摘要:

Increasing occurrences of blue-green algal blooms in lakes throughout the western United States have been linked to recreational use, sewage inputs, and nonpoint runoff from agricultural and grazing sources. In certain instances these blooms produce toxins that can be lethal to fish, aquatic invertebrates, mammals, and humans. Black Lake in northern Idaho has experienced late summer and fall growths of a toxic alga,Anabaenaflos-aquae. Demonstrated fatal toxicity to cattle and small mammals occurred in 1981, 1982, 1983, and 1985. The eutrophication and subsequent toxic blooms in Black Lake can be related to its large nonpoint nutrient input from the surrounding watershed. The presence or absence of cattle on adjacent meadows may be a major determining factor in bloom formation. Despite a high proportion of sediment (55 percent) exposed to anaerobic conditions during summer stratification, it appears that internal loading alone does not play a significant role in the triggering of a toxic bloom in Black Lake. Development of a toxicA.flos-aquaebloom in Black Lake is dependent on a series of interdependent environmental controls. The most important conditions in Black Lake appear to be high spring nutrient load (compounded by the presence of cattle), high fall water temperature, and stable water column conditions in the fall. TheA.flos-aquaestrain present in Black Lake formed surface concentrations and produced anatoxin-a, despite comprising only 1–2 percent of the total algal biovolume in the water column. Anatoxin-a is produced at times other than when massive surface scums are formed, indicating toxic strains are more widespread in occurrence than previously perceived.

ISSN:1040-2381    

DOI:10.1080/07438148709354765

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The total biochemical oxygen demand (TBOD, g O2m−2) of two small, ≤ 5.0 ha, eutrophic lakes in central Iowa was estimated from measurements of the biochemical oxygen demand (BOD) from the top 25 mm of sediments (SBOD) and summation of the BOD values from each 1-meter strata of the water column (WBOD). Standard BOD procedures were used for both sediment and water column biochemical oxygen demand, although a special protocol was developed for the sediments. Continuous recording of the oxygen consumption of selected sediment samples during the five-day BOD procedure revealed a high initial oxygen demand which then declined exponentially over the five-day interval; the oxygen consumption in 20 minutes averaged 26 percent of the mean five-day SBOD value. The sediment and water column biochemical oxygen demand were measured for 28 months in both lakes. WBOD (9 O2m−2) values ranged from 2.0 to 13.1 and mean values were 5.1 and 6.5, respectively, in the two lakes. SBOD (g O2m−2) values ranged from 27.7 to 138.6 and averaged 79.6 and 80.3 in the two lakes. Monthly variation in water column and sediment biochemical oxygen demands were independent. Sediment values were greater than 90 percent (96.5 percent of the total demand in one lake and 94.0 percent in the other lake) of the total biochemical oxygen demand in 9 of 56 monthly samples in both lakes. During the winter ice-covered interval, sediment biochemical oxygen demand and the dissolved oxygen content of the water column were negatively correlated for the two 1-m strata nearest to the bottom.

ISSN:1040-2381    

DOI:10.1080/07438148709354766

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The EPA Clean Lakes Program was initiated in 1975 to protect publicly-owned freshwater lakes under Section 314 of the Clean Water Act. A review of the first decade of the Program by Battelle Memorial Institute highlights the accomplishments of the Clean Lakes Program, the results of federally funded projects and recommendations for the future. From 1975 to 1985, EPA funded 313 Clean Lakes studies and projects totaling $93 million in federal dollars. Forty-seven states and Puerto Rico participated. The majority of funds (87 percent) was awarded to lake restoration projects. The remainder was used for lake classification studies and diagnostic feasibility studies. Public concern about lake eutrophication was the most significant factor in prompting action that resulted in restoration. The Program has improved water quality nationwide; examples of public and economic benefits are cited. In addition, the Clean Lakes Program has contributed to the science of lake restoration through a better public and scientific understanding of lake eutrophication, detailed information on successful restoration measures and the development of new restoration techniques.

ISSN:1040-2381    

DOI:10.1080/07438148709354767

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Nonpoint Source (NPS) assessment, planning, and control programs to protect lakes top short of addressing the cumulative impacts of incremental development. Taken separately, each lakeside dwelling may appear acceptable; cumulatively such developments accelerate eutrophication. A new development may provide the infrastructure or precedent for additional development, and equity becomes a planning issue. The Clean Water Act touches on cumulative impacts in provisions dealing with antidegradation, load allocations and permits. Certain federal/state laws to protect envirionmentaliy-sensitive areas can also be interpreted to cover cumulative impacts. This paper explores the limits to which federal/state environmental laws and local planning and zoning can be used to handle the cumulative impacts of development on lakes. More use can be made of federal authorities, especially now that the Clean Water Act Amendments direct more attention to nonpoint source control. Comprehensive state and local land use planning and regulation needs to be strengthened. THis paper outlines a planning framework to consider cumulative impacts in planning and land use decisions to respect a lake's finite capacity. Comprehensive planning will develop the data and assumptions about environmental constraints and development activities needed to refine the framework and lend legitimacy; in turn, this framework can strengthen comprehensive planning.

ISSN:1040-2381    

DOI:10.1080/07438148709354768

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Colorado has institutionalized an innovative method for managing reservoir water quality which allows for point/nonpoint source phosphorus trading and for point sources to obtain phosphorus “credit” for controlling nonpoint source phosphorus. The State Water Quality Control Commission and the Environmental Protection Agency have approved this method for use at Dillon Reservoir, a high-altitude water body located in the heart of ski country, serving as a summer recreational resource and primary drinking water supply for the Denver metro area; and Cherry Creek, a plains reservoir which is the most intensely used water body for recreation in Colorado. Both reservoirs are threatened by eutrophication from increased point and nonpoint source nutrients loadings resulting from future growth. This approach has built-in economic and regulatory incentives for application of conscientious nonpoint source control. Dillon Reservoir is the first water body in the country for which this approach has been officially adopted.

ISSN:1040-2381    

DOI:10.1080/07438148709354769

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A nine-month water quality monitoring program was performed on seven lakes in Snohomish County, Washington to: (1) assess current lake quality, (2) identify potential pollutant loading sources, and (3) recommend appropriate restoration/management strategies. A major concern was the extent to which shoreline on-site wastewater systems were adversely affecting quality of the lakes. Two comprehensive septic leachate surveys of lake shoreline were performed to identify the number of concentrated effluent plumes to the lakes and characterize phosphorus loading from this source. A portable fluorometer specifically indexed to degradation products of wastewater was used with great effectiveness in the surveys. Initial fluorometer screening was followed by surface water and shallow groundwater quality sampling/analyses, site inspections/homeowner interviews, and dye testing to corroborate onsite system failures. Open-water areas of the lakes exhibited good to excellent water quality. However, several localized shallow shoreline areas evinced signs of incipient water quality degradation and coincided with effluent plumes from inadequately treated residential wastewater and discharges of surface water drainage. Management efforts were recommended to minimize pollutant loading by both the above sources.

ISSN:1040-2381    

DOI:10.1080/07438148709354770

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Economics has come to play an increasingly important role in decisions concerning lake protection and restoration. This study of the tillamook Bay, Oregon, nonpoint source control efforts illustrates a methodology by which a benefit/cost analysis can be accomplished for evaluating cost-effectiveness of such projects. Tillamook Bay has been periodically closed to shellfishing for several years because of bacterial contamination. Implementation of agricultural best management practice on about 60 percent of the identified critical sources in the watershed has produced a statistically significant reduction in bay fecal coliform concentrations. With plans for nearly 100 percent implementation by 1989, the bay waters should again meet shellfish water quality standards thereby removing the threat of further closures. Total government costs for the cleanup effort will probably be in the range of six million dollars. This paper develops a benefit/cost analysis to determine the cost effectiveness of this nonpoint source control effort. The analysis shows that the control effort is only marginally economically efficient when only lost commercial shellfishing revenues are considered. However, when the lost revenues from associated recreational activities are considered, the analysis shows that benefits of greatly exceed project costs.

ISSN:1040-2381    

DOI:10.1080/07438148709354771

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A study was conducted on a recreational fioatway in northeast Alabama to assess EPA's new bacteriological criteria. In relation to the new criteria, the floatway was found to be more contaminated compared to the longstanding fecal coliform criterion. High correlations were found between fecal coliform concentrations andE.Coliand enterococci concentrations. Regression models were developed which enable the prediction of new criteria values from historical fecal coliform data.

ISSN:1040-2381    

DOI:10.1080/07438148709354772

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Fuels for modern internal combustion engines contain nitrogen and phosphorus compounds as additives (e.g., alkyl phosphate, amine phosphate, etc.). In addition, nitrogen oxides are formed from atmospheric gases during combustion. In the case of marine engines, exhaust gases and incompletely burned fuel and oil are discharged directly into the water. In situ enclosure experiments were conducted to quantify nitrogen and phosphorus additions from two- and four-cycle outboard engines per liter of fuel consumed. The modern two-cycle outboard engine added to test tanks 8,600 mg carbon dioxide, 300 mg total nitrogen, and 1.0 mg total phosphorus per liter fuel consumed. A motorboat census was conducted on Twin Lakes, Kootenai County, Idaho, throughout the 1986 boating season and annual fuel consumption was estimated. Phosphorus and nitrogen loading to Twin Lakes from motorboat engine discharges were calculated and are low when compared to loading from other sources.

ISSN:1040-2381    

DOI:10.1080/07438148709354773

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The LaPlatte River Watershed in northwestern Vermont is the focus of an intensive land treatment program to control agricultural runoff and a long-term monitoring program to evaluate the effect of these treatments on water quality. Best Management Practices for controlling dairy manure and cropland erosion have been implemented on 90 percent of the priority areas in the Watershed. The 11-year monitoring program includes precipitation and streamflow recording and water sampling for suspended solids, phosphorus, and nitrogen analysis. Interpretation of monitoring data is confounded by incremental implementation of best management practices, climatic and hydrologic variation, and lack of pre-implementation water quality data. Application of four exploratory trend analysis techniques to six years of data from one monitored subwatershed is described. These techniques are (1) linear regression against time; (2) comparison of annual means; (3) analysis of frequency distributions; and (4) paired watershed regression. Results of these analyses suggest significant decreases in sediment and nutrient concentrations and loads since the project began.

ISSN:1040-2381    

DOI:10.1080/07438148709354774

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor