United States
Environmental Protection
Agency
.Office of Water
.. Regulations and Stan|ai'ds
«: i«-,hington DC 2046|
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Cover: Late afternoon at the Nature Con-
servancy's Santanoni Preserve in the Adiron-
dack Mountains of New York
Back Cover: The belted kingfisher, common
resident of lakeshores and streambanks over
much of North America
Contents Page: Cool swim on a steamy
summer day at Monroe Lake, Indiana
-REVIEW NOTICE-
This report has been reviewed by the Office of
Water Regulations and Standards, EPA, and
approved for publication. Approval does not
signify that the contents necessarily reflect the
views and policies of the Environmental Protec-
tion Agency, nor does mention of trade names
or commercial products constitute endorse-
ment or recommendations for use.
EPA-440/5-80-009
U.S. Environmental Protection Agency
GLNPO Library Collection
-------
c/EPA
Our Nation's Lakes
United States Environmental Protection Agency July 1980
Prepared by the Clean Lakes Program under the direction of Robert J. Johnson
Written by Elinor Lander Horwitz
Designed by Allen Carroll
Illustrated by Sandra Gold and Allen Carroll
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Contents
Foreword iv
Preface v
1. Where We Stand 1
2. How Lakes Form 5
Lake Ecosystems 9
The Water Cycle 11
The Lake and Its Watershed. ... 11
3. How A Healthy Lake Functions .... 13
Characteristics of Water 13
Classifying Lakes 14
Reservoirs 16
4. How Lakes Change 19
Sedimentation 19
Nutrient Enrichment 19
Other Pollutants 21
Case Report
Alcyon Lake 22
Regional Problems
Acid Mine Drainage 24
Irrigation Return Flow. . . .24
Acid Rain 24
5. Lake Restoration 27
Point Source Control 28
Diversion 29
Case Report:
Lake Washington 29
Control of Sedimentation 29
In-Lake Methods of Lake
Restoration 31
Dredging 31
Case Report
Lilly Lake 32
Nutrient Inactivation 32
Case Report:
Medical Lake 33
Aeration 34
Drawdown 34
Harvesting 35
Chemical Controls 35
Biological Controls 35
6. Yesterday, Today, and Tomorrow ... 37
Paleolimnology 37
Paying the Price 37
Recreation 39
What You Can Do 41
Case Report.
Cobbossee Watershed . . 42
Case Report
59th Street Pond 43
Clean Lakes 43
References 47
Appendix A. Glossary . .49
Appendix B. Federal Agency
Functions Relating to Lakes 53
Appendix C. Clean Lakes Water Act . . . . 55
Appendix D. List of Reviewers 57
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Foreword
This Nation has an estimated 100,000
lakes that are 100 acres or greater of which
37,000 are publicly owned. The public uses
these lakes for a variety of purposes, water
supply for municipal, industrial and agricul-
tural use; recreation including boating,
swimming and fishing; flood control; and
aesthetic enjoyment as centerpieces for
public parks. The value of these resources
is hundreds of millions of dollars.
Lakes are vital parts of the freshwater
ecosystems of this country. Their water-
sheds tap 42 percent of the surface area of
the United States. They contribute an essen-
tial part of the fish and wildlife habitat for
countless species of organisms. Pollution is
destroying many of these resources and the
public needs to know why That is the pur-
pose of this book. A significant portion of
lake pollution originates from mismanage-
ment of land and wastewater at the local
level. Such sources of pollution can be con-
trolled at that level, with minimal Federal
and State assistance if the public is adequate-
ly informed of lake pollution problems,
sources, and effective solutions.
This book is designed to inform the
general public about lakes and this problem.
It presents examples of these problems and
some solutions. It presents a discussion of
available sources of financial and technical
assistance offered by the Federal Govern-
ment EPA has awarded financial assistance
to States over the past 5 years to study and
clean up over 200 lakes under its Clean
Lakes Program.
We began this reporting project by assem-
bling a number of people from EPA and the
President's Council on Environmental Quali-
ty who know lakes. Together, we came up
with an outline and suggested format for the
author and illustrator Once the manuscript
was drafted, some 25 persons in the scienti-
fic community carefully reviewed it, noting
their suggestions and sending along addi-
tional material to the author. These review-
ers' names and affiliations appear at the end.
The author, Elinor Horwitz, has tried to
present the facts But beyond that, she has
explained the background, and the evolu-
tion, and the unique qualities of lakes in
clear, understandable terms. We hope the
book encourages the general public to
take an active role in lake pollution con-
trol so that we may enjoy our lakes for
many years to come
Steven Schatzow
Deputy Assistant Administrator
for Water Regulations and Standards
Sunrise over Lake Nummy in New Jersey's
Belleplain State Forest
IV
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Preface
It is a curious matter that widespread
public concern about lake degradation is of
such recent origin. All through history lakes
have been used for transportation, for food
supply, for bathing, and as a source of drink-
ing water for human beings and animals.
There is also no reason to believe that our
unfrivolous forebears were indifferent to the
recreational opportunities lakes provide.
Yet, perversely, lakes have routinely been
used as dumping places for trash and recep-
tacles for sewage, their surrounding wetlands
have too often been drained or filled to pro-
vide "useful" land for agriculture or con-
struction. The 20th century's wondrous
technological sophistication brought new
forms of abuse to our freshwater supply as
toxic, hazardous, often non-biologically de-
gradable substances were introduced into
our streams, rivers, and lakes, where they
may remain for very long periods of time.
Considerable effort has been made in
recent years to inform the public about the
newly recognized importance of our coastal
and inland wetlands—the swamps, marshes
bogs, and prairie potholes that serve such
useful functions in shoreline protection,
pollution and flood control, and as wildlife
habitats. It is difficult to learn that a swamp
should be treasured, because wetlands have
been viewed as unalluring, unwholesome
waste places by virtually everyone except
field biologists, duck hunters, and trappers.
Lakes, on the other hand, have always been
valued for the utilitarian and recreational
bounty they provide and also for their
aesthetic appeal. In both western and
eastern cultures, artists, poets, naturalists,
and philosophers have endowed our lakes
with a romantic image. The seer of Walden
Pond, Henry David Thoreau, wrote, "A
lake is a landscape's most beautiful expres-
sive feature, it is earth's eye onlooking into
which the beholder measures the depth of
his own nature."1
Perhaps. The fact is, it is difficult to
achieve a spiritual insight by looking down
into many of our lakes today. Based on the
National Eutrophication Survey, an esti-
mated two-thirds of the lakes, ponds, and
artificial impoundments in this country re-
ceiving discharge from wastewater treat-
ment facilities are thought to have serious
pollution problems.2 Some of our lakes are
sick, some are in extremis. Many can, with
present technology, be slowed in their de-
gradation or even be restored to health.
Others are too far advanced in their deter-
ioration to be treatable at a reasonable cost.
Although this book will consider lake re-
storation, it is important to realize that our
lakes need restoration because we have failed
to protect them. Today, we understand how
to prevent further degradation of our inland
waters, and lake protection must become a
vital priority.
An increasingly aware and environmental-
ly sensitized public now demands that some-
thing be done when a local lake is plagued
with unsightly algal blooms, loss of game
fish, unpleasant odors. Most lake protection
and lake restoration projects begin at the
local level with a call for action from private
citizens and local agencies. A number of
Federal, State, and local programs now offer
financial and technical assistance for public
lake cleanup and major watershed and tribu-
tary improvement activities.
Since 1976, EPA has offered cost-sharing
grants for public lake rehabilitation-the
Clean Lakes Program—under section 314 of
the Federal Water Pollution Act Amend-
ments (see Appendix). Original legislation
was drafted and introduced in the Senate by
Senators Walter F. Mondale of Minnesota
and Quenton Burdick of North Dakota.
Under this Act, publicly-owned freshwater
lakes—including ponds, reservoirs, and im-
poundments with no marine water intrusion
—are eligible for funding, currently limited
to 50 percent of the total project cost. Eli-
gible lakes must offer access through public-
ly-owned contiguous lands, enabling non-
residents to enjoy the same recreational
benefits as residents.
It is difficult to relate costs and benefits
in planning a lake restoration project. What
is a lake worth in terms of aesthetic enjoy-
ment and recreational potential? What is it
worth if it is the source of a city's drinking
water? What if it is needed for agricultural
irrigation? Is a lake primarily a precious
natural resource that should be, with great-
est possible vigilance, protected? Or is a lake
a recreational resource that should be en-
joyed by as many people as possible? The
two objectives are now recognized as being
frequently incompatible.
One principle that is constantly reaf-
firmed in lake protection and restoration
research is that the most effective methods
generally will not bring rapid results, will
require voluntary compliance and the
sacrifices inherent in a long-range commit-
ment. This book was written to inform all
those concerned with the present and
future quality of our Nation's lakes about
the causes and nature of lake degradation
and current ways of dealing with the
problem.
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Chapter 1
Where We Stand
Lake waters pristine and polluted: water
lilies, Chippewa National Forest, Minnesota:
factory stacks reflected in polluted water
(right).
Official recognition of the fact that out-
natural resources are both finite and threa-
tened dates from the establishment of the
earliest national parks in the latter part of
the 19th century. With the official closing
of the frontier in 1891, timberland was first
federally reserved under President Grover
Cleveland despite the objections of Joseph
Cannon, Speaker of the House, who voiced
a widely endorsed sentiment when he asked,
"Why should I do anything for posterity?
What has posterity done for me?"3
The question reflected not only an arro-
gant lack of concern for future generations
but also peculiarly American convictions
that natural resources are inexhaustible.
Guided by this certainty, a nation of small
farmers and a growing number of land
developers—often with financial encourage-
ment from Government agencies—drained
swamps and marshes, and leveled forests.
Our history of environmental abuse began
with the first settlers. Although our fore-
bears were noted for their pervasive thrift
and the care they took to guard possessions
that might be handed down to succeeding
generations, their attitude toward the
natural world was profligate.
The gradual westward movement was
given impetus not only by rapid increases
in population and rising land prices in the
east, but also by environmental devastation.
Visitors from Europe in pre-Revolutionary
War decades were horrified by the exploita-
tive land practices of the pioneers, who
knew that as land eroded and streams and
harbors silted in they could always pick up
and move farther west.
During the first half of the 20th century,
the pollution of our lakes, rivers, and
streams was accorded infinitely less notice
than the destruction of woodlands and crop-
land. Until recent decades, water pollution
was considered regrettable only insofar as it
constituted a public health menace. Devas-
tating epidemics of such waterborne diseases
as typhoid, paratyphoid, and cholera oc-
curred through the late 19th and early 20th
centuries, and control of pathogens became
a research priority. By 1908, as the result of
the first generation of clean water campaigns
in this country, chlorine was introduced as
a purifying agent for drinking water supplies
in large cities.4 In more recent decades,
bacterial, viral, and fungal infections that
lead to eye and ear irritation or intestinal
disturbances in swimmers have caused con-
cern from time to time about the purity of
water used for recreation. Public health mea-
sures of the 1970's resulted in bans on the
consumption of fish from polluted waters as
scientific understanding was brought to bear
on the way toxic substances in our waters
have entered the food chain.
Aesthetic deterioration of our lakes was
scarcely noted until after World War 11 when
a combination of elements—increased afflu-
ence, new highway construction, widespread
car ownership, and the shortening of the
work week—brought more and more people
to lakeside recreation areas. Exploitative
development of lake shores and the intro-
duction of phosphate-based detergents were
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Where We Stand
An estimated 80 percent of the Nation's
100,000 lakes have water quality problems.
At right, sunbathers at Walden Pond in
Massachusetts, site of Thoreau's cabin.
major factors in accelerating lake degrada-
tion and as early as the 1940's some States
initiated the first lake cleanup programs.
In the past decade, international concern
about inland water quality has led to exten-
sive research into the causes of lake degrada-
tion and the development of many effective
and financially feasible methods to control
or reverse these processes. Lake restoration
technology is still in its early stages, but the
critical necessity for clean lake policies and
programs is now broadly recognized.
As in other conservation issues, a decision
to save a lake often means that public inter-
est must do battle with private gain, with
the "right" of the owner of a lakeside lot to
site a house as he or she chooses, the "right"
of the farmer to plow to the edge of the
stream, the "right" of the factory owner
to discharge wastes into the waters. Today
we have regulatory measures that impinge on
some of these choices, other controls depend
on voluntary cooperation and an enlightened
surrender of short-term private gain for long-
term public benefit.
Partial surveys have been made, but we
do not know for certain how many lakes we
have. The most reliable estimates have set
the figure at 100,000 lakes larger than 100
surface acres excluding Alaska, which has
several million.5 As we enter the ever more
populous, urbanized, and energy short
1980's, the need for clean lakes—right nearby
—becomes more urgent. Although we have
3,700 urban lakes in this country that can be
used for recreation by millions of people, an
estimated 80 percent have significant water
quality problems.6 Unlike our ancestors, we
can no longer leave the mess we have created
behind and move west; we cannot all live up-
stream from an ecological disaster. Fuel
shortages threaten to restrict trips of hun-
dreds of miles to that pristine blue lake of
happy childhood memory which, in fact,
may now look distressingly like the murky
pond 5 miles away, where people also swam,
fished, sailed, strolled, and quoted from
Walden . . . only yesterday.
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Chapter 2
How Lakes Form
Most of the lakes now extant in the
northern United States were formed 10,000 to
12,000 years ago as the glaciers moved
across large areas of North America, Europe,
and Asia in the geological era commonly
known as the Great Ice Age. As the earth
warmed, these basins gradually became habi-
tat for a myriad of plant and animal species.
As dead plants and animals decomposed,
the nutrients released fostered the growth
of new generations of life.
Lakes have also originated in other great
natural events such as earthquakes and vol-
canos. Lake Baikal in Siberia and Lake Tan-
ganyika in equatorial Africa, the world's
deepest lakes, originated much earlier and
were formed by movements of the earth's
crust too deep to be classified as earth-
quakes.7 Lake Baikal, 1,738 meters deep
(5,700 feet), contains 20 percent of the
world's supply of fresh water8 and has ap-
proximately 600 species of plants and 1,200
types of animals, three-quarters of which are
found in no other lake in the world.9
Earthquakes were responsible for the
formation of many lakes in North America
including Reelfoot Lake in Tennessee, which
was created by the New Madrid earthquake
of 1811. Crater Lake in Oregon was formed
when the center of a volcanic cone col-
lapsed.10 Spirit Lake in Washington was
formed by the volcanic action of Mount St.
Helens In May of 1980 the volcano erupted
again, virtually destroying the lake.
Lakes can also be created by gradual
forces such as the corrosive movements of
rivers and the cutting off of meander chan-
nels to form oxbow lakes. These lakes are
seldom permanent. Shallow lake basins
known as sand dune lakes such as Moses
Lake in the State of Washington were creat-
ed when winds built up areas of dunes leav-
ing depressions below.
The shape of a lake basin is determined
by the manner in which it was created and
will, to a large extent, affect its degree and
type of productivity. Some lakes are deep
with steeply sloping sides. Others are shaped
like shallow soup bowls with a large littoral
zone—the region extending from the edges
to the depth at which sunlight can no longer
penetrate and permit rooted plants to grow.
In lake terminology the profundal area is the
central, deep, dark, lower region of the body
of water below which light penetration is in-
sufficient to support the production of green
plants. The limnetic region is the large ex-
panse of open water above. The percentage
of water volume in littoral, profundal, and
limnetic regions of individual lakes, which
varies greatly according to basin shape, is an
important factor influencing plant and ani-
mal communities, lake flushing time, and
other natural processes.
The sinkhole lakes of central Florida (left)
are formed as water seeping through frac-
tures in the limestone bedrock slowly
dissolves the rock to form round de-
pressions. In this satellite photo,
infrared film makes vegetation
appear magenta. At upper right is
the Atlantic Ocean. Right: a me-
andering, silt-laden river often
forms broad bends which are cut
off by erosive action to form
oxbow lakes.
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How Lakes Form
12,000 B.C.
11,700 B.C.
9,500 B.C.
8,800 B.C.
The scouring action of succes-
sive ice sheets formed the giant
rock basins that contain the Great
Lakes. From 12,000 B.C. (above)
to the present (far right) the lakes
have changed in size and shape as
glaciers advanced and retreated
and as water drained through
various channels to the southwest
and east. Today the Great Lakes
drain northeastward via the Law-
rence River.
In mountainous areas (above),
lakes may form behind landslide
debris acting as a natural dam. The
diagram at right shows three types
of glacially formed lakes. At left,
a lake basin is scoured out of till
or bedrock; center, a lake forms
behind material deposited at the
glacier's terminus; right, "kettle"
lakes form in depressions left by
melting ice blocks.
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6,000 B.C.
3,200 B.C.
3,000 B.C.
Present
Oregon's Crater Lake (above),
the Nation'sdeepest, fills a
cavity created by the collapse
of a volcano about 6,500
years ago. At right, a satellite
view of the finger lakes of
New York. The lakes were
formed by the damming of
long, narrow valleys by glacial
deposits. At top is Lake
Ontario.
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How Lakes Form
Energy
from the sun
Nutrients
from lake sediments and watershed
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- • - •**"'ltf>*- ''l''
PRIMARY PRODUCERS
PRIMARY CONSUMERS
Plant eaters
DECOMPOSERS
THE FOOD WEB
of a lake allows energy to be transferred
from organism to organism by the process
of eating and being eaten. At the base of
the food web are plants, like the diatom
illustrated here, which use the sun's energy
to produce food from raw materials. |
Primary consumers, such as cope- "«.^
pods, graze on plant material and
provide food for animals which
prey on them, such as minnows.
At the top of the food web are large fish,
birds, predatory mammals and man. Dead
plant and animal matter is broken down by
the decomposers. Most food webs are com-
plex interrelationships involving many
species.
PREDATORS
SECONDARY
CONSUMERS
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Lake Ecosystems
To understand lake protection and lake
restoration, it is essential to know how lakes
form and function. A lake is an inland body
of water, naturally or artificially impounded.
As opposed to a moving channel, a lake is
essentially a collecting basin, with biological,
chemical, and physical qualities very differ-
ent from those of a stream or a river in
which the water moves continually in one
direction. Within these large, small, shallow,
deep, warm, cold, alkaline, acidic, highly in-
dividual and complex bodies of water, an
awesome diversity of plant and animal life
exists in a delicate state of balance. It is the
nature of what we call an ecosystem that all
parts—the communities of plant and animal
life that make up the biomass together with
the nonliving environment—function in a
united interdependent fashion. The well-
being of the microscopic phytoplankton and
the waterlilies cannot be separated from the
well-being of the worms, insects, snails, frogs,
and fish.
From the variety of plants and animals
occurring in a region—the species pool—
those present in a given lake and their abun-
dance will be determined by the surrounding
geology and the structure of the lake, the
chemical content and turbidity of the water,
climatic conditions, and other natural forces.
Those species tolerant of the physical and
chemical environment of the lake will sur-
vive and multiply. And although the organ-
isms joined in a lake ecosystem form a little
world, this world is highly vulnerable to al-
teration in water quality. Both numbers of
organisms and diversity of species can be
affected by changes in chemical and physical
water properties, such as temperature and
turbidity; severe alterations can eliminate all
life.
As the sunlight penetrates the water,
plants, through a complex process called
photosynthesis, transform radiant energy
into the chemical energy of food, combining
carbon dioxide with water to produce sugars
and giving off oxygen in the process. The
maintenance of a balanced exchange of car-
bon dioxide and oxygen and the production
of sufficient oxygen for the needs of animal
life in the lake are processes as essential to
life as the food supply. The chain of con-
sumption in which aquatic animals eat plants
and big fish eat little fish extends out of the
lake ecosystem when fish are consumed by
birds, by human beings, or by other mam-
mals. Dead plants and animals, which sink to
the bottom, are decomposed by bacteria and
fungi, recycling nutrients to the water in
which they live and to the sediments in the
lake basin. Death and decomposition are as
necessary to the chain of nutrient exchanges
as is any other part of the organic cycle.
Mallard ducks and bullfrog: familiar mem-
bers of lake food webs
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How Lakes Form
EVAPORATION
PRECIPITATION
INFfLfRATION
GROUND WATER FLOW
UNDEVELOPED WATERSHED
URBANIZED WATERSHED
E3L
TIME
RAINFAL
SURFACE
RUNOFF
SURFACE
RUNOFF
TIME
10
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The Water Cycle
Water can enter a lake from a number of
different sources. Some lakes are fed entirely
by springs or groundwater and direct precipi-
tation. Many lakes are fed by rivers and/or
streams that bring water to the basin by
channeled routes. Water enters other lakes
overland, by runoff, and through precipita-
tion. All these seemingly separate routes are
intimately joined in the universal natural
process known as the water cycle.
In the first phase of the cycle, water is
taken up into the atmosphere by evapora-
tion from the oceans and to a much lesser
degree from land and inland waters and by
transpiration from plants. It then condenses
and is returned to the earth in the form of
rain or snow. Water that falls on the land
nourishes the growth of plants and is ab-
sorbed into the soil. Some of this moisture
percolates down to the water table, increas-
ing the groundwater flow. Excess water that
cannot be absorbed moves toward rivers,
streams, and lakes by overland flow or run-
off. In highly developed cities, where con-
crete and asphalt have replaced porous land
areas, street runoff from rain and snow melt
is very heavy compared with runoff in un-
developed areas. Eventually the water
returns to the ocean so that the finite supply
of water on our planet is never lost but is
constantly recycled.
The Lake and Its
Watershed
Although the vast and interconnected
oceans are only gradually affected by what
happens on land, everything that happens in
a lake intimately reflects activity in the
watershed. The watershed comprises not
only the streams and rivers that flow direct-
ly into the lake; it also includes wetlands and
the dry land areas, both adjacent to and up-
land from the lake. The water supply for a
specific lake will be determined by topo-
graphy as water moves by gravity from high-
er to lower elevations.
Although all drainage systems lead,
through the unifying water cycle, back to
the great reservoir, the ocean, the appear-
ance of a lake, its physical and chemical pro-
perties, and the nature of its ecosystem, will
to a very large extent be determined by the
quality of the waters received from the
drainage area. Most lake problems—evi-
denced by excessive plant growth or shallow-
ness from siltation—have their source on
land. Nutrients and sediments are brought
into the lake by water, whether the water
reaches the lake by channeled flow, runoff,
seepage, or precipitation.
The precipitation that nourishes plants
and fills rivers and lakes is one stage of the
global process called the water cycle (above,
left). Water that reaches the earth enters
the ground through infiltration or flows
over the surface as runoff to lakes and
streams. E vapor at ion-from oceans, lakes
and rivers, and from land-completes the
cycle. In urbanized areas (left), propor-
tionally less rainwater can enter the soil
to slowly seep into rivers and lakes. The
resulting increase in surface runoff may
worsen erosion and pollution. As the graphs
show, surface runoff is greater in volume
and peaks more rapidly in urbanized areas,
increasing danger and severity of floods.
A lake's watershed (right) includes all
wetlands, streams and upland areas from
which water flows into the lake (dark
arrows).
11
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Ifi
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Chapter 3
How a Healthy Lake
Functions
Powers Lake, Connecticut
Characteristics of Water
No one disputes the fact that water is
essential for all creatures that live on land,
but in a lake or a pond, water is everything.
It is the medium in which the plants and
animals of the ecosystem live and move,
breathe, and are nourished. It is because of
special characteristics such as transparency,
the ability to retain heat, and the ability
to dissolve matter, that water is able to sus-
tain the life in a lake.
Plant production, the basis of the food
web, is dependent on light, heat, and nutri-
ents. A healthy ecosystem begins with the
penetration of the lake's waters by sunlight,
and the degree of penetration depends on
the degree of transparency. Turbidity in a
lake or reservoir, caused by suspended silt
or other inorganic material or by excessive
plant or animal matter, can interfere drama-
tically with productivity by impeding light
penetration. When plant life, which can be
rooted in the bottom or freely floating, is
diminished in quantity or radically altered
in species, higher organisms are deprived of
food, shelter, and sites for reproduction.
One of the simplest instruments em-
ployed in measuring lake water quality is a
white disk 20 centimeters (8 inches) in dia-
meter invented in 1865 by an Italian physi-
cist. The Secchi disk, as it is now known, is
lowered into a lake to the depth at which it
can no longer be seen by the investigator. In
water with high turbidity it may disappear
within a few centimeters, but, in 589-meter
(1,932-foot) deep Crater Lake in Oregon,
Secchi disk readings of 40 meters (131 feet)
have been recorded.11 These readings are
virtually unequalled except in Lake Tahoe in
California-Nevada.
The ability of water to dissolve sub-
stances makes essential elements available
to living organisms. The two major nutrients
essential for aquatic plant growth, nitrogen
and phosphorus, dissolve readily in water in
a number of different compounds. The rate
and variety of algal growth will usually be
closely related to the concentration of nu-
trients in the lake.
Because of water's unique physical quali-
ties the temperature in freshwater below ice
rarely drops below 4 degrees Centigrade (39
degrees Farenheit). It seldom goes above 27
degrees Centigrade (80 degrees Farenheit)
during the summer.12 Under normal con-
ditions, changes in water temperature are
gradual and organisms living in water need to
adapt to a much narrower range of fluctua-
tions than many land animals.
Temperature layering or stratification in
lakes occurs because of differences in water
density related to temperature. As every lake
swimmer knows, the water may seem invit-
ing near the surface but suddenly a few feet
lower a chill is felt. The upper layer of a
stratified lake is known as the epilimnion.
The circulating waters of the epilimnion are
separated from the dark, non-circulating,
lower, colder waters of the hypolimnion by
a central layer of rapid temperature transi-
tion known as the thermocline.
In most North American lakes several
changes in heat distribution take place over
the seasons. When the air temperature drops
in the autumn, epilimnion and hypolimnion
water temperatures equalize and achieve the
same densities. As surface waters become
cooler and heavier, they begin to mix with
the water below, and the movement of
winds and currents results in a total overturn
with reoxygenation of the lower levels, pre-
viously depleted of oxygen. Another over-
turn occurs in the spring in northern regions
when ice melts and water temperatures
become uniform throughout the lake.
Both the autumnal and the spring over-
turns bring nutrients that have accumulated
in the lower levels to the surface, where
they stimulate development of algal popu-
lations.
In shallow lakes, the action of winds and
currents may prevent thermal stratification
and in subtropical, warm temperate, or deep
temperate lakes that do not freeze, the en-
tire lake circulates throughout the winter.
13
-------
How a Healthy Lake Functions
SEASONALTEMPERATURE LAYERING
SUMMER
Surface waters
(epilimnion) are
warmed by sunlight.
Below a transition area
(thermocline) lie the
cooler, noncirculating waters
of the hypolimnion.
FALL
In many lakes, surface
water cools until an over-
turn occurs, supplying oxy-
gen and nutrients to all parts
of the lake.
WINTER
When ice covers the
lake, a layer of water
just above freezing lies
above slightly warmer,
denser water.
SPRING
Another overturn
occurs when ice melts
and water temperature
becomes uniform from the
surface to the bottom.
Tropical lakes with high water temperature
show little seasonal temperature change at
the surface or in the depths, even though
they can become just as stably stratified as
temperate lakes.
Winter fish kills can happen in shallow
lakes when snow covers ice preventing sun-
light from reaching plants. The loss of pho-
tosynthesis and the decay of dead plants
lead to oxygen depletion in the water belo\
Summer oxygen depletion can be caused b1
excess amounts of decaying material, with
highly productive lakes particularly subject
to oxygen depletion. A measurement of coi
siderable significance in lake studies is the
D.O., or dissolved oxygen concentration,
which varies with the changing balance of
photosynthesis and respiration.
Classifying Lakes
Numerous ways have been devised for
classifying lakes' by physical qualities, by
chemical characteristics, by age. One phy-
sical means of classification is by thermal
characteristics.
Another classification relates to the
source of water supply. Seepage lakes are fi
entirely by groundwater, drainage lakes are
fed by overland sources. The chemical qual
ty of water in a seepage lake is strongly
affected by the length of time the water ha
been in contact with surrounding soils be-
fore reaching the lake and by the nature of
those soils.
Lakes also may be classified by such phr
sical characteristics as basin shape and by
whether or not they have an outlet. Water
flowing into a deep lake with no outlet or
with a very limited outlet will have a longe
"residence time" than it would have in a
shallow lake with rapid flow-through. The
extraordinarily deep Lake Tahoe has an es1
mated residence time of 700 years. The res
dence time of water in other lakes with
strong flushing action may be measured in
days or months. In reservoirs, which are coi
14
-------
Above, an aging, eutrophic pond in Conn-
ecticut supports many aquatic plants. At
right, plankton samples from 12 New York
lakes vary from oligotrophic (clear samples)
to eutrophic (bottles at lower right).
structed for purposes of flood control,
power production, irrigation, water supply,
recreation, or several of these uses, water
residence time is controlled to serve these
functions.
The most common way of classifying
lakes in discussions of water quality is by
their productivity. This is determined by the
nutrients brought in from the watershed and
by direct fallout from the atmosphere, the
chemistry of the bottom sediments, and the
geological nature of the drainage basin, as
well as by the climate and the depth and
shape of the basin. Based on organic cycles,
which in turn are based on "trophic" or nu-
tritional characteristics, lakes are commonly
divided into three categories: oligotrophic,
mesotrophic, and eutrophic.
Oligotrophic (poorly fed) lakes are
those in which plant growth is limited by a
low chemical concentration of nutrients.
Consequently, such lakes have few aquatic
weeds and algae or other plant life. The
number of species is usually high but the
number of individuals low. Oligotrophic
lakes are usually large and deep and clear
with high levels of dissolved oxygen and
Secchi disk visibility of 6 meters (20 feet)
or more.
Eutrophic (well fed) lakes have large
supplies of nutrients and heavy layers of
organic sediments on their bottoms. Inflow
of sediments makes the lake shallow and tur-
bid. Secchi disk visibility may be as little as
one-half meter (2 feet) or less and because of
shallowness and high nutrient levels there
may be extensive weed and algal growth. Al-
though during the summer photosynthesis,
particularly by blue-green algae, is extremely
high on sunny days, when sunlight is absent
species diversify and numbers in the animal
kingdom may be limited by low dissolved
oxygen levels. This results from the high
rates of both algal respiration and bacterial
action required to decompose dead vegeta-
tion. As a lake becomes increasingly eutro-
phic the number and type of bottom crea-
tures will change. The high rate of decompo-
sition produces excessive demand on the
oxygen supply by decomposing organisms,
with subsequent low oxygen levels. This
critical problem may cause distress or death
of organisms. Fish populations in temperate
oligotrophic lakes can include species such as
trout and salmon, which live in the cool,
well-oxygenated hypolimnion during the
warmer months. But in warmer eutrophic
lakes with low oxygen in the hypolimnion,
these fish are replaced by warrnwater species
such as perch, pike, bass, panfish, and bull-
heads which are capable of living in the
warm epilimnion
Mesotrophic lakes are at an in-between
stage nutritionally, with ecosystems func-
tioning in a stable fashion, supporting a di-
verse community of aquatic plant and ani-
mal life. Many of our most popular recrea-
tional lakes are at this mesotrophic stage of
evolution.
Although paleolimnologists, who study
the history of lakes, have found examples in
the eons of geological time that counter this
theory, in general, lakes evolve naturally
from oligotrophic to eutrophic stages. Eu-
trophic lakes are common in regions of
15
-------
How a Healthy Lake Functions
Below, top to bottom: Oligotrophic lakes,
with clear waters, few bottom sediments,
and low biological activity may evolve
(through cumulative or increased influx
of nutrients, represented by arrows) into
mesotrophic and finally eutrophic lakes,
characterized by turbid waters, sediment
buildup and large numbers of aquatic
plants.
fertile soils, but in less fertile soils attaining
this level of productivity may take many
thousands to millions of years. The eutrophi-
cation process, however, is accelerated by
man, who through urbanization and agricul-
tural practices may increase the supply of
nutrients and sediments to the lake.
Not all "healthy" lakes are clear, blue,
deep bodies of fresh water. Desert salt
lakes, such as the Great Salt Lake in Utah,
occur in arid climates. Salt concentrations
build up because of an imbalance in which
evaporation is greater than precipitation
Prairie potholes and bogs are sometimes
classified with lakes and sometimes wit!
wetlands. Potholes are seasonal bodies
of water, shallow depressions which range
size from less than !/•> to over 40
hectares (1 to 100 acres). Like many
floodplain lakes which have formed in
old ox-bows they are usually dry durini
some months of the year. Most are foun
in the northern Great Plains area extend
ing into south central Canada. Bog lakes
are most commonly found in the north
eastern and north-central States. Becausi
they have almost no inflow or outflow
they retain decayed humic material, mak
ing their water brown in color and highlN
acidic.13
A word about ponds. Although the ter
pond is loosely used to refer to small shall
bodies ,of fresh water, including natural
phenomena and those made by man or
beaver, it may also indicate, as in the ca;
of Walden Pond, a body of considerablf
size. Particularly in New England, becaus
of traditional regional usage, the word poi
should not be assumed to indicate dimer
sion. Ponds that become dry during the
summer as water tables fall may support
mobile organisms such as insects and frog:
which can find other temporary refuge,
or those that have special mechanisms
enabling them to survive in a state of dor
ancy.
Reservoirs
As opposed to a natural lake, a reser-
voir constructed for purposes of flood coi
trol, drinking water supply, irrigation, c
electric power generation, has a natural
inlet-i.e., a stream or river—and an arti
ficial outlet—the control gate of a dam.
Although reservoirs have ecosystems sirr
ilar to those of natural lakes, because of
their different morphology and water-
flow characteristics, they present special
problems.
-------
The bullhead (left) is tolerant of warm water
and is a common resident of the surface
waters of eutrophic lakes. The river trout
(right) often occurs in the cooler bottom
waters of temperate oligotrophic lakes.
A reservoir is an impoundment formed by
a dam. It has shallow water at the inlet and
deep water near the dam, unlike a natural
lake, which is more likely to have a shallow
littoral zone with deeper waters toward
the middle. Although a reservoir may be
very deep, the residence time of its water
can vary from a few days to a few years,
depending on the size of the lake relative
to its watershed area, the purpose for
which the dam is used, and the seasonal
rises and dips in the quantity of waters
it receives.
Reservoirs tend to have greater siltation
and turbidity problems than natural lakes
because they are fed by rivers, which carry
high loads of matter held in suspension.
Essentially, the reservoir becomes a settling
basin for the river
Waters drawn from an anaerobic hy-
polimnion of a reservoir may contain nox-
ious gases, including hydrogen sulfide,
which is highly toxic to aquatic life. The
Corps of Engineers has found that these
waters corrode outlet mechanisms, and
that high levels of hydrogen sulfide have
often made workers at reservoir dams
feel ill.14 These gases, which result from
decomposition of organic matter, may
also be accompanied by high concentra-
tions of iron and manganese in periods
of low flow, all lead to unpleasant odors,
tastes, and discoloration of water down-
stream—and high costs for removal of
these pollutants if water is to be used fo'r
consumption.
Releases of turbid water can interfere
with downstream fishing and other recre-
ation When water is withdrawn from the
hypolimnion of the reservoir, discharge
waters often bring cold water with lowered
dissolved oxygen concentrations to receiv-
ing streams, damaging fisheries downstream
or altering other components of stream
ecology Fisheries might also suffer damage
from waters drawn from the epilimnion
which are warmer than normal stream
temperatures. In some instances, however,
cold "tail waters/' provide excellent trout
fishing.
Management of reservoirs must take into
consideration the velocity of releases as
well, since large pulses of water rushing
downstream may utterly destroy habitats
simply by their force rather than by their
incompatible chemistry and temperature.
Other management problems involve pro-
viding fish passage around hydroelectric
dams and considering the results of fluc-
tuating water levels and velocity on fish
spawning habitats at appropriate times of
year. Drops in water level in reservoirs
and seasonal fluctuations in natural lakes
cause problems with public use turbidity
from bank erosion, unaesthetic views of mud
banks, and problems of access to docks and
other recreational facilities. In parts of the
West, irrigation drawoffs have completely
dried up reservoirs as well as stream beds.
Lake Powell, a reservoir on the Colorado
River, sprawls behind the Glen Canyon Dam
in Arizona.
-------
-------
Chapter 4
How Lakes Change
Utah's Great Salt Lake has been altered by
the construction of a railroad causeway
which separates the less saline waters of the
southern portion of the lake, which receives
more freshwater inflow, from the saltier
waters of the northern portion.
Sedimentation
Lakes are not permanent features of the
landscape. Eventually, even without human
influences, lakes will change and may dis-
appear. The process may be relatively
fast because of rapid siltation, or it may
be slow, occurring over hundreds of thou-
sands of years.
A primary natural cause of the death
of lakes is accumulation of sediments.
This occurs as fragments from dry land
are, by the forces of water, wind, and
gravity, moved to waterways, or as the
remains of organic matter accumulate
within the lake. As sediments build up,
lakes become increasingly shallow, the
light of the sun penetrates to the bottom,
and plant life proliferates. Eventually
the lake will become a wetland. Over a
long period of time the wetland will fill
in completely and appear to become dry
land except for intermittent wetness.
Sedimentation is generally a slow process
in a wilderness and in undeveloped coun-
tries, but it is hastened by the activities of
man. Development markedly speeds sil-
tation as earth is cleared and moved for
highway, residential, or industrial con-
struction Deep and surface mining speeds
the introduction of materials that belong
on land into waterways. Precipitation and
snow melt runoff carries sediments from
urban parks and gardens through storm
sewers and into rivers and streams. Tree
roots hold water and restrain erosion, but
when woodland is converted to farmland
the dynamics are altered. Four billion tons
of sediment are washed into lakes and
streams in this country each year, of which
an estimated 50 percent comes from agri-
culture '5 When cultivated land is left
without vegetative cover, it is extremely
vulnerable to erosion by water and by wind.
The loss of billions of tons of topsoil an-
nually reduces land productivity while
simultaneously supplying the major water
pollutant. Sediments entering lakes may
also carry nutrients, toxic chemicals, and
pathogens.
Runoff carrying solid materials from
the watershed may create unaesthetic lake
water conditions—or a serious public health
problem. Concern about contracting infect-
tious disease from water is low in this
country since few people have known
anyone who suffered more serious conse-
quences from unclean swimming water
than something a doctor cheerfully labeled
"swimmer's ear" or "summer diarrhea."
It is important, however, to note that
several outbreaks of typhoid contracted
from drinking water have taken place here
and in developed nations around the world
in the past three decades, proving that
the dread diseases of our grandparents'
time are not extinct.16
Nutrient Enrichment
Among the essential ingredients in any
chemical mixture designed to stimulate
plant growth on land are nitrogen, phos-
phorus, and potassium. For gardens, these
nutrients may be added in the form of
commercial fertilizers, or by recycling
animal manure and composted vegetable
wastes. The nutrients are soluble in water
and therefore penetrate the soil with rain-
fall. An excess of nutrients can enter water-
ways and lakes from this source alone in
"sheet" runoff from gardens, cities, parks,
and farmlands.
Nutrient enrichment of a lake and sed-
iment loading lead to eutrophication. To
understand the management of lake prob-
lems, a distinction must be made between
natural eutrophication, which occurs as
nutrients wash from undeveloped water-
sheds, build up in lakes, and are recycled
by the sediments, and "cultural eutro-
phication," an accelerated enrichment pro-
cess caused by human activities.
Cultural eutrophication occurs in dev-
eloped areas as essential plant nutrients,
19
-------
How Lakes Change
Photos (above) taken in 1920 and 1936
document the death of Lake Como in
Hokah, Minnesota. The lake was filled with
sediment from steep slopes that had been
cleared of timber and cultivated without
erosion controls. At right, sediment fills
a ditch at a Virginia construction site.
20
-------
particularly nitrogen and phosphorus, enter
the lake from a variety of specific and
diffuse sources. Organic wastes enter water-
ways from inadequate or faulty sewage
treatment plants, from septic tank seepage,
from cattle feedlots, and from a variety
of food, paper, and textile industries.
Municipal wastewater carries high con-
centrations of phosphorus from two major
sources-human fecesand phosphorus-based
detergents. Industrial wastes may contain
nutrients and a wide spectrum of toxic and
hazardous materials. Storm sewers carry
soil, lawn fertilizers, salt, pet droppings,
sand, lead, and many other materials.
The National Eutrophication Survey,
conducted on lakes receiving municipal
wastewater by the Environmental Protec-
tion Agency from 1971 to 1977, found
eutrophic conditions in 68 percent of the
800 lakes surveyed. Four percent of these
lakes were classified as hypereutrophic.
Not all the problems are recent or controll-
able. Oneida Lake in upstate New York was
known to the local Indians in the 18th cen-
tury by a name that means "stinking green,"
because of its algal blooms.17
Eutrophication is unmistakable. Over-
stimulation of plant growth occurs, with
consequent deterioration in water quality
and changes in fish species. Heavy growth
of blue-green algae makes the lake green
and murky, with seasonal algal blooms and
scums and mats formed by deteriorating
plants. Excessive growth of macrophytes—
rooted aquatic plants-may clog the lake,
making it unattractive for swimmers, boat-
ers, and fishermen. Unpleasant odors and
tastes are noticed as decomposition of
plants results in depleted oxygen supply.
Mosquito populations thrive when shallow
wind-protected waters stagnate. Fish may,
in some instances, die and populations
change as those species that require good
oxygen supply and cool waters, such as
trout, salmon, black bass, and walleye,
disappear and are replaced by species which
are tolerant of warm water and low oxygen
such as bullheads, carp, and mudminnows.
Algae and aquatic weeds, symptoms of
eutrophication, can be an aesthetic nui-
sance and a hindrance to recreation. At
right, eutrophication in Lake Mendota,
Wisconsin.
Some eutrophic lakes do support excellent
bass fisheries.
Other Pollutants
Pollutants, in ordinary terms, are silt
and biologically degradable substances. The
term includes human and animal wastes as
well as many other types of foreign matter
that may enter a lake as, for example, veg-
etable wastes from a cannery. Such wastes
become troublesome pollutants only if they
produce undesirable alterations of the plant
or animal life or result in uninviting con-
ditions for recreation. When organic wastes
enter a lake they are greeted by a host of
biological organisms designed to cope with
the problem. Natural cleansing forces go to
work as microorganisms metabolize pollu-
tants into carbon dioxide and water. Prob-
lems come from overload, which exerts a
high biochemical oxygen demand for decom-
position and this may decrease dissolved
oxygen to concentrations too low for
higher plants and animals. Decomposition
also adds nutrients to the lake that are avail-
able for algal blooms.
Today a range of synthetic chemical
contaminants for which there are few or
no decomposer organisms have found their
way into our lakes. Runoff from both
urban and rural areas and discharges from
industry carry to the lake such substances
as toxic pesticides, PCB's (polychlorinated
biphenyls), asbestos, and toxic metals such
as arsenic, mercury, lead, zinc, and copper.
Even in rivers, where self-cleansing action
disperses pollutants more rapidly than in
lakes, grave pollution problems may persist.
Kepone-contaminated substances in the
James River in Virginia are expected to
remain there beyond the year 2000.18
Materials carried into lakes may recycle
within the system for generations.
-------
How Lakes Change
Toxic substances can reach dangerous
levels in animals near the top of the food
chain through a process called biological
magnification. Small animals with low
concentrations of toxins are consumed
by larger animals, in whose tissues the
toxins accumulate.
Pollutants such as the insecticides Kepone
and DDT can remain in the lake and become
toxic to animals and to humans as a result
of "biological magnification." Toxic sub-
stances tend to become concentrated in
the tissues of organisms by this process
as smaller animals are consumed by lar-
ger ones. Ironically, the very qualities that
made DDT such an exciting discovery in
the 1940's-the fact that it worked fast,
attacked a wide range of pests, and was
persistent—resulted in widespread ecological
damage. The fact that it was also cheap re-
sulted in flamboyant overuse. Although
DDT was banned in the United States in
1972, in 1976 fish in Lake Michigan were
still found to have concentrations of the
chemical in their bodies in excess of those
permitted for human consumption.19
Fish in Lake Michigan were also discov-
ered to be high in concentrations of PCB's,
a group of industrial chemicals now usable
only under strict control and no longer
manufactured in the United States.20
Like DDT, PCB's degrade extremely slowly
and accumulate in animal tissues. Women
who lived near the Great Lakes and con-
sumed fish from the lakes were found to
have PCB's in breast milk and in fatty
tissues. Although sport fishing thrives,
trout and salmon from Lake Michigan
are prohibited from being commercially
harvested because of high PCB levels.21
The Food and Drug Administration con-
siders unfit for human consumption any
fish containing two parts per million of
PCB's since these chemicals have caused
fish kills and been implicated in human
mutation.22 Approximately 400 million
pounds of PCB's have been discarded al-
ready and are present in the environment
while an added 30 million pounds are still
in use.23 In Lake Superior there is con-
cern about concentrations of asbestos in
parts of the lake from which drinking
water supplies are taken, this resulted
from direct dumping of tailings from a
mining operation 24 In a number of States
not bordering the Great Lakes, consump-
tion of fish from certain waters is also
restricted because of unacceptable levels
of PCB's and pesticides, particularly DDT
and Dieldrin.25
Case Report:
Alcyon Lake
In March of 1980 the Justice Departmen
on behalf of the Environmental Protectior
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/>/IV" 'S^PXV X>1*'
f-^Xi~ -vStis- '*sms
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22
-------
Agency, filed suit against the owner of the
LiPari Landfill in Mantua Township, New
Jersey, to force cleanup of the inactive
chemical disposal site from which dangerous
chemicals are leaking into nearby streams.
Chemicals such as benzene, lead, cadmium,
and others—some of which are suspected of
causing cancer—were dumped on this site
starting in 1958 and have worked their way
through adjoining soils and waterways. Now
they are threatening the public. Two streams
adjacent to the landfill are contaminated and
are bringing contaminants to Alcyon Lake,
half a mile away in Pitman, New Jersey.
Leaching from the chemical dump is the
most dangerous assault to this lake, which
has had severe pollution problems for over
20 years. This formerly popular recreational
lake was once the site of an amusement park
and annual agricultural fairs. It was des-
cribed in 1928 as a beautiful swimming, fish-
ing, and boating spot and the town's major
asset, but it was closed to swimming in 1958
because heavy loads of fecal matter were
entering the waters from a malfunctioning
privately owned treatment works in nearby
Glassboro. The malfunction, in turn, was
attributed to intake of wastes at the treat-
ment works from a metal-plating plant.
In 1972, new regional sewage collection and
treatment facilities cut off one source of
pollution, but in addition to the critical
chemical leachates, five storm sewers now
empty into the lake and runoff from sur-
rounding agricultural areas carries high
levels of fertilizers, pesticides, herbicides,
and fungicides. Inflow of sediment has re-
duced average depth in the lake from 2.7 to
1.2 meters (9 to 4 feet) and has sealed fresh-
water springs.
The LiPari Landfill, only 305 meters
(1,000 feet) upstream from Alcyon Lake,
accepted a wide variety of industrial, hazar-
dous, and toxic materials as well as munici-
pal refuse through mid-1977. Careless stor-
age of these wastes created dangerous
conditions and the necessity for the costly
cleanup. New EPA regulations, announced
in May, 1980, represent the first attempt
The waters of Alcyon Lake (left) in Mantua
Township, New Jersey have been contam-
inated by chemicals dumped at the LiPari
Landfill, 1,000 feet upstream from the lake.
Below, leachate from the landfill contains
dangerous chemicals such as benzene, lead,
and cadmium.
23
-------
How Lakes Change
Acid drainage from a coal mine stains the
water of a small stream.
to effectively control the disposal of
hazardous wastes26
Regional Problems
Chemical pollution is not the sole prob-
lem: salinity and acidity in lake waters now
stand at unacceptably high levels in many
regions of the country. Acid precipitation is
a major environmental concern. In some
States in the South and the West, the dis-
posal of brine from oil fields contributes to
salinity of lake water. Predominantly in wes-
tern States, irrigation return flows are a
major source of salt, while in some of the
northern States runoff of highway de-icing
compounds is a troublesome problem.
Acid Mine Drainage
Acidity in lake waters is often traced in
mining areas to acid mine drainage. Mine
drainage is associated with both deep and
surface mining of coal and a number of
metals. Acid drainage is a mixture of iron
salts, other salts, and sulfuric acid in runoff
from mining wastes. Acid from mining
operations can extract heavy metals present
in small quantities in soil.
Currently, an EPA clean lakes restora-
tion project at Missouri's Finger Lakes State
Park is expected to provide considerable
information about the reclamation of sur-
face mined lands. The park, on land that wa:
formerly a coal strip mine, has many small
lakes formed by surface drainage in mining
trenches. Eighteen of these lakes will be
formed into one large lake by constructing
dams and canals; acid leaching control
methods will be used to improve water
quality for recreational use.
Irrigation
Return How
The major water pollution problem in
many western river basins is salinity caused
by irrigation. The water diverted into irriga-
tion systems from mountainous watersheds
is of excellent quality. During irrigation
procedures, however, one-half to two-thirds
of this water is lost to evaporation or trans-
piration from plants. As the water evapo-
rates, the salts dissolved in it stay behind anc
then percolate into the soils. This soil water
may become more saline by dissolving salts
in the ground as it passes through.
Since crop production is also reduced by
salt in the soils, efforts have been made to
develop crops more tolerant of this salinity
Adoption of new methods, such as trickle
irrigation and lining canals to minimize
seepage, depends on the success of edu-
cational programs designed to demon-
strate benefits that will accrue from irriga-
tion return flow management
Acid Rain
It is only since the 1960's that those
concerned with lake quality have realized
that in certain cases airborne pollutants may
24
-------
be more damaging—and certainly more diffi-
cult to control—than substances carried
along our watercourses. Although most of us
still enjoy the old poetic images, it is not
unduly skeptical to question the gentleness
of rain, the purity of the driven snow. Our
ram is sullied, our snow, ditto One of the
most alarming and pervasive causes of lake
pollution in the Northeast today is acid
rain—a phenomenon brought about by the
increasing emission of nitrogen and sulfur
oxides into the atmosphere from the burn-
ing of fossil fuels, especially coal. The
United States discharges approximately 50
million tons of sulfur and nitrogen oxides
into the atmosphere annually.2 7
Acid rain results when these gases,
released by combustion, combine in the
atmosphere with water vapor and are hydro-
lized to become acids. The acidified vapor is
carried by prevailing winds and may come to
earth hundreds of miles from the source of
the contamination. Efforts to improve local
air quality by increasing the height of
smoke stacks—some to a towering 500
feet—have increased the problem by
shooting noxious fumes high into the
prevailing winds. Plans to increase coal use
in the coming years are expected to exa-
cerbate the problem.
Chemically, even the purest rain is
slightly acidic because of dissolved carbon
dioxide Rain is considered normal when
its pH level is 5.6, although the level for
distilled water is pH 7. This is caused by the
Acid rain, which in severe
cases can effectively sterilize
lakes, is caused when sulfur and
nitrogen oxides from the burning of
fossil fuel combine with atmospheric
water vapor to become acids through
hydrolysis. Acidity of rain in the east-
ern United States is greatest in New York
(darkest area of map).
formation of carbonic acid from the carbon
dioxide in the atmosphere. Acidity and alka-
linity are measured on a pH scale of 0 to 14,
with 0 highly acid, 14 highly alkaline, and
7 neutral In the 1970's pH values in rain of
2.4 have been recorded in Scotland and
readings as low as 3 0 are now routinely
recorded in parts of New England
The earliest and most pervasive effects of
acid rain were noted in Norway and Sweden,
New England, northern New York State, and
eastern Ontario. By the middle of the 1960's
changes were being noted in fish populations
in lakes in the Adirondacks. A 1975 study of
214 lakes in the region found that 82 wkh a
pH under 5.0 had no fish. A followup study
in 1979 found that 170 were sterile.28 Half
the lakes in the Adirondack region at alti-
tudes above 2,000 feet now have an average
pH of 4.2 and are devoid of fish.2 9
The relationship between acid rain and
sterile lakes is a matter of international
concern. At a 1979 conference on the sub-
ject in Toronto, the Canadian Minister for
the Environment referred to it as "a
catastrophe of a leisurely kind," because,
unlike great natural disasters, the effects
of acid rain on delicate lake ecosystems are
slow and pervasive.
In addition to reducing pH readings in
water to unacceptable levels, toxic heavy
metals such as lead, mercury, cadmium,
aluminum, zinc, beryllium, and nickel
can be released by acid rain from lake
bottom sediments and leached from sur-
rounding soils.30 High concentrations
of aluminum in lake water can lead to
fish mortality 3'
Little is known about the effect of acid
precipitation on trees, plants, and agricul-
tural products although studies are being
conducted in all these areas. Its threat to
aquatic communities, however, is becoming
well understood. What happens in a lake
when the waters become increasingly acid?
Although many lakes in Florida, for
instance, naturally have pH levels of 4.5 to
5.5 with a variety of flora and fauna, the pH
levels of most healthy lakes are usually in
the range of 6 to 8. When these levels
begin to drop because of acid precipita-
tion, the effects may be dramatic.
In an ecosystem damage to one tiny cog
signals trouble for the entire tidy little
world. At pH 6.6 most freshwater snails do
not survive and the eggs of certain salaman-
ders fail to hatch. Tadpoles and shrimp die
in waters below pH 6.0. Many species of
microscopic zooplankton and phytoplank-
ton which form the lowest rungs of the food
chain die out along with a number of higher
species as the pH level continues to drop.
When pH slips below 5.5 northern pike,
perch, and other fishes disappear. Species
die out for two reasons' either adult fish die
or eggs fail to hatch. When pH levels reach
4 5 in lakes, most frogs and insects, and all
fish are dead.32 Acid-loving plants, such as
sphagnum moss, commonly found in highly
acidic bog waters, take over.
The lake looks beautiful—completely
clear and blue—and as clean and lifeless as
a swimming pool.
Recognizing the acid rain problem,
President Jimmy Carter in August 1979
called for programing $10 million per year
for research to be co-chaired during the
next 10 years by the Environmental Protec-
tion Agency and the Department of Agri-
culture.33 Acid rain research is also being
carried on by a research arm of the electric
industry, the Electric Power Research
Institute, at Hubbard Brook Experimental
Forest in the White Mountains of New
Hampshire, by the National Atmospheric
Administration, and by the Department
of Interior's Office of Water Research and
Technology. A broad spectrum of EPA
programs is currently investigating effects
of acid rain on aquatic systems, forests, and
agricultural lands.
Current proposals for dealing with the
source of the problem center on installing
stack "scrubbers," on fuel desulfunzation,
modified combustion procedures, and alter-
native energy sources.34
25
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IMB
<•£"•"-.-.
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Chapter 5
Lake Restoration
Lake restoration begins with knowledge
of lake processes and problems. At left,
Cornell University researchers collect plank-
ton samples from Cayuga Lake, New York.
The subject of lake restoration, and lake
protection, is explored and debated today in
national and international conferences, in
academic sessions, at Federal, State, and
local governmental agencies,at meetings of lake-
shore owners' associations and other com-
munity groups Although the need to do
something about our degraded lakes is
beyond dispute, the science of lake restora-
tion is still in its early stages, and even the
terminology can be obscure What do we
mean by lake restoration? Restoration to
what? To some ideal of pristine beauty7 To
an oligotrophic condition that may have
existed in the lake's ancient past7 To
accepted levels for projected use? A lake
with extensive growth of aquatic weeds may
be a good fishing pond and yet not look
inviting to swimmers. A perfectly clear lake
may be blue and transparent because high
levels of acidity have killed off both plant
and animal life.
Clean lakes projects are generally insti-
tuted to alleviate the effects of excessive
siltation or cultural eutrophication.
Decisions about how far to go in cleaning up
a lake that has become shallow and over-
grown may be a matter of philosophy or a
matter of economics Often a judgment must
be made about feasible limits of expendi-
ture and effort without the reassurance of
a solid basis for predicting results.
Once a project for lake restoration is
undertaken the results of this effort must
be carefully monitored, evaluated, and
recorded. Lake management requires careful
planning based on the best scientific and
technical advice, direct action, and com-
munity cooperation, particularly as regards
revised land use practices and priorities
In restoring the aquatic balance of a
lake by a program of lake management, all
plans must be made on a lake-watershed
basis. Although actual water use can alter
water quality—an obvious example is fuel
lost from motor boats-it is the uses of the
watershed that will determine the condi-
tion of the lake in the most significant
ways.
The approaches to treating a degraded
lake can be divided into two broad cate-
gories, watershed measures and those
methods that intrude into the lake itself to
clean up the results of natural and acceler-
ated processes. Although sometimes viewed
as opposite or alternative approaches, lake
restoration projects often involve both
watershed and m-lake methods.
Identification of watershed sources of
pollution should be the first step in any
rehabilitation project. Treating the sources
of lake degradation may be expensive and
results not as dramatic as hoped for, but
effects are likely to be lasting and, for this
reason, more cost-effective in the long run.
In-lake methods may also be required to
speed improvements in the appearance and
quality of the water. Although lakes differ
biologically, chemically, and physically, so
that one method may bring gratifying results
in one lake and not in another, permanent
lake rehabilitation begins with halting
the entrance of undesirable substances.
Unless this is done, weed harvesting, for
example, will prove about as permanent as
lawn mowing, chemical treatments will have
to be repeated frequently with possible
danger to the ecosystem, dredging will
become a recurring expense.
Liberty Lake, in the State of Washington,
is a prime example of this principle. In
1974, alum was used extensively with
apparent success to precipitate phosphorus
and control algal bloom, but algae reap-
peared profusely in 1976, 1977, and 1978.
Since then, in conjunction with an EPA
clean lakes grant and with a high level of
community action and cooperation,
sewers have been installed to replace faulty
septic systems. An adjoining marsh,
formerly used as pasture, has been diked to
halt nutrient leaching to the lake.
A second alum treatment, scheduled for
this year, is expected to be the last, now
that nutrient supply to the lake has been
cut back greatly.
27
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How Lakes Change
Reducing the input of contaminants is
accomplished by three general methods
point source nutrient removal and control,
nutrient diversion, and sediment control.
Point Source Control
In water pollution parlance "point"
sources are those that are discrete and
definable such as factory or sewage treat-
ment plants that empty wastes into water-
ways through discharge pipes.
"Nonpoint" sources, such as urban and
rural runoff, septic tank seepage, and acid
rain, are diffuse. Many of the nonpoint
source pollutants result from agricultural
and silvicultural activities, mining practices,
land development, and urbanization in
general.
Discharges from point sources are, for
obvious reasons, more amenable to control.
Because water polluters are now bound to
a schedule of pollution abatement under the
National Pollutant Discharge Elimination
System, the cost of cleaning up waste pro-
ducts before channeling them into rivers,
streams, and lakes is now considered part of
the expense of running a manufacturing
plant.
But despite regulations on industrial
discharges, 72 percent of the drainage basins
in the country are still tainted by both con-
ventional and toxic pollutants from indus-
trial sources.35
Adverse effects on water quality stem-
ming from municipal discharges are found in
an even higher percentage—89 percent—of
drainage basins.36
The pollutants that most often reach
unacceptable levels in such discharges are
fecal coliform bacteria, oxygen-demanding
wastes, and the major plant nutrients,
nitrogen and phosphorus.
Domestic waste water carries large quan-
tities of plant nutrients that are, to some
extent, removed by conventional waste
treatment methods.
Primary treatment, which eliminates
suspended solids by settling tanks and
filtration, reduces phosphorus by only
5 to 15 percent.
Secondary treatment systems which use
biological processes to break down organ-
ic material can remove up to 50 percent of
the phosphorus in waste water
Because the quantity of phosphorus
is usually the main factor limiting plant
growth in fresh water, reducing phosphorus
loadings into waterways is essential.
Currently, approximately 1,200 waste
water treatment plants which utilize some
degree of advanced waste treatment tech-
nology are either in operation or in con-
struction.
These new plants and reduction of
phosphorus in detergents which was'
achieved in 1973 in some States and in
Canada, are the major reasons for improved
water quality in the Great Lakes.
Combined sewer systems, which collect
domestic wastes from homes and excess
water from storms, are common in our
cities built before 1870, and are a major
source of water pollution.
In dry weather the combined waste
waters travel to the treatment plant effi-
ciently. During seasonal storms or rapid
snow melt, some of this waste water, in-
cluding quantities of raw sewage, bypasses
the treatment plant and flows untreated
into waterways.
Raw sewage may enter our lakes carryinc
heavy loads of nutrients and disease-causing
microorganisms.
Many lakes have been polluted by seepag
from septic tanks, the most conventional
waste treatment method in lake and pond-
side communities. The problem is avoidable
when systems are correctly sited, designed,
and maintained if there are the right kinds
28
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of soils in adequate amounts for drainfields
to function.
A major Federal public works program
in this country is EPA's construction grants
program for waste water treatment. Con-
gressional authorization has been $4.5 bil-
lion per year, but appropriations have been
lower recently.
Although faulty or inadequate means of
sewage disposal have, without question,
been a major source of water pollution,
the theory that, in all cases centralized
collector sewers should replace individual
systems has recently come under critical
scrutiny. The Clean Water Act Amendments
of 1977 provide for raised levels of Federal
funding for upgrading and managing indi-
vidual and multi-family systems, and new
funding guides of 1978 and 1979 authorize
construction of collector sewers only if
severe water quality problems or threats
to public health exist.
In many sparsely settled communities,
the projected costs of installing conven-
tional treatment plants bordering lakes
range from high to staggering. A recent
study in Wisconsin indicates that in one
area the population to be served by a new
system would have been faced with local
and private costs ranging up to two and
a half times the value of the average
house.37
Attempts to reduce phosphorus loading
to lakes include utilizing the natural clean-
sing effects of our wetlands. In Minnesota's
Lake Minnetonka it was demonstrated that
a major source of phosphorus was storm
water runoff from an urban area. When this
storm water was routed through a large
wetlands region, 78 percent of the phosphor-
us and 94 percent of the total suspended
solids were trapped before entering the
lake, subsequently reducing algae.3 8
Considerable attention has been focused
in recent years on an obvious measure to
reduce nutrient loadings in waterways—the
banning of phosphorus-based detergents.
Since these detergents were first introduced
to consumers in the 1940's they have been
responsible for 50 to 70 percent of the phos-
phorus in our municipal sewage. Phosphate-
based detergents are now banned in many
lake areas, in States such as Indiana, New
York, and Michigan, and in other parts of
the world Some legislation bans detergents
with higher than 8.7 percent phosphorus,
other legislation totally bans phosphates in
laundry detergents for household use.
Diversion
Diversion, a second lake restoration
method, involves the rerouting and treat-
ment of nutrient rich waters, usually in
such a way that they are discharged into
the stream below the lake.
Diversion treatments have been criticized
because, although they can improve condi-
tions in the given lake, the problem may
simply be passed on to the stream or to
another lake, if sewage treatment is not
included in the plan.
Case Report:
Lake Washington
Once an oligotrophic lake. Lake Washing-
ton, near Seattle, became significantly
eutrophic over a short time because, prior to
1963, 11 secondary sewage treatment
plants discharged directly into it. These
effluents were found to be bringing in 56
percent of the phosphorus and 12 percent of
the nitrogen that entered the lake annually.
Measurements of the abundant algal growth
showed that in 1962 concentrations were
15 times what they had been in 1950.39
During that period Secchi disk readings had
dropped from about 3 meters (10 feet) to
0.9 meters (3 feet).
In the 1950's, in an early lake restoration
project, the Municipality of Metropolitan
Unvegetated slopes of construction sites
are major contributors to lake sedimenta-
tion.
Seattle, assisted by Federal Water Pollution
Control Act funds, formulated a plan to
treat and divert this sewage from Lake
Washington into Puget Sound. When the
first stage was completed in 1963, 25 per-
cent of the effluent had been diverted
from the lake, by 1965 another 20 percent
of the original load had been diverted.
The third stage was completed in 1968, and
algal growth was significantly reduced.
Secchi disk measurements rapidly returned
to pre-pollution levels 40
Control of Sedimentation
The major pollutants arriving from non-
point sources are suspended solids, nutrients,
29
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How Lakes Change
-------
construction erodes rapidly when rain con-
tinues to fall on the ground after the
soil's capacity to absorb it has been
exceeded.
Sedimentation rates can be retarded only
by sound land use practices within the
watershed. Good agricultural conservation
practices include contour plowing, crop
rotation, keeping vegetative cover at all
seasons, using minimum tillage methods of
cultivation, and proper grazing practices that
don't strip the land. Leaving buffer zones
between cultivated fields and streams can
also aid in retaining valuable fertile soil
where it is needed and keeping it out of
waterways where it becomes a major
pollutant.
Since its construction in 1938 as a Works
Project Administration project, the 148 hec-
tare (300 acre) artificial Broadway Lake in
Anderson County, South Carolina had pro-
vided many years of recreation in an area
short of such facilities. But, in less than 40
years one-quarter of the lake had become
completely silted in. Water quality was poor
because of pollutants in the sediments from
the 12,400 hectare (25,000 acre) hilly, red
clay watershed. One-crop agriculture in the
area, currently soybeans which have replaced
cotton, has led to critical erosion problems.
The lake is now being restored in a special
Federal cost-sharing and technical assistance
program sponsored by USDA and EPA and
involving two State agencies. Methods in-
clude smoothing gullies and eroded road-
banks and planting grasses or trees,
constructing debris basins in the watershed
that will catch and store sediment, and con-
structing animal waste lagoons. Landowners
will be assisted in developing terraces,
grassed waterways, and improved timber
stands, and will be instructed in the use of
field borders and minimum tillage
techniques.41
Soil erosion may also occur when builders
of subdivisions leave bulldozed land without
cover for years. Both construction and
logging ventures should be avoided on steep
slopes, and activities that leave the land-
A lake dredger at Collins Park, New York
scape bare should not be undertaken in
rainy periods. Grassed waterways and
terracing, channel lining, mulching with
straw, hay, or other materials, and use of
sediment traps, are all good long and short-
term measures for erosion control. Lake-
shore erosion can be halted both by vegeta-
tive and structural means, and retaining
walls should be considered on steep grades.
In-Lake Methods of
Lake Restoration
A number of mechanical, chemical, and
biological methods have been employed to
restore lakes that have become clogged with
sediment or with overabundant plant
growth. These techniques are particularly
effective when used after all possible sources
of pollutants have been analyzed and
checked or reduced. Without in-lake restora-
tion processes lakes with slow flushing
action may show no improvement for long
periods of time because nutrients already in
the lake are readily recycled. Flushing time,
the period it takes to completely replace one
lake volume, varies from a few days for some
reservoirs to a few centuries for Lake
Superior. Flushing time for bottom waters
may be longer than for surface waters in a
stratified lake because the surface waters
are replaced over and over while the deep
waters can be replaced only during fall and
spring overturn.
Since lakes vary so greatly, there has been
considerable trial and error in experiments
with in-lake restoration methods. A rapidly
expanding body of information has, how-
ever, provided a basis for a higher level of
predictability. Some of the more successful
methods include dredging, nutrient inactiva-
tion, aeration, drawdown, and use of chemi-
cal and biological controls.
Dredging
Dredging a lake is an obvious means of
removing accumulated sediments, increasing
lake depth, and simultaneously removing
nutrients incorporated in the sediments.
-------
How Lakes Change
Algae and weeds choke Lilly Lake in Ken-
osha County, Wisconsin. Opposite: Chemical
treatment begins for the eutrophic waters of
Medical Lake near Spokane, Washington.
Although dredging can accomplish all these
things and may show rapid and dramatic
results, serious problems can arise and
results may not be entirely anticipated.
Studies from Japan show that when PCB-
contaminated lakes are dredged, the toxic
material, which adheres to the smallest
particles, may be resuspended either by
dredging itself or by disposal area return
flow. Other studies have found that if
proper techniques are not used, toxic sub-
stances such as pesticides, herbicides, and
industrial wastes bound up in the.sediments
of a lake also may be resuspended by
dredging, liberated in soluble form, and
reintroduced to the food chain.42
Several methods have been devised for
dredging a lake, and all are expensive Once
the cost has been justified, finding an
ecologically acceptable means of disposing
of dredged material may be the limiting
factor. Although dredge spoils used to be
routinely dumped on adjacent wetlands,
we now know that smothering useful wet-
lands with dredged material is damaging
to needed resources and is also illegal.43
Case Report:
Lilly Lake
In January 1976, Lilly Lake in Kenosha
County, Wisconsin, received a $273,000
EPA Clean Lakes grant primarily to combat
a buildup of organic detritus that had made
the lake unusable for recreation. The restor-
ation process involved removal by hydraulic
dredge of 650,000 cubic meters (780,000
cubic yards) of muck. The depth of the
88-acre lake, which had been reduced to an
average depth of a meter or less (2 to 3 feet),
was increased to a maximum depth of 7
meters (22 feet).
The lake is located in the southeast
corner of the State and once offered att-
ractive opportunities for boating, swimming,
fishing, water skiing, and ice skating. Silting
and decomposition of organic material
interfered with recreation and depleted the
dissolved oxygen, particularly in winter,
resulting in frequent fish kills Weeds inter-
fered with the appearance of the lake
and made swimming and boating imposs-
ible.
In the restoration of Lilly Lake, local
residents voted to tax themselves, State
aid became available, and Federal aid was
offered through a Clean Lakes grant. Em-
phasis was placed on using the dredged
materials in an environmentally satisfactory
way Some of the dredged material was
piped to high land where it was spread to
dry for use as a soil conditioner. Since
the lake was dredged, increased depth has
eliminated fish kills and the value of lake-
front property has increased. Recreational
use has been restored and wildlife values
have been enhanced since the gravel pits
to which most of the dredged materials
were piped have now become two arti-
ficial perched ponds attractive to water-
fowl.44
Nutrient Inactivation
Although the influx of nutrients from
point sources may be sharply reduced by
diversionary treatment and other measures,
lack of evidence of improved water quality
may indicate the need to control phos-
phorus release from the lake's sediments.
The materials used, which will bond with,
immobilize, or absorb nutrients and make
them inaccessible to plants, are salts of
iron, aluminum, and other metals commonly
employed to remove phosphorus in ad-
vanced waste treatment. As opposed to
dredging, nutrient inactivation presents no
disposal problem and does not disrupt
lake use. When it is successful, results
appear very quickly and if sources of nut-
rients have been stopped, the effects will
be long-lasting.
Aluminum sulfate, currently the chemica
of choice, has been found effective in
32
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binding phosphorus and in preventing
its recycling from lake sediments. Some
concern is felt, however, about the unknown
but possibly toxic effects of introducing
a metal used as a precipitant as well as
about the effect on organisms of altered
pH levels.
Case Report:
Medical Lake
Although the lake had been named for
the supposed therapeutic quality of its
waters, which are high in sodium bicarbon-
ate, by the 1970's only the most daunt-
less pleasure-seekers were bold enough to
swim in Medical Lake. Lying 14 miles from
Spokane, Wash., the lake had spas along
its shores in the early 20th century and later
became a popular recreational resource for
Spokane County, offering a public swim-
ming beach and boat launching facilities.
But for many years before its restoration
in 1977, spring brought unsightly masses
of algae to the lake's surface. When the
swimming season began the lake was covered
with decaying mats of green, which impeded
boating and swimming for most of the
summer. Fish killed by depletion of dis-
solved oxygen rose to the surface where
they putrified and attracted thick swarms
of insects. Noxious odors rose from the
unwholesome water and assaulted the
sensibilities of weekenders and the 2,600
inhabitants of the town, also named Medical
Lake.
The lake is deep, for its region, averaging
10 meters (33 feet), with some areas as
deep as 18 meters (60 feet). It is entirely
spring-fed, a closed lake with small littoral
area. No wastewater effluents enter the lake
and the only point source of nutrients,
a cooling water discharge pipe, was elim-
inated. The lake had been completely ringed
by interceptor sewers but, because of its
depth and lack of outlet and consequent
slow flushing rate it was decided that further
in-lake measures were needed to halt the
internal recycling of nutrients. During the
summer of 1977 in a plan funded through
EPA's Clean Lakes Program, liquid alumin-
um sulfate (alum) was released on the sur-
face and also injected directly into the
hypolimnion from a barge. Because of
the high alkalinity of the water, substan-
tial doses were needed for phosphorus
removal. During treatment, which lasted
41 days, over 900 metric tons of liquid
alum were used.45 The chemical combined
with phosphates to produce insoluble
compounds, forming a floe which then
settled to the bottom. Recycling of nutri-
ents was slowed and, with in-flow of further
33
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How Lakes Change
Drawdown was the technique used for the
restoration of Steinmetz Lake in New York.
Material was also dredged from the lake
bottom and replaced with sand.
nutrients cut off, results should be lasting.
The increased clarity of the water and
decreased algal concentrations were dra-
matic at Medical Lake. With autumnal
turnover the total concentration of phos-
phorus dropped over 80 percent, with
phytoplankton down 90 percent and blue-
green algae replaced by green and flagel-
lated species 46 Since completion of treat-
ment the lake has been stocked with
rainbow trout, which are notably thriving
and the beach is once again inviting.
Aeration
Three methods of introducing oxygen
into lakes have been devised. One involves
aeration of the hypolimnion without dis-
turbing the stratification of the lake. The
second technique artificially destratifies the
lake to circulate oxygen throughout the
water column. A third technique keeps
sections of the lake from freezing to allow
uptake of oxygen from the atmosphere
during winter.
Because silver salmon were dying in
Erdman Lake, Washington, aeration with
destratification was tried, and survival rates
increased 500 percent. At Lake Roberts in
New Mexico, however, aeration brought
oxygen concentrations to near zero through-
out the lake, killing all the fish.47 This
resulted from mixing the large volume of
deep water containing no oxygen with the
epilimnion.
The mechanisms designed to circulate
water in the hypolimnion without dis-
rupting natural stratification may help fish
in the bottom regions. In Michigan's Hem-
lock Lake, rainbow trout in summer were
confined to a small band of water in the
thermocline by too-warm waters above
and low-oxygen waters below. Aerating
only the hypolimnetic regions provided
adequate oxygen throughout the deep
water, enabling the fish to move into the
The water flea, which eats I
algae, has been introduced m
in lakes as a biological con-
trol.
lower areas of the lake.48
When water is required for domestic use
aeration is sometimes employed to reduce
the concentrations of substances that
cause offensive tastes and odors. Aeration
undertaken for these purposes may also
solve such problems as discolored water,
scaling and clogging of pipes, and high
concentrations of iron, manganese, hy-
drogen sulfide, and ammonia.
Drawdown
Manipulating water levels can control
the growth of rooted aquatic vegetation
and nutrient release from the sediments.
Drawdown may be used in combination
with some other in-lake method such as
sediment covering or harvesting. An early
use of drawdown techniques was to supprei
anopheline mosquito reproduction in Tenn
essee Valley Authority reservoirs.49
Observations of the biological changes
accompanying natural drops in lake levels
that caused sediments to dry or freeze
suggested this non-toxic, relatively inexpen
sive, and often valuable method Water is
pumped from the lake in either summer or
winter, and sediments and the seeds and
vegetative structures of plants are exposed
to drying or freezing conditions, generally
for a month or more. Drawdown may
interfere with recreational uses in summer
or be complicated by heavy snowfall or
rainfall in winter. If drawdown is scheduled
for summer, other lake work, such as im-
proving and rebuilding docks or deepening
swimming beaches or repairing shorelines,
may be undertaken at the same time.
Although in a few cases drying and
freezing processes have been found to
stimulate plant growth and other undesir-
able growth has proven resistant, good
results have been observed in Florida,
TVA lakes, and lakes in Louisiana and
Wisconsin in destroying the very trouble-
-------
some exotic weed, Eurasian water milfoil.50
Drawdown also deepens the lake by de-
watering and compaction and provides a
diffusional barrier against the passage of
nutrients to the water on reflooding.
Harvesting
When lakes are heavily infested with
nuisance weeds, harvesting with specialized
cutting machines may be advisable in con-
junction with control of point and nonpoint
source pollution and before other in-lake
methods, such as drawdown. Harvesting
equipment has been designed to deal with
floating surface plants such as water hya-
cinth, emergent plants that are rooted in
the bottom and pierce through the surface
of the lake such as rushes and weeds, and
submersed macrophytes. It has been used in
the Madison (Wisconsin) lakes where, early
in the 1960's, the Eurasian water milfoil
(Myriophyllum spicatum) grew so explos-
ively that it displaced native species.51
Harvesting may also reduce phosphorus
availability, although the degree to which
it does so is small and long-term results are
questionable. The process is expensive and
the collection and removal of debris a
problem. Research is underway to find
marketable use for harvested material as
animal feed or compost.
Chemical Controls
One means of destroying unsightly
growths of algae or rooted aquatic plants
in a lake that brings almost immediate
although temporary improvement is the use
of algicidal chemicals. As in all other in-
lake procedures, this last ditch method
is recommended only after nutrient input
has been tackled at the source. Although
many different compounds have been de-
veloped, most contain copper. Some, how-
The gentle manatee consumes
water hyacinth, an aquatic weed,
in Florida waterways.
ever, contain highly toxic organic com-
pounds effective on specific target organ-
isms. Currently over 12,000 tons of chem-
icals are used for this purpose annually;
their concentrations vary according to the
severity of the problem.52
The major objection to chemical controls
is that not enough is known at this time
about the long-term effects on aquatic
animals at various life stages. Breakdown
rates of these chemicals have not been
sufficiently investigated, and we do know
that crops may be damaged if irrigated
by water in which these chemicals have
been used.53
Uneasiness about chemical controls in gen-
eral is based on past experiences with insuf-
ficiently understood toxic pollutants, and
has led many to favor the more benign
mechanical methods
Biological Controls
A major side effect of using such broad
spectrum pesticides as DDT was that they
killed off both prey and predator. New
emphasis on integrated pest management
seeks to harness natural forces to combat
one problem pest by, among other methods,
introducing a predator, rather than by
spraying a poison.
In lake research an area of considerable
interest is the use of biological controls to
combat unwanted vegetation. Various mem-
bers of the animal kingdom have been
experimentally introduced into eutrophic
lakes where they are greeted by an alluring
array of edible vegetation. Water fleas have
been introduced to eat algae, a stem borer
has been brought in to feast on alligator
weed, and in canals in Florida the strange
aquatic mammal, the manatee or sea cow, has
been introduced to chew up the water hya-
cinths that clog waterways. Although the
manatee has proven to have a virtually
insatiable appetite for aquatic weeds, it is
unfortunately a rare animal, difficult to
catch and transport, and unwilling to
breed in captivity or in fresh water."
S4
Recent experiments have centered on the
white amur or grass carp, a native of Nor-
thern China. This fish will eat over 20 types
of aquatic weeds although it cannot eat
micro-algae. In China, where grass carp are
used to keep waterways free of weeds, some
fish have devoured so much vegetation that
they have grown to weigh as much as 180
kilograms (400 pounds).55 In 1963, over
100 lakes in Arkansas were stocked with
grass carp in a carefully monitored experi-
ment. Since other introduced species of
carp have proven to be pest animals, the
import of this fish was originally restricted
to the State of Arkansas. So far no apparent
harm has come to native fish from its pres-
ence since the fish is truly herbivorous, but
the possible environmental impact is not
fully understood and many professionals in
the field fear that undesirable effects on the
ecosystem may emerge. Some concern is
felt that duck habitats could be damaged if
plant-eating fish are permitted to denude
them of vegetation.56 It had been thought
that, because of their fastidious spawning
needs, which require particular river con-
ditions, the grass carp would not reproduce
in this country. But since they have now
escaped from Arkansas lakes into the Ohio
and Missouri Rivers, rivers in Florida and
Georgia, and several in the Mississippi basin,
there is a possibility that they are repro-
ducing and careful ecological watch is in
effect. Authorities believe, however, that
any spawning which occurs will result in
small populations with little impact, and
that the fish has further potential as a food.
Other experiments in biological controls
include sterilizing fish, subjecting the
greenery to fatal plant diseases, and intro-
ducing new plants that compete for light
and nutrients and crowd out others that
are less desirable. In one California project
a slender spike rush was introduced to a
lake and has covered the bottom in sodlike
fashion, preventing nuisance weed growth.57
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i '
i, ' 1 :
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Chapter 6
Yesterday, Today, and
Tomorrow
Paleolimnology
Sunrise at Wilson Pond, Maine
A lake has a past, a present, and a future.
The specialized academic field of paleolim-
nology concerns itself with uncovering the
mysteries of a lake's distant past. Studying
the lake basin, its water, and its sediments,
paleolimnologists also concern themselves
with the past history of the entire drainage
area. Here, as in other limnological studies,
the basic unit is the lake watershed.
The major objective of research in paleo-
limnology is to disclose the evolutionary
sequences through which a lake has passed
on evidence revealed by the lake's sediments.
The accumulated sediments in lake basins
result both from the geomorphology of the
lake and materials brought into the lake
through the ages from the watershed.
Although paleolimnology is considered
a relatively new research field which requires
sophisticated methods of analyzing sedi-
ments and measuring other indications of
productivity in the remote past, it is of
interest that the first major and often cited
investigation was geologist G.K. Gilbert's
study in 1891 of the freshwater ancestor of
the Great Salt Lake of Utah.58
The paleolimnologist, whose evidence
comes from studying the mineralogy and
organic and inorganic chemistry of the
sediments as well as the fossil remains of
organisms, interprets his or her necessarily
fragmented findings by inferring that fossil
organisms required environments similar to
those needed by their descendants today.
Incredibly, many aquatic plants and nearly
all aquatic animals leave some type of identi-
fiable remains in sediments as do terrestrial
organisms, such as the pollen and spores of
plants that grew in the watershed. Some
remains can be identified by species, some
only by genus or family, particularly when
the material preserved represents one stage
of the life cycle—a cocoon, larva, egg, or
cyst. The various species of profundal
midges, which are associated with particular
levels of dissolved oxygen in the hypolim-
nion, are interpreted as indicating similar
conditions in previous eras when found in
a lake core.
Studies in paleolimnology have demon-
strated beyond question that what is gener-
ally assumed to be a one-way route from
oligotrophy to eutrophy can turn in the
other direction as well. Because of changes
in nutrient level lakes can become less, as well
as more productive over time. In the 20th
century, the common route towards
eutrophy is associated with man's activities.
In less populous and urbanized periods of
history production often declined due to
changing land use practices and gradual loss
of nutrients in a watershed through leaching.
Paying the Price
Most successful lake restoration projects
are easily appreciated by people familiar
with the "before." Although the average
lake user may be unaware of phosphorus
loadings and erosion problems and extreme-
ly reluctant even to consider the significance
of fecal coliform counts, lake users know
what they like. What they don't like is a
lake choked with weeds and covered with
green scum, a lake that is difficult to boat
around, uninviting to swim in, and smells
bad to boot. Whether they are anglers, ani-
mal lovers, or just plain squeamish they
definitely find the floating corpses of dead
fish distasteful. A lake restored to health
and beauty is an irresistably exhilarating
sight.
One attempt to more objectively evalu-
ate the results of lake projects is to compare
cost and benefits, to set up a method of
placing dollar and cents values on lake im-
provements and relate these totals to the
amount of money spent. This is an appealing
approach in a society in which government
expenditures are constantly under scrutiny
by a public aware that action means tax
money.
The Environmental Protection Agency's
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Yesterday, Today and Tomorrow
Paleolimnology involves scientific detective
work to trace the history of lakes and their
watersheds. Use of such clues in lake sedi-
ments as fossil pollen grains and plant and
animal remains enable paleolimnologists
to reconstruct climatic and biological
changes in the lake's past.
Clean Lakes Program, which awarded its first
grant on January 6, 1976, had approved 105
grants totaling $40,097,110 by the end of
the fiscal year 1979. A study was under-
taken in an attempt to discover whether
we—the taxpaying, lake-using public-
are getting our money's worth.
The investigation examined 28 of these
projects, costing $15,349,053 in Federal
funding matched by equal sums from State
and local governmental agencies. In sum-
mary, their answer was a resounding "yes."
Although it may shiver the sensitive aesthe-
tic timbers of nature lovers even to consider
such numerical evidence—and stir skepticism
in others who find calculating the joy of
watching the sun set over a translucent lake
arbitrary at best-the study concluded that
the 10-year present value of benefits measur-
able in monetary terms is $127,488,500, or
a return of $8.30 per EPA dollar expended
and half that sum per total dollar of expen-
diture.59 The project investigators also
found that virtually everyone involved in tl
restorations felt that the value received in
terms of public benefits was indisputable. I
some communities lake restoration project
facilitated obtaining other grants for park
improvement and similar undertakings.
Benefits measured fell into 12 categorie:
recreation, aesthetics, flood control, econ-
omic development, fish and wildlife,
agriculture, property value, public health,
multiple use (commercial fishing and pubh
water supply), education and research
development, pollutant reduction, and
associated items such as resource recovery
and reduced management cost.
Obviously, some of these categories are
more easily quantified than others. Measur-
ing the number of people who are likely to
benefit from the recreational facilities of
clean lakes revealed that an astonishing 99.
percent of us live within an hour's drive of
publicly-owned lake, with one-third of our
population living 5 miles or less from such
lake. Restoration projects promote increase
use of lakes and also may open up uses lost
through long periods of degradation. A poi
scale was set up to assign a dollar value to
a day of recreation at a lake. Since most lat
restoration projects are undertaken to
develop recreational and aesthetic enjoy-
ment, these categories accounted for the
highest share of total discounted benefits.
Public health benefits were primarily reduc
tion in fecal coliform counts and in tur-
bidity, which can endanger swimmers. An
example of an educational benefit was
heightened awareness of and interest in
environmental protection.
The restoration of Medical Lake, des-
cribed earlier in this book, is one of the less
complex examples. The Clean Lakes Pro-
gram grant amount, awarded in December
1976, was $128,217. Total discounted
benefits from the project are estimated at
$931,750 over a 10-year period of time. In
addition to restoring the lake to its former
uses, a new benefit—trout fishing—resulted.
Success of the alum treatment was un-
•3Q
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equivocable, with virtually immediate
recreational, aesthetic, and fish and wildlife
benefits Property values have risen, as the
lake's attractiveness returned. Whereas prior
to restoration, at most 100 people visited
the lake for any purpose during a weekend,
weekend usage now is between 750 and
1,000, even though trout fishing is not yet
permitted. The summary of benefits shows
$89,400 for recreation including wildlife
improvement and $225,000 in terms of
property values. The total is $314,400
the first year and the net value for 10 years,
including $17,100 in annual fishing benefits
which will begin to accrue in the third year,
is $931,750 60
The project does not reveal what view the
mayor of the town of Medical Lake might
have on assigning dollar values to free swim-
ming at the town beach, but it does quote
him as enthusiastically insisting that the
town's share of the project was "the best
money we've ever spent."
Recreation
The relationship between clean water as
an environmental goal and clean water as a
resource people can use and enjoy may seem
too obvious for comment. National goals as
stated in the Federal Water Pollution Con-
trol Act Amendments of 1972 set forth
1983 as the year in which all waters in the
United States are to be swimmable and
fishable and 1985 as the year when dis-
charge of all water pollutants will be halted.
As citizens we have committed ourselves
to these aims through the votes of our
representatives and senators and in our
support of State and local policies as well.
One of the provisions of the Clean Water
Act of 1977 is that from that year on no
town or county can be granted Federal
funds for wastewater treatment facilities
unless it also has "analyzed the potential
recreation and open space opportunities
in the planning of the proposed treatment
works".61 Wastewater treatment facilities
are normally sited near a body of water and
often can be integrated with such multiple
uses as hiking trails, bike paths, fishing piers
and boat launching areas, skating rinks,
swimming areas, and greenways— corridors of
open space and recreational land running
along waterfronts— while still filling com-
munity sanitation needs.
Although water pollution problems and
recreational opportunities have traditionally
been handled by totally different Govern-
ment agencies, today cooperation is the key
word An enthusiastically supported urban
project co-sponsored by EPA and the Heri-
tage Conservation and Recreation Service of
the Department of Interior for the restora-
tion of the 59th Street Pond in Central Park,
New York City, is currently nearing com-
pletion (see page43).ln a rural watershed in
Maine, EPA and the U.S. Department of
Agriculture are jointly sponsoring lake
cleanup by revising agricultural methods
(see page 42).
Multiple-use is far from a new idea at
reservoirs. Approximately 150 hydroelectric
projects now have recreational facilities or
plans to create them through the coopera-
tive efforts of Federal agencies, private
electric utilities, and State or local govern-
ments. These include swimming, boat
docking facilities, nature study trails, and
hiking paths.62 TVA lakes in the seven
Tennessee Valley States offer recreational
opportunities for millions of visitors. At
Lake Mead in Nevada, considerable attentioi
has been given to maintaining sport fisheries
at the highest possible level New guidelines
for combining efficient use of the dam with
superior fishing opportunities involve
timing drawdown to avoid spring spawning
period, and providing rising levels in summei
to give better living space and escape cover
for the young fish63
Whether recreation takes place on reser-
Water skiing in southern Washington. This
scene has changed dramatically since Mount
St. Helens, in background, erupted in 1980.
t « >, S> * *
3<
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Yesterday, Today and Tomorrow
voirs or in natural lakes, a current major
problem is overuse. Excessive activity at a
lake may lead to destruction of banks and
increased turbidity, to excessive noise from
motor boats or simple overcrowding, to the
lack of peace and safety that arises from
conflicting uses Everyone who has ever
vacationed at a lake knows some horror
story of an accident—to a swimmer, a
boater, a water-skier, a snorkler—that
might have been avoided
Toilets of sailboats and motor boats that
empty directly into the water can bring
pathogens into the lake. EPA regulations
now prohibit overboard discharge of raw
sewage into navigable waters of the United
States. New marine sanitation devices are of
two basic types those that break down and
treat toilet wastes, resulting in effluent with
a vastly reduced fecal coliform count, and
"no-discharge" systems with holding tanks.
The latter type is now required in lakes
where entrance and exit by boat is not
possible
At many lakes the great charm of the area
and the resultant massive increase in devel-
opment of the shoreline pose an ominous
threat to the spectacular beauty that first
attracted visitors to the scene.
Lake Tahoe, the country's second deepest
lake, is invariably described as "unique"
because of its extraordinary clarity, deep
blue color, and exquisite mountain setting.
In the past two decades development, which
has raised the permanent population of the
lake from 3,000 to 75,000 and the number
of visitors from a few thousand per year to
as many as 250,000 on a peak summer
day,64 has fostered rapidly increased pro-
ductivity in the lake as the result of nutri-
ents carried in eroded soil. Recreational
facilities now include campgrounds, State
Lakes such as Walden Pond in Massachu-
setts provide opportunities for recreation
and contemplation for people of all ages.
-------
Lake Tahoe, straddling the California-
Nevada border, is, despite its pristine
appearance, beset by problems associ-
ated with development of its shoreline.
parks, boat ramps, ski areas, and such non-
lake related entertainment as gambling
casinos and nightclubs featuring big name
entertainers. The peerless beauty of the lake,
which attracted all these residents and
visitors, is now threatened by soil erosion,
loss of wildlife and natural vegetation,
air pollution, and the aesthetic desecration
of tasteless construction.
Can Lake Tahoe be saved from the grow-
ing number of people who come to enjoy its
charms and from local governments and pri-
vate entrepreneurs on both the California
and Nevada sides of the lake who profit
from these hoards of visitors? The struggle
to save Tahoe, which has engaged the
passionate attention and often conflicting
interests of environmentalists, land use
planners, and local, State, and Federal
policymakers, is an example of what the
Council on Environmental Quality calls
"The Quiet Revolution in Land Use"65
—the movement away from the idea that the
owner is entitled to make as much money
as he can from the use of his land, the
attempt to find a policy that reconciles
the conservationist's view of land as a
resource rather than a commodity and
Constitutional guarantees of the right
to buy, own, and sell property. This
struggle will not only have to be faced at
Lake Tahoe but at smaller recreational
lakes all across the country.
What You Can Do
Although the field of lake management is
reaching new levels of expertise each year,
the best approach to lake problems is to be
aware of how to prevent them. Owners of
waterfront homes interested in maintaining
a healthy aquatic balance in their lake can
help avoid costly restoration projects by
voluntarily reducing use of fertilizers and
phosphate detergents, by good landscaping
practices and maintenance of septic systems,
and by other conservation techniques.
Experiences with severe pollution problems
at the Love Canal in New York and the
LiPari Landfill in New Jersey dramatically
demonstrate how low the cost of prevention
would have been compared with restoration
expenses If lake restoration is needed, it is
the local landowners and the local officials
who can bring it about. Over the past two
decades considerable incentive and support
for lake cleanup programs have come from
a long list of citizens' groups, conservation
groups, sportsmen's associations, and labor
unions.
At new lake-oriented land developments,
plans designed to protect the lake specify
shoreline buffer zones. Lake protection is
also the focus of building and health depart-
ment regulations covering construction and
siting of homes and septic systems. Property
owners' associations establish regulations for
maintenance of the shoreline and shared
open space. Such associations, which are
often set up as non-profit corporations with
year-round and seasonal residents pooling
time, energy, and funds, may enjoy tax
advantages while protecting the environment
—and owners' investments. Membership may
be mandatory as part of the deed of coven-
ant of the lot.
Such associations should be concerned
with controlling construction activity and
commercial development, controlling
aquatic vegetation, and providing lifeguard
services. Members should maintain com-
munity septic tanks They may also recog-
nize the ecologically destructive, peace-
destroying, and physically dangerous results
of conflicting lake uses and restrict motor
boating, trail-biking along the shore, or
other activities.
If the lake offers public access, the devel-
opment may be eligible for State or Federal
financial or technical assistance. The State
may, for instance, stock the lake if public
fishing is allowed, or provide safety equip-
ment and post public areas with regulations
set up by its game, fish, and parks depart-
ments.
Besides joining associations, lake area
owners may also, in some States, form a
sanitary district or a lake management dis-
trict, special units of government with
authority to take on certain responsibilities
for lake protection. States vary considerably
in the encouragement and funding they offer
for lake protection and rehabilitation, but
-------
Yesterday, Today and Tomorrow
many have special grant programs. State
agencies may assist with shoreline protection
projects, such as the establishment of lateral
parks or greenways along lakes and rivers
State agencies may also offer funds for
recreational land acquisition, assist construc-
tion of wastewater facilities, and work
cooperatively with Federal programs, such as
EPA's Clean Lakes Program.
On the local level, functions relating to
lake conservation may be dealt with by
planning and zoning boards, conservation
commissions, and public works departments
Communities interested in initiating lake
cleanup projects should also be aware that
many corporations, philanthropic organi-
zations, and public interest groups may be
successfully approached for funding or
technical or planning advice.
On the Federal level, programs relating
to lakes are funded by the Department of
the Interior, the Department of Housing
and Urban Development, the Department of
Agriculture, and the Army Corps of
Engineers (see Appendix), as well as by the
Environmental Protection Agency. Usually
these programs involve cooperation of State
and local agencies, and large community
investments may be required to match
Federal and State funds In 1974, members
of the Penn Lake Homeowners Association
petitioned the Bloomington (Minnesota)
City Council for help when they noticed
that ducks were dying and that the lake was
in trouble because of low water levels. With
State, local, and EPA funding, a well was
dug to provide supplemental water in arid
periods, sediment-catching basins were con-
structed, and aeration was instituted to
maintain dissolved oxygen levels.
Under its Clean Lakes Program, EPA
offers cooperative agreements for restoring
publicly-owned freshwater lakes. In evalu-
ating grant proposals, EPA is particularly
interested in controlling nonpoint sources
(municipal point source control is offered
under section 201 of the same law, which
relates to wastewater treatment facilities
including stormwater management).
Section 402 relates to the control of indus-
trial point sources through issuing permits
on industrial discharges. In weighing cost-
effective solutions to significant clean lake
problems the concern is with long-term
public benefits through such pollution con-
trols as construction of sediment basins and
nutrient traps, leasing or purchasing buffer
lands, diverting nutrients, improving agri-
cultural practices, and instituting sound lane
management practices. In-lake methods sue!
as chemical precipitation, dredging, aeratior
and drawdown will be considered only as
part of more permanent restoration plans.
Increasingly, Government agencies co-
operate in both urban and rural lake restora
tion projects through cost-sharing and
technical assistance in related water quality
problems.
Case Report:
Cobbossee Watershed
District
In a rural county in Maine, three eutro-
phic lakes, Annabessacook Lake, Cobbossee
Lake, and Pleasant Pond, are currently bem<
restored. Current emphasis is on control of
pollution from agricultural runoff. Starting
in 1943, lake property owners had com-
plained of nuisance algae, and studies
revealed severe oxygen depletion in the
hypolimnion. For years, untreated sewage
flowed directly into the lakes from munici-
pal and industrial sources. Primary treatmen
was instituted but this effluent continued tc
be discharged into the lake. In 1972 inter-
ceptor sewers were installed, reducing
nutrient loading by 90 percent, and nutriem
inactivation was accomplished with alumi-
num sulfate. Continued nutrient enrichmem
is from runoff carrying pollutants from barr
yards and fields of 38 nearby poultry and
dairy farms. Because of poor manure storage
facilities, farmers were spreading wastes on
42
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Central Park's 59th Street Pond undergoes
a much-needed restoration.
frozen ground in the winter, increasing
the likelihood of runoff from fields.
Now State and local agencies, the U.S.
Environmental Protection Agency, and two
divisions of the U.S Department of
Agriculture—the Soil Conservation Service
and the Agricultural Stabilization and
Conservation Service—are offering financial
and technical assistance to correct the prob-
lem by entering into cooperative agreements
with landowners. Construction of concrete
floored manure storage facilities is in
progress and other control measures are
being instituted. Farmers are asked to contri-
bute 20 to 50 percent of the cost of these
improvements and an intensive educational
program is demonstrating how investment in
manure management systems will improve
both lake water quality and farm efficiency.
Through private and group discussions, a
newsletter, and slide presentations by local
soil and water conservation officials, pollu-
tion from farm lands is being stopped and
farmers are able to store manure over the
winter and plow it into the ground in the
spring to effectively enrich soil.66
Case Report: 59th Street Pond
A charming 4-acre artificial pond
located at the southeast corner of Central
Park in New York City near the inter-
section of 59th Street and 5th Avenue is
currently in the final stages of restoration.
To call the pond "charming" involves a
forward look toward its reopening and a
backward glance to earlier decades. During
recent years the pond has been about as
lacking in charm as a handsomely sited
well-designed urban lake could possibly
be.
The pond adjoins the popular Wollman
Skating Rink and was included in the
original plan for the park by its designer
Frederick Law Olmsted. This masterpiece
of urban planning—a vast park in the
center of one of the world's biggest cities-
is now designated both as a National Land-
mark and as a New York City Scenic
Landmark
A favorite place for strollers and pic-
nickers, for New York City residents and for
visitors, the 59th Street Pond has been
gathering silt rapidly since 1950, when it was
last dredged. Although the lake was
originally 1.5 meters (5 feet) deep, at the
time restoration began depth ranged from
1 meter (3 feet) to 0.15 meters (6 inches).
Even the most optimistic urban nature lover
could not describe the waters as refreshing
Turbidity and discoloration resulted from
high bacterial levels and quantities of organic
material. Algal growth made the pond
scummy and murky. Coliform counts were
off the top of the scale. Although the pond
once had fish and ducks as well as other
aquatic life, the stagnant conditions led to
abandonment for more inviting waters.
The restoration, which involves draining,
dredging, and making the bottom impene-
trable to avoid future problems, bank
repairs, and repair of clogged drainage pipes,
is being jointly funded on the Federal level
by the Environmental Protection Agency
and the Heritage Conservation and Recrea-
tion Service (Department of Interior). The
responsibility of the latter is a major land-
scaping project that will anesthetically
enhance the surroundings and correct pre-
sent erosion problems. It will include
regrading, and also improving walkways. The
project is being managed by the New York
City Department of Parks and involves
State, regional, and local agencies as well
as devoted members of volunteer and
community groups—which first agitated
for restoration of their historic and valuable
59th Street Pond 6 7
Clean Lakes
In Congressional testimony on funding
for the Clean Lakes Program, then Senator
Walter F. Mondale said,
I am always amazed, as I go around my
State, by the number of people that come
up to me to talk about problems with
their community lake. This is a prize
jewel in the community. This is where
43
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Yesterday, Today and
Tomorrow
An increasingly strong ethic of conservation
has created a mandate against abuse of our
nation's lakes, such as the pollution of
Alcyon Lake, New Jersey (above, right),
and a demand for protection of lakes such
as this pond (right) in Chippewa National
Forest, Minnesota.
the kids swim, this is where they fish,
this is where they go boating, waterskiing,
this is where they get a little breath of
fresh air. And most of our communities
—many of them—are built around the
lake. It is the most prized recreational
asset that they have. But those lakes are
putrifying, they are suffering from accel-
erated aging, and unlike rivers and so on
that can scour and cleanse themselves,
these lakes die, and they die at an accel-
erated rate unless tactics are used to
protect them against that process by
cleaning them up and preventing their
further pollution.
We do not know how many communities
are losing their "prize jewel"—how many
lakes nationwide are irretrievably lost
because they are now too degraded for
restoration measures to be effective. What
we do know is that lake protection must
become a priority and that abuse of our lake
resources must cease. After centuries of
indifference and misguided actions, Federal,
State, and local governments are now ready
to assist in the campaign to clean up our
natural environment. Their mandate comes
from a populace that, with ever-increasing
sensitivity and enthusiasm, has become con-
verted to an ethic of conservation rather
than of waste.
We who walk the earth today have
viewed, through the eye of the camera
mounted on the spacecraft, the fragile planet
on which we live. Lake guardianship is only
a part, but an essential part, of the effort
to save the earth—for ourselves, our children,
and distant generations.
It is consonant with the viewpoint pre-
sented in this book to adorn both the
early and the final sections with quotations
from Walden. Although Thoreau had never
heard of an ecologist or a photograph from
outer space, he took the measure of his own
soul on the shores of Walden Pond. The
question he asked, well over a century ago,
was: "What is the use of a house if you
haven't got a tolerable planet to put it
on?"
44
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Jl
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References
Left: Pickerel frog meets a dragonfly at a
pond's edge. Right: a trout egg and trout
fry.
1 Thoreau, Henry David. 1971. Walden. Jay
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2 Council on Environmental Quality. 1979.
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4 Briggs, Peter. 1967. Water, the Vital Essence.
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6 Counc. Environ. Quality. 1979.
7 Wetzel, Robert G. 1975. Limnology.
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1 Coker, Robert E. 1954. Streams, Lakes and
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Quality.
20 Counc. Environ. Qual. 1979.
21 Clean Lakes and Us. 1979. Prepared for the
U.S. Environ. Prot. Agency by the University
of Wisconsin-Extension, Madison.
22 Fisheries and Wildlife Research. 1979. Activi-
ties in the Divisions of Research for the Fiscal
Year 1978. U.S. Fish Wildl. Serv.
23 National Water Quality Inventory. 1975. Re-
port to the Congressional Office of Water
Planning and Standards. Washington, D.C.
24 Code of Federal Regulations. 1978.21:109.30.
25 Natl. Water Qual. Inventory.
26 Federal Register. 1980.45:33063-33285.
May 19.
27 Acid Rain. 1979. Research Summary. Off.
Res. Dev. U.S. Environ. Prot. Agency.
28 Peterson, Spencer A. 1979. Dredging and
lake restoration. Lake Restoration: Proc.
Natl. Conf. U.S. Environ. Prot. Agency. U.S.
Government Printing Office, Washington,
D.C.
29 Austin, Phyllis. 1979. Acid rain is 'catastrophe
of a leisurely kind.' Maine Times. Nov. 23.
30 West, Susan. Acid from heaven. Sci. News
117:76.
31 Cronan, C.S. and C.L. Schofield. 1979. Alum-
inum leaching response to acid precipitation:
Effects on high elevation watersheds in the
Northeast. Science 204:304.
32 West.
33 West, Susan, Acid solutions. Sci. News
117:106
34 Acid precipitation in the United States. His-
tory, extent, sources, prognoses. Interim Re-
port. Environ. Res. Lab., U.S. Environ. Prot.
Agency. Corvallis, Ore.
35 Council on Environmental Quality. 1978. En-
vironmental quality: the 9th annual report.
36 Counc. Environ. Qual. 1978.
37 Peters, Gerald O. and Alfred E. Krause. 1979.
Decentralized approaches to rural lake waste-
water planning: seven case studies. Presented
at Natl. Sanit. Found. EPA's Sixth Natl. Conf.
Individual Onsite Wastewater Systems. Ann
Arbor, Mich.
38 Maugh, Thomas H., II. 1979. Restoring da-
maged lakes. Science 203: 425.
39 Measurements for the restoration and en-
hancement of quality of freshwater lakes. Off.
Air Water Progr. Div. Water Qual. Nonpoint
Source Control and Off. Res. Dev. Natl.
Eutrophication Res. Prog. U.S. Environ. Prot.
Agency.
40 Measurements for restoration.
41 Clean water models. An SCS environmental
quality aid. Soil Conserv. Mag. U.S. Dep.
Agric.
42 Peterson.
43 Horwitz.
44 Lilly Lake Records. U.S. Environ. Prot. Agen-
cy.
45 Maugh.
46 Maugh.
47 Lorenzen, Marc, and Arlo Fast. 1977. A guide
to aeration/circulation techniques for lake
management. Environ. Res. Lab. U.S. Envir-
on. Prot. Agency, Corvallis, Ore.
48 Lorenzen.
49 Cooke, G. Dennis. 1980. Lake level draw-
down as a macrophyte control technique.
Water Res. Bull. 16:317.
50 Cooke.
51 Carpenter, Stephen R. 1979. The invasion and
decline of Myriophyllum spicatum in a eutro-
phic Wisconsin lake. Aquatic plants, lake
management, and ecosystem consequences of
lake harvesting. Proc. Conf. Madison, Wis.,
Feb. 14-16.
52 Measurements for restoration.
53 Measurements for restoration.
54 Measurements for restoration.
55 Lembi, C.A. 1975. Chemical and biological
weed control methods. Lake Manage. Conf.
May 12-14. Angola, Ind.
56 Lewis, W.M., et al. 1978. Am. Fish. Soc.
107:223.
57 Survey of lake rehabilitation techniques and
experiences. 1974. Tech. Bull. No. 75. Dep.
Nat. Resour. Madison, Wis. Sponsored by
Upper Great Lakes Regional Comm.
58 Frey, David G. 1963. Limnology in North
America. University of Wisconsin Press, Madi-
son.
59 Economic benefits assessment of the Section
314 Clean Lakes Program. 1980. JACA Corp.
Feb. 4.
60 Economic benefits.
61 Clean Water Act of 1977. Sect. 201 (g6).
62 A recreation success through Federal/private
cooperation. A look at the HCRS role in the
licensing of hydroelectric power projects.
Water Resour. Section, Heritage Conserv.
Recreation Serv. U.S. Dep. Inter.
63 Hoffman, Dale A. and Al R. Jonez. 1973.
Man-made lakes: their problems and environ-
mental effects. Geophysical Monogr. Serv.
64 Lake Tahoe environmental assessment. 1979.
Western Fed. Regional Counc. Interagency
Task Force.
65 Bosselman, Fred, and David Callie. The quiet
revolution in land use control. Counc. En-
viron. Qual.
66 Cobbossee Watershed Records. U.S. Environ.
Prot. Agency.
67 Proposal for renovation of the 59th Street
pond, Central Park, New York City. 1976.
New York City Dep. Parks Recreation.
68 Subcommittee Hearing for HUD and Indepen-
dent Agencies. Senate Appropriations Comm.
March.
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Appendix A Glossary
ADVANCED WASTE TREATMENT. Often
abbreviated AWT and also referred to as
tertiary treatment. Wastewater treatment
usually directed at major plant nutrients:
results in a high quality effluent.
AEROBIC. Environment in which oxygen
is present. Also refers to processes occur-
ring in presence of oxygen.
ALGAE. Simplest green plants having
neither roots, stems, nor leaves; those
in fresh water are usually microscopic
in size.
ALGAE BLOOM OR ALGAL BLOOM.
Very rapid growth of algae with forma-
tion of large concentrations which
sometimes form floating mats or dis-
tinct coloration of the water.
ALGICIDES. Chemical substances that
are toxic to algae.
ANAEROBIC. Environment in which
oxygen is absent. Also refers to pro-
cesses occurring in absence of oxygen.
AQUATIC PLANTS. Plants that grow in
water. Some aquatic plants are rooted,
some are free floating.
BIOTA. The plants and animals of an
area.
CHLORINATION. Application of the
chemical chlorine to water to serve as
a disinfectant.
CULTURAL EUTROPHICATION. The
acceleration by human activities of the
natural aging processes in a lake.
Satellite view of the Salton Sea, a saline
ake in south-central California. South of
he lake, irrigated land appears as a bright
latchwork. A horizontal line bordering
:he brightest area of farm-land marks the
i/lexican border. Above, right: diving beetle,
a voracious lake predator. At right: a water
lyacinth, an aquatic plant that chokes
many southern waterways.
BACTERIA. Microscopic single cell organ-
isms that are similar to plants but lacking
in chlorophyll
BIOMASS. Total quantity of plants and
animals in a specified area.
D.O. Dissolved oxygen required for the
maintenance of aerobic aquatic organ-
isms. Low D.O. levels approach anaer-
obic conditions.
ECOLOGY. A branch of science concerned
with the interrelationship of organisms
to one another and to their environment.
EFFLUENT. Treated or untreated waste-
water that flows from sewers, treatment
plants, or industrial plants.
ENVIRONMENT. All the external condi-
tions that surround living things, such as
soil, water, and air.
EPILIMNION. Upper warm circulating
layer in a stratified lake.
DECOMPOSITION. Breakdown of mater-
ials into simpler forms by action of
aerobic or anaerobic microorganisms.
DETRITUS. Minute particles of the
decaying remains of dead plants and
animals.
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From near to far right: a common loon,
perched at the top of the food web of
northern lakes; macrophytes at the edge
of a Connecticut pond; sediment exposed
to the sun in a western lake-bed; foliage
frames a New England pond.
EROSION. Process by which soils are
loosened and moved from one place
to another.
EUTROPHIC. Waters with high rate of
nutrient supply and resulting high
levels of organic production.
EUTROPHICATION. The addition of
sediments and plant nutrients to a lake,
leading to decreased volume and in-
creased biological material. This can
occur either as a natural stage in lake
maturation or in an accelerated fashion
due to human activities. (Cultural eutro-
phication).
FECAL COLIFORM BACTERIA. Bacteria
found in feces of warm-blooded animals.
FLUSHING RATE. Time it takes for the
total volume of a lake to be replaced.
Also known as retention time.
FOOD WEB. A system of interlocking
food chains in which energy and mater-
ials are first converted to organic matter
through photosynthesis and then passed
through a series of plant-eating and
meat-eating consumers.
GROUNDWATER. Water found below the
surface of the soil in the zone of satura-
tion where it fills spaces in soil and
rocks. The top level of the groundwater
is the water table.
HABITAT. Area which provides the require-
ments for, and therefore the home for,
specific plants or animals.
HYPOLIMNION. The deep, cold, lower
level of a stratified lake.
LITTORAL ZONE. Shallow water interfac
area between the land of the drainage
basin and the open waters of the lake.
LIMNOLOGY. The study of freshwater
systems.
MACROPHYTE. Large, rooted aquatic
plant.
MESOTROPHIC. Waters with a moderate
supply of nutrients and moderate level
of organic production.
NUTRIENT. A chemical element or com-
pound which promotes the growth
and development of organisms.
PERCOLATION. Downward movement o1
water through spaces in soil and rocks.
PALEOLIMNOLOGY. Study of the histor
of freshwater lakes.
PELAGIC ZONE. Free open water area
of the lake.
PHOTOSYNTHESIS. Synthesis of organic
compounds with the aid of light by
chlorophyll-containing cells.
PLANKTON. Microscopic free floating
plants and animals.
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'OLLUTANT. A substance, medium, or
agent that causes physical impurity.
Official EPA definition in PL 95.217
Sect. 502(6) is: dredged spoil, solid
waste, incinerator residue, sewage, gar-
bage, sewage sludge, munitions, chemical
wastes, biological materials, radioactive
materials, heat, wrecked or discarded
equipment, rock, sand, cellar dirt, and
industrial, municipal, and agricultural
waste discharged into water.
•ROFUNDAL ZONE Deep central area
of a lake.
RESIDENCE TIME. Amount of time a
substance will remain in a lake before
being flushed or settled out.
3ECCHIDISK. A white disk 20 centi-
meters (8 inches) in diameter used to
measure transparency of water.
SEDIMENT. Particles of material trans-
ported to a lake or suspended in its
water. Also refers to bottom material
in lakes that result from its formation,
the remains of organisms, erosion from
land.
STRATIFICATION. Thermal layering of a
lake in which the water column is divided
by density into a cold lower region and
a warm upper region with a relatively
thin boundary area between.
THERMOCLINE. Region of rapid temper-
ature transition in a stratified lake that
separates the epilimnion.
TRIBUTARY. Stream or river that flows
into a lake.
TURBIDITY. Condition of opacity or
muddmess m water resulting from par-
ticles in suspension
WATERSHED. Land area that is drained by
a stream or river system.
51
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Appendix B
Federal Agency Functions
Relating to Lakes
Large enough to look and act like an ocean.
Lake Superior assaults shoreline at Eagle
Harbor on Michigan's Keewenaw
Peninsula.
Included are directly related financial and
technical assistance programs that can be
used to match Clean Lakes Program funds
(Clean Water Act, section 314) and also
indirectly related opportunities for funding
and advice that can be coordinated with a
Clean Lakes project.
Department of
Agriculture
Agricultural Stabilization and Conser-
vation Service. Project grants and advis-
ory services are offered under 10-year
agreements to owners of wetland areas
who agree not to destroy these areas
or use them for agriculture. Other pro-
grams offer individuals and groups
cost-share grants for testing admin-
istrative, engineering, and management
systems designed to improve water
quality in rural areas and for estab-
lishing approved conservation practices
on agricultural land. Aims are to help
solve water, woodland, and pollution
abatement problems on farms and
ranches.
Farmers Home Administration. Guaran-
teed/insured loans are available through
this branch of the USDA through a
variety of programs designed to improve
the economic and environmental aspects
of farm and rural community life. Funds
are available for such projects as land
conservation measures, pollution abate-
ment measures, irrigation, drainage, treat-
ment of sanitary, storm, and solid wastes,
improvement of sedimentation control,
fish and wildlife development, and public
water-based recreation.
Forest Service. Grants for research and
financial assistance are offered in the
fields of watershed management, wild-
life habitat management, reforestation,
and other forest-related areas.
Science and Education Administration.
This branch of USDA disseminates tech-
nical information and makes funds
available in agricultural research. Many
previous research projects have been
directly related to lake protection.
Soil Conservation Service. Cost-share
grants are available for soil and water
conservation measures designed to
prevent erosion in the Great Plaines
area. Other programs offer similar
assistance in resource conservation
in other parts of the country. Grants,
advisory services, and counseling are
offered in projects involving flood pre-
vention, irrigation, and water-based
fish and wildlife recreation programs.
Over 140 varieties of grasses, legumes,
and shrubs are available for conserva-
tion purposes such as erosion control,
streambank protection, wildlife food
and cover, and beautification. Direct
payments and advisory services are
offered for reclamation of land and
water areas affected by coal mining
activities.
Department of Commerce
Economic Development Administration.
Project grants and direct loans are avail-
able to encourage long-term economic
growth in areas lagging behind the rest
of the Nation. Included as qualified pub-
lic facilities are water and sewer systems.
Department of Defense
Department of the Army, Office of the
Chief of Engineers. Specialized programs
attack problems of control and eradica-
tion of undesirable aquatic plants and
beach and shore erosion. Corps of
Engineers flood control projects may
also relate in various ways to lake pro-
tection.
Office of Education
Environmental Education. Project
53
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Appendix B
Glossy ibis (above) and wood duck (right)
make lakes their feeding grounds.
grants are available to support research,
development, and pilot and demonstra-
tion projects designed to improve public
understanding of environmental issues
as they relate to the quality of life.
Department of Housing and
Urban Development
Community Planning and Development.
Grants are offered to communities to
undertake activities for improvement to
community facilities that affect public
health and safety including water and
sewer projects.
Department of the
Interior
Office of Surface Mining Reclamation
and Enforcement. Grants and direct
payments and technical assistance are
available for projects to protect society
and the environment from adverse
effects of coal mining operations.
Heritage Conservation and Recreation
Service. Project grants are available
for the preparation of comprehensive
statewide outdoor recreation plans and
acquisition and development of outdoor
recreation areas and facilities for the
general public. Project grants are also
offered to economically hard-pressed
communities for rehabilitation of exist-
ing recreational facilities and for
demonstration of innovative ways to
enhance park and recreation opportun-
ities and develop recreation plans. Advice
and demonstration on recreation-related
matters are offered to States, localities,
and private interests.
Water and Power Resources Service
(formerly the Bureau of Reclamation).
Project grants and direct loans are
offered for such rehabilitation and
improvement projects as irrigation
and drainage and for multi-purpose
plans involving flood control, fish and
wildlife, recreational development,
municipal and industrial water supplies.
U.S. Fish and Wildlife Service. Formula
grants are available to support projects
designed to restore and manage sport fish
populations and for restoring or managing
wildlife populations. Information and
technical assistance are available on pro-
tection and enhancement of freshwater
fishery resources, the effects of pesti-
cides on fish and wildlife ecology, and
management of waters for sport fishing.
Office of Water Research and Technol-
ogy. Grants provide Federal funds
through State water resource institutes
for research and development of water
resources management techniques which
are, in most instances, applicable to lakes.
Geological Survey. Assistance is offered
in cooperative projects to prepare geo-
logic maps. Technical information and
maps provide information for develop-
ment and management of natural re-
sources and efficient operation of
interrelated projects at the Federal,
State and local level.
Environmental Protection
Agency
Office of Water and Waste Management.
Project grants are offered for construc-
tion of wastewater treatment works
including privately owned individual
treatment systems. The project may
include but may not be limited to
treatment of industrial wastes. Formula
grants are available for the establishment
and maintenance of adequate measures
for prevention and control of water
pollution. Broad support is available
for permit programs, pollution control
studies, planning, surveillance, and
enforcement. Project grants are pro-
vided to areawide and State planning
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Appendix C
Clean Lakes Water Act
(33 U.S.C. 1251 et seq.)
agencies to develop a water quality
management plan for areas approved by
the appropriate regional EPA admin-
istrator. Solid and hazardous waste
management program support grants
assist in the development and implemen-
tation of State and local programs and
| support rural and special communities
i in programs and projects for solving
solid waste management problems.
Project grants are available to promote
the demonstration and application of
solid waste management and resource
recovery technology and assistance to
preserve and enhance the quality of the
environment and conserve resources.
Office of Research and Development.
Project grants are available to support
research and to determine the environ-
mental effects and control requirements
associated with energy, to identify,
develop and demonstrate necessary
pollution control techniques; and to
evaluate the economic and social con-
sequences of alternative strategies for
pollution control of energy systems.
Other project grants may be used for
research, development, and demonstra-
tion projects relating to the causes,
effects, extent, prevention, reduction,
and elimination of water pollution.
Office of Planning and Management.
Guaranteed/insured loans are available
to assist and serve as an incentive in con-
struction of municipal sewage treatment
works that are required to meet State
and Federal water quality standards.
Programs Providing Labor. A number of
programs provide labor for conservation
work. They are administered by the Forest
Service of USDA (Youth Conservation
Corps and Young Adult Conservation
Corps), the Department of Labor's Em-
ployment and Training Administration
(CETA and other employment and train-
ing programs), and Action (Retired Senior
Volunteer program and others.
A water strider on a woodland pond
Section 3I4.
(a) Each State shall prepare or establish,
and submit to the Administrator for his
approval —
(1) an identification and classification
according to eutrophic condition of
all publicly owned freshwater lakes
in such State,
(2) procedures, processes, and methods
(including land use requirements),
to control sources of pollution of
such lakes; and
(3) methods and procedures, in con-
junction with appropriate Federal
agencies, to restore the quality of
such lakes
(b) The Administrator shall provide
financial assistance to States in order to
carry out methods and procedures approved
by him under this section. The Administra-
tor shall provide financial assistance to
States to prepare the identification and
classification surveys required in subsection
(a) (1) of this section.
(c) (1) The amount granted to any State
for any fiscal year under this section shall
not exceed 70 per centum of the funds
expended by such State in such year for
carrying out approved methods and pro-
cedures under this section.
(2) There is authorized to be appro-
priated $50,000,000 for the fiscal
year ending June 30,1973,
$100,000,000 for the fiscal year
1974; $150,000,000 for the fiscal
year 1975; $50,000,000 for the
fiscal year 1977; $60,000,000 for
fiscal year 1978; $60,000,000 for
fiscal year 1979; and $60,000,000
for fiscal year 1980 for grants to
States under this section which
such sums shall remain available
until expended. The Administra-
tor shall provide for an equitable
distribution of such sums to the
States with approved methods and
procedures under this section.
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Appendix D List of Reviewers
it left, a snapping turtle, whose shell and
lowerf ul jaws place it at the top of its
ood chain. Above, a red-eared turtle,
esident of the south central U.S.
Mary Blomquist
National Biocentric, Inc.
St. Paul, Minn.
Walter Bogan
Office of Environmental Education
400 Maryland Ave., S.W.
Washington, D.C. 20202
Patrick Brezonik
University of Florida
Gainesville, Fla. 32601
David Burmaster
Council on Environmental Quality
722 Jackson PL, N.W.
Washington, D C 20006
Frank Carlson
U.S. Department of Interior
18th& C St., N.W.
Washington, D.C. 20240
Louis S. Clapper
National Wildlife Federation
1412 16th St , N.W.
Washington, D.C. 20036
G. Dennis Cooke
Kent State University
Kent, Ohio 44242
Tom Franklin
Urban Wildlife Research Center
4500 Sheppard Lane
EllicottCity, Md. 22043
David G. Frey
Indiana University
Bloomington, Ind. 4740I
William Funk
Washington State University
Pull man, Wash. 99163
Charles Goldman
University of California at Davis
Davis, Calif. 95616
Harold F. Hemond
Massachusetts Institute of Technology
77 Massachusetts Ave.
Cambridge, Mass. 02I39
Lee Ishinger
U S. Fish & Wildlife Service
Ft Collins, Colo. 80521
Lowell Klessig
University of Wisconsin
1815 University Ave.
Madison, Wis. 53706
Al Krause
EPA Region 5
230 S. Dearborn
Chicago, III 60604
Patricia Langord
R.D. 1
Mill Run, Pa. 15464
Daniel Leedy
Urban Wildlife Research Center
4500 Sheppard Lane
Ellicott City, Md. 21043
Kenneth Mackenthun
Enwright Laboratories Inc.
104 Tower Dr.
Greenville, S.C. 29607
Richard Macomber
U.S. Army Corps of Engineers
940I Cherwek Rd.
Lorton,Va. 22079
Raymond Oglesby
Cornell University
Ithaca, N.Y. 24853
Joel Schilling
Minnesota Pollution Control Agency
1935 W. County Rd. B-2
Roseville, Minn. 55421
57
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Sandy Silver
U.S. Forest Service
Washington, D.C. 20013
Zel Steever
EPA Region I
Narragansett, R.I. 02882
Carl Sullivan
American Fisheries Society
5410 Grosvenor Lane
Bethesda, Md 20014
Paul Uttormark
University of Maine
Orono, Maine 04469
O'.l Environmental Protection Agency
GUSPO Library Coliec ion (PL-12J)
7f West Jackson Boulevard,
Sfcago,tL 60604-3690
Photo Credits
Cover: T. Loomis, The Nature Conservan
Title Page: H.E. Alexander, Soil Conserv;
tion Service; Contents page: J. Bruce
Bauman © National Geographic Society;
iv. Allen Carroll; vi. Allen Carroll, vi' T.
Loomis, The Nature Conservancy; 1,2:
EPA Documerica; 3' Allen Carroll; 4.
Landsat satellite imagery; 6-7' Allen
Carroll; 7. Landsat; 9 top Allen Carroll;
9 bottom. Soil Conservation Service; 12,
15 right: Ray T. Oglesby, Cornell Univer
sity; 17' Allen Carroll; 18: James L. Amc
© National Geographic Society; 20 left-
Soil Conservation Service; 20 right. Aller
Carroll, 21,23. U.S. Environmental Pro-
tection Agency; 24 Soil Conservation
Service; 26' Ray T. Oglesby; 29, 30' Alle
Carroll; 31-34' U.S. Environmental Pro-
tection Agency; 36. Reed Huppman; 39'
U.S. Environmental Protection Agency;
40 left: Allen Carroll; 40 right: Marjorie
Hunt; 41: Soil Conservation Service, 43
U.S. Environmental Protection Agency,
44 left: Allen Carroll; 44 center' U.S.
Environmental Protection Agency; 45.
S. Bournique, The Nature Conservancy;
46. Bianca Lavies © National Geographic
Society; 48 Landsat, 49: U.S. Environ-
mental Protection Agency; 50 left. S.
Bournique, The Nature Conservancy; 50
right Allen Carroll; 51 left' Soil Conser-
vation Service; 51 right: Sandra Gold, 52
James L. Amos © National Geographic
Society; 55 Allen Carroll; 56: Bianca
Lavies © National Geographic Society.
Illustrations of plants and animals are b'
Sandra Gold. Diagrams are by Allen Carn
58
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