.  These effects     2580



decrease the quality of water released downstream which may   2581



violate water quality standards.                              2582







     This brief discussion of changes in water guality        2584



caused by water impoundments demonstrates the typical         2585



problems faced.  Available methods, processes and procedures  2586



to ameliorate or mitigate these problems will be presented    2587



and discussed.  A bibliography will be presented to enable a  2588

-------
                            118
more detailed presentation of a particular subject for those  2589



contemplating use of a particular method.







     Reference is here made to a report prepared in           2591



compliance with Section 30U(i)  of P.L.92-500 entitled,        2592



"Measures for the Restoration and Enhancement of Quality of   2593



Freshwater Lakes."  That report covers in more detail many    2594



of the same techniques which are applicable to both lakes     2595



and reservoirs.








SITE PREPARATION                                              2597



     Water quality may be affected by many characteristics    2599



of the location site.  Factors which affect future water      2600



quality include maximum and operating depth range,            2601



configuration, relation of principal axis to prevailing wind  2602



direction, geology of area, characteristics of the            2603



underlying soil, and the type of native vegetation.
     The characteristics of the underlying soil and the       2605



vegetation that remains before inundation are important to    2606



future reservoir water guality.  Both the soils and           2607



vegetation require investigation to determine the amount of   2608



organics present in the soil and its state of decay so that   2609

-------
                            119
the amount of leachable color, nutrient release, organic and  2610



production and decrease in pH can be predicted.  Additional   2611



soil analysis can determine the amount of leachable



inorganic salts present which tend to increase the total      2612



dissolved solids in the overlying water.  Based on such       2613



determinations, decisions regarding the necessity of          2614



removing organic soils prior to inundation or using a         2615



mineral soil covering of the organic soils to prevent their



undesirable effects.                                          2616







     The chemical, physical and biological reactions that     2618



occur at the soil-water interface are complex and not         2619



particularly well understood.  It has been shown however      2620



that these reactions are more of a biochemical nature than    2621



purely chemical or physical.  The organic content of the      2622



soil and pre-inundation vegetative cover are responsible



more than other characteristics for the undesirable effects   2623



on overlying water.  The adverse effects caused originally    2624



by freshly inundated soils are reduced with time.  This       2625



aging process is a combination of leaching, or organic        2626



destruction and of being covered by sediment transported      2627



into the reservoir.  Estimates of the time required for       2628



reservoir bottoms to stabilize so that tastes, odors and      2629

-------
                            120
color are not imparted to the water indicate that 10-15       2629



years may elapse.  The equilibrium condition is defined as    2630



the point where reservoir water quality is determined by the  2631



quality of the inflowing water.  The effects on dissolved     2632



oxyqen concentrations usually are significant for only the    2633



1-2 years with normal reservoir site preparation although     2634



minor effects may occur for substantially longer geriods.     2635
     It is generally agreed in the literature that to         2637



minimize changes in water quality caused by natural           2638



materials it is necessary to remove all standing timber,      2639



brush, stumps, logs, structures and man-made debris.  Grass   2640



and other forms of herbage should be mowed with trimmings



removed just prior to inundation.  Additionally organic       2641



mucks from swamps should be substantially removed with the    2642



residual covered with 2 or more inches of clean sand.  It is  2643



also desirable to cut channels to pockets within the          2644



reservoir bottom to provide drainage when water levels are



lowered.  To protect the sanitary quality of the reservoir    2645



cleaning of barnyards, privies and cesspools should be        2646



performed.

-------
                                     k    Ar
                            121
     Occasionally, soil stripping is employed -to remove       26U8


soils with heavy organic content (IX to 2%).  This operation  2649


is expensive and of only temporary benefit when compared      2650


with non-stripped reservoir bottoms.  Without the effects of  2651


significant sediment inflows, the effects on overlying water  2652


quality are equivalent in 10-15 years as between stripped     2653


and non-stripped reservoir sites.  Sediment in reservoir      2654


inflows may reduce this time for equilibrium to occur.





MULTILEVEL OUTLETS                                            2656


     Multilevel outlets are increasingly incorporated in      2658


storage reservoirs to provide flexibility in the withdrawal   2659


level for released water.  Two principal water quality        2660


criteria are used to gage the need for such variable          2661


releases: temperature and dissolved oxygen.                   2662




     Multilevel outlets provide the ability to withdraw       2664


aerated epilimnetic (near surface)  water during periods when  2665


hypolimnetic _£near bottom)  water may be low or devoid of      2666


dissolved oxygen.  This release procedure provides water of   2667


suitable quality to support fish and aquatic life             2668


downstream.

-------
                            122
     When dissolved oxygen levels are sufficient throughout   2670



the reservoir, the temperature of the released water may be   2671



critical to support anadromous fish runs, induce spawning or  2672



to maintain cold water species of fish.  Multi-level outlets  2673



provide the opportunity to furnish water of the desired       2674



quality if available at any level in the reservoir.           2675







     The hydraulics of selective withdrawal have been         2677



extensively researched in recent years.  It is on the basis   2678



of this theory that multi-level outlets can be rationally     2679



designed.  Several reports listed in the bibliography         2680



discuss the prediction of thermal stratification and others   2681



discuss the hydraulics of selective withdrawal.               2682







DESTRATIFICATION AND HYPOLIMNETIC AERATION                    2684



     In reservoirs with deep withdrawal points that do not    2686



contain multilevel outlets or any method to release aerated   2687



epilimnetic waters, methods to provide aerated water at the   2688



withdrawal point provide alternatives to construction of      2689



such facilities.  Two principal methods have been developed,  2690



reservoir destratification and hypolimnetic aeration without  2691



destratification.

-------
                            123
     Destratification is most commonly accomplished by        2693



compressed air diffuser aerators or mechanical pumping.  By   2694



either method mixing of the hypolimnion and epilimnion is     2695



accomplished to destroy the thermally-induced density         2696



stratification.  The induced mixing provides aerated water    2697



at all reservoir depths which prevents water guality          2698



deterioration within the reservoir caused by anaerobic



processes and thereby maintains the quality of water          2699



released downstream.  Aerobic conditions inhibit leaching of  2700



color, solubilization of metals and nutrients from the        2701



bottom sediments, and provide for biological distribution     2702



throughout the affected area.








     Compressed air aeration has an advantage in that oxygen  2701



is absorbed directly from the rising bubbles in addition to   2705



the aeration of the surface that occurs because of the        2706



mixing.  However, in deep reservoirs operating costs may be   2707



greater than pumping because of the necessity to increase     2708



air pressure above the static level of the depth of water     2709



above the diffusers.  Pumping conversely only requires        2710



sufficient lift to move the water from the water surface up



to the £ump  (plus minor intake pipe friction losses)  which    2711



may be only a few feet.                                       2712

-------
                            124
     Both relatively large and small reservoirs can be  .      2714



destratified.  Under given morphologic conditions a long      2715



reservoir has been mixed for a substantial distance upstream  2716



from the dam by providing mixing from a  single location.     2717



Smaller reservoirs can be entirely mixed.  It is not          2718



necessary to destratify an entire lake to achieve outflows



of good quality water.  Only the area near the outlet's       2719



structure may require aeration.                               2720







     Hypolimnetic aeration is a procedure to provide          2722



aeration of the hypolimnion without destroying the existing   2723



thermal stratification.  The purpose of avoiding the          2724



disturbance of the thermal stratification is to protect       2725



existing cold water in the hypolimnion.  This water may be    2726



required for releases to support anadromous fish runs and



fish spawning.  By restricting aeration to the hypolimnion    2727



the temperature change inherent in mixing is prevented but    2728



the water quality is protected or enhanced.                   2729
     Several techniques for accomplishing hypolimnetic        2731



aeration have been developed.  U-tube designs, that is where  2732



water is withdrawn f_rom the hypolimnion, pumped to the        2733



surface and returned to the hypolimnion are a common method.  2734

-------
                                       F •?.'„; ***». A
                            125
Compressed air may be injected into the water at the intake   2735
of the U-tube, which provides contact time while traveling    2736
to the surface, and be subsequently vented at the surface;
or low pressure air or pure oxygen may be injected at the     2737
surface of the TJ-tube before returning to the hypolimnion     2738
utilizing the increased pressure during the descent to        2739
effect oxygen absorption.  Care must be exercised in          2740
operation to avoid creating sufficient turbulence to destroy  27m
the thermal stratification.

DERATION OF RESERVOIR RELEASES                                2743
     In order to discharge water with sufficient dissolved    2745
oxygen concentrations to meet water quality standards and     2746
thereby meet downstream water use requirements, it may be     2747
necessary to provide aeration of the discharge.  Proper       2748
design of multilevel outlets and other procedures may be      2749
insufficient to meet downstream needs.  Several methods of    2750
discharge aeration are available including turbine aeration   2751
by venting, Venturi tubes and Howell-Bungen valves.

     The Venturi tube aeration device has not been tested on  2753
full scale reservoir releases and therefore must be           2754
considered experimental.  In the device, air was injected     2755

-------
                            126
into the throat of a Venturi section.  The air was admitted   2756



used the inherent vacuum created by these devices.  The       2757



maximum efficiency of such a device occurs with only 0.5      2758



mq/1 increases; higher oxygen transfers required increased    2759



water velocity and subsequent friction losses.  The device



may only be efficient on small flows and not full size        2760



reservoir discharges.                                         2761
     Turbine aeration uses the water flowing through the      2763



power turbines which are vented with air to produce           2764



increased dissolved oxygen levels.   In the older horizontal   2765



type turbines existing draft tube vents have been used which  2766



are frequently available to control cavitation.  Oxygen       2767



transfer efficiencies of 37* have been reported with turbine



power losses of about 5X.  Modern turbine units may have the  2768



turbine water wheel at elevations less than tail water        2769



elevation which produces only small negative pressures and    2770



is not conducive to efficient aeration.  One solution to      2771



this constraint has been the installation of wedge shaped     2772



deflector plates in the draft tubes slightly below the        2773



turbine wheel.  The negative pressure created in the wake of  2774



the turbulent flow past, the deflectors is used to induce



aeration flow.  Aeration efficiency for water initially 80S   2775

-------
                            127
saturated with oxygen varied from 25% - 50*.  Turbine         2776



efficiency was decreased by 0.83X.                            2777







     The Howell-Bunger valve is a fixed dispersion cone       2779



valve which can be used for reservoir releases to provide     2780



aeration.  The Tennesse Valley Authority has performed        2781



extensive evaluation of this device for aeration purposes.    2782



The valve produces a spray discharge which is similar to the  2783



common garden hose spray nozzle except that the cone is



fixed rather than adjustable.  Aeration efficiencies were     2784



determined during the TVA testing program and were defined    2785



as the ratio of final dissolved oxygen deficit to the         2786



initial dissolved oxygen deficit.  Efficiencies of 80% were



achieved when exit velocities exceeded 6 meters per second    2787



for a free discharge.  Initial dissolved oxygen               2788



concentrations for these tests were less than 1 mg/1.







     In addition to the possibilities for aeration while      2790



passing water through the dam, the aeration may be applied    2791



in the tailrace or immediately downstream.  Methods           2792



previously discussed such as U-tube aerators and diffused     2793



air aerators can be used as well as mechanical surface        2794

-------
                            128
aerators which are frequently used in waste treatment         2794



processes.                                                    2795







     Factors to be considered before installing aeration      2797



include feasibility and costs.  Many methods are              2798



theoretically available but selection requires evaluation of  2799



local factors in addition to theoretical considerations.      2800








CONTROL OF BIOLOGICAL NUISANCE ORGANISMS                      2802



     Nuisance organisms in reservoirs related to water        2804



quality include excessive numbers of algae and rooted         2805



aquatic plants.  The 2°Pulations of these plants depend on a  2806



myriad of factors including nutrient concentrations and       2807



sufficient light.  The most satisfactory and only long term   2808



control of these plants requires the institution of measures  2809



to reduce the causative factors.  Nutrient reduction in



inflows, shoreline alteration to reduce existence shallow     2810



areas, and the implementation of reservoir operation          2811



schedules are factors in controlling aquatic plant            2812



populations.







     Temporary control measures are principally mechanical    2814



or chemical.  Operational techniques of fluctuating           2815

-------
                            129
reservoir water levels can also be practiced.  In addition    2816



to reservoir destratification previously discussed,           2817



mechanical techniques include algae harvesting by



centrifuqation, coagulation and filtration, microstraining,   2818



and flotation; and the use of special cutting machines for    2819



harvesting rooted aquatics.                                   2820







     Harvesting algae from natural water bodies by any of     2822



the above methods has not received extensive investigation.   2823



The efficiency of such harvest is inversely proportional to   2824



the population density because of the volumes of fluids to    2825



be processed to recover a given amount of algae.  Without a   2826



market for the removed alqae to recover substantially the     2827



cost of removal, in-situ chemical treatment methods for



alqal control are less costly to apply.  There appears to be  2828



little hope of developing an economically feasible            2829



harvesting technique for the naturally occurring relatively   2830



dilute algal population densities.







     The development of efficient, specialized cutting and    2832



harvesting machines allows the direct removal of rooted       2833



aquatic plants.  In addition to the expense of operating the  2834



machines, disposal of the voluminous plant residue also must  2835

-------
                            130
be taken into account.  Various methods have been employed    2836
to reduce the volume of the plant material before final       2837
disposal.

     Mechanical removal in natural waters is also a nutrient  2839
removal process.  The typical standing crop of algae of 2     2841
tons per acre (wet weight)  would contain about 15 pounds of   2842
nitrogen and 1 1/2 pounds of phosphorus.  Typical yields for  2843
submerged aquatic plants are 7 tons per acre Jwet weight)      2844
which contain 32 pounds of nitrogen and 3.2 pounds of
phosphorus.  Under nuisance conditions yields may be          2845
substantially higher.  Comparison of mechanical removal       2846
costs of nutrients with other control techniques generally    2847
are unfavorable at least where controllable point discharges  2848
are the principal nutrient source.

     The usual application of mechanical methods is for       2850
control where chemical methods would possibly cause a severe  2851
oxygen demand because of the dead plant residues and          2852
subsequent development of anaerobic conditions.  The odorous  2853
conditions and fish kills caused may be more aesthetically    2854
undesirable than the nuisance organisms in the water.

-------
                            131
     Chemical control methods use alqicides on herbicides to  2856



control giant populations.  Attributes of a satisfactory      2857



alqicide or herbicide include:  reasonably safe to handle     2858



and apply; kill specific nuisance plants; be relatively non-  2859



toxic to fish, other aquatic animals and terrestrial animals  2860



at plant-killing concentrations; be safe for water contact    2861



by humans or animals or for withdrawn water uses; and be of



reasonable cost.  Table 1 presents those herbicides           2862



presently registered in accordance with the Federal           2863



Insecticide, Fungicide, and Podenticide Act for use in or on  2864



water.  Table 2 lists those registered for use at or above    2865



the water line.  These tables indicate dosages and typical



application locations and limitations.                        2866








     The suppression of rooted aquatics by water-level        2868



management has been utilized because of its practical         2869



advantages in economy and simplicity.  Various kinds of       2870



plants can be controlled by drowning if depth and duration    2871



of submersion are sufficient.  Use of lowered water levels    2872



is also efficient to control some plants although care must   2873



be exercised because other varieties of plants than the



target species may become established while water levels are  287U



down.  Flooding following mechanical cutting or herbicide     2875

-------
                            132
application may assist in eliminating the return of nuisance  2876
species.

-------
               f* F''-;"A'"
               / -, '- fj
                               '33
                                HERBICIDES
                            REGISTERED FOR USE
                              IN OR ON HATER
   Chemical
Summary Page
Acrolein
  I-A-1
Amitrole
Amitrole - T
Copper sulfate
  5!120

  I-C-14
       Dosage
As Active Ingredient
 1.2 - 7.2 ppm
                       1.2 - 46.0 ppm
 8  -  20 Ibs./A.
       10 Ibs./A.
                       8-20 Ibs/A.
                             1.5 Ibs./A.
 0.05 -  2.3xppm
             Sites, Types of
          __Weeds ,„ Li mi tati ons
 (psntahydra'te)  (exeunt) reservoirs ;  algae
Lakes, ponds; algae, submersed
weeds.
Do not apply to water used for
domestic purposes.
May use for irrigation and farm
uses 3 days after application.

Irrigation canals and drainage
ditches.
Do not use treated water for
irrigation until concentration
falls to 13.8 ppm.

Site unspecified - cattails.
nn nnt rnntaminflte water used
for domestic or irrigation
purposes.

Drainage ditches, marshes; cattails
Do not apply where water may be
used for domestic or irrigation
purposes.

Drainage ditches, marshes;
phragmites.
Do not apply where water may be
used for domestic or irrigation
purposes.

Drainage ditches, marshes; water
hyacinth.
Do not apply where v/oter may be
used for dories tic or irrigation
purposes.

Lakes, ponds, potable water

-------
                                  /JV
                                  -  2  -
  Chemical
J>tpmary_ Page,
      Dosage
 Copper sulfate
   chelated

   I-C-14
 Dalapon
 Dehydroabietyl-
   amine  acetate
 Dichlobenil

   I-B-4.3
 Dichlone

   I-D-5

 Diquat

   I-D-25.2
1.0 - 4.0 ppm
(pentahydrate)(exempt)

1.6 - 12.0 ppm
(pentahydrate) (exempt)

11 - 22 Ibs acid/A

(10 - 15 Ibs)
( 100 gal. H20)

0.4 - 0.68 ppm
1.0 - 12 ppm


10 - 15 Ibs/A
0.025 -.Q;055
2 - 4 Ibs cation/A
     Sites, Types of
   Jjee ds,.Limitations.
Lakes, ponds, potable water
reservoirs; algae.

Industrial ponds.
Drainage ditches, spot treatment;
cattails.
Do not contaminate water used for
irrigation or domestic purposes.

Lakes and ponds; algae.  Do not
appTy to water used for domestic
purposes.

Irncation canals, ditches; algae.
Do not use treated water on crops^

Lakes, ponds; submersed weeds.
Apply to water surface.
Do jiot use treated water for
irrigation or for human or
livestock consumption.
Do not use fish for food or feed
within 90 days after treatment.

Lakes, ponds, canals:, certain
blcom producing blue green algao..
Do not use in potable water.

Lakes , ponds , di tc'nes , 1 aterals:
submersed weeds.  Do not use
treated water for animal con-
SL'roticn, swimming, spraying, or
irrigation until 10 days after
tric'trc'ivt.  Do not use treoteci   *
water for drinking purposes until
14 days after treatment.

-------
                                   - 3 -
  Chemical
 Sugary  Page
 Diquat  (continued)

   I-D-25.2
Endothall
   (dimethyl
    alkylamine)
  I-E-1.2
Endothal1
  (dipotassium)
  (disodium)
     Dosage
As Active Ingredient,
 1-1.5 Ibs  cation/A
                      2 Ibs cation/A
                      0.5 - 1.5 ppm cation
 0.05 -  0.83 ppm



 0.5 - 2.5  ppm




 1   -  5 ppm
 0.36  -  3.5  ppm
      Sites, Types of
     Heeds, Limitations
 Lakes, ponds, ditches, laterals;
 floating weeds.  Do not use
 treated water for animal con-
 sumption, swimming, spraying, or
.irrigation until 10 days after
 treatment. ' Do not use treated
 water for drinking purposes until
 14  days after treatment.

 Lakes, ponds, ditches, laterals;
 emersed marginal.  Do not use
 treated water for animal con-
 sumption, swimming, spraying, or
 irrigation until 10 days after-
 treatment,  uo nou use uredLeu
 water for drinking purposes until
 14  days after treatment.

 Lakes, ponds, ditches, laterals;
 algae.  Do not use treated water
 for animal consumption, swimming,
 spraying, or irrigation until 10
 days after treatment.  Do not use
                                               treated water
                                               until  14 days
                                       for drinking purposes
                                       after treatment.
 Lakes and ponds; algae.  Do not
 use treated water within 7 days
 at 0.3 ppm, 14 days at 3.0 ppm.

 Lakes and ponds; submersed weeds.
 Do not. use treated water within
 7 days at 0.3 ppm, 14 days at
 3.0 ppm.

 Irrigation canals, drainage ditches
 weeds.  Do not use treated water
 within 7 days at 0.3 ppm, 14 days
 at 3.0 ppm, and 25 days at 5.0 ppm.

 Lakes and ponds: weeds.  Do not
 use treated water for irrigation
 or domestic purposes within 7 days.

-------
                                  13 (•
                                 - 4 -
  Chemical
^Summary _Page	
 Petroleum  Solvents

   I-P-3.5
 Si 1 vex

   I-S-1.2
 Simazine
 Sodium penta-
   chlorophenate

 2,4-D

   I-D-7.7
 Xylsnc

   I-X-1
       Dosage
As Active Ingredient
        Sites, Types of
       Weeds, Limitations
1000 ppm
8 Ibs/A  Liquid
40 Ibs/A Granular
                       9 9 nnm I i m 11 H

                       40 Ibs/A Granular
0.78 ppm



4.5 - 18 ppm


2.4 Ibs acid/A



43.5 Ibs acid/A




6.0 Ibs ac-k!/A




740 ppm (exemnt)
Irrigation and drainage ditches,
inject into water.
Do not contaminate water used
for domestic purposes.
Do not use treated water for
irrigation until emulsion breaks
or waste treated water.

Lakes, ponds; emerged floating
weeds.
Do not contaminate water intended
for domestic, irrigation, or crop
spraying purposes.
I at/oc  nnnrlc •  c i ihmo vcorj i'
Do not contaminate water intended
for domestic,  irrigation,  or crop
spraying purposes.

Ornamental ponds.
Do not use in  water intended for
domestic or irrigation purposes.

Paper mill supply impoundments,
algae.

Lakes, ponds;  floating weeds.
Do not use treated water for
domestic or irrigation purposes.

Lakes, ponds:  submersed weeds
(granular).
Do not use treated water for
domestic or irrigation purposes.

Lakes, ponds;  emerged marginal
weeds .
Do not use treated water for
do:rc-stic or irrigation purposes.

Irrigation ditches, inject  into
water.  Treated v:ater may be used
for  furrow or  flood irrigation.

-------
                                 137
                                HERBICIDES
                           REGISTERED FOR USE
                         AT OR ABOVE  WATER  LINE
Chemical
  Summary Page
     Dosage
As Active Ingredient
       Sites, Types of Weeds,
           Limitations
Amitrole


Amitrole-T


Ammonium Sulfamate

   I-A-7
Bromaci 1
Dimethyl
  arsinic acid
Diuron

DSMA
Erbon
Fenuron
 4 - 10 Ibs/A
 2 - 4 Ibs/A
 57 - 171  Ibs/A
 (57 lbs/100 gals.)
                       95 -  190 Ibs/A
                       (95 lbs/100  gals.)
 1.8 - 4.8 grams/plant
                       3.0 -  24.0
 (2.6 - 5.2 Ibs.)
 (100 gals. H20 )
 16 - 48 Ibs/A
 2.3 - 4.5 Ibs/A
     5.33 Ibs  )
  100 gals H20 )
 120 - 174 Ibs/A
 10 - 30 Ibs/A
Drainage ditchbanks.  Do not
contaminate edible crops.

Ditchbanks.  Keep livestock
off treated areas.

Around lakes, ponds, potable
water reservoirs and their
supply streams; brush.
Do not contaminate water.

Around lakes, ponds, potable
water reservoirs and their
supply stream; weeds.
Do not contaminate water.

Drainr.ge ditchbonks - spot
treatment; brush control.
Do not contaminate water or
use in irrigation ditches.

Ditchbanks; weeds.  Do not
contaminate domestic water.

Drainage ditches; weeds.
Do not contaminate water used
for domestic or irrigation
purposes.

Drainage ditchbanks.

Ditchbanks, spot treatment.
Do not contaminate water used
for domestic or irrigation
purposes.

Drainage ditchbanks.  Do not
contaminate domestic or
irrigation water.

Drainage ditchbanks; brush
control.

-------
Chemical
  Sun>n_ary Page
    Dosage

As Active Ingredient
       Sites, Types of Weeds,
            Limitations
Fenac
Hexachloro-
  acetone

MCPA

MSMA
Petroleum
  solvents

 I-P-3.5

Picloram
Sodium TCA
TBA

2,4-D
 I-D-7.7
 4.5 - 18 Ibs/A
 (4.5 - 36 Ibs)
 (TOO gal. H20)

 2.6 - 5.3 gals/A
 3/4 - 3.0 Ibs/A

 2 - 4.5 Ibs/A
 (4 - 8 lbs/100 gals.)
 100 gals/A
 2-3 Ibs/A
 33 - 166 Ibs/A



 20 - 40 Ibs/A

 6.0 Ibs/A
Ditchbanks.  Do not contaminate
water used for irrigation or
domestic purposes.

Drainage ditchbanks; weeds.
Apply in oil.

Ditchbanks; weeds.
Drainage ditchbanks, spot
treatment.  Do not contaminate
water used for domestic or
irrigation purposes.

Ditchbanks, irrigation and
drainage.  Do not contaminate
irrigation water.
Non-crop area - outer slope of
ditches only, spot treatment.
Do not contaminate water used
for irrigation or domestic
purposes.

Drainage ditchbanks.  Do not
contaminate water used for
domestic or irrigation purposes.

Ditchbanks.

Margins of lakes, ponds; emerged
weeds.  Do not use treated water
for domestic or irrigation
purposes.

-------
                               131
                                HERBICIDES
                            REGISTERED FOR  USE
                       ON MUD BOTTOMS AFTER DRAWDOWN
Chemical
 Summary Page
       Dosage
As Active Ingredient
     Sites, Types of Weeds,
         Limitations
Dichlobenil
 I-D-4.3


Diuron

 I-D-27.8
Fenac
Monuron
 I-M-10.2
Xylene
  7-10 Ibs/A
  16 - 48 Ibs/A
  15 - 20 Ibs/A
  32 - 80 Ibs/A
  100 gals/A
Lakes, ponds; submersed weeds.
Apply to exposed shore and
bottom.

Drainage and irrigation ditches.
Drain off water, spray moist soil
in ditch.  Fill ditch and let
stand 72 hours, then waste contained
water before use of ditch.  Do not
contaminate domestic water,

Lakes, drainage ditches; submersed
weeds.  Drain area and apply to
exposed bottom.  Do not use treated
water for domestic purposes.

Irrigation and drainage ditches;
drain water off area, spray bottom,
fill ditch and hold 72 hours, then
waste contained water before use
of ditch.

Ponds, canals; drain off water and
spray vegetation.  Do not refill.
for 5 days.
                            w f\

-------
                            1UO
gONTROL OF ADVERSE EFFECTS ON GROUNDWATER                     2919



     Methods to control groundwater pollution by dams could   2921



include use of one or several of the alternatives.  The dam   2922



and its foundation could be designed so that there is a       2923



minimum restriction to the down-valley flow of groundwater.   2924



The feasibility of this approach will depend, of course, on   2925



the size and type of dam as well as the geologic conditions   2926



of the dam-site.  The design could make provision for



controlled releases of groundwater past the dam.              2927








     The water table upstream from the dam could be lowered   2929



by appropriately placed pumping wells.  This would reduce     2930



the opportunity for pollution from ground surface sources     2931



and would reduce the residence time of stored groundwater.    2932



In general, water pumped from the wells would be of           2933



satisfactory quality for any available local beneficial



uses; if none existed, the water could simply be released     2934



downstream from the dam.  This procedure would increase the   2935



outflow of salts from the basin, minimizing accumulation.     2936
     A more drastic measure would be to minimize potential    2938



sources of pollution in the area upstream of the dam.  This   2939



could involve changes in land use, reduction in application   2940

-------
of agricultural fertilizers, or removal of cattle from the    2941



area.  Justification for such a measure would require the     2942



absolute necessity for good quality water down gradient.







     If the reservoir is to store poor-quality water, a site  2944



should be selected where seepage losses will be minimal.  If  2945



such a site does not exist, it may be necessary to wholly or  2946



partially line the reservoir bottom using, for example,       2947



compacted clay.

-------
                            142
                        Bibliography
2950
 1. Fair, G.M. and J.C. Geyer, Water Suggly and Waste-Water    2952
 Disposal. John Wiley 6 Sons, Inc., New York~(195U), pp  232-239.  2953
2. Anon., "Measxires For The Restoration and Enhancement of Quality
 of Freshwater Lakes," a. S. Environmental Protection Agency,   2956
                  Washington, D.C.  (1973).                     2957
      2955
3. Toetz, D., J.William, and R. Summerfelt, "Biological Effects   2959
  of Artificial Destratif ication and Aeration in Lakes and     2960
Reservoirs - Analysis and Bibliography,1* Bureau of Reclamation   2961
Report REC-ERC-72-33, O.S. Department of the Interior, Denver,   2962
                      Colorado  (1972).                         2963

-------
                             143
10.  Mackenthun, K.M. , Thg Practice of Water Pollution         2996
     Biology» U.S. Department of the Interior,  Federal  Water   2998
     Pollution Control Administration  (1969).

jll.  Martin, A. C., R.C. Erickson, and J.H. Steenis,            3000
     ^Improving Duck Marshes by Weed Control,"  Circular 19-    3002
     Revised, 1-60, U.S. Department of the Interior,  Fish
     and Wildlife Service (1957).                              3003

-------
12.  Elder, R.A.,  M.N.  Smith,  and W.O.  Wunderlich,  "Aeration
     Efficiency of Howell-Bunger Valves," Jour. Water Poll.
     Control Federaiton,  41,  4,  629 (April,  1969).

13.  Sylvester, R.O.  and  R. W. Seabloom,  "Influence of Site
     Characteristics  on Quality of Impounded Water",
     Jour.Amer.Water  Works Assoc., 57,  1528  (December,
     1965).

14.  Deutsch, M.,  "Hydrologic  Aspects of  Ground Water
     Pollution, "Water  Well Journal, 15,  9,  pp 10-39 (1961).

-------
       Guidance for the Identification and Evaluation         3



               of the Effects of Urbanization                 4







INTRODUCTION                                                  7



     Urbanization is the concentration of people and of       9



domestic, commercial, and industrial structures in a given    10



geographic area.  Urban areas commonly include both suburban  11



and central city complexes.  The rapid trend toward           13



urbanization is indicated by the fact that more than two      14



thirds of the nation's population now reside in urban         15



centers that occupy about 7 percent of the land area of the   16



United states.  By the year 2000 the urban population may     17



include as much as three-fourths of the population.           18







     This concentration of people and their activities        20



results in a concentration both of water resources and of     21



the wastes produced.  Water may be diverted and conveyed to   23



an urban area from sources hundreds of miles away.  An        25



example is the Los Angeles-San Diego metropolitan complex



which receives water from the Colorado River and from         26



Northern California.  Runoff and infiltration in urban areas  28



are markedly different than in the original undeveloped       29



area.  Thus, urban areas produce hydrologic and hydraulic     30



problems connected with development of water supplies;        31



increases in peak streamflows; and increased mineralization   32

-------
of water resources due to changes in land-use patterns.       33



These urban-area problems are discussed briefly in the        34



material that follows.                                        35







     Extensive research has been directed toward the effects  37



of urbanization especially directed toward surface water      39



quality and surface water hydrology.  This discussion will    40



concentrate on the degradation of ground water resource,      41



which has not been as extensively recognized.  Bibliographic  43



material for both surface and subsurface material are         44



included.








SOURCES OF POLLUTION                                          46



     §eawater intrusion in coastal aguifers is often          48



associated with urban areas due to overpumping, reduction in  50



natural recharge, and sometimes loss of recharge from septic  51



systems that have been replaced by public sewers.  Runoff     53



from urban areas is heavily polluted, especially the initial  54



flows.  Urban leachate, the source of ground water            55



pollution, owes its composition to dissolved organic and      56



inorganic chemical constituents derived from a multiplicity   57



of sources such as dirty air and precipitation, leaching of   58



asphalt streets, inefficient methods of waste disposal, and   59



poor housekeeping techniques at innumerable domestic and      60



industrial locations.  Urban leachate can be a direct         61

-------
contributor to stream pollution because many urban centers    62
are located in lowlands adjacent to large streams.  In        6U
reverse, ground water withdrawals may permit flow of
polluted water from streams to hydraulically interconnected   65
aquifers.  The expansion of densely populated urban and       66
suburban developments into former rural or heavily            67
fertilized agricultural areas has compounded the problem of   68
ground water pollution by causing a mingling of the effluent  69
from cesspools and septic tands with fertilizer contaminated  70
ground water.  Moreover, in many urban and suburban areas,    71
wastes that are accidentilly or intentionally discharged on   72
the land surface often reach shallow aquifers.                73

     The pollutional effects of urbanization change as        75
development proceeds.  Initially, large amounts of erosional  77
debris are produced as the original land surface is           78
disturbed by construction.  Jn the mature stage, domestic     79
and industrial sewage, street runoff, garbage and refuse are  80
the principal sources of pollution, which intensify with      81
time.

     Pollution from urban areas is not confined to the areas  83
themselves or to the immediately adjacent areas.  The         85
effects often extend for considerable distances in ground     86
waters as well as in surface waters.  A relatively recent     87

-------
and unique problem that has attracted Considerable attention  88
is the pollution of ground water resulting from application   89
of deicing salts to streets and highways in winter.  The      91
region affected is largely the Northeast and the North-
Central states.  The salt appears to reach the ground water   93
both from storage stockpiles (Figure   )  and from solution    94
of salt that has been gpread on roadways.                     95
     Long-term degradation of ground water guality has been   100
the experience of the New Hampshire Highway Department with   101
highway deicing salts.  Year after year, chloride contents    103
of water in certain shallow wells rose, to concentrations of  104
3800 mg/liter.  Not only was the ground water guality         105
degraded, but also the casings and screens of the wells were  106
badly corroded, so that 37 wells had to be replaced.  A       108
similar situation has been reported in Michigan where water

-------

    ,
/LAND SURFACE / '
   V
    \
                 '/y////'////////////////////////

                ' '/;?//'///7rrfi.'r//> //////"'/..
                LT STOCK PILE////// /
               /




              '/
' / / ' PUMPED WELL// '/



    '"'"/'//I
        J_ / _/__/ ' ' /
                                          /I	? /
                                    FRESh WA1LI!
                        WATER TABLE.
                                           I I
      Figure 5-2.  Flow pattern showing downward leaching of

                contaminants from a salt stockpile and

                movement toward a pumped well (Dcutsch,

                1963).
5-6

-------
from wells was found to contain as much as 4400 mg/liter of   109
chloride due to infiltration of highway salts.                110

     An analysis of the steady-state concentration of road    112
salt added to ground water has been made for east-central     113
Massachusetts.  Assuming an application rate of 20 metric     114
tons of salt per lane mile per year, and taking into account  115
local rainfall and infiltration values, a chloride            116
concentration of 100 mg/liter was obtained for the gross
area.  Ijocal deviations from this regional average could      118
easily be from two to four times this figure, especially      119
near major highways,  wells in at least 15 communities in     120
eastern Massachusetts produce water containing more than 100  121
mg/liter of cloride per leter.

     The problem is widespread, litigation on the matter is   123
not uncommon, and research on alternative non-polluting       124
substances is underway.

     Ground water iff an urban environment^ may contain        126
almost every conceivable inorganic and organic pollutant.  A  128
brief summary by source of the principal potential urban
pollutants is given in Table  .                               129

-------
     Table
Summary of urban ground water pollutants
133
          Source
Atmosphere


Precipitation


Seawater encroachment


Industrial lagoons
Cesspool, septic tank, and
sewage lagoon effluents
Leaky pipelines and
storage tanks

Spills of liguid chemicals


Urban runoff


Landfills




Leaky sewers
Stockpiles of solid raw
materials

Surface storage of solid
wastes
                                                                        134
                    Principal Potential Pollutants  136
                                                                         137
               Particulate matter, heavy metals,  139
               salts.                          140

               Particulate matter, salts, dissolved  142
               gases                           143

               High dissolved solids, particularly  145
               sodium and chloride             146

               Heavy metals, acids, solvents, other  148
               inorganic and organic substances  149

               Sewage contaminants including high  151
               dissolved solids, chloride, sulfate,  152
               nitrogen, phosphate, detergents,  153
               bacteria                        154
               Gasoline, fuel oil, solvents, and other  155
               chemicals                       156

               Heavy metals, salt, other inorganic  158
               and organic chemicals.          159

               Salt, fertilizer chemicals, nitrogen,  161
               and petroleum products          162

               Soluble organics, iron, manganese,  164
               methane, carbon dioxide, exotic  165
               industrial wastes, nitrogen, other  166
               dissolved constituents, bacteria  167
               Sewage contaminants, industrial  169
               chemicals, and miscellaneous highway
               pollutants                      171
                                                                    170
               Heavy metals, salt, other inorganic and
               Organic chemicals               174
         173
               Heavy metals, salt, other inorganic and  176
               organic chemicals               177
Deicing salts for roads
               Salts
179

-------
TYPES OF POLLUTANTS                                           18U



Degradation of water quality may occur in both shallow and    186



deep aquifers.  Increased mineralization, including           188



increases in the content of nitrogen, chloride, sulfate, and  189



hardness of the water, has resulted in limitations on         190



pumping from some shallow aquifers in California and Long     191



Island.








     In scattered places illnesses have resulted from         193



contamination of water by sewage and industrial wastes.  The  195



occurrence of nitrate, MBAS (detergent), and phosphate in



ground water in Nassau County, Long Island, New York, has     196



been investigated in detail.  Figure   shows the location     197



and subsurface extent of MBAS contamination in shallow        198



ground water beneath an unsewered suburban residential area   199



in southeastern Nassau county. Long Island, New York.  The    201



Nassau-Suffolk Research Task Group  (1969) has made detailed



studies of pollution near individual septic systems in Long   202



Island.







Gaining streams in Long Island also show significant          204



contents of nitrate and MBAS from inflow of contaminated      205



ground water.  High nitrogen content of ground water in       206



Kings County, Long Island, New York, is attributed largely    207



to long-term leakage of public sewers.  Contamination of      208

-------
      EXPLANATION
                              _____^                    ,
                                                                  .. aw*mo ******
1 ""
-fe
! ^'
f'lf.-Vl
-,;,--:;•-; " _.~[~ .1 	
_---!-- - 	 	
. 	 ,d i^ ^j"" ' ;' ._r;o'
term tfpostt*
-\
=-1
1
 Figxire 5-1.   Hydr o^eochemicr ]  t,*.--.  ,ius obLnvi^ to tlxe clifcction of
                grouiif'v-:ater flow,  f-i.i\^mg b:u:^ o' ^qual  concentration
                of NiJjAo in Nabrtu-.i 'Z-- .iiy,  I^i-:.'.1; i.uand,  New York.
                Contaminated water i-,  :iado«..; l.-v«-i  liira: shown at
                about 0. 1  mg/lif-r >"i    iniuttu:-,  ..'. 'd, 1°>VS).
i-4

-------
shallow public-supply wells by detergents from cesspoll       208



effluent in Suffolk County, Long Island,  New York, has        209



resulted in shutdowns of wells except during periods of peak  210



demand.  Similar problems occur in California.  The contents  212



and trends in salinity and nitrate in the Fresno-Clovis area  213



have been analyzed to confirm this trend.







METHODS OF POLLUTANT TRANSPORT                                215



Urbanization grossly alters the hydrology of an area.  In     218



general, this results in a decrease in the natural recharge



to underlying ground water unless compensated by artificial   220



recharge.  This, in turn, has an adverse effect on ground     221



water guality if the guality of the natural recharge was      223



high.  The decrease is due to the impervious surfaces of an   224



urban area—houses, streets, sidewalks, and commercial,       225



industrial, and parking areas, which reduce direct            226



infiltration and deep percolation of precipitation.  Peak     227



storm runoff and total runoff is increased but over shorter   228



time periods, resulting in decreased streambed percolation.



Natural streambed recharge is further decreased by concrete   229



storm drains and the lining of natural channels for flood     230



control purposes.
                              1 'I

-------
      In the Santa Ana River Basin in Southern California,     239



 pollution of ground water has resulted from the importation   240



 by municipalities of Colorado River water,  which is high in   241



 salinity (750-850 ing/liter total dissolved  solids) .           242



 pollution has resulted from artificial recharge and also      243



 from percolation of water used for irrigation of lawns and    244



- parks,







      High local ground water temperatures attributed to       246



 recharge of warm water used for air conditioning have been    247



 investigated in Manhattan, the Bronx, and in Brooklyn, New    248



 York.  A 5-to80-degree Celsius rise in the  summer             249



 temperature of water in gaining streams on  Long Island has    250



 been attributed to a variety of urban factors such as pond    251



 and lake development, cutting of vegetation, increased



 stormwater runoff into streams, and decreased ground water    252



 inflow.







      Several pollution incidents related to urbanization in   254



 Minnesota have been reported.  These included drainage of     256



 surface water through wells in sumps which  produced



 discolored and turbid water as well as positive coliform      257



 determinations, pollution from leachate in  poorly designed    258



•landfills, and pollution from solvents disposed of in pits    259



 and basins.  Poor housekeeping practices at an 80-acre        260

-------
industrial site resulted in the saturation of the area with   261



creosote and other petroleum products over a lonq period of   262



time.  The severity of the cresosote leaching problem was     263



recoqnized when the water from a nearby municipal well        26U



developed an unpleasant taste.







     The principal mechanism of ground water pollution in     266



urban areas are infiltration of fluids placed at or near the  267



land surface and leaching of soluble materials on the         268



surface.  The sources of fluids include deliberate disposal   269



through wells, pits, and basins, and seepage from hundreds    270



or thousands of miles of leaky storm water and sanitary       271



sewers, water mains, gas mains, steam pipes, industrial       272



pipelines, cesspools, septic tanks, and other subsurface



facilities.  some natural treatment of the fluid occurs as    273



it seeps downward through the soil zone; however, large       274



quantities of pollutants, particularly the mineral            275



constituents, may reach the water table in the uppermost      276



aquifer.  From there, the polluted water may move laterally   277



toward natural discharge areas or toward pumping wells.       278







MAGNITUDE AND VARIATION                                       281



     Major surface water sources have quality information     283



available for urbanized areas.  Smaller streams draininq      285



localized watersheds frequently do not have such              287

-------
                                          DRAFT
information.   Frequently the local drainage streams,  do  not   288



have flow other  than during the annual wet season or          289



following rainstorms.  The effects of urbanization or these   290



waters is most noticeable when street, drainage and storm     291



water from sewers constitutes the flow.







     Ground water quality information in general is not       293



nearly as available as surface water quality information.     294



wells are frequently sampled upon completion for chemical     295



and becteriological analyses,  in urban areas where few       297



wells exist and  these principally for lawn sprinkling,        298



quality analyses are relatively rare.







     Information in areas with particularly severe ground     300



water problems associated with urbanization is available.     301



For example,  extensive efforts have been made to determine    302



the ground water quality on Long Island, New York. Much of   304



this information is available in a professional paper series  305



(No. 627) of the U.S. Geological Survey.  Additional          306



information is available from state geological surveys.







     Surface water quality is available for some local        308



streams from counties and cities in addition to the state     309



water guality monitoring agency.  Many of these agencies     310
                          DRAFT

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                                        DRAFT
produce annual  monitoring reports describing water  guality    311



in local streams.







     Where urban areas use ground water from local  wells,     313



the wells should be monitored for pollutants that are         314



associated with urban activities but may not be included  in   315



standard water  analyses; for example, heavy metals. When    317



specific threats to ground water guality from past  or



present practices  of waste disposal  (accidental or            318



deliberate)  can be identified, special monitor wells may  be   319



warranted to provide advance warning of pollutants            320



approaching water-supply wells.








     Even though local ground water may not be a presently    322



important source of supply in many communities, monitoring    324



of its ambient  guality is highly desirable in order to



detect degradation and take action to reduce or prevent      325



further pollution.                                          326
                              :AFT

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                                         DRAFT
PREDICTION METHODS                                           329
     Prediction methods for the effect  of urbanization .for    332
surface waters traditionally utilize  basic hydroloqical
methods to predict the quantity of  run-off produced  for       333
various intensity storms coupled with field  surveys  of the    334
pollution sources tributary to the  stream.   The most common   336
hydrological model is the so called "rational method" which   337
takes into acount the imperviousness  of the  area and the
time of concentration for rainfall  to runoff to the           338
collection point.  Experience factors for determining         339
pollutional loads from storm sewers and direct run-off can    340
be applied to determine resulting water guality               3U1

     More sophisticated techniques  have been devised using    343
the concepts of synthetic hydrology and stochestic processes  344
to develop expected runoff and resulting water quality from   345
various intensity storms,  such models  are useful for         346
planning channel capacity requirements  as well as justifying  347
treatment of incoming wastes.  By projecting changes in       348
runoff characteristics, the projection  of future conditions   349
is also possible.

     Ground water prediction methods  are generally much more  351
crudely designed than surface water models.  Highly           353
sophisticated mathematical hydraulic  models  are available

-------
but these lack the ability to predict mass transport of       354



adsorbed or 2arti.ally soluble compounds because of the        355



difficult chemistry involved.  Additionally, surveys of       356



ground water conditions are expensive because of the great    357



number of observation wells required to establish flow        358



directions and existing water quality.  Jhus models must use  359



scanty field data for verification or development.  As        360



ground water in urbanized areas becomes a more important



source of supply and its quality continues to deteriorate     361



adversely affecting the uses to which that water which is     362



extracted is put, quality prediction techniques will be



improved.

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              Procedures and Methods to Control Pollution     366



                Resulting jfroin Urbanization                   367
     Control of the effects of urbanization for surface run-  370



off has received extensive research attention,  control       372



methods have been identified and in some cases demonstration



projects performed for evaluation.                            373







     Ground water effects have not received this research     375



effort so that suggested control methods are more intuitive   376



in some cases rather than proven techniques.  For this        378



reason, these ideas are presented in a brief form.







     The following list suggests procedures that can          380



prevent, reduce, or eliminate pollution in urban and          381



suburban areas.  The applicability of any particular method   382



depends, of course, on local circumstances.                   383



     -    Pre-treatment of industrial and sewage wastes       385



          before disposal into lagoons and pits.              386







     -    Lining of disposal basins where the intent is to    388



          prevent leaching into ground water.                 389

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Collection, by means of drains and wells, and       391



treatment of leachate derived from landfills,       392



industrial basins, and sewage lagoons.              393








Proper management of ground water pumping to        395



prevent or retard seawater encroachment in coastal  396



aquifers.








Creation, by means of wells, of injection ridges    398



or pumping troughs to retard seawater               399



encroachment.








Abandonment or prohibition of cesspool and septic   401



tank systems in densely populated areas and         402



replacement by sanitary sewer systems.              403








Proper construction of new wells and  plugging of    405



abandoned wells.                                    406







Implementation of better housekeeping practices     408



for land storage of wastes, and monitoring of       409



potential industrial polluters through permits and  410



on-site inspection.







Reduction  in use of road deicing salts.             412

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Storage of stockpiles of chemicals under cover and  414



on impermeable platforms to prevent leaching;       415



recovery and treatment of leachate which has        416



occurred.







Publicizing procedures for optimal applications of  418



lawn fertilizers and garden chemicals to minimize   419



potential leaching.







Freguent and adeguate cleaning of streets.          421







Provision for artificial recharge with high         423



guality water to compensate for reduction in        424



natural recharge.








use of high-guality water for municipal and         426



industrial purposes where return flow from those    427



uses will contribute to ground water;



alternatively, desalination of wastewaters before   428



discharge.







Provision for adequate treatment of runoff from     430



urban areas grior to discharge into streams which   431



recharge ground water.

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References                                                    434

I,   Brashers, M.C. Jr., "Ground water Temperatures on Long   436
     Island, New York as Affected by Recharge of Warm         437
     Water," Economic Geology^ Vol. 36, pp. 811-828 (1941).   438

2.   Cohen, P., Vaupel, D.E., and McClymonds, N.E.,           440
     "Detergents in the Streamflow of Suffolk County, Long    441
     Island, New York," ^.S^Geo!. Survey Prof.Paper 750-C,    442
     EP- 210-214 (1971).                 -  -    -      -     ^3

3.   Deutsch, M., Ground Water Contamination and Legal        446
     Controls in Michigan, U.S. Geological Survey Water       447
     Supply Paper 1691, 79 p.  (1963).                         448

4.   Hackett, J.E., "Water Resources and the Urban            450
     Environment," Ground Water, Vol. 7, No. 2, pp. 11-14     451
     (1969) .

5.   Hanes, R. E., Zelazny, L. W., and Blaser, R. E.,         453
     Effects of Deicing Salts on Water Quality and Biota,     455
     Highway Research Board, Report 91, 71 p.  (1970)".         456

6.   Ruling, E.E., and T. C. Holocher, "Ground Water          458
     Contamination by Road Salts:  Steady-state               459
     Concentrations in East Central Massachusetts," Science,  460
     Vol. 176, pp. 288-290, April  21  (1972).

7.   IRS Research Company, water Pollution Aspects of Street  463
     Surface Contaminants San Mateo, California,              464
     Environmental Protection Agency, Office of Research and  465
     Monitoring Report R2-72-081,  236 pp.  (1972).             466

8.   Kimmel, G.E., "Nitrogen Content of Ground Water in       468
     Kings county. Long Lsland, New York," U.S. Geol. Survey  470
     Prof. Paper 800-D, pp. D199-D0203  (1972).

9.   Leopold, L. B., Hydrology for Urban Planning—A          473
     Guidebook on  Hydrologic Effects of Urban  Land Use.U.S.   475
     Geol. Survey Cir.~554, 18 pp.  (1968).

10.  Little, Arthur D. Inc., "Salt, Safety,  and Water         477
     Supply,"  Interim  Report of  the S_ep.cial  Commission 013     479
     Salt Contamination of Water Supplies  and  Related         480
     Matters, Commonwealth of  Massachusetts, Senate No,       481
     !18J>/  97  pp.  (1973) .

11.  Nassau-Suffolk Research Task  Group, The Long  Island      484
     Gj.o.SSd  Wa.£e.r.  Pollution Study, New  York  State  Dept. of   485
     Health,  395 pp.  (1969).
                             DRAFT

-------
12.  Nightingale, H. I.,  "Statistical  Evaluation  of  Salinity  487
     and Nitrate Content  and Trends  Beneath  Urban and         488
     Agricultural Areas-- Fresno, California,  "Ground Water,    489
     Vol. 3, NO. 1, EP- 22-29  (1970).                          490

15.  Perlmuter, N.M. and  Arnow, Ground Water .in the  Bronx*     492
     New York, and Richmond Counties,  with Summary Data on     494
     £i.B2§ and Queens Counties, New  York, N..Y.., New  York      496
     Water Resources Comm. Bull. 32,  (1953) .

14,  Perlmutter, N.M., and Guerrera, A. A., Detergents and     499
     Associated Contaminents in Ground Water at Three         500
     Public- supply WeJLl Fields in Southwestern Suffolk        501
     £2ufitY» L2D3 I^i5DJ» E£.V I2£k»  U.S. Geol. Survey Water    502
     Supply Paper 2001-B, 22 pp. "(1970).

15.  Perlmutter, N.M. and Koch, E. ,  "Preliminary  Findings on  505
     the Detergent and Phosphate contents of Water of
     southern Nassau County, New York,"  U-.S.. Geol. Survey     507
     Profi £§EeE 750-D. pp. D171-177 (1971) .
16.  Perlmutter, N.M. , and Koch, E. ,  "Preliminary             509
     Hydrogelogic Appraisal of Nitrate  in  Ground  Water and    510
     Streams, Souther Nassau County,  Long  island,  New York,"  511
     U.S.. Geol.. Survey. Prof... Paper  800-g,  pp.  B225-B235       512
     Il972) .

_17.  Permutter, N.M. , Lieber, M. and  Frauenthal,  H.  L. ,       514
     ^Contamination  of Grcund Water by  Detergents in a        515
     Suburban Environment — south Farmingdale  Area,  Long       516
     Island, New York, "U..S.. GepJ..  Survey  Prof,. Paper 501-C,  517
     EP. 170-175 (1964).                             ~         518

J.8.  Pluhowski, E.J., Urbanization  and  its Effects  on the     520
     Temperature of_  Streams on Long Island, New York U.S.     522
     Geol. Survey~Prof. Paper 6^7-D,  108 pp.  (1970).

19.  Rantz, s. E. , Urban Scrawl and  Flooding in southern       524
     California, U.S. Geological Survey Circular  601-B. 11    525
     pp.  (1970).

JO.  Schneider, W. J. and Spieker, A.M., Water for the         528
     Cities — the Outlook, U.S. Geol.  Survey Circ.  60l-A,  6    529
     pp.  (1969).

21.  Seaburn, G.E. ,  Effects on Urban  Development  on Direct    532
     Bu.22.ff to East  Meadow Brook, Nassau County,  Long         533
     !§!aQcJ» New York, U.S. Geol. Survey Prof.  Paper 627-B,
     14 p.  (1969).                                             534

-------

22.  Santa Ana watershed Planning Agency,  California,  Finai   537
            to the Environmental Protection  Agency  (1973) .
23.  Sartor, J. D. , and Boyd, G.B. , Water  Pollution  Aspects    539
     2t Strget Surface contaminants. EPA-R2-72- 081, "office    541
     of Research and Monitoring,  EPA,  236 pp.  (1972).

24.  Soren, J. , Ground Water and  Geohydrolggic  in O.ueens       5U4
     County, Long Island, JN.Y_. U.S. Geol. Survey Water-        545
     Supply Paper 2001-A  (1970) .

25.  Thomas, H. E. , and Schneider, W.J. , Water as an Urban     548
     Resource  and Nuisance, U.S.  Geological  Survey  Circ.       549
     601-D, 9  pp.  (1970) 7"

26.  Varrin, R.D. and Tourbier, J.J.,  "Water Resources as a   551
     Basis for Comprehensive Planning  and Development in       553
     Urban Growth Areas," international S^ossosiunj on Water    554
     Resources Planning,  Mexico City,  Vol.  2,  33 pp. (1970).   555

21.  Wikre, D. , "Ground Water  Pollution Problems in           557
     Minnesota," Report on  Ground Water 2ua^i.ty               558
     §ubc_o.mm:i.£t:ee7 Citizens" Advisory Committee,  Governor's    559
     Environmental Duality  Council, Water Resources Center,   560
     Univ. of~Minnesota7  pp. 59-78  (1973).                     561

28.  Butler, s. , Engineering Hydrology, Prentice-Hall, Inc.,   564
     Englewood Cliffs,  N.J.  (19577.

29.  Todd, O.K., Ground Water  Hydrology,  John  Wiley 6 Sons,   567
     Inc., New York, N7 Y.  (1959)."

JO.  Anon., "Urban Water  Resources  Research" A study by ASCE  570
     sponsored by Office  cf Water Resources Research, U.S.    571
     Department of the  interior   (1968) .

-------
                                       O&?Ar 3
                                       \ND
                               OF DREDGING
Current Involvement

     The Corps of Engineers has been concerned with the
development and maintenance of navigable waterways in the
United States ever since congressional Authorization was
received in 1821 to remove sand bars and snags from major
navigable rivers.  The Code of Federal Regulations, Title
33, Chapter II, Part 209 assigns tc the Corps of Engineers
responsibility for enforcement of the principal laws for
protection and preservation of navigation and navigable
waters with respect to work or structures in or over such
waters.  Not only is the Corps of Engineers responsible for
its own operations in navigable waters, it is also
responsible for issuing permits for such activities by other
Federal agencies, state or municiapl goverments, and private
citizens or corporations, all of which are subject to the
provisions of the laws for protection and preservation of
navigable waters.

     The River and Harbor Act of 1970  (Public Law 91-611)
authorizes the secretary of the Army, acting through the
Chief of Engineers, to construct, operate, and maintain
contained disposal facilities to handle polluted dredge

-------

spoil from the Great. Lakes.  The National Environmental
Policy Act of 1969 requires a detailed statement of
environmental impact of proposed new navigation projects and
projects requiring maintenance dredging.  In a report on
"Ocean Dumping A National Policy" submitted to the President
in 1970 by the Council on Environmental Quality it was
recommended that ocean dumping of polluted dredge spoil be
phased out as soon as aternatives can be employed and that
dumping of unpolluted spoil be regulated to prevent damage
to estuarine and coastal areas.  The Federal Water Pollution
Control Act Amendments of 1972 under Section 104 requires
the Administrator of the Environmental Protection Agency to
develop guidelines for selection of spoil disposal sites and
gives the Administrator authority to restrict the use of any
defined area for spoil disposal.  These recently enacted
laws indicate the public's increasing awareness and concern
over the adverse environmental effects associated with
dredging and dredge spoil disposal.  While most of the
public attention has been directed at the effects on the
aquatic environment  (which will be extensively treated under
Section i»01 of the Act) this section will focus mainly on
the pollution of ground water  from dredging and dredge spoil
disposal.

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Current Practices

     Dredging is currently empolyed in channel development
and maintenance, construction of canals, to provide material
for landfill, in lake and pond improvements, and in mining
of minerals including sand and gravel.

     Methods available for dridging can be classified as
either mechanical dredging or hydraulic dredging.
Mechanical dredges are analogous in operating principal to
land-based excavation equipment such as the dragline,
shovel, or treching machine, and can be operated from either
dry land or the water surface.  Hydraulic dredges employ a
pump to lift the material from the lake bottom and transport
it by boat or pump it through a pipeline to the point of
disposal.  Cutter heads of various configurations are
employed depending on the nature of the materials to be
removed.  Primary concern in dredging operations is
generally with the volume of material to be removed and the
location of the disposal site.  Until recently little
consideration was given to potential dangers to the
environment, and even now little thought is given to the
possible consequences to the ground water region.

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Sources of Pollution

     The environmental impacts associated with dredging are
those resulting from the removal of bottom material and
those resulting from the redeposition of this material.  The
physical alterations resulting from the removal of bottom
material include changes in bottom geometry and the creation
of deep water regions, new open water, changes in bottom
substrates and habitats, alterations in water velocity and
current patterns, changes in future sediment distribution
pattersn, alteration of the sediment water interface with
subsequent release of biostimulatory or toxic chemicals, and
the creation of turbidity clouds.  The most common adverse
environmental effects associated with spoil disposal
include: turbidity which is aesthetically displeasing,
reduces light penetration, flocculates planktonic algae, and
decreases the availability of food for aguatic organisms;
sediment build-up which destroys spawning areas, smothers
benthic Organisms, reduces bottom habitat diversity, reduces
food supply and vegetative coverings; and oxygen depletion
which suffocates organisms in the area and releases noxious
materials such as methane, sulfides, and metals.1

-------
     Potential sources  of ground water pollution associated
with dredging and dredge spoil disposal include: the
breaching of aquicludes and the resultant direct
introduction of contaminated  surfaces waters to shallow
ground waters; changes  in surface water flow or circulation
patterns with subsequent seepage of contaminated surface
waters to the ground water regime; and infiltration of
seepage and leachate from land deposited spoil.

Types of pollutants

            Types of Pollutants Resulting from
                   Dredging  Operations

Sediment

     The principal pollutant  created by dredging operation
is sediment.  Disturbance of  the channel, harbor, estuary,
lake or other water body results in the development of
suspended solids in the dredge area.  These vary in
physical, chemical and  biological character and may result
in both short-term and  long-term effect on the quality of
                           DRAFT

-------
water at the site or even at some distance from the actual
operation.

     Direct effects of bottom disturbance is the generation
of suspended solids.  If these are composed of a large
amount of very fine clays, silt and organic materials, the
resulting increase in turbidity will effectively reduce
light penetration and subseguently impair primary food
production necessary to the survival of higher organisms.
In relatively deep water,  turbidity effects can alter the
rate of temperature change and promote thermal
stratification.

     Disturbance and resuspension of sediments following
dredging can blanket an undisturbed bottom, thereby burying
and smothering benthic organisms, destroy fish eggs, and
generally destroy spawning areas and bottom-dwelling animals
and plants.

     Direct effects of sediment created during dredging on
fish includes such harmful effects as reduction of gill
function, impairment of swimming ability reduction of rate
of growth and increase in susceptability to disease.

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               Sediments     associated with chemically and
physically sorbed toxic materials  and biostimulants such as
heavy metals,  pesticides,  phosphates,  nitrates and organics,
may be     reintroduced to further  solution, thus degrading
water quality.  Exposure of organic materials through
disturbance often reduces the dissolved oxygen content of
the water.  Oxygen depletion, in turn, suffocates organisms
whose decay may release methane and other  toxic gasses,
further degrading water quality.

     Ordinarily,  the most adverse  effects  of sediment on the
aquatic ecology result from maintenance dredging where the
volume of fine silt, clay, mud, organic muck, sewage and
sludge, together with municipal and industrial debris is
high.  Maintenance spoil (sediment)  may also contain
considerable amounts of heavy metals,  sulfides, phenols, and
other toxic elements.

     Sediments dredged from previously undisturbed areas are
ordinarly of relatively high chemical and  physical quality
inasmuch as their composition is similiar  to that of the
geologic strata which they represent.  These sediments are
primarly, sand, gravel, rock particulates clay and shale .
                          DRAFT

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                           7V
                                   • V
Contamination by organic  and  toxic materials, nutrients,
pesticides and municipal-industrial wastes may be
slight or even absent,  in "new" work  areas.

Adsorbed Chemicals Attached to Sediment

     Among the principal  pollutants sorbed on sediments are
plant nutrients and pesticides.   The sorption usually takes
place while the sediment  is a part of  the land surface,
i.e., topsoil, or a compound  of  an industrial or municipal
procedure, i.e., waste water facility.

     Sorbed constrtuants  ordinarily give rise to long-term
pollution effects on water.  Prior to  disturbance, the
sediment with their sorbed chemicals have a  minimum exposure
to the water.  As a result the  release of sorbed material is
very slow inasmuch as detachment normally only occurs at the
sediment water interface.  This releace on intercharge  is a
function of bottom sediment movement.

     Desorption is the release  of adsorbed molecules from
the surface of particles including colloidal sizes.
Desorption has been demonstrated for a number of herbicides
                           DRAFT

-------
including 2, H-D, amiber, monuron, dalapon, atrazine, and



simazine.  These are concentrated in the bodies of aquatic



animals and the stored pesticides passed on the to their



consumers.  The estuary is the primary breeding ground and



nursery of many oceanic species.  Any accumlation of



pesticide in these species will be carried to the ocean and



then passed on to higher trophic forms of the open ocean and



then to man.







     Aquatic vegetation can sorb significant quantities of



pesticides which may be metabillieally degraded or stored.



Those stored may become a part of the flood sequence or ?



retired to the bottom sediment where they become again



subject to resuspension.







     Nutrient sorption on sediment is limited almost



entirely to phosphatic compounds.  The principal organ of



these constitrent are in the soil system and in sewage,



wasted or discharged into the area of dredging.  Disturbance



leading to resuspension and redistribution of the bottom



sediments encourages solution of the slowly-soluble



phosphatic compounds, facilitating excessive algal growth as



a result of phosplorous enrialment.





     Corbed secondary and micronutrient such as the compound of copper, nickel



mnranese, iron, etc. released as a result of disturbance nay be a factor in



accelerated water degradation.   .1
                              DRAFT

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                T'F:.n;oDP or pomn'ANT  TRANSPOPT

Leaching from Freshly Exposed Surface

Nutrients
   ^suspension of dredged and otherwise excavated materials,
particularly those 3n heavily populated or intensely tilled
areas may contain excessive amounts of relatively insoluble
nutrients associated with  the sedlmsnt.  These are usually in  the
form of phosphate cortpounds originating from Industrial
processes or agricultural  pursuits.  A signlfleant percentage
of the municinal contribution may stem from small homeowner
fertilization of lawns  and gardens, flushed Into the storn
runoff system following heavy precipitation or indiscriminate
irrigation.  Limited treatment of municipal sewage effects
little or no reduction  in  phosphate compounds and these
will subsequently find  their way into the water body to
either combine chemically  with, or be sorbed by, the sediments.
nitrate compounds are much more soluble than phosphates and tend
to be removed to more remote areas by currents and wave action.

   Disturbance of the bottom sediment along with its sorbed
nutrients exooses a surface areas to the surrounding solvent
(water) far greater than existed in the undisturbed
condition which prevailed  within the quiescent sediment-
water interface and vastly Increases the amount of nutrient
                               DRAFT

-------
entering Into solution—previously held in the nutrient "bank".


This access may cause accelerated eutrophication, particularly if


the dredged body is a pond, lake or reservoir.  In other instances


the sudden or catastrophic increase in nutrient concentration


may be toxic to certain aquatic biota.




Metals


   Sediments polluted by compounds containing metals are common


in highly industrialized areas where discharges have been


occurrinp- over long periods of time.  These metallic


conpounds vary widely in character and in their toxicity to


aquatic biota, particularly animals.  The principal metals


are conpounds of iron, cadium, copper, chromium, arsenic


and nickel.  Disturbance resulting from resuspension during


dredging displaces, relocates and tends to dissolve these


compounds to the detriment of aquatic animal life within


their environment.  Knowledge of the spoil comnosition, with


particular attention Accused on toxic metal content is


necessary in order to evaluate the pollution status of the


sedir.ient.




0?'garde "aterials


   Organic conpounds associated with dredge spoil include peat,


sludre, organic muck and municipal-industrial wastes.  Host


o*" this material is very fine-pained and the components nay
                              i**^t
                              Di

-------
                                  17?
ranfie down to colloidal size.  If disposed of in open water,



orririic material can cause adverse effects such as serious



oxy,<-en (depletion in addition to the release o^ toxic and



noxious "Tser, such as methane, hydroren sulfide, etc.  Organic



opo51 conronly contains penticider- oripinatinr from both municipal



anti a;Ticultural sources.  Industrial phenols comprise a group



of chemicals toxic to aquatic biota and are highly detrimental



to rrunicipal and domestic vater supplies.  Bottom sediments



may also contain undesirable quantities of organic carbon—now



believed to be an irnoortant factor in accelerated eutrophication.





^abitat Destruction in Dredge and Spoil Disposal Areas



   Direct effects o^ dredginr on biological communities and/or



vrater quality are the result of the physical disturbance and



chemical pollutional effects on the aquatic biota.  The



principal concern is ordinarily with the direct effect on



biological communities but lonf-term effects cannot be



ij-Tiored.  Destruction or impaiment of the benthic



environment and its inhabitants conprise a very serious



nroblem associated with dredging.  The effects may vary



greatly.  The possibility of benthic extermination or, at



a mininum, extensive damage, is greater in those locales where



"new" work has been instituted than in old or maintenance areas.



The reason for this difference is that areas previously disturbed



repeatedly have discouraged extensive benthic development.

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                                  17*
   T'he direct effect of dredging activity confined to the project



area, and usually short-tern, are:



   Turbidity Effects                   aesthetically displeasing;



                                      reduction of light penetration;



                                      flocculation of nlanktonic  algae;



                                      and reduction of availability of



                                      flood in the initial stage  o^ the



                                      food chain.
   Sediment  Buildun
   Oxygen Depletion
   Removal of substrate where



   Benthic Organisms Grow,



   results in:
   Resuspension of Solids and



   burial  or organisms including



   direct  destruction of fish eggs.
destruction of spawning areas;



smothering of benthic organisms,



reduction of benthic habitat



diversity and reduction of food supplies.





suffocation of organisms; release



of toxic and noxious gases such as



methane, sulfides  and metallic



compounds.
destruction of bottom dwellers;



destruction of burrowing forms;



destruction of spawning areas.
                             DRAFT

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Suburbanization



   The development of or the addition to, existing urban areas increases



the likelihood of pollution of sediments by municipal and industrial



wastes.  Potential pollutants also stem from domestic usage of fertilizers



and pesticides on lawns and gardens.    Spoil is often placed near or



adjacent to urban centers or in congested areas as fill.  In the past



many fill areas developed as a result of a secondary or indirect



(by-product) effects of dredging.  In more recent years such fill was



intentionally carried out to reclaim or improve land.  This practice



is proceeding at an accelerated rate.  Under these conditions spill is



confined or contained and tends to limit destruction that ordinarily occurs



in unconfined areas of land disposal.  Suburban development Involves land



that is scarce and costly.  Foundation conditions are generally competent,



allowing spoil to be placed to considerable heights.  There are, however,



coastal community, coastal resort, and other recreational areas where



poor foundation conditions prevail, (i.e., wetlands  and marshes) due



to the proximity of the groundwater table.  Disposal in these locales is



further aggravated by the fact that drainage is poor.  In the initial



stage of a new fill, seepage may be excessive and must be controlled.



Teepagp through and beneath containment dikes should be analyzed to determine



the pollution potential.  The extent of possible groundwater contamination



:-,hru!-' be established and reiTedial npasures adooted.  Spoil containing



a high percentage of fine-grained organic material yields very compressible



mC. v;e?L (incompetent)  foundation.  The unstable condition is aggravated



viiori the ^111 is placed on vet, organic and compressible subsurface soils, many



of which are found in reclaimed areas such as marshlands, wetlands and  low-lying



coastal areas of the continental margins.

                                                fV> ;"'-.  " •>*•
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                                                      sr-H  '•

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Increased Commercial and Recreational Use —





Land environments adjaoent to the ocean, estuaries, and major



streams offer valuable sites for oontnercial, industrial and



recreational development.   Spoil disposal practices in these



areas can be very useful if properly managed.  The construction



of spoil islands to provide additional habitat for fish and



wildlife is a worthwhile method of utilizing spoil.  Spoil



islands/ particularly on the Atlantic and Gulf Ooast have



attracted a wide variety of waterfowl and other forms of wildlife,



both migratory and sedentary.  In addition to the creation of



artificial habitat, spoil landfill can be directed to the develop-



ment of recreational areas to the benefit of man.  The use of



life-supporting "top" material on a spoil fill will encourage



rapid development of terrestrial vegetation.



    Fills created specifically for land development including



commercial and industrial purposes need be composed of ccnpetent



material inasmuch as foundation requirements relating to heavy



loads for structures such as industrial plants and multistory



buildings are relatively severe.  This places a requirement for



"cleaner" spoil, i.e., sand, gravel and medium grained soils,



and may create a necessity for development of "new" work



areas which, in turn, will create water pollution problems.
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METHODS OF POLLOTANT TRANSPORT





Instream Activities



Pollutants stemming from dredging operations are transported both



in the solid and dissolved phase.  This is true whether the



removed and redeposited material is discharged into water or



transferred onto land.





If the discharge is into water, the solids will be carried in



the direction of current movement.  In a river, the downstream



effects of the pollutant are a function of the quantity, particle



size, particle density, current velocity and amount and type of



turbulence.  Additional factors affecting travel are slope of



channel, irregularity of stream bottom, slope or gradient, depth,



and discharge volume.  The rate of change of velocity is an



inportant factor regarding the range of sediment travel.  In



streams of low velocity laminar flow predominates and at this



rate sediment, along with other pollutants, may be transported



along the maximum cross-section over considerable distances.



Sorbed pollutants and those in solution follow the same pattern.





Spoil discharged into large water bodies such as estuaries,



harbors and bays form turbidity plumes whose extent and geometry



are a function of the water movements with which they come in



contact.  Restoration of lakes, either partial or total, is



accompanied by removal of sediment, nutrients, organic and
                    #"V
                    all

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toxic materials.  Dredging, then, is a method of in-lake (or
reservoir) treatment and eutrophication control measures.  Lake
deposits are largely a product of the adjacent land.  Sediments
derived from sheet/ gully and shoreline erosion constitute the
inorganic phase of bottom particles.  A lake is also the storage
basin for products or organic composition, soluble and relatively
insoluble nutrients, domestic sewage, sorbed and free pesticides
and entrapped gasses ordinarily the products of decomposition of
the aggregate whole (collectively referred to as "nuck").

Dredging disturbs the bottom material and may release entrapped
gasses along with toxic substances which may be poisonous to
aquatic biota and domestic water supplies.  Sediment, along with
sorbed pollutants may be distributed by lake currents and wave
action to fish spawning areas.  Aesthetic and recreational
pastimes such as boating, swimming and fishing may be adversely
affected by resuspension of sediments created by dredging operations.
Care must be exercised during the operation in order to avoid
disturbance, rupture or removal of any sediroantery bottom seal
in areas where the lake immediately overlies porous formations
into which the contents could drain by percolation.

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                                                                                 -r


                                           D8°% A ^**w*
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Runoff from Disposal Sites IncliyHng leachates
-                     -

Qn-land dredge spoil disposed sites, unless carefully chosen,


are frequently instrumental in polluting both adjaoant water


bodies and the groundwater environment beneath the landfill.


In addition to objectionable odors,  spoil masses, if fine -


grained, may retain their high water content and remain slurry -


like for considerable periods of time.  This condition results


in a high degree of instability, particularly in marginal areas


destined for residential, commercial, and industrial sites and


often creates intolerable and ever dangerous foundation problems.



Where disposal takes place in a containment area, consideration


must be given to outlet structures such  as outfalls and return


ditches necessary to discharge and convey the fluid fraction


of the spoil.  The return flow is comncnly contaminated and may


contain a high percentage of suspended solids, dissolved chemicals


and sorbed pollutants.  Removal efficiency of these pollutants


in the fill area is often very low due to limited retention time.


A large percentage of the escaping solids are colloidal and


essestially impossible to remove by  relatively inexpensive,


conventional, procedures.  Channelization at the outlet works


and further erosion of the land surface  by discharged water


may occur.  The fill area often becomes  a mosquito breeding


ground and haven for undesirable forms of wildlife.  High

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                                            r" A   "« y'1 ff» "Vf
                                            fs,"-a Mr F

bacteria counts are frequently encountered in the fill area.

Leaching of Materials into Ground Waters
Damage to the groundwater province beneath, and  adjacent  to
fill areas through leaching of soluble minerals, chemicals,
nutrients and toxic substances is an ever-present hazard
associated with any landfill operation.  Cnce contaminated,
damage to the aquifer may be "permanent" — or at best — long
term and may result in the ultimate abandonment  of water  wells.
Mater quality effects on the aquifer in a proposed fill area
should be carefully evaluated prior to disposal.

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Magnitude and Variation
     To date over 22,000 miles of waterways have been
modified for commercial navigation and over 19,000 miles of
waterways and some 1,000 harbcr projects are currently being
maintained by the Corps of  Engineers.  Annual quantities of
material being removed are  currently averaging about
300,000,000 cubic yards in  maintenance dredging and about
80,000,000 cubic yards in new work dredging.  Total annual
costs are now exceeding $150,000,000.00.* The volumes of
material removed at a single project may vary from a few
thousand cubic yards in a harbor maintenance project to many
millions of cubic yards in  channel development projects.
Variation in the nature of  the material removed ranges from
clean sand and gravel to organic muck, sludge and municipal
and industrial wastes or any combinations thereof.
                         DRAFT

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                           It?
                                   DRAFT
     Figure  1, illustrates the average  annual quantities of
spoil generated by CE district and  methods of disposal;
figure 2,  illustrates the average annual quantities of spoil
type generated by CE District; and  figure 3 illustrates the
amount of  polluted spoil generated  in maintenance dredging
operations by deposition area and district.

     The following criteria for determining the
acceptability of dredged spoil for  disposal to the nation's
waters have  been developed by the EPA:

Criteria

     The decision whether to oppose plans for disposal of
dredged spoil in United States waters must be made on a
case-by-case basis after considering all appropriate
factors; including the following.

     (a)  Volume of dredge material.

     (b)  Existing and potential quality and use of the
          water in the disposal area.
                       DRAFT

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                               DRAFT
(c)   Other conditions at. the disposal site such as
     depth and currents.

(d)   Time of year of disposal (in  relation to fish
     migration and spaqning, etc.)

(e)   Method of disposal and alternatives.

(f)   Physical, chemical, and biological characteristics
     of the dredged material.

(g)   Likely recurrence and total number of disposal
     requests in a receiving water area.

(h)   Predicted long and short term effects on receiving
     water quality.  When concentrations, in sediments,
     of one or more of the following pollution
     parameters exceed the limits  expressed below, the
     sediment will be considered polluted in all cases
     and, therefore, unacceptable  for open water
     disposal.

Sediments in Fresh and Marine Waters    cone % (dry wt basis)
                      DRAFT

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                                      DRAFT
         *Volatile Solids                       6.0



         Chemical Oxygen Demand (C.O.D)          5.0



         Total Kjeldahl Nitrogen                0.10



         Oil-Grease                            0.15



         Mercury                               0.001



         Lead                                  0.005



         Zinc                                  0.005
     *When analyzing sediments dredged from  marine waters,



     the following correlation between volatile solids and



     C.O.D. should be made:







         T.V.S.X  (dry)  =  1.32 + 0.98 (C.O.D.*)







     If the results show a significant deviation from this



     equation, additional  samples should be  analyzed to



     insure reliable measurements.







The volatile solids and C.O.D. analyses should be made



first.  If the maximum limits are exceeded the sample can be
                         DRAFT

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                               V
                                       DRAFT
characterized as polluted and the additional parameter would
not have to  be investigated.

     Dredged sediment having concentrations of constituents
less than the limits stated above will  not be automatically
considered acceptable for disposal.   A  judgement must be
made on a case-by-case basis after considering the factors
listed in (a) through (h) above.

     In addition to the analyses required to determine
compliance with the stated numterical criteria, the
following additional tests are recommended where appropriate
and pertinent:

     Total Phosphorus                       SuIfides
     Total Organic Carbon (T.O.C)            Trace Metals (iron,
                                           cadmium, copper,
                                           chromium, arsenic,
                                           and nickel)
     Immediate Oxygen Demand (I.O.D)         Pesticides
     Settleability                          Bioassay
                                                        %
     The first four analyses would be considered desirable in almost all
                          DRAFT

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                                        DRAFT
instances.
They may be added to the mandatory  list when sufficient experience with their
interpretation is gained.
                                                                           +
For example, as experience is gained,  the T.O.C. test may prove to be a valid
substitute for the volatile solids  and C.O.D. analyses.
Tests for trace metals and pesticides  should be made where significant
concentrations of these materials are  expected from known waste discharges.
Prediction ^ethods
     To predict the potential for water pollution from a dredging program    ^
requires the consideration of a number of interacting
factors involving the hydraulics of the altered channel, the adjacent waters
and the spoil pile; and the chemistry  of the spoil,                          •
the water involved and the newly exposed surfaces.

     Prediction of the flow patterns and associated bank scouring, silt      %
deposition, bottom scouring and flooding is facilitated by mathematical
modeling and, where the data, resources and time available are adequate,
scale modeling is an excellent tool.                                        ^

     In those instances that involve the scalping of an aquifer, or the
                                                                           •
alteration of the flow of groundwater, hydrogeological investigations are
also in order wlftch may involve surface geological mapping, strati graphic  dr,i!J
core analyses, pumping tests and mathematical or analog modeling.

           U.S. Er.v'.c       '       .M  Agency                                     *
           Regie.! V  •'                  ^>
           230 Sc;jt:!  i           _\
           Chicago,  !!!,M;,, ,  • .. .... j.          ,fj
                          DRAFT

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                                     DRAFT
Very little work has been done in the •effects on groundwater1 area.

     Groups currently involved in predictive studies include:

     United States Geological Survey
     Environfmental Protection Agency
     United States Army Engineers
     North Carolina State University
     Skidway Institute of Oceanography
     Clemson University
     Northwestern University
     Oklahoma State University
     Texas ASM University
     University of Hawaii
     University of Rhode Island
     University of Southern Mississippi
     University of Maryland
                       DRAFT

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                                       DRAFT
BIBLIOGRAPHY
O'Neal, Gary and Jack Seeva, "The Effects of Dredging on Water
Quality in the Northwest."  Region  X, Environmental Protection
Agency, Seattle, V/ashington. July 1971.

Boyd,  M.B., R.J. Saucier, J.H.  Keeley, R.L.  Montgomery, R.D. Brown,
D.B. Mathis and C.J. Guice, "Disposal of Dredge Spoil Problem
Identification and  Assessment and Research Program Development."
Tech.  Report H-72-B.  Office, Chief of Engineers, U.S. Army Engineer
Haterways Experiment Station, Vicksburg, Mississippi.  November 1972.

Pierce, Hed D., Inland Lake Dredging Evaluation."  Tech. Bulletin No. 46,
Department of Natural Resources, Madison, Wisconsin.  1970.
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