United States Environmental Protection Agency Office of Water Planning and Standards Washington, D.C. 20460 EPA-440/5-79-021 oEPA Clean Lakes and Us ------- CLEAN LAKES AND US prepared for th U. So Environmental Protection Agency by University of Wisconsin-Extension Madison, Wisconsin March, 1979 For sale by the Superintendent of Documents, U ri (Jorernmr-nt Fruiting Office Washington, D C. 20102- Price 51.20 Stock Number 055-001-01085-1 ------- This booklet was prepared for the Environmental Protection Agency by George Gibson Stanley Nichols Klessig James Peterson Environmental Resources Unit University of Wisconsin--Extension The authors gratefully acknowledge the review and editorial comments of Thomas Sinclair, Thomas Pierce, and Robert Johnson. Graphic Designer: Susan McQuade Typist: Nan Erickson This report has been reviewed by the clean lakes program staff, EPA, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the U.S. EPA, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. The statements contained herein are ascribed solely to the author. ------- Preface Public use and enjoyment of our nation's lakes and waterways is a theme that underlies the efforts by EPA to achieve the Clean Water Act's mandate to improve water quality. Lakes are given special consideration in the legislation under Section 314, the Clean Lakes Pro- gram, because of their importance in the lives of most of the public. Lakes mean more than water and water chemistry. Lakes and associated parks frequently are popular places where large segments of the urban population can enjoy out- door recreation, visit with friends and family, and relax and get away from the pressures of everyday life. Lakes are vital to the ecosystem because they are part of the valuable water resource system so essential to our life and because they provide necessary habitat for many fish and wildlife species. This booklet explains some of the processes, geological and man-induced, that formed lakes and chem- ical, physical and biological principles that affect their quality. It is also about lake protection and cleanup and the recreation potentials this brings both to our lake waters and adjacent lands. It is about EPA programs and other programs designed to revitalize these potentials. And above all, it is about the public's interest and respon- sibility to manage and protect our lake resources. A very important message in this booklet is how civic groups working with their local government can expand their community's recreation and open space opportunities by incorporating water cleanup programs into their plans. Comprehensive planning and management of limited financial resources to accom- plish water conservation and pollution control is the necessary first step in achieving the nation's water quality ob- jectives. For example, many EPA-funded wastewater treatment facilities are located adjacent to, or very near lakes. Others are in lake watersheds. In secur- ing shorefront locations for recreation and open space opportunities, a community's recreation budget can accomplish more if recreation functions are integrated into the design for an EPA-funded wastewater treatment facility in the early steps of a community's application. This is termed multiple use. Similarly, future recrea- tion opportunities in conjunction with wastewater treatment plants or other water resource management projects can be iden- tified in the state and areawide water quality plans and coordinated with a state's comprehensive outdoor recreation plan. Other EPA programs, state and fed- eral agency programs and similar local efforts should be considered and inte- grated to achieve the most comprehensive lake management objective. The extent to which your community obtains more for the time and money it invests in lake recreation, water clean- up, and shorefront protection measures depends largely on your involvement in coordinated programs. Greater benefits can be obtained if you work hand-in-hand with local and state government on re- source management, multiple use, joint development, recycling, environmental education, and greenway projects that the Environmental Protection Agency and the other agencies promote. ------- I. Introduction The nation's inland lakes are an important public resource to be pro- tected, restored, and managed. A report by the Outdoor Recreation Resources Review Commission determined there are more than 1,586,000 lakes, ponds and reservoirs in the United States. Great Lakes (U.S.) 53,878,000 acres Alaskan Lakes 7,363,960 acres Other U.S. Lakes 19,493,000 acres Within the continental United States the surface areas of natural and man-made lakes are nearly equivalent, excluding the Great Lakes. The central element of most lake problems is "eutrophication" (or enrich- ment) of the lake by plant nutrients such as phosphorus and nitrogen. This is a natural process, but human use can greatly accelerate it. Common sources of these man-introduced nutrients are deter- gents, lawn and agricultural fertilizers, and sewage. Sewage discharges to water- ways and lakes also may pose a threat to public health by introducing disease- causing bacteria or viruses (pathogens) from human or animal intestinal tracts. Nutrients added to an otherwise evenly-balanced lake system can cause aquatic weeds or algae to intensify their growth rate until much of the shoreline and open water of some lakes is obstruc- ted. The appearance of the lake and the quality of swimming, fishing, and boat- ing all decline. Storm water from city streets and runoff from agricultural land or suburban lawns can carry pathogens from livestock and pet wastes. This same runoff carries pesticides, oil, gasoline, lead and asbestos from cars and trucks. By applying the knowledge gained from limnology (the study of lakes and other inland bodies of water), lake managers can now take steps to prevent or remedy the damaging effects of human development. ------- Some examples of these remedial approaches, which have been assisted by the Clean Lakes Program are described as follows: Lafayette Reservoir The 125-acre Lafayette Reservoir was constructed in 1929. It functions as an emergency standby domestic water supply and recreational, fishing and boating area for the Lafayette, California region. The lake suffers from severe eutrophica- tion. Dense algal growths regularly occur, depleting the lake's oxygen levels and threatening the fishery. The problems ren- der the water unsuitable for both emergency drinking water and recreation. To remedy this, plans are underway to aerate the hypolimnion (deep water portion) of the reservoir and to remove phosphorus from the lake by chemical treatment with aluminum. Adding air to the cool, deep waters of the lake should restore trout fishing to the reservoir without stirring up addi- tional nutrients on the lake bottom. At the same time, the phosphorus precipitation with alum should break the cycle of algae "blooms" that have thrived on the phosphorus in the upper water. The project is expected to cost about $100,000, 50 percent of which is being funded by a grant from the EPA Clean Lakes Program. When the program is completed, the reservoir should support a year-round trout fishery and, should its waters be needed, provide a much more pal- atible drinking water supply. Vancouver Lake Vancouver Lake is a 2,600-acre lake that lies in the floodplain of the Colum- bia River in Vancouver, Washington. It is highly polluted by coliform bacteria, suspended sediments, and nutrients. These problems are compounded by the lake's shallowness. Urbanization in the drainage basin has substantially increased storm water runoff and associated sediment loads in tributary creeks which, in turn, de- posit sediments and pollutants in Vancou- ver Lake. Runoff ,from agricultural crop lands is a seasonal problem. The poor water quality of Vancouver Lake becomes particularly severe during late summer--the optimum period for recreational use of the lake. The warm, shallow, fertile water promotes excessive algal growth. This growth, in turn, causes other water quality problems so Vancouver Lake no longer meets state water quality standards and is unacceptable for drinking, swimming, boating, fish and wildlife, or viewing. The Port of Vancouver proposes to rehabilitate the lake with financial assistance from the Washington Depart- ment of Ecology's Lake Rehabilitation Program and a grant from the EPA Clean Lakes Program. Accumulated sediment will be dredged from the lake. Then a channel and culvert system will be con- structed to allow Columbia River water to be used for flushing the lake. This will dilute and remove pollutants before they can accumulate to problem levels. A comprehensive plan is also nearing completion that proposes con- trols for wastewater generated in the principal lake tributary watershed, Burnt Bridge Creek. Pollution con- trols and best management practices contained in the plan will be imple- mented as part of the EPA grant agreement. Lake Temescal Lake Temescal is a 10-acre man-made urban lake in the Temescal Regional Rec- reation Area in Oakland, California. It is less than three miles from downtown Oakland and is used intensively for swim- ming, sun bathing and fishing. Its principal problems are sedimentation from nearby residential and commercial development, particularly acute during winter storms, and pollution from non- point surface runoff in summer. Two tri- butary streams entering the lake contri- bute bacterial concentrations high enough to pose a health hazard to swimmers. ------- A Clean Lakes Act grant of $488,972 from the Environmental Protection Agency will help restore the quality of this recreational lake. To relieve sedimentation and intense eutrophication, 57,000 cubic yards of sediments will be dredged from Lake Temes- cal to provide a maximum depth of 24 feet near the dam and gradually decreasing depths upstream. A system of impoundments and diversions will be constructed to re- duce the coliform bacteria problem. The series of small retention basins (designed as natural ponds) along the tributary streams will increase the exposure time of coliform bacteria in the water and in- crease their die-off rate. In addition, when bacterial concentrations exceed the capacity of the retention basins, the flow from both streams can be diverted around the lake. This will be accomplished by installing pump stations in the retention ponds at the mouth of each stream. By making these modifications to the drainage system, EPA and the East Bay Re- gional Park District of Oakland intend to show that urban lakes can be helped so that the quality of a valuable recreation resource can be restored to the people of Oakland. were added to the lake from a storm sewer and by municipal snow and leaf disposal at the lakeside. As the lake deteriorated, water chestnut, curly-leafed pond weed and algae invaded its waters. The swimming beach, which served a population of 100,000 within a five-mile radius, dimin- ished as a public resource. •Cal Welch, a local banker has en- couraged the Village of Scotia to recog- nize the lake as a major public asset worthy of management. A full-scale man- agement scheme has followed with local enthusiasm and financial support from the Clean Lakes Program. The lakeside dumping of leaves, other organic matter, and snow was stopped; improved mainten- ance of the tidal gate to curtail inflow of nutrient-rich flood waters from the river has been achieved; a berm populated with aquatic plants to filter and screen the storm water is being developed; and about 63,000 cubic yards of sediment have been dredged out of the lake. A recent review of this project (one of the first sponsored under the federal Clean Lakes Program) by a Union College evaluation team found that the restoration program is proceeding well. Collins Lake Collins Lake in Schenectady County, New York was formed when the Mohawk River eroded a short cut across one of its mean- ders and left behind an oxbow lake. The river has continued to affect the lake through periodic flooding and the malfunc- tioning of a tidal gate designed to keep river flood water from backing up into the lake. Nutrients and sediments also White Clay Lake White Clay Lake (named for its marl deposits) is a 250-acre lake in a 3,000- acre dairy-agricultural watershed in north- eastern Wisconsin. While the lake is con- sidered to be of good quality now, recent changes in agricultural practices—larger dairy herds, concentrated feeding areas, and greater emphasis on corn production-- pose a water-quality threat. ------- The EPA Clean Lakes Program has pro- vided half of the $214,000 being used to protect White Clay Lake from further degradation. The project will demonstrate the designs, costs, arrangements and water quality results of implementing a watershed management plan in a rural area. Plans in- clude lake district formation, streambank stabilization, contour cropping, grass waterways, clear-water diversions, stabil- ized standing areas, manure storage, pro- tective zoning codes and an effective voluntary conservation program. Water quality monitoring of barnyard effluents, streams, a littoral-zone marsh, and the lake itself will provide an assessment of the benefits of the protec- tive plan. Mirror and Shadow Lakes The kettle hole lakes, Mirror (10 acres) and Shadow (35 acres) received stormwater runoff from a small central Wisconsin city for several decades. Once used as a municipal drinking water source, Mirror Lake decreased in quality to the point where it could no longer be used even for block ice production. Oxy- gen depletion, fishkills, algal blooms and lake weeds characterized the eutro- phic state of the lakes. Renovation plans were developed based on studies by Wisconsin's Inland Lake Renewal Demonstration Project funded by the Upper Great Lakes Regional Commis- sion. Implementation money from the EPA Clean Lakes Program made the renewal efforts possible. Stormwater diversion, periodic mixing/aeration and aluminum .treatment to hasten phosphorus removal have renewed the lakes. Little Pond Seventy-acre Little Pond in Damari- scotta, Maine is a principal public water supply for the towns of New Castle and Damariscotta. The pond has had problems with a dense growth of Daphnia zooplank- ton (water fleas) to the extent that the communities complained of adverse tastes in their drinking water. These tiny organisms were previously controlled by treating the pond with copper sulfate, but concern developed over the use of this chemical because high concentrations have killed the fish. A biological control technique was developed which involved stocking the pond with alewives, an anadromous fish which feeds on zooplankton. The alewife spawns and develops in fresh water, but normally lives as an adult in the Atlantic Ocean. With the assistance of a $4,000 EPA grant, the Maine Department of Environmental Protection stocked the pond in the spring of 1976 with spawning adult alewives. They and the developing young fed on and con- trolled the Daphnia all summer. In the fall the fish were trapped and removed from the pond at the discharge stream as they began their migration. Alewives that didn't migrate and escaped trapping were unable to survive the winter in the pond. The stocking and removal process was conducted for two years and assessments of the results are now being completed by researchers. In the meantime, the people in Damariscotta and New Castle have noted that their drinking water tastes better. ------- II. Lake Processes What is a Lake? Lakes are more than just standing bodies of water. They have physical and chemical characteristics which make them ideal homes for an immense variety of organisms. The lake ecosystem is a com- munity composed of interating animals and plants and the physical and chemical environment in which they live. The sun provides the energy for the entire system. A lake cannot be separated from the drainage area that supplies its water. The drainage area consists of the uplands, shorelands and wetlands adjacent to the lake. How the land within the drainage area is used or abused by society will greatly affect the quality and clarity of the lake. For example, soil erosion caused by construction activities during intensive development can result in a loss of 100,000 tons of soil per square mile per year. (By comparison, natural soil erosion rates from a wooded water- shed are only about 100 tons per square mile per year.) Much of this soil ends up as silt in the bottom of lakes and streams. This sediment not only "muddies" the water but also makes a lake shallow and adds nutrients and pollutants to the water. Dredging projects such as the one proposed for Vancouver Lake, Washington remove these accumulated sediments. 6 ------- SOLAR. EtSER&V DRIVES THE CVCUE ------- t&W&tfwzs • V'o> V°vr ";.V.i"'«''-l>:*'-V-"':« \'-:'.'b>';>V-VVv''^-.Ot?> :,'•; * . ••• '. '£? - »•••'.'•.* * •'*• .•'*.*'•,• • ' ' ^ , . * • . O * , ,t?, • 'o • • i ' " *0 '»' . * a*' .-•'• \.fl- - . .' «"Q, ' • o .••:•*• •, • 'Q* ". * v ..*..'-. »•'*'.•••..-.•.,• >*o>'..-:.»<.' -.^.v..-'.q*. v.*.>!.*. How Lakes are Formed Lakes are formed in a variety of ways. You may be more familiar with one type of lake or another depending on which region of the United States you come from. Listed below are some typical types of lakes: 1. Glacial lakes—natural lakes common to New England, the northern lake states, high mountain areas and Alaska. 2. Earthquake lakes—lakes formed by crustal movements of the earth. Pyramid Lake, Nevada; Lake Tahoe, Cali- fornia; Reel Foot Lake, Tennessee; and Lake Okee- chobee, Florida are examples. 3. Volcanic lakes—Crater Lake, Oregon is a spectacular exam- ple of a lake formed by vol- canic action. 4. Solution lakes—many lakes, particularly in Florida, but also in Indiana, Kentucky and Tennessee are formed by water-carving basins in easily soluble bedrock. 8 ------- 5. Sloughs and oxbow lakes-- these lakes are found in the floodplains of old river systems and are basins left behind when the rivers changed their paths. Examples are Collins and Vancouver Lakes. 6. Lakes formed by wind action-- Moses Lake, Washington and the lakes behind the dunes of Lake Michigan are examples of lake basins formed by wind action. 7. Lakes formed by human action-- humans are prolific builders of reservoirs and ponds for recreation, power, navigation, and irrigation. Central Park Pond in New York City is one example of not only a man-made lake, but one in an intensely developed area. Such urban lakes and reservoirs often have very high recreational value because of their loca- tion and the scarcity of natural water bodies in the area. To understand the ecology and develop management strategies for lakes it is important to understand how they are formed. Some lakes are more suscep- tible to human damage than others and some are more easily managed than others. Lake Aging A lake is nurtured by its watershed. Sediment transported from the watershed enters the lake. Nutrients such as nitrogen, phosphorus and potassium are adsorbed into the sediment particles and dissolved in the drainage water. They fertilize the lake so organisms, partic- ularly algae and aquatic plants, can grow. Under the traditional scheme of things, nutrients from the watershed are washed into the lake. These nutrients promote the growth of algae and other aquatic plants. When these plants die and decompose, the nutrients within their tissue recycles and supports further plant growth. As the nutrient levels increase, greater plant growth occurs. This builds gradually to a point where there is more plant growth in one year than can be de- composed before the next year. The sedi- ment changes from a mineral sediment which came from the watershed to an organic sediment caused by dead algae atid aquatic plants settling on the lake bot- tom. Much of the nutrients for further plant growth can be supplied from the decomposing organic matter. The lake is eutrophying. Ultimately, the organic matter will fill the lake and then develop into a marsh, then a wet meadow and then a dry meadow. There are other processes, too. Some basins are very high in calcium carbonate (lime). Calcium carbonate chemically ties up phosphorus so it is unavailable for plant growth. Consequently, even though nutrient inputs are high, plant producti- vity in the lake is low and organic sedi- ments do not build up. These lakes are called marl lakes. In other watersheds, inputs to the lake consist chiefly of leaves, sticks or other organic matter rather than mineral nutrients. This organic matter decomposes very slowly so the nutrient supply to the lake is poor. The water in these lakes is tea colored and they are called stained- water or dystrophic lakes. The acid water limits plant growth and animal life so organic matter doesn't build up rapidly. Eventually a bog may form around the edge and a mat will grow out across the water. This contributes organic material to the lake and may later fill it in. Human activity can greatly increase the rate of lake aging, and nutrient inputs from different land uses varies tremen- dously as shown in the following table. 9 ------- LAKES 7 I v 'HIGH DISSOLVED OXYGEN 'LOW NITROGEN ^ PHOSPHORUS 'FEW AQUATIC WEEDS OR ALGAE 'COUP WATER. FISH-I.E. TROUT INPUTS TO LAKE ARE PRIMARILY LEAVES, STICKS, TWIGS. ETC. FROM SHORELINE \ INPUT INVOLVES HIGH AMOUNTS OF CALCIUM SUCH AS DISSOLVED LIMESTONE INPUTS TO LAKE ARE PRIMARILY MINERALS^ SEDIMENT INCLUDING* N ITRO&EN ^ PHOSPHORUS \ &OG- PVSTROPHIC LAKES MARL LAKES EOTROPHIC LAKES •COLORED WATER -LOW PISSOL.VEP OXYGEN •LOW NITROGEN ^ PHOSPHORUS •FEW PLANTS OR. ANIMALS IN LAKE ITSELF •HARP WATER. • VARIA&LE CONDITIONS OF NUTRIENTS^ PLANTS i, ANIMAL LIFE -LOW •DISSOLVED OXYGEN -HIGH NITROGEN £ PHOSPHORUS -ABUNDANT WEEPS AND/OR ALGAE -WARM WATER. FISH-I.E. 0>ASS WETLAHD WET DRV LAND WITH INVASION OF TREES 10 ------- TIME I •...«'.'TtvTv.'TLa-.•:>•.x r V Aquatic Life in the Lake The type of lake will largley deter- mine what types of plants and animals live within it. Oligotrophic lakes are usually deep and cold, with a good oxygen supply distributed throughout the water. Trout, salmon, cisco, whitefish and herring are common to these lakes. Overall, their productivity is low. On the other hand, as lakes eutrophy, northern pike, largemouth bass, walleye and a variety of panfish become more common. These lakes may be shallower and warmer and may not have an abundance of oxygen in the water year-round. Bloodworms and a variety of other organisms can live in their organic sediments. In lakes that are highly eutrophic, blue-green algae abounds. Sludge worms live in the bottom sediments and fish such as bullheads, mud- minnows and carp which are tolerant of ex- tremely low oxygen are found in this area. Dystrophic lakes .are both oxygen and nutrient poor; they have very low productivity and little aquatic life exists in them. Lake Communities The lake is a complex community composed of many interacting habitats and populations. Shallow, warm bays and marshes may support northern pike and bass, pond weeds and pond lilies, cattails and muskrats. The deep water area supports algae, water fleas, yellow perch and walleye. The bottom muds throughout support a unique com- munity of worms, insect larvae and bacteria. These communities are not mutually exclusive. A northern pike may move out to deep water to feed on a young walleye, or a perch may take a dragonfly nymph from the surrounding wetland. 11 ------- IS) ------- . Lake Problems Pollution and Contamination We have already discussed some of the problems caused by nutrients and sedi ment in a lake. Overfertile lakes grow blue-green algae, aquatic weeds and low quality fish. As stated before, eutro- phication or nutrient and sediment en- richment is a natural process, but cul- tural activities such as poor land use can greatly increase the eutrophication rate. Nutrients and sediment contributed by poor land use are not the only lake problems. Wastewaters discharged from sewage treatment plants (and other "point sources"*) are nutrient-rich (including large amounts of phosphorus). Turbidity alone (suspended solids and color) from sediment, trash, organisms and organic materials, is a form of water pollution. Not only is it unpleas- ant to look at, but in high concentra- tions it can also clog fish gills and smother fish eggs and bottom organisms. CLEARING — OF FORESTS -> FAR/A^ TOWN OROWTH ORB Att IXATION I75O 1800 2OOO *"Point" sources of pollution are those operations in which the pollutants can be identified as being from a discrete point such as a discharge pipe. This is in contrast to "non-point" pollution from a broad, ill-defined source such as the runoff from many acres of fields, or from a diffuse housing or commercial area. 13 ------- Organic materials which naturally enter a lake, such as leaves, exert a biochemical oxygen demand (BOD). As they decompose, they remove oxygen from water. This reduces the supply of dissolved oxy- gen available to fish and other life forms in the lake. Organic matter such as pulp and canning wastes, or raw sewage added to the water also will deplete oxygen as will certain forms of inorganic chemicals. Good supplies of dissolved oxygen are needed for fish and other organisms to survive and reproduce. Pesticides (like DDT), heavy metals (mercury, lead, zinc, and copper), arsenic, oil, asbestos and a wide array of other toxic and inhibitory substances are com- monly present in urban and rural runoff. Metal processing wastes, chemical and paper processing effluents, cooling water discharge and rain water itself contain contaminants in polluted areas. Some in- jure and kill aquatic plants, fish and other water life directly. Others become concentrated in aquatic food chains and are passed on from prey to predator, in- cluding man, with potentially adverse effects. In the Great Lakes area, for instance, there is a ban on the commercial harvest of Lake Michigan trout and salmon because of high PCB (polychlorinated bi- phenols) levels. METAL LOADIMG FROM ROAD SURFACE RUNOFF RESIDENTIAL SECTOR 75% LEAD 600 CADMIU/A 1.2. NICKEL 10 LBS COPPER. 36 |_BS> Z.\MC KO l-BS IROH 7.9OO UBS AAAN&AHESE I SO l_BS CHRO/AIU/A &O COMMERCIAL SECTOR. 5% INDUSTRIAL SECTOR 2O% O.I INCH OF RAINFAUL UASTIM& FOR. I HO OR. Adapted from: Pit, E. E. and G. Amy, 19?"6. Toxic Materials Analysis of Street Surface Contaminants, Environmental Protection Series. U.S. Environmental Protection Agency, Washington, D.C., 133 p. 14 ------- Another noteworthy problem, as indi- cated in the figure, is the amount of heavy metals that run off city streets. Such runoff remains largely uncontrolled and untreated. In the illustration, the loadings to water runoff are generated by a "hypothetical city" of 100,000 people covering an area of 14,000 acres. Such a metropolitan area may be expected to have about 400 curb miles of streets and to generate about 12,000,000 gallons of sanitary sewage flow per day. Our increasing demand for energy can cause lake problems. Radioactive and/or heated wastes enter surface waters from nuclear power plants, research labs and testing facilities, industrial cooling waters and conventional power plants. Radioactive wastes may be a health and a genetic hazard. Increased water tem- perature may result in undesirable changes in aquatic communities. Warm water, for instance, holds less dissolved oxygen and certain species of blue-green algae grow much better in warm water than in cold. Many of the early water pollution control laws were passed to protect public health. A wide variety of diseases such as typhoid and paratyphoid fever, dysen- tery, gastroenteritis, and hepatitis are transmitted by contaminated water supplies. Public health is also important for rec- reational users of water. Body contact with contaminated water can cause diseases such as eye, ear, nose and throat infec- tions and skin rashes. Most of these diseases are transmitted by bacteria, viruses or other microorganisms which enter the water via urban and agricultural runoff, domestic wastes including sewage and septic tank discharges, and some in- dustrial wastes such as those from animal processing plants. The standard test for determining contamination of water is the fecal coli- form test. Although these organisms are not normally a direct threat to humans, they do indicate that water is contamin- ated from either human or animal sources and there is a strong possibility it will contain disease-producing organisms. The criterion set up by most municipal health departments for full body contact recrea- tion (swimming) allows an average of only 200 fecal coliform organisms in five or more 100 milliliter water samples. If the average count exceeds this value, recreational use of the water may be restricted to boating and fishing. 15 ------- Water Levels For some people, a lake problem in- volves keeping a lake a lake. As has already been discussed, sedimentation can cause serious infilling. In some lakes., particularly those formed by dams on large watersheds with easily erodable soils, the sedimentation rate is so rapid that the lake fills in within a few decades. Over the years, this can be very bothersome to lakeshore property owners. In wet years, they may have a swimming pool in the basement. In dry years, a longer pier may be needed to reach the lake. This problem may become seasonal and can be particularly dramatic for urban lakes for which the main source of supply is stormwater runoff. There are also problems where ground water supply influences lake levels. Some lakes are located where the topography is low enough to intercept the ground water. Ground water levels can fluctuate from season to season and year to year, depend- ing on the amount of precipitation and withdrawal. During or after very wet years, ground water levels are high and lake levels are up. During or after dry years, ground water levels are low and lake levels drop. Another problem with ground water fluctuation in lake communities having extensive septic tank systems is flood interference with drain fields when ground water levels are high. Contamin- ation of ground water by the septic tanks is also a potentially serious problem in these communities. Too many septic tank systems in one area or in the wrong soils could cause sewage contamination of local well water and possibly of the lake with both nutrients and pathogens. OROUNPWATER. LEVEL I WET YEAR, PRY YEAK 16 ------- People Pressure How many people does it take to phys- ically degrade the resource? How many different activities by fishermen, power boaters, water skiers, sailors, canoeists, or divers can a lake handle before it begins to show signs of wear and tear? How many people, in general, can a lake accommodate before they start getting into each other's way? How many people can a lake hold before they disrupt each other's aesthetic experience with the lake? These questions are difficult if not impossible to answer because they involve individual perspectives. When we don't know the answer, it is best to keep our options open. The State of Wisconsin, for instance, has a wilder- ness lakes program to set aside certain lakes in their relatively undeveloped state and to keep them this way while scientists study more about the effects and controls of development. This allows some of the "how much is too much" ques- tions to be answered and gives people a diversity of options for lake enjoyment. ,£**«••* 17 ------- IV Protection, Restoration, and Management The State of the Art Degradation of the quality of lakes is the result of lake-aging processes . . . eutrophication and sedimentation . . . speeded up by cultural activities. These synergistic processes cause or aggravate some of the familiar lake qual- ity problems: algae "blooms," nuisance rooted-plant growth, odors, diminished usable water surface, changes in fisheries and fishkills. 18 Numerous difficulties complicate lake renewal and management efforts: the state- of-the-art is still rather primitive; lakes are complex ecosystems. In spite of many years of study, prediction of the response of a lake system to a given treat- ment program is tenuous. Furthermore, the tendency for each lake to be characterized by its own "unique personality" hinders extrapolating results obtained on one lake to solve problems in other lakes with apparently similar problems. ------- The complexities of lake rehabilita- tion suggest that it is likely to be ex- pensive and difficult. No doubt the prob- lem is best handled by its prevention through wise planning and careful use. Where lake rehabilitation is necessary, the objective should be to restore "nor- mal" aquatic balances to the lake eco- system, not swimming pool conditions. The restoration of normal balances should also include the lake shoreland and water- shed. Understanding the interrelation- ships of all parts of the lake system is essential to its rehabilitation. It may be important to protect or restore the original basin; make efficient use of remaining open spaces and green areas; or reclaim critically important portions of the watershed for nutrient and sediment management. Secondly, the technology for lake renewal is in an early stage of develop- ment and some lake restoration schemes become prohibitively expensive. Costs increase rapidly in moving from protection schemes to more extensive rehabilitation projects. Doing nothing now ultimately may lead to a prohibitively expensive project later. A third factor frustrating lake renew- al efforts is that of time. Considerable data may be needed to define the problem adequately, and remedial programs may span several years. Public demands and expec- tations are hard to satisfy over such a period of time unless the public is well informed. Nonetheless, the community does have several options available for lake man- agement depending upon the state of the lake. EXTENT OF UAKE, AAANAGEMENT PROTECT 4 LIMITED LAKE MAMA&fcMENT AS IS LAKK MANAGEMENT LAKE RENEWAL AFTER SCRIOUS 19 ------- Lake Protection Some situations call for better water quality maintenance or protection efforts, guided by a carefully developed, comprehen- sive land and water management plan to pre- vent degradation of lake quality. Protection measures display the high- est levels of foresight and commitment to maintenance of water quality. A goal has been defined; a plan has been developed; the letter and spirit of the tasks are supported; work has begun. People care; the program proceeds. Resistance to implementation of protec- tion measures may be born of the "it won't happen here" attitude about eutrophication: the lake has been like this for a hundred years ... can you prove that there will be changes? This is a difficult question to answer, in view of the infancy of docu- mented lake restoration schemes and of the science of describing the maturity proces- ses in lakes. The same techniques apply to protec- tive plans as to restoration-maintenance ones: stabilizing, contouring, mulching, zoning, stacking, diverting, prohibiting, chisel plowing, terracing, riprapping, oxygenated cold vi rwturn •anchor fr. •';.•> :.".<•:.; ..^^^-f^^^^; \ fencing, greening. Why not do it in ac- cord with a plan that helps solve the most important problems first? In addition to a coordinated plan, everyone can contribute to lake protection by responsible, individual actions to cur- tail the nutrients entering the lake. Lake residents should avoid the use of high phosphate dish detergents, laundry products, and household cleansers. Anythir that goes down the drain should be phosphal free or at least low in phosphorus. When shopping for detergents, read the label anc buy reduced or non-phosphorus products. "Biodegradable" is nice too, but the phos- phorus content of the product is what count most. Another way to personally reduce nutri ent loads to your lake is by avoiding or curtailing your use of garden and lawn fer- tilizers. Don't use too much fertilizer tc often. The excess fertilizer is not only wasted money, but is eventually washed into the lake where it fertilizes weeds and algae to further increase your costs in lake management later. If you feel com- pelled to fertilize your lake property lawn see your County Extension Agent first. He can recommend the best fertilizer combina- tion and the best application practices for your particular soil. Septic tanks can also be a problem. In addition to using low phosphorus house- hold products, you should also be water conservative to avoid 'overloading the drain field. The system should be inspecte about every two or three years, and the tank pumped regularly. Because a faulty septic tank system may be dangerous to - public health in addition to contributing to lake degradation, any failures should be repaired immediately. Restoration or Renewal Where it is too late for such before- the-fact action alone, lake rehabilitation projects may stem or reverse the aging process. A water quality maintenance pro- gram can then provide a lasting solution. 20 ------- Two general approaches for rehabili- tating nutrient-rich lakes are (1) limi- ting fertility, either by restricting nutrient inputs or by direct in-lake schemes aimed at reducing nutrient re- cycling by accelerating nutrient out- flows; and (2) treating or managing the symptoms of over-fertilization (see table on next page). Nutrient input can be significantly reduced by (a) removing nutrients from wastewaters through advanced treatment of municipal and industrial effluents (Sha- gawa Lake, Minnesota), (b) diverting nutrient-rich wastewaters (Lake Washington, Washington; Mirror Lake, Wisconsin), (c) utilizing land-use management practices and controls (White Clay Lake, Wisconsin), (d) treating inflowing streams, and (e) modify- ing products, e.g., phosphate-regulated detergents (Connecticut, Indiana, Maine, Michigan, Minnesota, New York, Vermont, Wisconsin, Chicago and Akron). Direct in-lake schemes to remedy eutrophic lake problems are varied and include: (a) dredging to remove nutrient- rich sediments (Collins Lake, New York), (b) using chemicals such as iron, fly ash and aluminum salts to inactivate or re- move nutrients in a lake (Medical Lake, Washington; Lafayette Reservoir, Cali- fornia; several Wisconsin lakes [Dunst, 1974]), (c) dilution or flushing of nutrient-rich waters (Green Lake, Washington; Snake Lake, Wisconsin; Moses Lake, Washington, Vancouver Lake, Washington), (d) aerating lakes suffering from low dissolved oxygen conditions (Penn Lake, Minnesota; Vancouver Lake, Washing- ton; Lafayette Reservoir, California), (e) discharging or withdrawing nutrient-rich waters of a lake (commonly the bottom waters or hypolimnion, as planned at Lake Ballinger, Washington), (f) removing nutrients by harvesting plants or fish (Lake Sallie, Minnesota; Little Pond, Maine), and (g) manipulating the lake bottom, including sealing with sand blan- kets, plastic sheeting and other materials (Marion Millpond, Wisconsin). Management Although nutrient limitation is most desirable, other management schemes main- tain a lake in a usable condition. Aera- tion, dredging, weed harvesting or chemi- cal control, water level manipulation, and similar techniques may be cosmetic in nature and treat the symptoms rather than the causes of the problem. Nevertheless, they provide short-term relief and can yield widespread satisfaction to lake users or be part of a larger-scale rehab- ilitation project. Commonly, no single renewal technique is sufficient. Rather, a combination of nutrient restrictions, in-lake modifica- tions and symptom-management is prescribed as noted in the lake restoration summaries at the beginning of this booklet. Paralleling these scientific and tech- nological approaches, public institutions are being developed for undertaking such programs and despite the problems, encour- aging progress has been made in recent years. 21 ------- LAKE MANAGEMENT TECHNIQUES I. Limiting Fertility and Controlling Sedimentation A. Curbing Nutrient Influx 1. Wastewater Treatment 2. Diversion 3. Land-Use Practices 4. Treatment of Inflow 5. Product Modification B. In-Lake Schemes to Accelerate Nutrient Outflow or Prevent Recycling 1. Dredging for Nutrient Control 2. Nutrient Inactivation/Precipitation 3. Dilution/Flushing 4. Biotic Harvesting 5. Selective Discharge 6. Sediment Exposure and Desiccation 7. Lake Bottom Sealing 8. Lake Aeration II. Managing the Consequences of Lake Aging A. Aeration and/or Circulation 1. Hypolimnetic Aeration 2. Whole Lake Aeration B. Lake Deepening 1. Dredging 2. Drawdown and Sediment Consolidation C. Other Physical Controls 1. Harvesting 2. Water Level Fluctuation 3. Habitat Manipulation D. Chemical Controls 1. Algicides 2. Herbicides 3. Piscicides E. Biological Controls 1. Develop Predator-Prey Relationships 2. Inter-Species Reactions 3. Plant Diseases PRODUCT MODIFICATION Florida manatee feeding on water hyacinth 22 ------- TIME LAKE MANAGEMENT ALTERNATIVES PROTECT PRESERVE AS URBAN RUNOFF INDOSTRIA E.FFL.OENT LIMITED LAKE EXTENSfVE LAKE MAHA&EMEHT LAKE RCH6WAL AFTER, DEGRARATION HUMAN J/APACT ACCELERATED RATE OF LAKE EUTROPHI CATION DO NOTHING 23 ------- V What Our Lake Community Can Do Who Represents Us? Individual property owners and rec- reationists are responsible for managing their own property and controlling their own behavior. However, many problems re- quire collective concern and action. NATIONAL FOREST EAST COUNTY 24 ------- An Informal Group of Neighbors Initial discussions about lake prob- lems and potential solutions occur under many different circumstances. Fishermen might discuss the issue at the boat land- ing or the bait shop. Neighbors might discuss the lake across the fence or over coffee. It is important for property owners to recognize that others also are concerned. Informal groups can undertake some small neighborhood projects, lobby, and exert some pressure on "insensitive" neighbors or recreationists. A Lake Association At some point, a community leader will invite interested people to get together to discuss alternative courses of action and the possibility of crea- ting a formal organization. A lake association often results with voluntary membership and a modest fee. Lake asso- ciations are able to undertake social activities which bring people together, and then can lobby for the entire commun- ity. Many lake associations incorporate as non-profit organizations and sponsor certain limited projects. A Special Purpose Unit of Government Since lake associations have limited financial and legal ability to manage a lake system, some states such as Wisconsin have given lake communities the option of forming a unit of government for that specific purpose. The enabling legisla- tion differs from state to state, but these special purpose units typically have defined legal authority to manage the water and to raise money in certain geographic areas. For example, the far- mers around White Clay Lake in Wisconsin formed a special lake district to under- take a lake protection project. A General Purpose Unit of Government Other states have chosen not to en- courage proliferation of special purpose units of government. In these states, the cities, villages, towns and counties are expected to provide the essential govern- mental services. In some cases, a lake community may attempt to incorporate and become a new village or city. In most cases, the lake community must convince the elected officials of existing units that the lake can be managed and must be managed. The general purpose units of government have the broadest array of man- agement, financing, and police powers available to them. For instance, the Village of Scotia, New York organized the restoration effort at Collins Park Lake. However, lakes often cross political boun- daries and lake management is inhibited by multiple jurisdictions. 25 ------- What Kind of Lake Do We Uant? No lake will satisfy perfectly every- one's desires. A lake with ideal swimming conditions is not likely to provide good fishing. A lake that is used primarily for water supply may be drawn down in summer and the bare mud flats may not be aesthetically pleasing. Some uses are incompatible on the same lake. Other uses can be accommodated on the same lake but must be separated by time or zones. A community should decide what type of activities are possible and what acti- vities are preferred on the lake and then attempt to manage the lake accordingly. The compromise should reflect the inter- ests of the various user groups and the broader public as represented by state agencies. you can't swim in a weed bed you can't fish in a swimming pool Vl|l you can't build a home in a greenway you can't tax a cattail you can compromise 26 ------- What Do Me Need to Know About the Lake? Lake problems might be obvious, but the solutions often are not. Some members of the community are likely to have strong opinions about what to do, and these opin- ions are likely to differ. Before devel- oping a management plan and undertaking any project, certain basic information is essential. A Water and Nutrient Budget Lake water can originate from direct rainfall, direct drainage, storm sewers, stream flow, groundwater flow, and sewage treatment plants. The source of the water often determines the amount and type of nutrients, sediments and other pollutants entering the lake. Similarly, the way water leaves determines the impact of these materials. In some lakes, most nutrients are flushed through the lake by a flowing river before algal blooms can occur. In other lakes most nutrients stay in the lake and accum- ulate to feed more weeds. A water budget indicates where the water is coming from and where it is going. A nutrient budget points out what sources need to be con- trolled. Hypothetical and Lake Water, Phosphorus Nitrogen Budget Water Rainfall /evaporation Direct drainage Sewage treatment plants Streams Groundwater Total IN 5 10 10 50 25 100% OUT 20 0 0 20 60 100% 5 5 35 50 5 100% Nutrients IN 20 5 25 15 35 100% OUT 0 0 0 20 30 - 50% 0 0 0 20 40 60% 27 ------- Hydrographic and Vegetation Maps The water depth and type of bottom material determine the distribution of aquatic vegetation in a lake. In turn, the bottom contours of the lake and type of vegetation determine the temperature and oxygen levels which influence the array of fish and other animals in the lake. Depth contour maps and vegetation maps show the areas and types of nuisance weeds as well as the areas which might be considered for dredging, aeration or other management treatments. A Watershed Analysis It is important to know the general land use in the watershed. Certain land uses are more likely to contribute sedi- ments and nutrients and other pollutants that can't be traced to a particular source. It is also critical to identify specific sources of pollution such as storm sewers, sewage treatment plants, certain industries, some barnyards, and areas of rapid erosion. In-Lake Water Analysis Regular sampling and testing of the water in the lake throughout the year will help indicate particular problem areas and will monitor lake response to management changes in the watershed. Testing may involve bacteria, toxins, water depth, sediment depth and type, and vegetation changes as well as nutrient concentrations. 28 ------- COURTHOUSE DIRECTORS COOHTV UNIVERSITY ZOHIN6 SAHVT PLAN 66JST6R OF TRA1H1H6 Who Can Help Us?—Local The best place to start looking for help is in your own conmunity. A science teacher at the local high school or com- munity college might be able to conduct some of the analyses as well as help resi- dents understand the lake. For instance, professors and students from Union College were heavily involved in the Collins Park Lake, New York, project. Retirees in the community might also be able to volunteer certain skills. Other professionals may be found within a few miles of your community, often in the county courthouse. The planning and zoning office can provide information on present and future land use around the lake and in the water- shed. The Soil and Water Conservation District in cooperation with the U.S. Soil Conservation Service can provide soils maps and help in formulating plans to reduce erosion. State and federal cost-sharing programs for land management are often administered at the county or town level. The Univer- sity Extension Service can provide tech- nical assistance, help organize educa- tional meetings, and assist in preparing applications. 29 ------- Who Can Help Us?—State Some states have developed a complete lake management program. Some offer lim- ited assistance as a part of other pro- grams. In other states, very little assis- tance is available. In such states, lake communities may wish to encourage their state legislature to provide assistance. Information Assistance No one has a monopoly on information and many institutions can provide a valu- able service with regard to understand- ing the lake, lake management techniques, and organizing for action. The Extension branch of a state-supported university is usually willing and able to provide such information. Other sources include federal, state, and county natural re- source agencies; community colleges; libraries; and high schools. Technical Assistance Specialized information and services might be obtained from limnologists, aquatic biologists or fish managers who are employed by a state conservation, natural resources, or environmental agency. In other situations, it may be necessary to hire a consulting firm to gather and interpret data on the lake. Financial Aid A few states have special grant pro- grams for lake protection and rehabili- tation projects. The White Clay Lake community received such a grant from the Wisconsin Department of Natural Resources to build manure storage facilities. In other states, various grant programs might be utilized depending on the nature of the project. Parks might be purchased and developed. Protective vegetation might be planted on roadsides and gullies. Greenway areas provide open space and pro- tect the fragile ecology of the shoreline. 30 ------- Who Can Help Us?—Federal The following programs can provide financial assistance for a variety of activities designed to enhance lakes as public resources. These programs are typically combined with state and local assistance. In some cases, it is also possible to enlist the support of more than one federal program. For instance, Penn Lake in Bloomington, Minnesota re- ceived assistance from both EPA and the Department of Housing and Urban Develop- ment. AGRICULTURE—Soil and Water Conservation The Department of Agriculture has a long history of helping farmers conserve their soil. Born in the dust bowls of the Great Depression, the Soil Conserva- tion Service (SCS) has provided technical assistance to landowners. The Agricul- tural Stabilization and Conservation Ser- vice (ASCS) has assisted with cost sharing of certain land management practices. In recent years, emphasis has also been placed on keeping soil and nutrients out of water; major new funds have become available to assist with control of "non- point" pollution, such as animal wastes. The Farmers Home Administration provides grants and low-interest loans for construc- tion of public sewers in rural areas. The programs are typically administered at the county level. COMMERCE--Regional Commissions Environmental management and economic development can be complementary. In recog- nition of that complementarity, the regional commissions have provided grants to enhance management of natural resources, including lakes. For example, the White Clay Lake project began under a grant from the Upper Great Lakes Regional Commission. DEFENSE—Army Corps of Engineers The Corps has a long history of in- volvement in lakes and reservoirs regard- ing navigation and recreation. Financial assistance is available for aquatic nui- sance control. 31 ------- vvEPA EPA--Clean Water Act Since 1976, the U.S. Environmental Protection Agency has been awarding funds; under the "clean lakes" section (314) of the Clean Water Act (33 U.S.C. section 1251 et_ se£.). Cost sharing grants have been made to rehabilitate or protect lakes in every part of the country. See the last page of this booklet for EPA regional offices. In addition to the "clean lakes" program, other parts of the Clean Water Act provide funding for activities re- lated to lakes such as construction of sewage treatment plants and alternative waste management systems (Sec. 201-205) and area wide planning for wastewater management (See Sec. 208). HUD—Block Grants Grants for either single purpose or comprehensive community development acti- vities are available from the Dept. of Housing and Urban Development. Eligible projects include construction of sewer lines, purchase of parkland, and construc- tion of recreational facilities. Prefer- ence is given to communities with low and moderate income families. Local or re- gional planning and development agencies are likely to be familiar with this pro- gram. INTERIOR—Lawcon The Land and Water Conservation Fund provides cost-sharing grants to local units of government that have completed a com- prehensive outdoor recreation plan. The grants can be used for either acquisition of land or the development of basic out- door recreation facilities. The grants are administered through the state natural resources agency,, 32 ------- HARVEST, AERATE What Are Qur Options?—Management Alternatives Understanding the Options With the assistance of private consul- tants and public agency personnel, community leaders can consider atlernative courses of action. Typically there will not be a single easy solution. The development of a management plan requires public participa- tion as well as professional expertise. A component of the public participation effort should be a systematic educational effort. A Mix of Benefits Recreational benefits are the most widely recognized benefits of lake protec- tion and rehabilitation projects. However, potential benefits include: 1. Increases in property values 2. Aesthetic enjoyment (solitude and beauty) 3. Growth in tourism 4. Recreation (fi'shing, swimming, boating, etc.) 5. Community self-image and pride Recognizing the Risks The community should be aware that lake management is still a young science with limited predictability. For instance, a program to eradicate rough fish may im- prove game fishing, but water skiing may be hampered by the resultant growth of rooted vegetation. Unless the source of plant nutrients is controlled, attempts to poison weeds may lead to more algae. Caution is advised and the risks should be discussed by the entire community. Certain risks are acceptable in terms of the goals for the lake; others are not. Proceed with caution, but proceed. 33 ------- How Do Me Implement Our Lake Management Projects? Management Flowchart A plan for lake management often in- volves a sequence of events which unfold over a course of several years. A sample outline follows: Year 1--Organizing Year 2--Studying Year 3--Deciding: Management plan to: divert storm sewers from the lake, treat the lake to pre- cipitate out phosphorus from the water, and aerate to im- prove oxygen content. Year 4--Diverting Storm Sewers Year 5--Treating lake with alum to precipitate phosphorus Year 6--Aeration Year 7--Monitoring Once a decision on a project has been reached, formal documents can be prepared to obtain the necessary services. The administrative rules of granting agencies and general statutes are likely to require certain bidding and contracting procedures. Raising Local Matching Funds A substantial community investment may be necessary to match grants from federal and state agencies. The particu- lar method of raising revenue will depend on the statutes of each state and the decisions of the community. Project Management A project director will be necessary for any major project. At certain junc- tures, an attorney's assistance may be necessary. Provision should also be made for accounting services. Publicity The local newspaper, radio, and TV reporters are a critical link to public education and project acceptance. The whole development of a project should be fully chronicled. What Happens After the Project? Monitoring and Continued Lake Management Lake management is not simply a one- shot project. The impacts of human use on the lake and in the watershed continue, Management means continuing care and con- cern, the same as exercised on a home or a business. Management means lake monitoring after the project is completed to: 1. Determine the success of the project. 2. Detect any new sources of pol- lutants at an early stage. 34 ------- future efforts. A minimum of an annual meeting and a mid-year newsletter are sug- gested to keep the organization functioning. Continued Citizen Involvement It is especially difficult to convince citizens that lake management is a contin- uing responsibility demanding their inter- est and participation. Unless the beach is closed or weeds choke the channel again or water levels change dramatically or toxic chemicals are found in fish, most citizens probably will not pay too much attention to lake management efforts. Nevertheless, it is important that regular opportunities be provided for education and participation between the crises. Some of those crises can be avoided by diligent preventive efforts and a continuing program of lake monitoring and management. Management means constant vigilance regarding lake or land use changes in the watershed and readiness to represent the interest of the lake community at public hearings and other meetings. Management also means the operation of a dam or a weed harvester on a contin- uing basis if necessary and the planning and completion of subsequent projects as suggested by the monitoring data. Organizational Maintenance Once the project is completed, commun- ity leaders often sigh with relief and bask in congratulations. It is important to reward dedicated leaders with community recognition. However, the right-to-pride should complement a commitment to continue-- to maintain the organizational structure for 35 ------- For Further Information For information regarding the Federal Clean Lakes Program, contact the Clean Lakes Coordinator at the U.S. Environmental Protection Agency regional office: Region 1 -- EPA John F. Kennedy Federal Building Boston, MA 02203 Region 2 — EPA 26 Federal Plaza New York, NY 10007 Region 3 — EPA Curtis Building 6th & Walnut Street Philadelphia, PA 19106 Region 4 — EPA 345 Courtland Street, N.E. Atlanta, GA 30308 Region 5 -- EPA 230 S. Dearborn Street Chicago, IL 60604 Region 6 — EPA First International Bldg. 1201 Elm Street Dallas, TX 75270 Region 7 -- EPA 1735 Baltimore Ave. Kansas City, MO 64108 Region 8 -- EPA 1860 Lincoln Street Denver, CO 80203 Region 9 — EPA 215 Fremont Street San Francisco, CA 94105 Region 10 -- EPA 1200 6th Avenue Seattle, WA 98101 For information on state programs, contact your state agency with responsi- bility for fish and game, water quality, outdoor recreation, or natural resources management. For information on local, state and federal programs, many of which are ad- ministered locally, contact your local county agent in the University Extension Office or other agencies with local offi ces. 36 ------- Suggested References Bouldin, D. R. et al., 1977. Lakes and Phosphorus Inputs, A focus on management. Information Bulletin 127, Cooperative Extension, Building 7, Cornell University, Ithaca, New York. Deardorff, Howard, 1977. The Public Benefits of Cleaned Water: Emerging Greenway Opportunities. Booklet. U.S. EPA, Office of Land Use Coordination (A-101), Washington, D.C. Nichols, Stanley A., 1974. Mechanical and Habitat Manipulation for Aquatic Plant Management. Technical Bulletin No. 77, Department of Natural Resources, Madison, Wisconsin. Dunst, Russell C. et al., 1974. Survey of Lake Rehabilitation Tech- niques and Experiences. Technical Bulletin No. 75, Department of Natural Resources, Madison, Wisconsin. Ehrenfeld, David W., 1970. Biological Conservation. Holt, Rinehart and Winston, Inc., New York, New York. 226 pp. Klots, Elsie B., 1966. The New Field Book of Freshwater Life. G. P. Putnam's Sons, New York, New York. 398 pp. Lind, Owen T., 1974. Handbook of Common Methods in Limnology. C. V. Mosby Company, St. Louis, Missouri. 154 pp. Migel, J. Michael, Editor, 1974. The Stream Conservation Handbook, Grown Publishers, Inc., New York, New York. 242 pp. Needham, James G. and J. T. Lloyd, 1937. The Life of Inland Waters. Comstock Publishing Company, New York, New York. Reid, George K., 1961. Ecology of Inland Waters and Estuaries. VanNostrand Reinhold Company, New York, New York. 375 pp. Ruttner, Frantz, 1972. Fundamentals of Limnology, 3rd Edition. Univer- sity of Toronto Press, 295 pp. Vallentyne, John R., 1974. The Algal Bowl, Lakes and Man. Misc. Special Publication 22, Canada Department of the Environment, Fisheries and Marine Service, Ottawa. 186 pp. Wetzel, Robert G., 1975. Limnology, W. B. Saunders Company, Phila- delphia. 743 pp. *U.S. GOVERNMENT PRINTING OFFICE : 1979 O -260-173/6140 37 ------- |