摘要:

Comparing water quality data with standards, criteria, or management guidelines can be a major part of any water quality assessment. The effort required for manual comparisons of data for a large reservoir or watershed project can become a formidable task. One solution to the problem is to utilize a digital computer in conjunction with appropriate software designed to compare numerical water quality data with Federal and State criteria or standards as well as user-specified management guidelines. Aside from reducing the labor cost of data analysis, more accurate, rapid, and flexible analyses of water quality data can be readily performed. Utilization of such software can also allow a more extensive comparison of water quality data and criteria than would otherwise be possible. A software package of this type has been developed for the U.S. Army Corps of Engineers, Vicksburg District. The program, WATERCHECK, is used primarily in comparing project water quality data with Federal and State standards; a comparison which was not always feasible without the program. The processing of a data set which previously required 2–4 man-days now can normally be accomplished in 1 man-day. WATERCHECK is especially useful for State and regional water quality management organizations responsible for assessment of large amounts of data. User-specified options which allow the data to be compared against criteria or standards for different water use classifications are useful for water resource planning purposes as well as water quality management.

ISSN:1040-2381    

DOI:10.1080/07438148409354483

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Spatial and temporal variations in water quality and biological conditions were investigated in the lower 77 miles of Kentucky Reservoir in a series of monthly surveys conducted from February to September 1982. Factors investigated included dissolved oxygen and nutrient dynamics, algal community structure and standing crop, primary productivity, limiting nutrients, and water chemistry. Significant longitudinal and seasonal variations were observed for most parameters. Only minimal variations were observed with depth. Although thermal stratification was not observed, weak dissolved oxygen stratification did occasionally develop. Reservoir hydrodynamics appears to have pronounced effects on water chemistry and algal productivity.

ISSN:1040-2381    

DOI:10.1080/07438148409354484

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

During recent hearings on a unit of the Duck River Project, Columbia Dam and Reservoir, the question “How far downstream can water quality problems related to iron and manganese be expected to occur, and why?” arose. The two most prominantly unknown variables were time-of-travel below the dam and oxidation-precipitation rates. No rates were found for field studies and laboratory rates were either very high or very low. Most laboratory studies involved considerable pH shifts. Since the literature produced little information useful for predicting the oxidation rates of iron and manganese in tailrace streams, a study of iron, manganese, and sulfide kinetics was designed and performed at Normandy Dam, a TVA multipurpose project on the Duck River upstream of the Columbia Dam near Tullahoma, Tenn. The study found that manganese in the Normandy tailrace exists largely in the Mn++form which passes a 0.1μ filter. Only a small percentage of the total manganese is particulate. Mn++is oxidized as a linear function of time-of-travel at a rate of 0.041 mg/l per hour at a pH of 7.1 and a temperature of 17°C. The oxidized Mn precipitate is quickly settled and/or sorbed upon rocks and debris resulting in a a linear loss of total Mn with time-of-travel. The total Mn loss rate is 0.035 mg/l per hour at the previously stated conditions. Precipitation rates in the Duck River below Normandy Dam are as much as 50 times greater than rates determined in laboratory studies. Iron in the Normandy tailrace exists in three forms: particulate, colloidal, and dissolved. Exchange between the colloidal fraction and the dissolved Fe++fraction occurs in the river. The total iron decreases only slightly with time-of-travel in the Duck River. The colloidal fraction will not settle and evidently the particulate fraction is too buoyant to settle. Only 27 percent of the total iron was revoved during 29.5 hours of travel time. The presence of Fe++apparently keeps the S=concentration very low at less than 0.025 mg S=/l both in the lake and the tailrace stream due to formation of FeS which is insoluble. This research was conducted during the time period of June through December 1982.

ISSN:1040-2381    

DOI:10.1080/07438148409354485

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

In support of the Bureau of Reclamation effort to manage eutrophication trends in Flaming Gorge Reservoir, Utah and Wyoming, remote sensing studies employing multispectral digital imagery were undertaken. Specifically, the imagery was used to extrapolate point measurements of chlorophyll concentration and light penetration to characterize conditions throughout the reservoir. In 1981 and 1982, aircraft and satellites acquired digital imagery of the reservoir concurrent with surface sampling. Sampling stations were identified within the imagery and the digital values at these points recorded. The surface measurements of chlorophyll and light penetration were regressed against the digital image values to obtain predictor equations for these indicators of primary productivity. The equations were then applied to the images of the whole reservoir to obtain maps of the distribution of chlorophyll and light penetration. A unique set of equations was defined for each data-gathering date. The favorable results obtained in the date-specific studies prompted a search of data archives for other dates for which surface sampling and satellite imagery were both available. An atmospheric radiative-transfer model was also obtained to allow for correction of imagery for sun angle and atmospheric effects. This effort served two purposes: (1) to permit development of chlorophyll and light penetration predictor models from as many surface observations as possible, regardless of date of collection, and (2) to permit estimation of reservoir conditions from imagery for which no concurrent surface sampling was available. Seven satellite scenes were processed to estimate and map chlorophyll and light penetration, although concurrent surface sampling data were available for only four of them. The maps produced were used by reservoir managers to follow year-to-year trends in primary productivity.

ISSN:1040-2381    

DOI:10.1080/07438148409354486

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

As part of a diagnostic restoration/feasibility study of La Plata Lake in Puerto Rico, we have examined seasonal, vertical, and (some) horizontal patterns of nutrient distribution. The eutrophic state of this reservoir is evidenced in a series of characteristics including epilimnetic (0–4 m) chlorophyll concentrations averaging 15 mg m−3, virtually total absence of dissolved oxygen below 4m, and water hyacinth areal coverage estimated at 40 percent. Annual loadings of nitrogen and phosphorus have been calculated in 107 and 30 gm−2yr−1respectively, giving N:P loading ratios of 8:1. The ratio of N to P in the entire water column crop averaged 10:1 during the study period. The epilimnetic (0–4m) ratio averaged only 6:1. During a stratified dry period N:P ratios as low as 0.9:1 were observed whereas during periods following heavy runoff and lake mixing, the ratios approached values of 16:1. This pattern of inorganic nitrogen distribution suggests surface depletion from assimilation by hyacinths and algae. The suggestions currently being examined are that nitrogen is limiting to primary productivity in the La Plata system and that the principal controller of lake function is the pattern of hydrological events. Any plan to manage this and similar reservoir systems in Puerto Rico must take these factors into account.

ISSN:1040-2381    

DOI:10.1080/07438148409354487

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A simulation model was used to assess how agricultural practices used to reduce soil erosion, such as no-till cropping, affect the plant nutrient and suspended sediment levels in streams. The model is based on principles developed by the Soil Conservation Service, such as the Universal Soil Loss Equation and the Hydrologic Curve Number Equation. Annual model predictions for discharge and the mass loadings of phosphorus, nitrogen, and suspended sediment compare favorably to actual data collected for Irondequoit Creek, in western New York State during 1980 and 1981. The model was then run, driven by 20 years of meterological data, in order to assess various agricultural Best Management Practices. The effect of selected practices on discharge, nutrient loadings, and sediment loadings is presented.

ISSN:1040-2381    

DOI:10.1080/07438148409354488

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Lake Herman is a nitrogen limited, hypereutrophic, shallow (mean depth 1.7m), warm water lake located in Lake County, S.D. The lake has experienced extensive blue-green algal blooms, fish winterkills, and receives a high sediment load. Algal and macrophyte growth has diminished the open water surface area. The predominant land use is agriculture with permanent homes, small businesses, and public recreation areas surrounding the lake's shoreline. On January 13, 1978, Lake Herman and its associated watershed were selected to participate in the U.S. Department of Agriculture and U.S. Environmental Protection Agency sponsored Model Implementation Program. The primary objective of the project was to improve the water quality of Lake Herman by reducing phosphorus, nitrogen, and sediment loads through voluntary application of Best Management Practices (BMP's) and construction of sediment control structures. Approximately 5 years of water quality data from the lake, the tributaries, the outlet, and above and below the BMP's, and the sediment control structures are available from this project. Although the results of t-test analyses indicated that the sediment control structures are reducing the sediment and nutrient load, a corresponding reduction has not been observed in the lake. Therefore, two phosphorus mass budget models were used to predict the phosphorus concentrations in the lake: neither predicted the high phosphorus concentrations observed in the lake. It is assumed that another nonpoint source of phosphorus affects the lake (internal loading from resuspended sediments or aquatic macrophytes). The next step in the Lake Herman restoration project is to dredge selected areas to deepen them and reduce the resuspension of sediments.

ISSN:1040-2381    

DOI:10.1080/07438148409354489

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Initial water quality management planning efforts documented that agricultural activities are a major source of pollution in Illinois and mandated the development of plans to control this nonpoint source pollution from agriculture. The most severe agriculturally-related problem is soil erosion and its effects upon the aquatic environment. In Illinois estimated gross erosion exceeds 180 million tons annually, 88 percent of it caused by sheet and rill erosion from cropland. To control agricultural non-point pollution from its source, efficient and effective land management practices and programs must be developed. A fundamental component of this strategy is the identification of specific areas that significantly contribute to the problem, to permit targeting of resources. Illinois Department of Agriculture (IDOA) formed the Soil Erosion and Water Quality Advisory Committee (SEWQAC), which implemented a two-tier targeting system. Local targeting within each district is the first level. The second is statewide targeting to solve problems identified locally that cannot be addressed with local resources. A subcommittee formed by SEWQAC developed a uniform process to identify, screen, and prioritize rural water resource and lake rehabilitation projects within the State. The process provides a uniform and systematic method for local Soil and Water Conservation Districts, ASCS County Committees, and other interested local units of government to identify and compete for funding under three program authorities. Designed to set meaningful State priorities, the system provides equal access for each project to all the program authorities and gives the local county responsibility for identifying and prioritizing its projects. The local Soil and Water Conservation Districts are assisted by a State Association Water Quality Coordinator and assistant funded through an IEPA contract. The process has been successful to date.

ISSN:1040-2381    

DOI:10.1080/07438148409354490

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The State of New Jersey has approximately 1,100 lakes of which 345 are publicly owned. Many of these lakes are located in urban–suburban areas with high density residential and commercial land use activities on their watersheds. In 1975, the New Jersey Department of Environmental Protection (NJDEP) initiated a lake management program, inventorying and conducting water chemistry sampling in over 450 of these lakes. Based on these observations, over 30 percent of these lakes were presumed eutrophic. Final determination of trophic status and the development of management plans, however, necessitated more extensive analysis. To accomplish this NJDEP secured a $100,000 Section 314 Lake Classification Grant on Nov. 17, 1979. Of the lakes inventoried, 25 were selected for intensive study. They represent a reasonable cross section of the types of lakes and lake problems in New Jersey. These 25 lakes were ranked on the basis of their trophic status as determined by land use, unit areal loading, methodology, and verified to the extent possible by intensive survey data. Point and nonpoint sources of nutrient loading were identified and quantified. Reduction in nutrient loadings required to improve their trophic status was estimated and management and restoration recommendations to accomplish nutrient reductions described. This evaluation indicated that, for the most part, nonpoint sources related to urban, suburban, and in some cases agricultural stormwater runoff were the major source of nutrient loads to these lakes. The identification of storm water as the major source of loadings to these lakes is timely since New Jersey has just finalized new storm water quality management regulations.

ISSN:1040-2381    

DOI:10.1080/07438148409354491

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Lake management involves the formulation of objectives, not all of which are compatible in a given water body. Common objectives such as high quality water supply, suitability for contact recreation, and pleasing aesthetic properties are generally associated with low plankton standing stock, especially as regards phytoplankton. On the other hand, production of fish for food or sportfishing is often impaired by decreases in plankton biomass. Strong correlation has been found between measures of plankton production or standing stock and fish yield. Investigated relationships between phytoplankton, zooplankton, planktivores, and piscivores are consistent with an energy pyramid model of the pelagic food web; greater production at the top of the pyramid is caused by a corresponding increase at its base or through increased internal energy transfer efficiency. Management for higher energetic efficiency is in its infancy and that for greater plankton biomass conflicts with other management objectives. Division of responsibility among various organizations and agencies of government may help achieve single objectives, but impedes progress toward a unified systems approach to lake management. Management objectives may be less conflicting for poorly aerated systems or where fishery management is aimed at certain target species, but serious consideration should be given to potential conflicts during goal formulation. Lake associations and managers should establish management priorities early in their planning processes. Their decisions should use expertise from both fishery and water quality science.

ISSN:1040-2381    

DOI:10.1080/07438148409354492

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor