Restoration of Aquatic Ecosystems Science, Technology, and Public Policy (1992) / Chapter Skim
Currently Skimming:
4 Lakes
4 Lakes
Pages 71-164
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 71... ...
Sport fishing, swimming, and boating are highly popular pastimes, and lake-front property has a high economic value. Large lakes and reservoirs are used as drinking water supplies; the Great Lakes alone serve as the domestic water supply for approximately 24 million .
|
From page 72... ...
. Return of a lake to its pristine condition has not been an explicit goal of most lake restoration projects, although these actions often improve some aspects of a lake's ecological attributes.
|
From page 73... ...
Our ability to assess the effectiveness of past lake restoration projects and to compare the effectiveness of different restoration methods is severely limited by three factors. First, and perhaps most important, surveillance of lake conditions for an adequate period of time before and after a restoration attempt has been done on relatively few lakes.
|
From page 74... ...
When wetlands are considered at all in lake restoration projects, it is typically for diversion of nutrient-laden storm water runoff or sewage effluent into the wetland in an effort to obtain nutrient uptake by wetland vegetation. Such diversions may provide a temporary lowering of nutrient loadings to lakes, but wetland flushing during high flow periods may result in little net annual retention of nutrients by the wetlands.
|
From page 75... ...
In regions where natural lakes are rare or absent, artificial lakes (reservoirs) have been developed by damming rivers and streams to provide the benefits (e.g., recreation, water supply, water storage capacity)
|
From page 76... ...
comes from impounded surface waters (natural lakes and man-made reservoirs)
|
From page 77... ...
Their replacement by stress-tolerant native or exotic species often does not fully compensate for the loss and leads to lower biodiversity and simplified food webs. Many types of stress result in loss of habitat; often this is the proximate cause of species losses.
|
From page 78... ...
. Proliferation of macrophytes is also associated with eutrophication, especially in shallow lakes, but these problems are not tied directly to excessive rates of nutrient loading (see "Exotic Species," below)
|
From page 79... ...
in this analysis would require control of nonpoint sources of nutrients to achieve measurable improvements in trophic conditions. HYDROLOGIC AND RELATED PHYSICAL CHANGES The watersheds of lakes in urban and agricultural areas clearly are no longer ecologically the same as they were in presettlement days, and such land use changes are a primary cause of the stresses described in this section.
|
From page 80... ...
EXOTIC SPECIES Lakes are island habitats. Like islands, they are highly susceptible to invasion by exotic species that lead to extirpation of native species
|
From page 81... ...
Cases have been reported of swimmers becoming entangled in excessive growths of macrophytes and drowning. Dense beds of plants alter water chemistry and habitat structure, leading to changes in invertebrate and fish communities, and they are a major source of organic matter to the water column and sediments.
|
From page 82... ...
The fish was controlled in the Great Lakes primarily by stocking the lakes with other exotic fish, coho, and Chinook salmon. The latest in a series of exotic species to invade the Great Lakes, and potentially the most devastating, is the zebra mussel (Dreissena polymorpha)
|
From page 83... ...
However, ecological impacts generally are greater at the population level than at the community level, and effects on some integrative measures of ecosystem performance, such as total primary production and community respiration, have not been demonstrated conclusively, especially for mild levels of acidification. In contrast, rates of decomposition of organic matter, especially leaves and other terrestrially produced materials, are slowed in acidic lakes (Perry et al., 1987; Brezonik et al., 1991a)
|
From page 84... ...
. Some Florida lakes with a pH as low as 4.5 have apparently healthy fish communities, although fish production is low because acidic lakes tend to be very oligotrophic.
|
From page 85... ...
have accumulated to problem proportions in the food web of a lake (particularly in game fish) because of industrial accidents or inadequate disposal practices, but in other cases, the source of the toxic material is more diffuse- nonpoint source runoff or deposition from the atmosphere.
|
From page 86... ...
The accumulation of mercury varies widely among different species of fish; biomagnification proceeds as mercury moves through the food web, and top carnivores such as walleye have the highest body burdens. Within a given species, body burdens increase with size (and age)
|
From page 87... ...
Another illustration of the importance of long-range atmospheric transport is provided by Siskiwit Lake, on Isle Royale, more than 90 km from the nearest shore in western Lake Superior. The island is a wilderness area (and a national park)
|
From page 88... ...
, 33 provided data on the nature (causes) of impairment (e.g., nutrients, siltation, and toxic substances)
|
From page 89... ...
LAKES TABLE 4.2 Designated Use Support in Lakes and Reservoirs 89 TOta1TOta1ACreS ACreS ACreS NumberACreSACreSFU11Y Partially NOt StateOf LakesOf LakesSUrVeYedSUPPOrting SUPPOrting SUPPOrting AL 43 504,336 491,566 405,486086,080 CA 4,955 1,417,540 1,076,891 568,73995,505412,647 CO 4,069 265,982 124,973 123,3001,6730 CT 6,000 82,900 21,701 9,31212,3890 DC 8 377 136 00136 FL 7,712 2,085,120 947,200 309,760536,320101,120 GA 175 417,730 417,730 412,3575,34726 IL 2,940 247,188 183,572 22,931100,59160,050 IN 560 104,540 104,540 104,36163116 IA 282 81,400 80,249 26,80152,0581,390 KS 232 175,189 173,911 116,65548,1419,115 KY 92 228,385 214,483 179,33531,4713,677 LA 101 713,719 517,476 376,335141,1410 ME 5,779 994,560 994,560 958,08036,4800 MD 59 17,448 17,448 14,8382,6037 MI 35,000 840,960 424,021 304,18562,83457,002 MN 12,034 3,411,200 1,435,554 1,198,70967,622169,223 MS 500,000 500,000 481,74018,2600 MO 362 288,012 288,012 285,7012,3110 MT 4,018 756,450 663,363 345,367305,39612,600 NB 412 145,300 85,518 82,3042,779435 NH 1,300 151,000 149,854 130,70818,756390 NM 126,500 119,666 72,35847,3080 NY 7,500 750,000 750,000 454,668267,34327,989 NC 1,500 305,367 305,367 293,4702,0759,822 ND 216 625,503 619,333 571,20848,1250 OH 2,500 117,323 90,771 30,93650,9888,847 OR 6,095 610,808 504,928 374,30358,91871,707 PR 38 11,146 11,146 3,8014,2403,105 RI 113 16,520 16,089 14,688787614 SC 1,418 525,000 410,407 409,242840325 SD 789 1,598,285 662,532 567,81217,98476,736 TN 117 538,657 538,657 452,00950,83035,818 TX 5,700 1,410,240 1,410,240 1,225,6290184,611 VT 719 229,146 227,121 177,91537,71311,493 VA 248 161,562 161,089 147,35213,7370 WA 808 613,582 156,518 122,83433,104580 WV 94 19,171 19,171 017,4411,730 WI 14,998 971,000 971,000 249,000478,000244,000 WY 2,629 427,219 427,219 396,81530,4040 TOta1 131,615 22,486,365 16,314,012 12,021,0442,701,5771,591,391 SOURCE: RePrinted from U.S. Environmental Protection Agency, 1990.
|
From page 91... ...
Similarly, a 1983 survey of state lake administrators by the North American Lake Management Society (NALMS; Duda and Johnson, 1984) showed an alarming increase in problem lakes since the survey of Ketelle and Uttormark (1971~.
|
From page 92... ...
Canada has the largest acreage of lakes in the world, and a complete inventory, much less an assessment of their trophic states, is not available at this time. Most of them are thought to be oligotrophic, and in terms of raw numbers, the great majority of Canadian lakes lie in wilderness or undeveloped forests.
|
From page 93... ...
About three-fourths of the acidic lakes were attributable to acidic deposition; most of the remainder were colored and were thought to be acidic from the presence of natural organic acids. Although only a small percentage of lakes in the NSWS were found to be acidic, several cautions must be considered before the results are accepted as an accurate portrayal of the impact of acidic precipitation on U.S.
|
From page 94... ...
and sources of dominant acid anions in the acidic lakes and streams of the NSWS (lower)
|
From page 95... ...
Regions in which acid mine drainage is a problem have few natural lakes, and this source accounts for only a few acidic lakes nationwide. TOXIC SUBSTANCES The importance of toxic substances in lake degradation can be illustrated with data from the Great Lakes.
|
From page 96... ...
The Great Lakes all suffer from a variety of exotic species problems, and with the recent zebra mussel invasion, problems caused by exotic species appear to be getting worse. No national statistics are available on the extent of damage caused by physical and hydrologic changes to lakes; in many cases, these manipulations are not even recognized as a factor in lake degradation.
|
From page 97... ...
Increased nutrient and organic matter loading, usually from cultural sources such as wastewater treatment plants and runoff from urban or agricultural land, often leads to sharply increased nutrient concentrations in the water column and ultimately to algal blooms, dis
|
From page 98... ...
Shallow lakes, particularly those exposed to wind-induced mixing, are likely to have high internal loading rates. Water residence time also plays a role in determining lake water column nutrient concentration.
|
From page 99... ...
Central Corn Belt Plains 55. Eastem Com Belt Plains 56.
|
From page 100... ...
ecoregions. Lakes in the latter two ecoregions are unlikely to have water with few algal blooms, regardless of the amount of lake management activity.
|
From page 101... ...
Lake restoration is possible for a eutrophic lake in any of the ecoregions, but the attainable trophic state for lakes can vary significantly between adjacent ecoregions. The ecoregion idea has been used to predict the restoration potential of Ohio reservoirs subjected to varying degrees of nutrient, silt, and organic matter loading (Fulmer and Cooke, 1990~.
|
From page 102... ...
The predicted phosphorus concentrations in the reservoirs were compared with measured values, and the data were transformed into an index number, a Carlson trophic state index (TSI) value (see "Water Quality and Human Use Criteria," below)
|
From page 103... ...
The approach can take into account regional factors related to attainable water quality and thus can be used to designate lakes for protection and to establish lake restoration goals appropriate for each ecoregion. Stream water quality in some watersheds of an ecoregion, and ultimately lake trophic state, can be greatly improved through changes in land use (e.g., wetland restoration, improved agricultural practices)
|
From page 104... ...
Criteria for Successful Restoration and Measures of Success Most lake restoration projects undertaken in the United States over the past 20 years have focused on improving the fitness of a degraded lake for human uses such as swimming, other water contact sports, fishing, or drinking water supply. Undoing ecological damage from past human perturbations and restoring the lake's ecosystem to its pristine state are not the primary goals of typical restoration efforts.
|
From page 105... ...
In the example given, once the herbicide disappears, the macrophyte problem probably will return. WATER QUALITY AND HUMAN USE CRITERIA As stated above, the goal of most lake restoration projects is to remove a specific problem-a nuisance organism, excess chemicals, or unwanted physical condition and make the lake more desirable (based on human-centered criteria)
|
From page 106... ...
(1988b) used modified versions of Carlson's TABLE 4.5 Values of Secchi Disk Transparency, Total Phosphorus Concentration, and Chlorophyll a Concentration Corresponding to Carlson Trophic State Index (TSI)
|
From page 107... ...
FEDERAL AND STATE PROGRAMS FOR LAKE RESTORATION AND MANAGEMENT Federal Programs The principal federal program dealing with restoration of degraded lakes is EPA's Clean Lakes Program (CLP) , which was established by P.L.
|
From page 108... ...
For example, to remain eligible for CLP grant funds, each state is required to submit a biennial report that includes a revised lake classification list, an assessment of status and trends in lake water quality, and a restoration plan for degraded lakes. In addition, EPA was authorized to establish a Clean Lakes demonstration program to enhance understanding of the effectiveness of various lake restoration techniques, and the Water Quality Act directs that specific attention be paid to mitigation of acidified lakes.
|
From page 109... ...
Only 42 states reported on lake management activities in the broadest sense, and in most of the states only a few people were involved in the program. More than 30 of the states reported that the federal Clean Lakes Program was the major source of funding for proposed lake restoration projects.
|
From page 110... ...
Baker and Swain (1989) found similarly dismal statistics in attempting to analyze lake restoration projects in Minnesota.
|
From page 111... ...
LAKES TABLE 4.6 Comparison of Economic Benefits and Project Costs (federal share only) for 28 Clean Lakes Projects 111 Economic Benefitsa o 0 _ u O ~ ~ ~ ~ ~<; ~-,, Discounted Grant Lake ~ ~ O ~ ~ - c~ D ~ ~ uBenefitsbAmount Annabessacook + + $ + $ + 23,246,100 497,906 Bomoseen $ + + + 1,830,500 74,640 Buckingham $ + + 127,700 23,250 Charles $ $ + 2,286,600 387,163 Clear $ $ + + + + 471,500 358,682 Cochrane $ + $ + + 52,500 9,906 Collins Park $ + + 51,700 79,355 Ellis $ $ $ $ + $ + + $ 11,123,000 1,625,000 59th St.
|
From page 112... ...
In 1977, 936 ma of liquid aluminum sulfate were added to remove phosphorus from the water column and retard its recycling. After treatment, phosphorus concentrations and algal density were reduced; blue-green algae were largely replaced with less noxious species of green algae; water clarity increased; and large-bodied zooplankton, Daphnia pu/ex, became the primary regulators of phytoplankton density.
|
From page 113... ...
. The Medical Lake restoration project had the rare benefit of long-term monitoring.
|
From page 114... ...
need be used only once to achieve long-term TABLE 4.7 Restoration Techniques for Major Categories of Lake Degradation Problem Category Eutrophi- Silta- Acidifi- Exotic Toxic Con Technique cation lion cation Species taminants Nutrient source X X X X reduction Diversion X X Land disposal X Product modification X Wastewater treatment X Interception of nonpoint sources X X Dilution X X Flushing X X X X X X X In-lake methods X X X X Alum treatment X Sediment skimming X X X Sediment oxidation X Deep-water discharge X X Biomanipulation X X Artificial circulation X Biocides (algicides/ herbicides/piscicides) X X Biocontrol agents X Drawdown/sediment desiccation X X Bioharvesting X X Aeration X Dredging X X Liming X
|
From page 115... ...
Eutrophication CONTROL OF ALGAL BLOOMS Nutrient Source Reduction High loading of nutrients to lakes produces algal blooms and other problems. In many cases, oxygen-demanding organic matter, silt, or toxic materials accompany the nutrient loadings.
|
From page 116... ...
Municipal wastewater treatment (tertiary treatment for N and P removal)
|
From page 117... ...
Bans are not instituted to reduce phosphorus loadings to a single lake local ordinances are ineffective because consumers will obtain the products in nearby areas where they are not banned. This approach thus is used to lower phosphorus levels in surface waters on a statewide or regionwide basis.
|
From page 118... ...
This blue-green alga is widely recognized as an indicator of excess nutrient enrichment ~ Deteriorating water quality from algal growths was reported in the press, and related issues were addressed by the scientific community (see Lehman, 1986; Edmondson, 1991~. By 1957, public concern had resulted in state legislation to form a metropolitan governmental agency to address the problem of water supply and waste management.
|
From page 119... ...
treatment units. Phosphorus removal is achieved by adding alum, calcium, or (more rarely)
|
From page 120... ...
, when the most severe blue-green algal blooms occurred (chlorophyll levels of 60 ,ug per liter and sometimes up to 100 lug per liter)
|
From page 121... ...
Continued research in Shagawa Lake to determine the long-term interplay between reduced external loading and internal loading would be helpful. Long-term data may be required to establish trends because of interannual variability in biological productivity caused by climatic factors (independent of nutrient loading)
|
From page 122... ...
The costs of treating nonpoint sources by engineered systems are high, and diversion of inputs to other ecosystems may have high political and social costs, as well as untoward ecological and hydrological effects. This has led to the development of pre-lake interception systems as "low-technology" supplements to tertiary wastewater treatment and agricultural best management practices to decrease nonpoint sources of nutrient loading.
|
From page 123... ...
shows greater removal efficiency. A prereservoir detention basin with a water residence time of 5 days was found to retain 60 to 70 percent of the total phosphorus entering it (Fiala and Vasata, 1982~.
|
From page 124... ...
Wahnbach Reservoir, an important municipal water supply for Bonn, Germany, is protected from nutrient, silt, and organic matter loading from its main tributary by a prereservoir detention basin and phosphorus elimination plant (Bernhard", 1980; Clasen, 1989~. Water from the detention basin is treated with iron to remove phosphorus and then filtered through an ion exchanger and a series of activated carbon and sand filters.
|
From page 125... ...
Columbia River water was diverted through the lake and then to agricultural areas for irrigation. Algal blooms were reduced by 50 percent and water clarity increased by 100 percent during the 9 years that dilution water entered the lake.
|
From page 126... ...
Under certain conditions, phosphorus released from lake sediments will be transported to the upper layers of a lake and stimulate an algal bloom. This process, in which sediments enriched in organic and inorganic matter from external loading and in-lake production cause dissolved oxygen consumption and phosphorus release, is known as internal loading.
|
From page 127... ...
, these nutrients are transp~orted~from the hyp~olimnion to the e~pili~mnion and subsidize algal blooms. Diversion of cultural ~n~ut~rient' toadying, although essential, may not be sufficient to return these lakes to their undisturbed condition; curtailment of internal loading may also be required.
|
From page 128... ...
Use of the reference lake was also an essential component in understanding the mechanism of recovery. Unfortunately projects with this type of design are rare in lake restoration.
|
From page 129... ...
. BOX 4~6 LAKE TRUMMEN, SWEDEN Lake Trummen, Sweden, received domestic wastewater and flax mill discharges for many years, and algal blooms and fish winter kill were common.
|
From page 130... ...
If release exceeds new external loading, the procedure should gradually deplete the sediments of phosphorus and could reduce the amount of nutrients entrained from deep to surface waters each summer. Summer and early autumn algal blooms should be reduced (Nurnberg, 1987~.
|
From page 131... ...
Also, high discharge rates could induce a midsummer partial mixing of the water column, and this is likely to trigger an algal bloom when nutrient-rich bottom waters are mixed with surface waters. hypolimnetic waters to receiving streams Management of Symptoms The techniques and procedures described above for control of algal blooms can be restorative because they produce a lasting decrease in nutrient concentrations.
|
From page 132... ...
In shallow lakes, fish removals that improved water clarity have been followed by expansion of submersed aquatic vegetation (Gulati et al., 1990~. Once established, the submersed plants shelter fish that may eliminate grazers, causing declining water clarity and reduction in submersed vegetation.
|
From page 133... ...
Loss of copper is especially rapid in alkaline waters, and most lakes with algal bloom problems fall in this category. Significant negative effects may occur as a result of copper sulfate treatment: dissolved oxygen depletion following decay of killed cells, sediment contamination, and toxicity to nontarget species, including fish and algae-grazing zooplankton.
|
From page 134... ...
These species often concentrate their biomass near the water surface and thus are much more conspicuous to lake users than are native species that grow deeper in the water (Nichols et al., 1991~. To date, macrophyte restoration techniques have been limited to methods for killing nuisance plants.
|
From page 135... ...
In Florida, where their use is common, many lakes stocked with grass carp are very turbid (because of algal blooms) , and shoreline erosion is so extensive, due to the absence of a "damping" effect by submersed plants, that shoreline trees have fallen.
|
From page 136... ...
Secchi disk transparency readings decreased from 6 m during the height of hydrilla infestation to approximately 1.5 m after hydrilla had been eradicated by grass carp. Chlorophyll a and total alkalinity also increased in the lake after hydrilla had been controlled.
|
From page 137... ...
The procedure is most likely to be effective only in northern and some midwestern areas. Water removal also allows other lake restoration activities to occur, including fish management, sediment removal, and repair of dams and shoreline structures.
|
From page 138... ...
Other negative effects include an increased likelihood of algal blooms and short-term increases in water column turbidity and nutrient concentrations (Cooke et al., 1986~. Nicholson (1981)
|
From page 139... ...
(Nevertheless, fluridone is registered for use in potable water supply reservoirs.) Brooker and Edwards (1975)
|
From page 140... ...
If aerators are operated continuously during the stratified period, a cold-water fishery can be restored, and the quality of raw potable water or deep-water discharge can be improved. Hypolimnetic aerators have not been shown to be effective in algal control, but there is evidence from ongoing work on Vadnais Lake, Minnesota, that an addition of ferric iron to the aerator can reduce internal phosphorus loading to the upper water column (D.
|
From page 141... ...
Excess Sediment Volume loss caused by excessive watershed and shoreline erosion and subsequent high sedimentation rates in a lake or reservoir is a common problem. High loading rates of inorganic sediments also reduce water clarity, possibly to the point of inhibiting primary production, which occurred in Lake Chicot, Arkansas, a riverine lake tributary to the Mississippi River (Stefan et al., 1990~.
|
From page 142... ...
because of deposition of agricultural soils. This led to increased water treatment costs, loss of shoreline property values, algal blooms, weeds, turbidity, rough fish, and impaired recreation.
|
From page 143... ...
In other cases, species invasions accompanied by extirpations of native species have permanently altered lake ecosystems. Depending on the outcome of efforts to establish reproducing populations of lake trout, Lake Michigan may be an example of a permanently altered ecosystem (see Lake Michigan case study, Appendix A)
|
From page 144... ...
. Liming is by far the most common in-lake restoration technique for acidified lakes, and a large amount of experience with this method has accumulated over the past decade.
|
From page 145... ...
Calcite treatments are often short-lived because many acidic lakes are in drainage systems with short water residence times (sometimes only several months, often a year or so)
|
From page 146... ...
have higher hardness and alkalinity levels than do surface waters in acid-sensitive regions. Advantages of this approach involve low cost (no chemicals need be added to the lake)
|
From page 147... ...
Conversely, lake restoration affects wetlands by influencing macrophyte distribution, water levels, and wave and ice impacts on littoral areas. Lake restorations and stream restorations interact through the life cycles of migratory fish.
|
From page 148... ...
NEEDS IN LAKE RESTORATION Needs in Federal Lakes Programs The sigruficance of lakes and reservoirs to the economy of the United States is apparent. Equally apparent are the deterioration of these resources over recent decades and the inadequacy of federal programs to restore lakes.
|
From page 149... ...
philosophical viewpoint that lake restoration is a problem for state and local governments and not a federal responsibility. As noted repeatedly in this chapter, in many cases lakes do not cleanse or restore themselves.
|
From page 150... ...
Currently, the CLP provides a 50 percent match to state and local funds for lake restoration. Administrators in the relevant state agencies are the best informed and equipped to determine state needs for lakes.
|
From page 151... ...
Need for Integration of Management Programs Effective lake restoration demands an ecosystem perspective. It often depends on land use in the surrounding watershed and interacts with the management of connecting streams and wetlands.
|
From page 152... ...
Environmental Protection Agency. Research Needed Lake restoration is a relatively new and developing field.
|
From page 153... ...
This is true even for such well-studied phenomena as phosphorus and algal bloom problems. Research should be undertaken to improve predictions of trophic state from nutrient loading relationships.
|
From page 154... ...
The committee recommends the following: · Public education and outreach should be components of aquatic ecosystem restorations. Lake associations and citizen monitoring groups have proved helpful in educating the general public, and efforts should be made to ensure that such groups have accurate information about the causes of lake degradation and various lake restoration methods.
|
From page 155... ...
1981. Prediction of total phosphorus concentrations, chlorophyll a, and Secchi depths in natural and artificial lakes.
|
From page 156... ...
1982. Change in lake trophic state and internal phosphorus release after aluminum sulfate application.
|
From page 157... ...
1987. Evaluation of lake restoration in Sweden.
|
From page 158... ...
1987. Analysis of regional patterns in lake water quality: Using ecoregions for lake management in Minnesota.
|
From page 159... ...
1981. A Carlson-type trophic state index for nitrogen in Florida lakes.
|
From page 160... ...
1983. CuSO4 treatment of nuisance algal blooms in drinking water reservoirs.
|
From page 161... ...
1987. Hypolimnetic withdrawal as a lake restoration technique.
|
From page 162... ...
1984. Lake restoration by biomanipulation: Round Lake, Minnesota, the first two years.
|
From page 163... ...
1981. Lake restoration: Medical Lake, Washington.
|
From page 164... ...
1981. The dilution/flushing technique in lake restoration.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.