摘要:

A new multiparameter lake assessment protocol, the Ohio Lake Condition Index (Ohio LCI), was developed by the State of Ohio to comply with the 305(b) guidelines in the Water Quality Act amendments of 1987. Thirteen in-lake parameters were assessed for each of Ohio's 417 publicly owned lakes. Both monitored data and evaluated information based on responses to a questionnaire were included in the assessment process. Raw data were transformed into subindex points for summation into a final numerical Lake Condition Index score. Sets of parameters were identified to determine whether or not designated uses and the goals of the Clean Water Act were being met. Applications of the Ohio Lake Condition Index are discussed, including using it to target lakes affected by nonpoint source pollution. The Lake Condition Index protocol can be modified to accommodate revisions to water quality standards and changes in a state's water quality management objectives for lakes. The authors question the appropriateness of reporting the status of lake condition based exclusively on the concept of trophic state.

ISSN:1040-2381    

DOI:10.1080/07438148909354675

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In lakes and reservoirs, productivity and biomass responses to nutrient loading are fairly predictable; resultant changes in phytoplankton taxonomic composition are not. Whether enrichment leads to dominance by procaryotic or by eucaryotic phytoplankton is important to lake trophic structures, to ecosystem modelers, and to lake managers. Much of the uncertainty about the effects of enrichment on phytoplankton composition stems from an inadequate understanding of how nuisance bloom-formers succeed in dominating plankton assemblages. The authors contend that investigations of nutrient effects on cyanobacterial buoyancy regulation provide a basis for understanding patterns of cyanobacterial dominance during the course of eutrophication as well as during seasonal successions in stratified, eutrophic lakes. Cyanobacterial dominance in the surface layers of enriched lakes should be more pronounced in HCO3-rich waters where synthesis of the cellular components involved in buoyancy regulation is not limited by nitrogen, phosphorus, or carbon. In mildly acidic and other low-carbon waters, carbon limitation of buoyancy regulation deters nuisance bloom formers, but not non-gas-vacuolate cyanobacteria. The authors also suggest that restoration by artificial mixing or by biomanipulation is less likely to succeed in HCO3-rich than in softwater basins.

ISSN:1040-2381    

DOI:10.1080/07438148909354676

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

There is considerable support in the ecological literature for the theory that phytoplankton communities experience non-equilibrium conditions. Therefore, it is possible that not all species of an algal community are deficient in the same nutrient, challenging the belief held by some aquatic scientists and lake managers that phosphorus is the universal nutrient limiting phytoplankton growth in lakes. Simultaneous additions of NH4+and PO43−were necessary to stimulate community photosynthesis – uptake of14CO2– during summer stratification in a number of northern Rocky Mountain lakes and reservoirs, whereas adding one nutrient had no significant effect on community photosynthesis. However, size-fractionated bioassays showed that additions of nitrogen alone stimulated photosynthesis of specific size classes of phytoplankton in these systems. The authors' data have the following implications for lake management: (1) phosphorus should not be assumed to be the only nutrient controlling photosynthesis; (2) simultaneous enrichment of nitrogen and phosphorus may be necessary to measurably increase community photosynthesis, especially in nutrient dilute systems; and (3) adding NH4+may cause changes in phytoplankton community structure without changing community primary production.

ISSN:1040-2381    

DOI:10.1080/07438148909354677

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The ability of nutrient enrichment bioassays versus physiological indicators to detect ecosystem changes in nutrient cycling were compared. Field data spanned four years in three lakes, two of which were subjected to fish manipulations in year two. The manipulations changed phytoplankton and zooplankton assemblages and nutrient cycling. Phosphorus and nitrogen enrichments (phosphorus enrichment bioassay (PEB), nitrogen enrichment bioassay, nitrogen plus phosphorus enrichment bioassay, specific alkaline phosphatase activity, ammonium enhancement response, and total nutrients (total phosphorus, total nitrogen) were measured before and after the manipulations. Although physiological indicators were often more sensitive, nutrient enrichments and physiological indicators both led to the same conclusions regarding changes in nutrient cycling. Total nutrients did not respond to manipulation. Physiological indicators measure the extant algal assemblage, are rapidly assayed, can be run more frequently than nutrient enrichments, and lead to the same conclusions as nutrient enrichment bioassays.

ISSN:1040-2381    

DOI:10.1080/07438148909354678

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In 1974, the Wisconsin Legislature recognized that many lakes needed more intensive management than could be provided by either the state's general pollution control efforts or the voluntary efforts of property owners' associations. The Legislature passed legislation enabling property owners to form a special purpose unit of government to manage a local lake. This article describes the history and activities of Wisconsin lake districts. Particular attention is paid to the differentiation of function between federal, state, and county/municipal governments – general purpose units – and the special purpose lake district. Data from a recent survey of 79 lake districts showed the most popular activities are mechanically harvesting aquatic vegetation, 57 percent; stocking fish, 48 percent; promoting boating and skiing regulations, 37 percent; chemically controlling macrophytes, 34 percent; controlling algae, 33 percent; patrolling water safety, 28 percent; promoting zoning, 25 percent; inspecting septic tanks, 25 percent; and providing public access, 25 percent. Such management efforts indicated lake districts have become a significant institution in the management of Wisconsin lakes.

ISSN:1040-2381    

DOI:10.1080/07438148909354679

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Taste and odor are frequently cited problems in Kansas water supply lakes in agricultural watersheds. This study assesses the relative magnitude of summer lake water taste and odor as it relates to lake enrichment levels in six representative Kansas lakes. Mean chlorophyll concentrations ranged from 3.05 μg/L to 16.63 μg/L. Algal species included various flagellates, green algae, and diatoms.Cryptomonaswas common in all lakes. While surface and bottom water odors increased during the summer, bottom water odors persisted longer, until lake destratification.AnabaenaandCyclotellawere most often associated with lake water odor. While bottom water odor ranking was not associated with lake trophic state (P = 0.21), surface water odors were associated with lake trophic state (r = 0.81, P = 0.05).

ISSN:1040-2381    

DOI:10.1080/07438148909354680

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Bacteria are often important indicators of nonpoint source water pollution. Runoff from farmland and agricultural activities such as animal waste management, feedlots, and grazing are the principal sources of bacteria to surface waters. Fecal coliform and fecal streptococcus levels have been monitored in four Vermont agricultural watersheds for eight years as part of the LaPlatte River Watershed Project. This project is a long-term monitoring program designed to evaluate the effects of implementing best management practices on water quality. Bacterial densities recorded in the monitored streams and in runoff from specific agricultural practices are reported. While levels of fecal streptococci in the streams have declined significantly since implementing land treatments, bacterial densities continue to exceed water quality criteria 20 to 30 percent of the time, particularly in summer. Bacterial densities in the streams appear related to agricultural activities within their watersheds such as corn production, pasturing, and animal density.

ISSN:1040-2381    

DOI:10.1080/07438148909354681

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The Saline Valley project is one of 20 national projects sponsored by the U.S. Department of Agriculture (USDA) under the Rural Clean Water Program (RCWP) to evaluate methods of controlling agricultural non-point source pollution. The goals of this project were (1) to evaluate whether a voluntary approach using cost-share incentives would produce adequate participation by local farmers and (2) to reduce phosphorus loads from the area by 40 percent. Water quality has been monitored since 1981 using weekly grab samples and flow measurements. Trends in empirical relationships between concentration and discharge at three sampling stations were used to examine the effectiveness of best management practices (BMP). These relationships were highly variable among the sub-basins and years, and did not appear to correlate with areal estimates of BMP implementation. Overall, low participation within the project area hindered the ability to quantify changes in water quality resulting from BMP implementation and prevented the project from meeting its phosphorus reduction goals.

ISSN:1040-2381    

DOI:10.1080/07438148909354682

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In 1984, intensive lake and watershed studies were undertaken by St. Paul Water Utility to identify causes and remedies for taste-and-odor episodes that had plagued the supply in recent years. Water is derived from the Vadnais Lake Chain, and fed mainly by diversions from the Mississippi River and runoff from local watersheds. Early phases of the study implicated algal blooms in the storage lakes as the immediate cause of the taste-and-odor problems. Historical control schemes, including routine copper sulfate applications and dosing of various chemicals at the water treatment plant, had been largely unsuccessful. Following three years of collecting baseline data control measures were implemented to address the basic problem of nutrient enrichment. These controls targeted sources of phosphorus including diversions from the Mississippi River, runoff from urban watersheds, and recycling from lake bottom sediments. Specific control measures included: (1) selecting supply sources based upon chemical factors – phosphorus, silica, iron; (2) injecting iron chloride to inactivate orthophosphorus in waters pumped from the Mississippi River; (3) using wet detention ponds to reduce phosphorus loadings in runoff from urban watersheds; (4) aerating the hypolimnion – plus iron chloride injections in 1988. This paper discusses the design and evaluation of control measures and observed lake responses over the 1984–88 monitoring period. Results indicate substantial progress has been made toward reducing nutrient enrichment levels in the supply lakes as well as undesirable impacts on the water supply; these include taste-and-odor, trihalomethanes, and water treatment costs. The ongoing monitoring program will track lake responses and control (success) over a wider range of hydrologic conditions.

ISSN:1040-2381    

DOI:10.1080/07438148909354683

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The Lake Assessment Program is a cooperative lake study program involving Minnesota Pollution Control Agency (MPCA) staff and local citizens. It was initiated in 1985 as a pilot program to fill the gap between the Citizen Lake Monitoring Program (Secchi disk monitoring) and intensive studies by MPCA and the Clean Lakes Program. Citizen involvement is the principal focus of the Lake Assessment Program. Citizens participate in sampling, watershed and lake review, defining the lake's history, and setting lake water quality goals. The Lake Assessment Program provides valuable information for the local citizens, MPCA, and others interested in protecting or improving the quality of a lake. Fifteen Lake Assessment Program studies have been completed. The Lake Assessment Program will be an integral part of Minnesota's Clean Water Partnership Program and U.S. Environmental Protection Agency's (EPA) Clean Lakes Program in Minnesota, providing information necessary to select projects and to communicate ideas about lake protection and restoration. An overview of this program is presented with examples of completed studies. Using an ecoregion framework in the goal-setting process will also be addressed.

ISSN:1040-2381    

DOI:10.1080/07438148909354684

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor