摘要:

The littoral zooplanktic communities of an acidic and a nonacidic lake in Hancock County, Maine, were studied. Although the lakes are less than 200 m apart and similar in character and physical habitat, average annual pH differs in the two lakes. Fish are absent in the acidic lake while the nonacid lake contains golden shiners (Notetnigonus crysoleucas), brook trout (Salvelinus fontinalis) and rainbow smelt (Osmerus mordax). The zooplanktic community of the acid lake is dominated by the adult and nauphlii of the copepod,Diaptomus minutus, the large cladoceran,Diaphanosoma brachyurum, and the acid water rotifer,Keratella taurocephala. The nonacid lake is dominated by four zooplankters,D. minutus, the caladoceran,Bosmina coregonis, and the rotifers,K. taurocephalaandKeratella cochlearis. The density of three species of zooplankton was greater in the acid lake and the density of ten species was greater in the nonacid lake. Notably, the large cladocerans,D. brachyurum, Polyphemus pediculus, andAcroperus harpae, were more dense in the acid lake. In the nonacid lake, the density was higher for the copepods,D. minutusand a cyclopoid, the cladoceran,B. coregonis, and the rotifers,K. taurocephala, K. cochlearis, Keratellasp.,Polyarthra remata, Asplanchnasp., andTrichocercasp. A. Three factors are probably responsible for these differences, (1) biotic changes caused by the absence of fish in the acid lake, (2) oligotrophication resulting from acidification and a shorter flushing time in the acid lake, and (3) toxic effects of acidification.

ISSN:1040-2381    

DOI:10.1080/07438148409354543

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A measure often taken and frequently discussed in Sweden is to try to restore the runoff quality from acidified watersheds by soil liming. In Scandinavian acidified soils, where the base saturation often is below 20 percent, the dissolution of calcite will proceed without significantly improving runoff water quality until the base saturation is close to 100 percent. The dissolution rate of the calcitic minerals is governed by the particle size of the limestone used. Particles with a diameter over 0.3 mm will be used to a very small extent. As nearly all the runoff percolates through the soil column, a high base saturation is needed to get a stable and long lasting effect on the runoff water. The amounts needed to get a satisfying base saturation are estimated to be 35 to 50 ton/ha. This implies that soil liming is one order of magnitude more costly than standard lake liming techniques for surface water. Although vast efforts may soon be needed in soil and forestry management in Scandinavia, the costs involved in soil liming emphasize the importance of defining the goal of every liming project.

ISSN:1040-2381    

DOI:10.1080/07438148409354544

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Long Lake, Wash., an impoundment of the Spokane River, has experienced high algal standing crop; low water clarity and extensive hypolimnetic anoxia during summer stratification. The City of Spokane's primary sewage treatment plant was shown to be the primary contributor of phosphorus to the reservoir and the major cause of its eutrophic state. To reduce influent phosphorus (P) loading and improve Long Lake's water quality, the city provided advanced wastewater treatment (AWT) with chemical (alum) phosphorus removal in 1977. Monthly mean P load from the AWT plant has decreased approximately 90 percent and the overall load to the reservoir during the growing season (June-October) has declined about 74 percent. Mean post-AWT reservoir algal biovolumes and chlorophyllaconcentrations are approximately 60 and 45 percent, respectively, less than pre-AWT values. A phosphorus load–chlorophyllarelationship, based on 5 years each of pre- and post-AWT data, was developed and provided excellent predictions of mean reservoir chlorophyllaconcentrations for the growing season. As a result of AWT, Long Lake has changed from a eutrophic to a mesotrophic body of water. In studying the effects of reduced P loading, it was determined that seasonal chemical phosphorus removal (April through October) could be as effective in reducing algal growth in Long Lake as year-around removal. This conclusion was based on the premise that temperature was the primary limiting variable outside the growing season. The city was granted a change in their AWT plant discharge permit and has implemented seasonal chemical P removal with no detrimental effects on the improved water quality of Long Lake.

ISSN:1040-2381    

DOI:10.1080/07438148409354545

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Studies were conducted on three eutrophic Illinois impoundments to determine practical and economically viable measures to reduce water quality related use impairments and evaluate the recreational benefits of those measures. As is typical in Illinois, these relatively shallow impoundments were constructed in fertile floodplains draining croplands, have large watershed area to lake surface area ratios, and relatively short retention times. Frequent inflows of nutrient and sediment laden water contribute to problems of hypolimnetic oxygen depletion, algal blooms, dense macrophyte growth, inorganic turbidity, and siltation. Even where the watershed has been controlled to the best practicable extent, runoff waters still carry nutrients in excess of eutrophic loading rates and significant amounts of sediment, and the lake remains eutrophic. Constraints imposed by morphologic, hydrologic, and watershed factors on lake quality were considered in developing an integrated lake/watershed management strategy for each lake to preserve and maximize its use at minimal cost. In-lake techniques such as aeration/destratification, groundwater/surface water blending (dilution), lake shoreline stablization, weed harvesting, and algal control were not found to be palliative measures but essential management tools to preserve the lakes and allow their full development as recreational resources. A recreational benefit assessment was performed for each project using the unit day value methodology recommended by the U.S. Water Resources Council (18 CFR 713, Subpart K, App. 3. 1982). Benefit/cost ratios were determined in two ways: (1) by the ratio of the total discounted benefits to the requested Sec. 314 grant amount, and (2) by the annual recreational benefit divided by the sum of the amortized capital costs and annual operation, maintenance, and repair costs. The recreational benefit assessment procedure appears to provide an excellent tool for evaluating lake management strategies. The technical information developed in these investigations may be applied to numerous other recreational and public water supply impoundments throughout the Nation.

ISSN:1040-2381    

DOI:10.1080/07438148409354546

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The City Park Lake and the University Lakes complex have long been a source of pride to the citizens of Baton Rouge. This five-lake system comprises 300 acres. Over the past 50 years all aspects of the lakes have deteriorated with massive fishkills occurring on a regular basis during the warm summer months. In 1977 the City–Parish Government of East Baton Rouge asked the Institute for Environmental Studies at Louisiana State University to draft an Environmental Impact Statement and a Section 314 grant application to the Environmental Protection Agency to correct the hypereutrophic conditions in the five lakes. Then followed 2 years of negotiations gaining public support for the dredging project and obtaining areas for dredge spoil deposition. In September 1980 the project went out for bidding to the contractors, but because of the distance the spoil had to be pumped, bids far exceeded the $3 million available for the project. After several new dredging plans were presented, a large majority of people affected by the dredging gave approval to a plan using 30 percent in-lake disposal, and 70 percent off-site disposal at a very close location. In June 1981, the low bid for $2.09 million was accepted. Dredging commenced in November 1981. After the removal of 490,000 m3of lake bottom material, dredging ended in May 1983. In the post-dredging monitoring program, a group of 15 interested citizens was designated by the mayor to serve on the University Lakes Commission to oversee the monitoring of the lake waters, stabilization of shorelines and spoil banks, and to recommend funding for recreational use of the lakes and the immediately adjacent land areas.

ISSN:1040-2381    

DOI:10.1080/07438148409354547

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Creve Coeur Lake, an oxbow lake located in the Missouri Bottoms area of St. Louis County, Mo., is decreasing in surface area by deltaic deposition. In the early 1900's, the main lake had a surface area of approximately 81 ha (400 acres) and a small upstream lake. The main lake was reduced to an area of 32.4 ha (180 acres) by 1974 and the small lake completely filled. The average water depth decreased from 3.85 m (10 feet) to less than .77 m (2 feet). A 1971 engineering report included soils information, hydrologic and hydraulic investigations, field surveys, laboratory analyses, alternate designs with estimated costs, and economic analyses of benefits. Water quality problems noted in the 1971 water quality sampling program indicated high pH (>9.0), excessive nutrients, influx of fecal conforms and excessive algal growth (>10,000/ml). The result of the analyses indicated an optimum lake with an area of 133.4 ha (330 acres) dredged to a depth of 3.85 m (10 feet). St. Louis County initiated dredging in June 1974, completing it in December 1981. Baseline data collected in 1978 indicated high concentration of solids, excessive nutrients, and high levels of some heavy metals, including mercury. Sediment samples contained excessive nutrients with total phosphorus ranging from 1,200 to 2,200 μg/g and exceeded Missouri State Water Quality Standards for cyanide, mercury, phenols, iron, lead, nickel, and zinc. Routine water quality monitoring was performed monthly at the inflow, outflow, and five sampling stations in the lake. Sampling occurred during March-December 1981, while dredging was in operation, and during March–December 1982, after dredging was completed. Parameters routinely monitored included temperature, dissolved oxygen, Secchi transparency, pH, total phosphorus, ortho phosphorus, total nitrogen, fecal coliform, mercury, phenol, cyanide, and zinc. Fish flesh analyses were conducted on three species each quarter to monitor a bioaccumulation of mercury in the food chain. Analysis of the parameters during the dredging operations and the year following completion. of dredging did not indicate any significant differences attributable to the dredging operations.

ISSN:1040-2381    

DOI:10.1080/07438148409354548

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Tellico Dam and Reservoir were constructed by the Tennessee Valley Authority (TVA) as a multipurpose water resources project on the Little Tennessee River in eastern Tennessee. Purposes of this project include industrial and residential shoreline development, recreation, water supply, navigation, flood control, and power generation. To achieve these objectives without sacrificing the high water quality in Tellico Reservoir, TVA has undertaken a water quality management program to guide reservoir development. The resulting reservoir water quality management plan will recommend maximum allowable waste loads, industrial siting requirements, water use classifications and criteria, and fisheries management. This in conjunction with a reservoir land use plan, will provide comprehensive development guidelines for Tellico Reservoir. Implementation of the plan is to be accomplished through a unique blend of regulatory and nonregulatory measures carried out by TVA and the State of Tennessee. To facilitate incorporation of its recommendations into the water quality regulatory program, the reservoir water quality management plan will be formally adopted as a portion of the State Water Quality Management Plan. Through its authority as manager of reservoir lands, TVA will implement nonpoint source control recommendations for which the State lacks regulatory authority. This integration of environmental planning into Tellico Reservoir development will provide for intensive uses of the reservoir's land and water resources while maintaining high levels of water quality.

ISSN:1040-2381    

DOI:10.1080/07438148409354549

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Trophic state is fast becoming a nonconcept because of the confusion over its proper definition. The lack of agreement to trophic definition stems from its early typological origins, the fusion of causal factors with the resulting biological condition, and the assumption of the complex nature of the concept. A medical analogy of obesity is used to illustrate that trophic state can easily and unambiguously be determined by the measurement of plant biomass alone.

ISSN:1040-2381    

DOI:10.1080/07438148409354550

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The degree of nutrient enrichment has classically indicated trophic state. Nutrients alone, however, inadequately describe a lake's trophic-dynamic structure. Therefore, trophic state indices are simplifications of a more dynamic process. The specific utility of trophic state indices for their intended uses (classification and ranking by trophic status) is limited by deviant behavior among the indices. Secondary index information may be obtained by examining these deviations. Often, these deviations indicate the nature of nontypical trophic behavior.

ISSN:1040-2381    

DOI:10.1080/07438148409354551

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Trophic state index systems provide a framework for data summary, interpretation, and communication. Carlson's indices can be viewed as reexpressions of bivariate regression analyses derived from phosphorus-limited, northern, natural lakes. Several studies have shown that lakes or reservoirs which are nitrogen limited and/or have relatively high concentrations of non-algal turbidity tend to deviate in various ways from these regressions. These deviations are “problems” only if misinterpreted but limit the use of the index system for comparisons or rankings within certain regions and/or types of impoundments. Analysis of data from 65 Corps of Engineer impoundments indicates that a classification or index system which incorporates effects of nitrogen and non-algal turbidity would be of more general use in reservoirs. A principal components analysis is used to summarize impoundment response data into two composite variables which explain 93 percent of the variance in the original measurements. The first component is interpreted as a quantitative dimension which reflects the total amounts of nutrients and light extinction in the water column. The second is a qualitative dimension which reflects the partitioning of nutrients and light extinction between organic and inorganic forms. Basically, this system takes advantage of the fact that some of the deviations from a Carlson-type index system are systematic and contain information on the partitioning of nutrients and light extinction. If the objective is a concise summary of water quality data, information on both dimensions provides a more complete description of reservoir water quality than any single composite variable or index.

ISSN:1040-2381    

DOI:10.1080/07438148409354552

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor