review of lake restoration procedures

WATER RESOURCES BULLETIN VOL. 9, NO. 3 AMERICAN WATER RESOURCES ASSOCIATION JUNE 1973

REVIEW OF LAKE RESTORATION PROCEDURES'

Charles J. Boyter and Martin P. Wanielista'

ABSTRACT. Relevant information on the restoration of lakes is presented. The restoration procedures considered are applicable to the water, the bottom sediments, and aquatic plant improvement. A summary of thirteen (13) suggested methods of restoration are reviewed. (KEY TERMS: lakes; restoration procedures; water quality; bottom sediments; aquatic plants)

INTRODUCTION

Our nation is faced with the critical problem of improving the water quality conditions which exist in many of our lakes. In our efforts t o provide for the needs of our society, the consequences of our actions have resulted in an environment which may not be fit for society. The water environment in some of our lakes has deteriorated and now methods must be found t o return these waters to a better condition. The complete elimination of a lake may not be a bad solution in some cases. However, this is very unfeasible in many situations.

In an effort to specify the type of procedures that can be used for lake restoration, an extensive literature review was performed and relevant information was abstracted. In addition, actual restorations in Florida were studied and documented. This paper reports on the results of a search to find what restoration procedure to use for a given lake condition.

BACKGROUND INFORMATION

The initial step in the lake restoration process is problem identification. Whether the deteriorated conditions are due to nutrient enrichment (eutrophication) and/or the result of organic, toxic, or other pollutional inputs will dictate primary control measures. Whereas the techniques reviewed are directed toward eutrophic lake situations, their source control aspects could apply in cases that involve other pollutants.

Eutrophication is the process of nutrient enrichment of water usually accompanied by a depletion of oxygen. It often results in symptomatic changes in lakes, including increased production of algae and other aquatic plants, deterioration of fish life, and other responses that impair water uses and are found objectionable [Bartsch, 1972; Doyle, 19711. Toxic inputs that increase concentrations of certain substances to levels at which lethal injury to fish occurs are common [Ellis, 19673.

In the control of eutrophication, Bartsch [ 19721 concludes that the limiting of phosphorus availability in lakes is the single, most important and necessary step to be taken. Of all the

Respectively, Ph.D. candidate, University of Colorado, Boulder, Colorado; Director, Environmental ' Paper No. 73054 of the Water Resources Bulletin. Discussions are open until January 1 , 1974.

Systems Engineering Institute, Florida Technological University, Orlando, Florida.

499

500 Boyter, Wanielista

nutrient elements known to be growth controlling in lakes, phosphorus is the only one which can be, to a great extent, controlled by man. This conclusion is also based on evidence provided by Vallentyne [ 19701 .

Control of only the point sources of pollutional discharge will not necessarily result in restoring the lake to the desired level [Tenney et al, 1972; Edmondson, 19641, Consideration must also be given to the biogeochemical cycling of pollutants within the lake. This inherent cycling of pollutants between the water, the bottom sediments, and the aquatic life is dependent in magnitude on the quantities of nutrients present. Tenney, Yaksich, and DePinto [ 19721 state that “The magnitude of these cycles characteristically increases proportional to the extent of pollution of the water body” .

The retention of pollutants in the lake depends not only on flows alone, but also on the absorption, release, and interchange of pollutants between the biota and bottom sediments with the water acting as vehicular transport [Tenney et al, 1972; Edmondson, 1964; Allyn,

Recent lake restoration procedures have included the aquatic plant life and the bottom sediments as potential pollution sources. The following subsections review techniques applicable to the improvement of the water, the bottom sediments, and aquatic plants.

1971-721.

THE WATER

The techniques of lake restoration which apply to the water include: 1) the elimination of pollutants entering the water from controllable sources, 2) replacing the water with high quality water, 3) direct treatment of the existing water.

Two principal approaches have been suggested for control of entering pollutants. One consists of collecting and diverting pollutional flows to a less susceptable watercourse; and the other involves selection of one nutrient, namely phosphorus, and curtailing its input.

Diversion has been employed at several locations in the United States and in Europe on flows of wastewater and from wastewater treatment plants [Bartsch, 1972; Edmondson, 19641 but relatively little attention has been given to diverting urban stormwater flows. Bryan [1972] found that “the total solids contribution annually by urban stormwater is substantially larger than would be expected from the discharge of raw sewage from the same area.” The phosphorus concentrations present in urban stormwater for the United States range from 0.1 t o 1.4mg/l [Bartsch, 19721.

One treatment process improvement reviewed, which could be applied to effectively remove phosphorus and other pollutants, involves the addition of a coagulation process to normal wastewater treatment procedures and the use of pH and zeta potential as well as coagulant dosage as parameters of control. McLellon er a1 [ 19721 found the addition of this process and controls t o be effective for removal of colloidal materials, COD, microbial cells, nitrogen, and phosphorus. During experimental operations, the removal efficiencies of residual phosphorus in trickling filter effluent were observed to exceed 99 percent.

There are several other pollution sources to be noted. Reported concentrations of phosphorus in precipitation range from 0.3 to 130 mg/l in the United States and Europe; estimates of nutrient inputs to lakes by wild ducks have been based on an average yearly excretion of 477 g nitrogen and 204 g phosphorus per bird; and runoff from agricultural and cattle grazing land contain enormous quantities of pollutants (Bartsch, 1972). Citrus farm drainage, as an example, contained nitrogen and phosphorus concentrations ranging from 4.54 to 33.4 mg/l and from 1.4 t o 52.9 mg/l respectively, when analyzed during Lake Apopka studies (Kaleel and Sheffield, 1971).

REVIEW OF LAKE RESTORATION PROCEDURES 501

Curtailment of all practically controlled pollution discharges is essential to any lake restoration procedure. However, when this action alone is employed, the rate and amount of improvement resulting will depend on the remaining hydrologic flows. Faster improvement will occur in lakes with short hydraulic residence times and that are being flushed with high quality water. Edmondson (1964) revewed several instances where only point source pollution curtailment or diversion were employed. Lake Monona in Wisconsin took twnety years t o make a noticeable recovery after pollution discharges were terminated. A small lake near Copenhagen showed signs of improvement within one to four years after discharges were diverted. But n o signs of improvement were noted fifteen years after diversion of discharges from Red Lake (Rotsee) at Lucerne, Switzerland.

REPLACEMENT WITH HIGH QUALITY WATER

The replacement of the existing water in the lake with that of a higher quality has the requisite that a high quality water is readily available and that a convenient discharge mechanism exists for the existing water.

The replacement can be accomplished by introducing the high quality water directly into the lake and allowing it to displace the existing water or by drawing out (drawdown) existing water and refilling with the high quality water. Drawing down, then refilling has the advantage of resulting in a higher water quality per unit volume than could be achieved with the displacement method due to the mixing of the waters during displacement. But, in most cases, the pumping requirements of the drawdown method would make it more expensive.

The drawdown method has additional advantages in aquatic plant control and bottom sediment manipulation which will be discussed in more detail in the respective subsections. Examples of drawdowns are: Lake Trafford, in Immokalee, Florida (a natural drawdown resulting from a drought in 1962); Lake Jackson, located in Tallahassee, Florida (a natural drawdown as a result of a sinkhole); and Lake Tohopekaliga in Kissimmee, Florida (an artificial drawdown). All of these resulted in improved lake conditions [Florida Game and Fresh Water Fish Commission, 1972; Florida Technological University, 19721 .

The displacement method was employed in Green Lake situated in Seattle, Washington. From '1962 to 1967 the lakes volume was displaced the equivalent of five times with the city's drinking water, resulting in a reduction of orthophosphate concentration from 80 mg/l to 20 mg/l and an increasing Secchi disc transparency readings from 1.3 to 6.3 meters [Oglesby and Edmondson, 19661. This has the distinct disadvantage of being expensive, but the results obtained probably were well worth the cost.

DIRECT TREATMENT OF THE EXISTING WATER

Treating the existing water can be accomplished by moving it t o external treatment facilities or consideration may be given to use of various proposed in situ treatment methods.

When external treatment is employed, any degree of treatment can be achieved. The particular treatment process used will depend on the quality desired for the return water. Some improvement can be accomplished with only chemical coagulation followed by plain sedimentation. This treatment will remove large amounts of color, turbidity, algae, bacteria, phosphorus, and many other impurities. When more efficient removals are desired, granular filtration and activated carbon can be included. The cost associated with this treatment range from $30 t o $60 per acre-foot [Tenney et al, 19721. Treatment modules, which could greatly reduce the installation costs associated with external treatment, are currently under


investigation [Tenney et al, 19721. In situ methods proposed for consideration include: destratification, which tends to

establish uniform profiles of nitrients; dissolved oxygen, and other parameters in the lake water; nutrient inactivation by the addition of metal ions or particulate materials to precipitate the nutrients; and the removal of nutrients by growth and control of aquatic plants.

Destratification techniques involve the installation of compressed air or mechanical pumps or diffused air systems. These systems set up currents to accomplish mixing of stratified waters. The uniform profile established for dissolved oxygen has favorable application in the control of releases from the bottom sediments.

The process of nutrient inactivation is similar to the process of coagulation in that an additive materials (metal ions or particulates) are mixed into the water to form flocs, precipitate and/or absorbed nutrients. The agglomerates subsequently settle to the bottom of the lake. Inasmuch as efficiency of this process would be dependent on the amount of mixing accomplished, it would tend to be less effective in lakes of considerable depth. Also, as coagulation and precipitation mechanisms involved in the process are pH dependent, the pH of the lake water could be the deciding factor in use of the process. Optimum pH values for coagulation with alum are in the range of 5.0 - 7.0 [Eckenfelder and Ford, 19701, and optimum pH values for precipitation of phosphorus with alum are in the range 7.1 - 7.7 [Eckenfelder, 19661. The pH decrease in the water accompanying both these mechanisms are potentially dangerous to aquatic life. Similar pH changes and optimal ranges apply when particulate materials are used depending on the chemical elements or compounds present in the specific fly ash or clay involved. In consideration of the use of nutrient inactivation in a lake, extensive testing should be performed to determine optimum pH, optimum dosage for the additive being considered and its effects on aquatic life forms, and the pH change to be expected during treatment for the particular lake water. Research for this study was unsuccessful in finding any work toward investigating possibilities of the ultimate return of inactivated nutrients to the lake water.

The use of aquatic plants to remove nutrients from lake water has favorable possibilities. Sheffield, [ 19691 employed water hyacinths (Eichornia crassipes) in a combination algae pond - hyacinth pond - coagulation series to effect the removal of 77-80 percent total phosphorus and 38 percent total nitrogen from wastewater treatment plant effluent. In the hyacinth pond alone, consisting of a three-feet deep pond and providing a two-day detention time, total phosphorus was reduced from 49 to 43 mg/l and total nitrogen was reduced from 16 to 13 mg/l. An unfavorable decrease noted was that of dissolved oxygen which can be accounted for by the plants occupying the entire surface area and preventing oxygen transfer. A conceivable remedy to this for application in lakes would be sectioning with a fencing material to insure that a relatively small area of the lake's surface is occupied by plants.

Dymond [1948] found that hyacinths grown in water with nutrients of optimum availability would contain 2.23 percent nitrogen and 8 percent phosphorus on a dry weight basis. He advocated the use of hyacinths for use in removing nutrients from sewage.

Steward [1968] postulated that water hyacinths, with a theoretical productivity of 67 tons 'of dry matter per acre per year in sub-tropical Florida, could effectively remove the yearly contribution of nitrogen in waste from 595 people per acre per year and the phosphorus contribution from 180 people per acre per year. He also indicated that hydrilla produces one dry ton per acre per year which could remove the nitrogen and phosphorus from 9 and 3 people per acre per year respectively. He observed the nutrient ratio of these plants to be about 10: 1 N to P.


Control and management techniques could conceivably be adapted, with only minor difficulty, for the aquatic plant control of nutrients in lakes of Florida and other southern states using the water hyacinth. Research is in process for uses of harvested water hyacinth (as will be discussed in the Mechanical subsection of Aquatic Plant Control) which offset the operational expense anticipated.

THE BOTTOM SEDIMENTS

Bottom sediments of lakes absorb and entrap nutrients from the water and those resulting from the decomposition of plant and animal materials. The desorption or release of these nutrients to the overlying water appears to depend on the capacity of the bottom sediments themselves, the dissolved oxygen concentration in the overlying water, the nutrient concentration in the water, and the nutrient concentration present in the interstitial water of the sediments [Tenney, 1972; Edmondson, 1964; Fishburn, 19691 .

Due t o the relatively insoluble characteristic of phosphorous compounds and the slowness of diffusion in sediments, only the top few millimeters (approximately 10) are actively engaged in phosphorous water and possibly most of the absorptive activity is confined to the top millimeter. In lakes with dense populations of bottom dwelling insects, mixing and transport from deeper depths may be made by animals, but this activity may be negligible below about 15 cm. depth [Edmondson, 19641. With these limitations noted and the possibility of rather high quantities of nutrients present in the top inch of sediment, it is important to note that if restoration techniques are employed to remove impurities from the water phase a new equilibrium can be expected between the sediments and the water (including accelerated releases of the bottom sediments).

Techniques to control pollutional releases from the bottom sediments have been divided into three categories: sediment covering, oxygenation, and dredging.

Sediment Covering

Methods proposed for consideration in sediment covering are covering with liner type materials such as rubber sheets and polyethylene sheets and covering with particulate materials, including fly ash, clay, and sand.

In the use of liners, one must consider the chances of destruction of the material and possible ballooning of the liner due to entrapped air and other gases. The liner most resistant to degradation from sunlight appears t o be black polyethylene. Wirth [1971] found that thicknesses in the range of 4 to 8 mil used in small ponds and lakes allow penetration of only the most stubborn grasses and weeds and suggests that the use of perforated sheets, weighted with sand, could overcome ballooning and still appreciably retard nutrient release.

Covering with fly ash or clay is favored over sand or silts when used on sediments of high water content because the latter have a tendency to sink below the top surface of such sediments. Sands and silts however, could be an effective barrier on low-water contained sediments. Fly ash will settle rapidly onto the bottom sediments, but clay will generally require addition of a flocculant t o assist in sedimentation. Taksich [ 19721 found laboratory studies to indicate that kaolinite in particular, is an effective clay. When kaolinite or fly ash were used on sediments, they had the additional advantage of removing phosphorus while settling.

Each method has additional research requirements prior to use. The probabilities of establishment of a beneficial benthic environment must be favorable. With fly ash or clay, the possibilities of releases of undesirable constituants and the desorption of pollutionary


impurities (absorbed while settling) are deserving of investigation.

Oxygenation

Bottom sediment releases under anaerobic conditions are large compared to releases when aerobic conditions exist in the hypolimnetic waters (roughly 1 0 to 1). This ratio and others [Mortimer, 19711 illustrate that as long as the dissolved oxygen concentration in the bottom waters remained above 1 mg/l, bottom sediments do not give up their nutrients to the water column. Methods suggested t o achieve this include destratification and aeration techniques. Destratification involves the use of compressed air lift pumps or mechanical pumps employed to move relatively small amounts of bottom water to the surface. This sets up currents to achieve mixing, in turn establishes a uniform profile of dissolved oxygen and prevents anaerobic conditions in the hypolimnium.

Symons [ 19691 found that, for lakes smaller than 10,000 acre-feet, the entire water mass can be mixed with one pump located at the deepest point in the lake. Pumping 10 to 20 percent of the cold (bottom) water to the surface set up the necessary currents for mixing. Capital or installation and operation costs decrease logarithimicaly as volume to be mixed increases [Journal American Water Works Association, 19711. Approximate cost for a 10,000 acre-foot lake are $3 per million gallons ($1 per acre-ft.) for installation and $0.45 per million gallons ($0.1 5 per acre-ft.) per year for operation.

For aeration of the hypolimnetric waters, a system was engineered by Hinde Engineering Company for the proposed project of restoring Lake McCoy at Apopka, Florida. Estimated cost of the equipment was $1,000.00 [Wanielista, 19711.

Speece [ 19701 contents that both aeration and destratification could have undesirable effects on the lake environment. Dissolved nitrogen concentrations in excess of 104% saturation, which would result from aeration with diffused air systems, have been proven to have adverse effects on trout and salmon. Also destratification could result in increased eutrophication effects due to the larger nutrient concentrations made available in the upper (photosynthetic) zone of the water. He advocates the use of pure oxygen in aeration procedures.

Dredging

Dredging of the bottom sediments has been suggested as a means of removing their pollution potential. This suggestion is understandable considering the fact that dredging is a common means of maintaining navigable harbors, rivers, and lakes and the equipment is readily available and understood. But used for such purposes, dredging has had the immediate effects of deteriorated water quality in many cases [Tenney, 19721,

Of the three basic types of dredges (dipper, ladder, and suction), only the suction type appears suitable for the purposes of lake restoration. The other two types would obviously mix a considerable amount of the sediment into the water resulting in a higher nutrient concentration and resettling, consequently defeating the purpose of the project. Suction dredges pick up the bottom material and water in suction pipes, and the mixture is discharged by pumping through a spoil pipe supported by floats to the desired spoil area [Linsley and Franzini, 19701. In dredging for navigation purposes, the spoil area is usually a point downstream from or on the shoreline near the dredging operation. But for lake restoration purposes, the spoil area could be an evaporation type pond in close proximity to the lake and of sufficient size to accomodate the water and dredgings.

The accessibility of barge-borne dredges to the lake could make dredging costs prohibitive.


AQUATIC PLANTS

The third major area of treatment in lake restoration processes is undesirable plants or plant productivity. Treatment in this area consists of removal or control of the particular plants with the goal of restoring the natural balance. The techniques for this purpose are categorized as chemical, mechanical, biological, and physical.

Chemical compounds have proven effective in temporary improvement of nuisance aquatic plant conditions. Many chemical compounds are commercially manufactured and readily available, as algicides and herbicides. In the choice of a chemical compound for aquatic plant control, consideration must be made as to whether or not:

1) It will kill the specific plant or plants; 2 ) be toxic to fish or fish food organisms at the concentration required t o kill the target plant(s); 3) have serious effects on the general aquatic ecosystems; 4) be toxic t o man; and 5) be reasonable in cost.

An immediate improvement of nuisance-plant conditions can be accompfished with chemical treatment, but it is at best only a temporary inprovement. The dead plants remain in the lake and no net nutrient reduction is effected. Other plant growth may be stimulated by nutrient releases resulting from decomposition of the treated plants. Chemical treatment, when used, generally requires retreatment periodically. Research is in process to find long-term low-dosage release mechanisms for chemical treatment of aquatic plants [Raynes, 19721, but adequate field testing will be required prior to their use.

Oxygen levels, characteristically, are reduced following chemical treatment due to the oxygen demand of the organic matter of the destroyed plants; similarly, nutrient levels will be increased due to cellular releases during plant decomposition. Also, of major significance, is the fact that potentially hazardous side effects can be observed for residual chemical concentrations a t sub-lethal treatment dosages. Extreme caution should be exercised in this regard in order to insure that the chemicals will not accumulate in the tissues of organisms.

Mechanical Control of Aquatic Plants

The most elementary method of removing obnoxious aquatic plants is to drag or throw them onto the banks with rakes or forks where they dry out and die. This, today, is impractical not only because of being the most expensive of all methods of control but because of considerations given to effects on the environment.

A number of mechanical weed cutting and harvesting devices have been developed and successfully, although expensively, employed in specific applications of aquatic weed removals. These have included spray equipment, crusher boats, wood chippers, devices for transporting personnel and equipment over difficult terrain, amphibious tractors, and even a machine which floats on its own air cushion at speeds up to 60 miles per hour [Raynes, 19721 . The high costs normally associated with mechanical operations previously deterred research on mechanical devices, but the limits placed on specific herbicides have caused more emphasis to be given to mechanical methods. Mechanical methods which physically remove obnoxious aquatic plants from a lake and dispose of the plants in such a manner as not to return their nutrients to the lake environment would obviously be more favorable.

The commercially available aquatic plant harvesters or cutters on the market today range in price from $40 to more than $40,000. Estimates of costs of acreages served by mechanical harvesters vary from $35/A. to $500/A. Estimates for hyacinths in particular range from $150/A. t o $500/A. averaging from 3 to 5 acres per day removal rates for mechanical harvesters [Raynes, 19721.


Uses for harvested aquatic plants, including hyacinths, are currently being investigated by the University of Florida in cooperation with the Florida Department of Natural Resources and the Florida Game and Freshwater Fish Commission and the Southwest Florida Water Management District which has been actively engaged in such studies since 196 1. Investigations include studies regarding nutrition values of aquatic weeds for use in feeding animals and mulch fertilizers [Raynes, 19721. These markets could greatly reduce harvesting cost and make the use of aquatic plants for nutrient removal from lakes more practical.

Studies on the use of hyacinths for fiber in fiber board production by Jim Walter Research Corporation in St. Petersburg, Florida has already proven favorable. The water hyacinth stock required less processing time and power consumption than did mixed hardboards and bagasse, which are normally used for fiber board production. The hyacinth fiber board also has additional toughness and resiliency qualities. Only present harvesting cost make its use in this application prohibitive.

Biological Control

The control of aquatic plant nuisances by natural or biological methods is a theoretical and ideal goal. It might be a permanent, built-in control which is self perpetuating at virtually no cost except that needed t o initiate the process. The methods proposed for this purpose includes the induction of insects, snails, manatee, herbivorous fish, pathogens, and competitive plants [Raynes, 19721, the primary objective being the reduction of the density of the target plant. The plant and the biological control agent must become a part of the aquatic ecosystem. The main disadvantage of biological control is that it is much slower in adequately reducing the target plant population.

Considerations recommended for selection oi a species for biological control include:

1. The selected species must be able to survive in the subject lake environment (e.g.,

2. The selected species must be able to reduce the population of the undesirable target

3. The selected species must be able to co-exist peacefully with other species desirable to the

4. Studies have been initiated with slender spikerush (Eleocharis acicularis) and other

maintain themselves against predation, sustain temperature changes, etc.);

species;

aquatic ecosystem, and

competitive plants at Davis, California [Blackburn et al, 19711.

Many other studies are either under way or have been proposed for the biological control of aquatic plants but at present the area is lacking for solutions applicable under the environmental conditions of the United States.

Physical Control

Physical controls reviewed for the purpose of aquatic plant control include: 1) water fluctuation and drawdown, 2) irradiation with laser beams, 3) and light limiting substances.

Natural water fluctuations and drawdowns reveal possibilities for use of controlled drawdowns in the control of aquatic plants. During drawdowns the aquatic vegetation along the lake periphery dries out and dies. Generally, it is replaced by terrestrial or swampy plant communities. Upon the reestablishment of the previous water level, the terrestrial vegetation now covered with water, dies, and the submerged plants increase in growth. However, it usually


takes several years for the submerged vegetation to regain its original proportion. An additional desirable effect noted with drawdowns is the increase in number of sport fish

after drawdown procedures are complete [Wohlschlag, 19521. This is believed to be the result of improvement in bottom surface, which is the spawning habitat of many sport fish.

In some instances, drawdowns may result in or eventually lead t o increased submerged vegetation being established in the deeper portions of the lake during the drawdown; where the light intensity had previously been insufficient for them to take hold. When the water level is again raised, the plants continue to grow where no vegetation could previously exist. To retard this expansion, it would be desirable that drawdown operations be performed during the colder months while plant growth rates are lower.

Laser beams are being studied for control of aquatic plants such as the water hyacinth, watermilfoil, elodea, and alligatorweed [Raynes, 19721. The beam used to irradiate floating hyacinths is not a concentrated beam but is diffused and spread by the use of mirrors. Initial effect of the high power, nitrogen-carbon dioxide-helium gas laser beam is a surface burning of the plant. During the three t o four weeks required for the plant to die and sink to the lake bottom after exposure, the plant may reproduce sending out stolens which can produce daughter plants. Tests indicate these daughter plants are not affected by their parent plant being exposed to the beam and they must be retreated to effect control. The laser beam does not penetrate the water surface and has no direct effect on aquatic life below the surface. Future studies include development of a laser unit for underwater use.

Some success has been obtained in controlling submerged vegetation with selective dyes or black plastic that filter out all or selective portions of sunlight in water [Blackburn, 19711 . The problem t o be considered in their use is that of the effects on all vegetation and side effects include the lake’s entire aquatic ecosystem. In addition to light limiting effects, one must insure that the substance itself is non-toxic, biologically stable and non-restrictive to oxygen transfer reactions with the atmosphere.

SUMMARY

The type of restoration procedure used on a lake can only be determined after an extensive investigation. There are thirteen (13) acceptable methods that have been practically used. Each method has its effects on water quality, bottom sediments and aquatic plants. A summary with comments of these methods is given in table 1 .

The decision to clean up our lakes has been made. Pollution control and water-management agencies must now make the choice of the restoration technique. This paper provides some additional information for that choice.

LITERATURE CITED

Allyn, J. 1971-72 Modeling a Marsh ecosystem. College of Engineering News. University of Michigan. Ann Arbor, Michigan.

Bartsch, A. F. 1972. Role of Phosphorus in Eutrophication. U. S. Environmental Protection Agency. Corvallis, Oregon.

Blackburn, R. D., Sutton, D. L. and T. Taylor. 1971. Biological Control of Aquatic Weeds. Journal of the Irrigation and Drainage Division. 97: IR3.

Bryan, E. H. 1972. Quality of Stormwater Drainage from Urban Land. Water Resources BuUetin. 8:578-58. Doyle, K. F. 1971. Phosphates - An Unresolved Water Quality Problem. Environmental Reporter. 9. Dymond, G. C. 1948. The Water Hyacinth a CTndereUa of the Plant World. Soil Fertility and Sewage. Eckenfelder, W. W. 1966. Industrial Water Pollution Control. 268 p.


Eckenfelder, W. W. and D. L. Ford. 1970. Water Pollution Control. 83 p. Edmondson, W. T. 1964. Water Quality Management and Lake Eutrophication: The Lake Washington Case.

Streams, Impoundments and Estuaries. A series of seminars intended for publication by the University of Washington Press.

Ellis, M. M. 1967. Detection and Measurement of Stream Pollution. Biology of Water Pollution. 129-185 pp. Fishburn, G. A. 1969. Release of Inorganic and Organic Pollutants from Limnological Sediments. Master’s

Florida Game and Fresh Water Fish Commission. 1972. Lake Tohopekaliga Drawdown. Florida Technological University. 1972. Lake Eola Proposed Restoration Plan. Foehrenbach, J. 1 9 7 2 Eutrophication. Annual Literature Review, Journal, Water Pollution Control

Journal American Water Works Association. 1971. Artificial Destratification in Reservoirs. 63597. Kaleel, R. T. and C. W. Sheffield. 1971. Lake Apopka-Sit Drying, Mudsilt Depth, Silt Settling, Artificial Reef

Reports. Orange County Pollution Control Department for the Florida Pollution Control Department, Lmsley, R. K. and J. B. Franzini. 1972. Water-Resources Engineering. 491 pp. McLellon, W. M. Keinath, T. M. and C. Chao. 1972. Coagulation of Colloidal-and Solution-phase Impurities

Mortimer, C. H. 1971. Chemical Exchanges Between Sediments and Water in the Great Lakes-Speculation on

Oglesby, R. T. and R. T. Edmondson. 1966. Control of Eutrophication. Journal Water Pollution Control

Perez, I., Huber, W. D., Heaney, J. P., and E. E. Pyatt. 1972. A Water Quality Model for a Conjuctive Surface

Raynes, 1. I. 1972. Research and Control of Obnoxious Aquatic Plants. Meeting Preprint 1631 of the ASCE

Robel, R. L.. 1962. Changes in Submerged Vegetation Following a Change in Water Level. J. Wildlife

Sheffield, C. W. 1969. Biological and Chemical Means of Removing Nutrients. 42nd Annual Conference

Speece, R. E. 1970. Aeration of Oxygen-Deficient Impoundment Releases. 5th International Water Pollution

Steward, K. K. 1960. Nutrient Removal Potentials of Various Aquatic Plants. Hyacinth Control Journal 8.

Symons, I. M. 1969. Water Quality Behavior in Reservoirs. A Compilation of Published Research Papers,

Tenney, M. W., Yaksich, S. M. and J. V. DePinto. 1972. Restoration of Water Bodies, Manuscript prepared

Vallentyne, J. R. 1970. Phosphorus and the Control of Eutrophication. Canadian Research and Development

Wanielista, M. P. 1971. Restoration of Inland Waterways The Environmental Systems Engineering Institute,

Wirth, T. L. 1971. Report on Inland Lake Renewal and Management Demonstration Project. Wisconsin

Wohlsciag, D. E. 1 9 5 2 Estimation of Fish population in a Fluctuating Reservoir. California Fish and Game.

Yaksich, S. M. 1 9 7 2 The Use of physical Barriers to Retard Pollutionary Releases from Eutrophic Lake

Degree thesis, University of Notre Dame.

Federation. 1150-1159 pp.

in Trickling Filter Effluents. Journal, Water Pollution Control Federation. 77-91 pp.

Probable Regulatory Mechanisms Limnol. and Oceanog.

Federation. 38: 1452.

- Groundwater System: An Overview. Water Resources Bulletin 5: 900-909.

National Water Resources Engineering Meeting.

Management. 2: 221-224.

Water Pollution Control Federation. Dallas, Texas.

Research Conference, published by Pergamon Press, Ltd., 111-29.

34-35 pp.

Publication No. 1930. Cincinnati, Ohio.

for publication in Environmental Engineers’ Handbook.

3.36-43 pp.

College of Engineering, Florida Technological University.

Department of Natural Resources. Madison, Wisconson.

1 63-7 2.

Sediments. Doctorate Degree Dissertation, University of Notre Dame.

TAB

LE 1

. Sum

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Lak

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ratio

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tival

- en

t met

al sa

lts,

fly a

sh, o

r cl

ay.

Fina

l wat

er q

ualit

y de

pend

ent u

pon

trea

t-

men

t pro

cess

es u

sed

and

mix

ing

dilu

tion-

ar

y ef

fect

s whe

n th

e tr

eate

d w

ater

is re

- tu

rned

to

the

lake

.

Prec

ipita

tes o

r abs

orbs

ph

osph

ate

and

som

e or

gani

c co

ntam

inan

ts.

Incr

ease

s tra

nspa

renc

y.

Des

orpt

ion

over

tim

e ha

s no

t bee

n ev

alua

ted.

No

dire

ct e

ffec

t N

o di

rect

eff

ect

No

dire

ct e

ffec

t

An

adeq

uate

tim

e pe

riod

m

ust b

e al

low

ed b

etw

een

draw

dow

n an

d re

W1

op-

erat

ions

for

oxid

atio

n,

com

pact

ion,

and

sta

bili-

za

tion,

or f

or th

e re

- m

oval

of

sedi

men

ts.

No

dire

ct e

ffec

t

Lay

er fo

rmed

ove

r bot

tom

se

dim

ents

may

ret

ard

pollu

tiona

l rel

ease

s.

No

dire

ct e

ffec

t

Imm

edia

te re

mov

al o

f al

gae,

bac

teri

a, a

nd

viru

ses.

Sub

mer

ged

plan

ts a

re d

estr

oyed

.

Imm

edia

te re

mov

al o

f al

gae,

bac

teri

a, a

nd

viru

ses.

Form

s a

floc

with

al

gae,

whi

ch s

ub-

sequ

ently

set

tles

to th

e bo

ttom

. E

ffec

t on

root

ed

aqua

tics h

as n

ot

been

eva

luat

ed.

Can

be e

ffec

tive i

n se

mi-

eutr

ophi

c la

kes w

ith s

hort

hy

drua

lic re

side

nce

times

.

Hig

h qu

ality

and

qua

nitit

y w

ater

sou

rce

requ

ired

. A

lso r

equi

res

disc

harg

e m

echa

nism

g S 2 F E 0

D

iffi

cult

in ri

ver a

nd

-I

sprin

g fe

d la

kes,

Pa

rtic

ular

ly e

ffec

tive

in in

crea

sing

spo

rt fi

sh

popu

latio

ns. C

onsi

dera

tion

m al

so m

ust b

e gi

ven

to g

roun

d-

wat

er [

Pere

z et

al,

1972

1.

Opt

imal

sepa

ratio

n of

w

ithdr

awal

and

retu

rn

pipe

s re

quir

ed to

min

imiz

e di

lutio

nary

eff

ects

of

mix

ing.

Por

tabl

e tr

eatm

ent

faci

litie

s cou

ld re

duce

w 8 8 E 75

9

2: L? U

inst

alla

tion

cost

s.

C

Rea

ctio

ns a

re p

H d

epen

dent

. Im

med

iate

eff

ectiv

enes

s de

pend

s up

on th

e am

ount

of

mix

ing

acco

mpl

ishe

d.

Wat

er s

olub

le c

hem

ical

co

nstit

uent

s of

fly

ash

may

be

detr

imen

tal t

o aq

uatic

eco

syst

em.

VI

0

v3

TAB

LE 1

. Sum

mar

y of

Lak

e R

esto

ratio

n T

echn

ique

s (C

ontin

ued)

Nut

rien

t rem

oval

by

con

trol

led

aqua

tic p

lant

s.

Oxy

gena

tion

by

dest

ratif

icat

ion

usin

g w

ater

pum

p or

dif

fuse

d ai

r or

oxy

gen

syst

ems.

Cov

erin

g of

bot

- to

m s

edim

ents

with

sa

nd, p

artic

ulat

e m

ater

ial o

r pl

as-

tic

liner

s.

Dre

dgin

g

Che

mic

al c

ontr

ol

of a

quat

ic p

lant

s

The

oret

ical

dec

reas

e of

nu

trie

nt b

udge

t in

lake

, N

utri

ents

are

take

n up

by

pla

nts

whi

ch a

re p

eri-

odic

ally

rem

oved

to

pre-

ve

nt t

he e

vent

ual r

etur

n of

the

nut

rien

ts to

the

wat

er.

Des

trat

ific

atio

n pr

ovid

es

over

all w

ater

qua

lity

impr

ovem

ent b

y m

ixin

g hy

polim

netic

with

epi

- lim

netic

wat

er.

No

dire

ct e

ffec

t

Can

incr

ease

nut

rien

t co

ncen

trat

ions

by

mix

- in

g bo

ttom

sed

imen

ts

into

wat

er.

Suct

ion

dred

ging

elim

inat

es

this

pro

blem

.

Dec

ayin

g pl

ants

rele

ase

nutr

ient

s in

to w

ater

.

Prev

ents

bot

tom

sed

imen

t bu

ild u

p by

dea

d pl

ants

of

the

con

trol

led

spec

ies.

Bot

h te

chni

ques

are

ca

pabl

e of

ret

ardi

ng

pollu

tiona

ry r

elea

ses

of b

otto

m s

edim

ents

by

mai

ntai

ning

aer

obic

co

nditi

ons i

n hy

po-

limni

on.

Cou

ld r

etar

d or

elim

i- na

te n

utri

ent r

elea

ses.

Nut

rien

t rel

ease

s sh

ould

be

sto

pped

if re

stor

ed

bott

om s

urfa

ce la

yer i

s of

low

nut

rien

t and

dr

edgi

ng te

chni

que

does

no

t per

mit

mix

ing

of

the

sedi

men

ts in

to th

e w

ater

and

sub

sequ

ent

rese

ttlin

g.

Bui

ld u

p of

sed

imen

ts b

y ad

ditio

n of

dea

d pl

ants

. T

oxic

ele

men

ts o

f ch

emi-

ca

ls m

ay b

uild

up

in

sedi

men

ts.

Prev

ents

nui

sanc

e pr

opor

tions

of

the

cont

rolle

d pl

ant

spec

ies.

Des

trat

ific

atio

n is

ca

pabl

e of

red

ucin

g al

gae

conc

entr

atio

ns.

May

hav

e un

desi

rabl

e ef

fect

s on

bent

hic

life.

Rem

oves

root

ed v

ege-

ta

tion.

Kill

s wee

ds a

nd/o

r al

gae.

Rel

ativ

ely

expe

nsiv

e an

nual

cos

ts a

ntic

ip-

ated

. The

con

trol

led

spec

ies s

houl

d ha

ve

rela

tivel

y hi

gh n

utri

ent

upta

ke a

nd s

houl

d no

t be

a fo

od so

urce

for

othe

r aq

uatic

life

.

Ach

ieve

d by

mec

hani

cal o

r co

mpr

esse

d ai

r lif

t pum

ps

or d

iffus

ed a

ir or

oxy

gen

syst

ems.

Alm

ost c

ontin

ual

tain

des

trat

ific

atio

n.

s 2 s 6 E

ffec

ts o

n be

nthi

c ac

tivity

L

.

mus

t be

eval

uate

d. D

if-

s j;.

ficu

lty in

pla

cing

and

e

mai

ntai

ning

act

icip

ated

.

oper

atio

n re

quir

ed t

o m

ain-

2

Siting a

rea

requ

ired

, w

hich

will

not

allo

w

repo

llutio

n of

ano

ther

w

ater

bod

y.

Tem

pora

ry m

easu

re. P

oten

- tia

l for

adv

erse

eff

ects

up

on a

quat

ic e

cosy

stem

.

TAB

LE 1

. Sum

mar

y of

Lak

e R

esto

ratio

n Te

chni

ques

(Con

tinue

d)

Mec

hani

cal c

ontr

ol

Theo

retic

al d

ecre

ase

of a

quat

ic p

lant

s of

nut

rien

t bud

get i

n th

e la

ke.

Cut

ste

ms

rele

ase

nutr

ient

s.

Bio

logi

cal c

ontr

ol

No

dire

ct e

ffec

t of

aqu

atic

pla

nts

Som

e re

leas

es m

ay o

ccur

, if

sedi

men

ts a

re d

istr

ub-

ed, i

n ad

ditio

n to

the

norm

al n

utri

ent e

xcha

nge

unde

r exi

stin

g co

nditi

ons.

No

dire

ct e

ffec

t

Phys

ical

con

trol

La

ser

tech

niqu

es w

ould

La

ser

tech

niqu

es w

ould

of

aqu

atic

pla

nts

resu

lt in

sed

imen

t bui

ld

up b

y de

ad p

lant

s, u

n-

less

the

irra

diat

ed p

lan-

ts

are

rem

oved

from

the

resu

lts in

the

ulti

mat

e re

leas

e of

nut

rien

ts

by d

ecay

ing

plan

ts in

to

the

wat

er u

nles

s th

e ir-

ra

diat

ed p

lant

s ar

e la

ke.

rem

oval

from

the

lake

Imm

edia

te te

mpo

rary

re

lief f

rom

aqu

atic

pl

ant p

robl

em

Goa

l is

to re

duce

the

popu

latio

n of

the

tar-

ge

t spe

cies

by

the

in-

trod

uctio

n of

a s

peci

- es

pro

perl

y se

lect

ed

for t

hat p

urpo

se.

Dra

wdo

wns

allo

w p

lant

s to

dry

out

and

die

. La

ser i

rrad

iatio

n ca

n ki

ll ex

pose

d pl

ants

. B

lock

ing

of s

unlig

ht

has

been

sug

gest

ed f

or

alga

l con

trol

.

Posi

tive

met

hod

of n

utri

ent

rem

oval

. Dis

posa

l pro

blem

s m

ust b

e co

nsid

ered

and

con

- st

ant m

aint

enan

ce m

ust b

e co

nsid

ered

.

Rel

ativ

ely

inex

pens

ive

and

easy

to

appl

y. C

ontr

ol

spec

ies m

ust b

e th

orou

gh-

ly re

sear

ched

pri

or t

o in

trod

uctio

n to

insu

re

agai

nst i

ts o

verp

opul

at-

ion

and

othe

r un

desi

rabl

e ef

fect

s.

Rep

eate

d ir

radi

atio

n by

la

ser b

eam

is r

equi

red

to

insu

re d

eath

. The

ir-

radi

atio

n ha

s no

eff

ect

on p

lant

repr

oduc

tion

until

dea

th is

eff

ecte

d.

Lase

r app

licat

ions

for

subm

erge

d ve

geta

tion

are

bein

g in

vest

igat

ed.

no fe

asib

le m

etho

d to

bl

ock

sunl

ight

yet

dev

el-

oped

.

2 E m

review of lake restoration procedures

Documents