摘要:

As a result of the diagnostic portion of the 314 Clean Lakes Study on Bear lake, three alternatives were selected because of their expected water quality improvement potential, technical feasibility, environmental impact, and estimated cost: (1) site specific recommendations—Upper Bear River watershed management, Dingle Marsh modifications, and the use of BMP's in two small problem watersheds within the Bear Lake drainage; (2) a site specific basinwide water quality management plan; and (3) an environment information and education program. Because of the limitation in Phase II Clean Lakes moneys, the implementation of the diagnostic study was difficult. A case history is presented on how the project was continued. Because of the location of Bear Lake, four Federal agencies and three States became involved in the existing Bear Lake Preservation Project. An example of the value of a Regional Commission and the important coordinating role played by this type of agency will be discussed.

ISSN:1040-2381    

DOI:10.1080/07438148409354513

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Adjacent to the north end of Bear Lake is a large (65 km2) freshwater marsh. Prior to 1912, Dingle Marsh was separated from Bear Lake by a naturally occurring sandbar and covered approximately 100 km2. Seventy years ago, Utah Power and Light constructed a canal system which effectively diverted the Bear River into Dingle Marsh. The present water system operates by diverting spring water from the Bear River through the marsh and into Bear Lake. During late summer when irrigation demand is high, water is removed from the lake, passed through the marsh, and released into the river. The major objective of this portion of the Clean Lakes Study was to determine the nitrogen, phosphorus, and carbon budgets of Dingle Marsh and define the factors that may regulate the flux of these nutrients into Bear Lake. Sixteen sites within the marsh and all major inflows and outflows were sampled over an 18-month period. The data indicated specific seasonal trends within the marsh (sources or sinks) of the target nutrients. Furthermore, the marsh mass balances indicated that on an annual basis, the marsh acted as a sink. However, during specific periods of time, nitrogen, phosphorus, and carbon were produced within the marsh system and exported (the marsh was a source). Management alternatives were generated as a result of this portion of the project to maximize the marsh as a nutrient sink for inflowing Bear River water.

ISSN:1040-2381    

DOI:10.1080/07438148409354514

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Bear Lake is a hardwater lake located in a limestone basin on the border of Utah and Idaho with a surface area of 282 km2, maximum depth of 63 m, and a mean depth of 10 m. The lake was formed by tectonic activity approximately 28,000 years B.P. with no natural outfall. Inflow mainly from small tributaries probably did not equal evaporation. These conditions resulted in a concentration of carbonate salts and a unique macrochemistry, with magnesium as the predominant divalent cation. The isolation from any major drainages also led to the development of endemic fish species. In 1912, Utah Power and Light Company completed a series of canals diverting water from the Bear River into the lake during the spring and later released for downstream irrigation and power needs. Diversion of the Bear River into the lake increased water flow and presumably loadings by as much as 70 percent above historic conditions. A 2-year study recently completed found nutrient loadings into Bear Lake at meso-eutrophic levels, but the lake limnologically oligo-mesotrophic. Phosphorus was the principal limiting nutrient. Because of this apparent anomaly in trophic status and the known relationship between calcium carbonate and phosphorus in marl lakes, this study was undertaken to quantify the reduction of potential algal biomass through coprecipitation of phosphorus. Initially, three different phosphorus levels were added to synthetic Bear Lake medium without algae to determine if coprecipitation would occur under ideal conditions. The pH of the medium was raised artificially with NaOH to 8.5, a value not uncommon in Bear Lake. After 4 days 100 percent of the phosphorus had precipitated in the 10 μg P/l treatment. Bioassays were then conducted in softwater and Bear Lake media withSelenastrum capricornutumat 10 different phosphorus levels. At similar nutrient levels the maximum biomass reached twice that of the biomass in the Bear Lake medium. These may explain the low primary production experienced in many hardwater lakes and Bear Lake in particular. It may also be inferred that a potential self-cleansing mechanism exists within Bear Lake that would allow a rapid reversion to historic water quality if nutrient loadings were reduced.

ISSN:1040-2381    

DOI:10.1080/07438148409354515

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Lake Hopatcong is a 1,087 ha lake located in the suburban New York metropolitan area in Sussex and Morris Counties, N.J., and is the head waters of the Musconetcong River in the Delaware River Drainage Basin. The lake watershed is 5,483 ha in area with 71 percent forested and 25 percent in high-density residential development that is clustered around the immediate shoreline of the lake. The recreational use of the lake is extremely heavy, with an excessive number of large motor boats. Also, stormwater from the residential areas empties directly into the lake via storm sewers and direct runoff. Preliminary analysis of selected sediment samples indicated substantial levels of metals (especially lead) in the surficial sediments. As part of a Sec. 314 Lake Restoration study a series of 30 shallow sediment core samples were taken at various locations throughout the lake. These were analyzed for lead, aluminum, iron, zinc, mercury, cadmium and percent of solids. The results indicated significant concentrations of lead and zinc in the most recent sediments as compared to the background levels in the older and deeper sediments. Also, the spatial distribution of sediment metals within the lake was investigated to attempt to identify their sources. The implications of these findings and management implications based on the information are discussed.

ISSN:1040-2381    

DOI:10.1080/07438148409354516

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Lake Whatcom is a large, deep, monomictic lake in the Puget lowlands of Washington State. Expanding development from the city of Bellingham and a large diversion of water from the Nooksack River to the lake are two recent impacts. Bellingham depends on the lake as its sole drinking and industrial water supply. Additionally, the lake is an important recreational resource. Monitoring of the lake began in 1962 and was continuous to 1972, and recent work began in 1979. These data and information from sediment cores have been used to determine trends in water quality. Historically, watershed uses were mainly logging and some coal mining. Sedimentation rates based on Pb-210 were about 0.5 cm/yr. More recently, sedimentation rates have increased to 0.8–1.2 cm/yr., apparently due to increased runoff related to urbanization and the diversion of Nooksack River water containing glacial meltwater with high particulate loads. Much of the particulate material is sedimented in a 6.5 ha lake below the diversion tunnel (volume has decreased 20 percent since 1962), but very fine particulates are transported through this lake to Lake Whatcom. These silt and clay-sized particles may sorb phosphorus descending through the water column. Nutrient concentrations and sediment metal concentrations increase toward the urbanized portions of the watershed. The city water intake is located in the shallowest, most nutrient-rich basin, containing the greatest development densities. Water level regulation is also an issue due to conflicting uses of shoreline development, water storage and use and downstream encroachment. Due to the flashiness of watershed streams, water and sediment transport can cause problems for lake level manipulation and water quality. A Phase 1 lake restoration study funded by the State of Washington is underway, and results will be discussed.

ISSN:1040-2381    

DOI:10.1080/07438148409354517

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Eau Galle Lake is a small Corps of Engineers impoundment on the Eau Galle River in west central Wisconsin. A sediment survey was conducted to document reservoir sediment characteristics in relation to reservoir morphometry, hydrodynamics, and water quality. Sediment conditions at Eau Galle Lake tend to be lakelike, rather than exhibiting a more typically reservoir-like dependence on hydrodynamics. Sediment distribution patterns in the reservoir are primarily influenced by basin morphometry, which has resulted in sediment deposition and quality being depth related. A deep central basin, circular shape, and multiple inflows have contributed to the existence of two distinct sedimentary zones. The transport zone, which is characterized as a high-energy environment, exists in the shallow, littoral areas of the reservoir. Turbulent processes dominate the transport zone, thereby, discouraging the permanent deposition of fine particulates. As a result, transport zone sediments have a relatively large median particle size and low moisture content. The deep central basin of the reservoir is characterized as an accumulation zone of low energy. Sediments in this less turbulent area are characterized by a smaller median particle size and high moisture content. Sediment chemical characteristics of nutrients, metals, and organic matter are higher in the accumulation zone. Therefore, the deep sediments may be more influential to water quality through exchanges at the sediment/water interface.

ISSN:1040-2381    

DOI:10.1080/07438148409354518

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Surficial sediment samples were collected from 63 Illinois lakes during summer 1979. Samples were analyzed for organic matter, nutrients, heavy metals and organochlorine compounds. For purposes of statistical analysis, lakes were placed into one of several groups (glacial, artificial or miscellaneous). Most lakes were artificial reservoirs and these were subdivided based on geographic location. Spatial variations of glacial lake means were contrasted with artificial lake studies. In an attempt to correlate fish flesh pesticide concentrations with sediment concentrations, no simple linear relationships were discerned. In general, the low organic content of Illinois sediments was probably attributable to the high non-volatile suspended solids loading characteristic of most Illinois lakes. Regardless of organic carbon content, the ratio of C:N remained fairly constant at 14:1. The N:P ratio for Illinois lake sediment of 6:1 was somewhat less than the generally conceded 7:1 for plant material. Most Illinois lakes exhibited fairly low sediment metal/metalloid concentrations. Most chlorinated hydrocarbon pesticides were undetected or occurred at low levels in sediment samples. PCB's were detected only in sediments from seven of the lakes sampled. A classification of Illinois lake sediments based on mean constituent concentrations and respective standard deviations was developed to facilitate interpretation of sediment data. The resultant four tier classification system categorized lake sediments as below normal, normal, elevated, and highly elevated.

ISSN:1040-2381    

DOI:10.1080/07438148409354519

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A perception of the engineering characteristics of dredged lake materials is necessary for making decisions regarding the size and type of hydraulic dredge best suited for the proposed project, dredge production rates, containment area size requirements, various containment area operating procedures, the nature of potential containment area reuse, the time necessary for the filled containment area to become available for reuse, and potential measures that may be used to increase the rate of improvement and ultimate strength characteristics of the dredged material in the containment area. The pertinent engineering characteristics are reasonably inferred from bulking, grain size distribution, specific gravity and organic content, Atterberg Limits, consolidation and shear strength data. Typical ranges for these data, including before and after dredging cases, as determined for several sites in the northeastern United States are presented. Significant differences in measured characteristics often occur among samples taken from the lake bottom, from the dredge effluent pipeline or from the containment area. The most important changes in dredged material composition resulting from the dredging and dredged material disposal process are the loss of fines and low specific gravity material. This change should be accounted for when planned dredging projects employ engineering data obtained from samples of lake material to be dredged.

ISSN:1040-2381    

DOI:10.1080/07438148409354520

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Lakes and reservoirs typically have been considered synonomous; in fact, Hutchinson classifies reservoirs as lake type 73. Processes such as internal mixing, redox reactions, nutrient cycling, and primary production obviously occur in both lakes and reservoirs. The forcing functions or driving variables for lakes and reservoirs, however, may not be identical so the response of these two systems may be different. Regional considerations of the climatic, geologic and geographic differences between lakes and reservoirs indicate why our understanding and available predictive techniques for lakes should be tempered for the proper management or reservoirs. Lakes and reservoirs generally are distributed in different parts of the U.S. Most lakes occur in the glaciated portion of the U.S. while most reservoirs are located in the southeastern, central, southwestern, and western U.S. Geologic differences in these areas have implications for differences in the loading of dissolved and particulate constituents to lakes and reservoirs. Climatic differences such as precipitation-evaporation interactions also result in distinct areas. In the eastern U.S., precipitation exceeds evaporaton, water is plentiful and lakes are prevalent. In the western U.S., evaporation exceeds precipitation, water is scarce and reservoirs are prevalent. Geographic differences influence the management of lakes and reservoirs. Operation of reservoirs for hydropower, irrigation, industrial and public water supply can influence the response of the system to external and internal inputs. The distribution of lakes and reservoirs in conjunction with geologic, climatologic, and geographic patterns would imply potential differences in the limnological response of lakes and reservoirs. Proper management of our water resources requires that we consider these potential differences in the decision process.

ISSN:1040-2381    

DOI:10.1080/07438148409354521

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Unlike small drainage lakes which receive nutrient inputs from relatively diffuse sources, reservoirs and other river-fed lakes receive a majority of their nutrient income from a single large source located distant from the lake's outlet. Interactions between lake and river, which are governed by hydrology, the thermal structure of the lake, and lake morphology, will, therefore, play an important role in determining the impact and ultimate fate of influent nutrients. These interactions may also affect the manner in which nutrients are recycled and/or distributed within the reservoir or river-fed lake and lead to the establishment of longitudinal gradients in concentration. Studies conducted at DeGray Lake, Ark., and West Point Lake, Ga., both large Corps of Engineers hydropower reservoirs, provide instructive examples of some of the effects of these interactions. Both lakes exhibit longitudinal gradients in nutrient and chlorophyll concentrations which are influenced by the hydrologic characteristics of the major tributary. Exchanges of water and material between hypolimnion and epilimnion are also affected by flow regime. These exchanges play an important role in the seasonal dynamics of nutrients and metals.

ISSN:1040-2381    

DOI:10.1080/07438148409354522

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor