摘要:

ABSTRACT:This paper summarizes key provisions of the Clinton Administration's proposals for change in the Clean Water Act. Two of the important themes for change are tougher controls for non‐point source pollution and the use of market‐based instruments. A detailed analysis of market‐based abatement suggests limited potential for reducing costs. The keys to nonpoint source pollution control are clearer definition of property rights combined with changes in government programs that encourage polluting activ

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03327.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:This paper first presents a brief review of an earlier effort to estimate the benefits associated with achieving the Clean Water Act objectives. It then discusses what would be involved in doing a retrospective benefit‐cost analysis of the Clean Water Act and some information on changes in several measures of water quality over the past 20 years. The paper concludes with a summary of a recent effort to estimate the realized benefits associated with the Clean Water Act and some implications for policy. (KEY TERMS: benefits; benefit‐cost analysis; costs; recreation; water pollution; water quali

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03328.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:The degree of progress achieved under the 1972 Clean Water Act is reviewed by reference to traditional measures of program implementation, and to evidence of tangible, or “real‐world” progress, such as beach closures, drinking water contamination, fishing bans and advisories, species health, and habitat degradation. Significant progress has been made in reducing pollution from point sources, but large point source releases of toxic and other pollutants remain. Little progress has been made in addressing runoff pollution, and in protecting aquatic habitats. Clean Water Act reauthorization should focus on pollution prevention to reduce further the release of toxics by point sources, a new program of mandatory but flexible controls on sources of runoff, and watershed protection programs to promote habitat protection and restoration. Economic factors should be considered in Clean Water Act programs, but must be balanced against scientific and governmental factors as

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03329.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:Spatial distributions of nitrogen and phosphorus in water were related to environmental setting as part of a regional water‐quality assessment of the Central Nebraska Basins. The environmental settings (Sandhills, Loess Hills, Glaciated Area, and Platte Valley) were characterized by different concentrations of nitrogen and phosphorus in ground water and stream water. Statistically significant differences in nitrate concentrations in both ground‐water and stream‐water samples were related to regional distributions of cropland and rangeland. Nitrate concentrations were larger, especially in shallow ground water, in environmental settings dominated by cropland and associated fertilizer use than in settings dominated by rangeland. Similarly, total‐nitrogen and nitrate concentrations were relatively large in selected streams draining primarily cropland. Comparative concentrations of phosphorus in stream water on the basis of environmental setting were similar to those of nitrogen, although the largest phosphorus concentrations probably relate to wastewater discharge into small streams. Nitrogen and phosphorus concentrations in much of the Platte River apparently reflected the quality of water entering the study unit from upstream and limited base‐flow contributions from within the Platte Vall

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03330.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:A synoptic sampling of five surface‐water sites in central Nebraska was conducted by the U.S. Geological Survey as part of its National Water‐Quality Assessment Program during storm runoff in May 1992 to relate transport, yields, and concentrations of atrazine to environmental setting. Atrazine was the most extensively applied pesticide in the study unit. Atrazine transport was related to the size of contributing drainage area, quantity of atrazine applied, amount of precipitation, and volume of stream‐flow. Estimated yields and mean concentrations of atrazine were related to the percentage of cropland in a drainage area. The largest estimated yields and mean concentrations of atrazine in surface water were associated from drainage areas with the highest percentage of cropland, and the smallest was associated with the smallest amount of cropland. Atrazine concentrations increased as streamflow increased but decreased at or near the time of peak streamflows, perhaps due to dilution. Atrazine concentrations then increased and remained elevated far into the stream recession. Atrazine is a regulated contaminant in finished public‐water supplies. Large concentrations of atrazine could affect the management of public‐water supplies because atrazine remains in solution in contrast to many other pesticides that are more easil

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03331.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:The 1986 Amendments to the Safe Drinking Water Act mandate a multifaceted approach to wellhead protection. This approach includes: (1) delineating wellhead protection areas; (2) identifying and managing potential contaminants; (3) developing contingency plans in the event of weilfield contamination; (4) siting new wells; and (5) encouraging public participation. These elements encompass technical, administrative, and educational considerations. In functioning both as a research tool and as a decision support system, a geographic information system (GIS) is shown to have proven utility in addressing these issues. This article describes the application of common GIS functionality in facilitating a comprehensive wellhead protection scheme for an agricultural municipality in North Dakota.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03332.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:The sensitivity of streamflow to climate change was investigated in the American, Carson, and Truckee River Basins, California and Nevada. Nine gaging stations were used to represent streamflow in the basins. Annual models were developed by regressing 1961–1991 streamflow data on temperature and precipitation. Climate‐change scenarios were used as inputs to the models to determine streamflow sensitivities. Climate‐change scenarios were generated from historical time series by modifying mean temperatures by a range of +4°C to—4°C and total precipitation by a range of +25 percent to ‐25 percent. Results show that streamflow on the warmer, lower west side of the Sierra Nevada generally is more sensitive to temperature and precipitation changes than is streamflow on the colder, higher east side. A 2°C rise in temperature and a 25‐percent decrease in precipitation results in stream‐flow decreases of 56 percent on the American River and 25 percent on the Carson River. A 2°C decline in temperature and a 25‐percent increase in precipitation results in streamflow increases of 102 percent on the American River and 22 percent

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03333.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:Under an approved remining program, a coal mine operator can remine abandoned sites without legally assuming treatment responsibilities of the previously degraded water, as long as these discharging waters are not further degraded. Determination of discharge degradation caused by remining of abandoned coal mines requires knowledge of mine water quality and discharge flow rate characteristics both before and after remining. Normality tests performed on the water quality and flow data from 57 mine discharges indicate generally nonnormal distributions and extreme right‐skewness. Exploratory data analysis (notched box‐and‐whisker plots) of the differences among medians indicates that the water quality of underground mines was more highly degraded in terms of acidity, iron, and sulfate concentrations than that from surface mines. Spearman's rank correlation tests, normality testing, and exploratory data analysis indicate that discharge flow rate is the primary controlling factor on the variability of pollution load rate. Reduction of recharge from the surface and adjacent unmined strata should decrease the mine discharge flow rate and in turn the pollution

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03334.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:Economic theory clearly indicates that the use of increasing rate structures will reduce the demand for water and produce monetary incentives for consumers to conserve. One problem with estimating the effectiveness of using rate structures as a conservation program is that they are usually accompanied by other conservation efforts. Thus, it is difficult to determine the effectiveness of any one conservation component. This paper examines the effectiveness of increasing rate structures in a situation where no other conservation program was introduced. The paper uses customer data from the Spalding County (Georgia) Water Authority where an increasing rate structure replaced a descending rate structure in January 1991. Since the imposition of the increasing rate structure, the number of customers has increased 21 percent while total water demand has gone up only 15 percent and per customer water use has declined 5 percent. The daily water use per connection has declined from 243 gallons in 1990 to 231 in 1993, and monthly use has gone from 7,381 gallons to 7,028 per connection over the same period. Statistical tests indicate that water consumption during the two periods was significantly different while weather factors were not.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03335.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:The unique characteristics of the hydrogeologic system of south Florida (flat topography, sandy soils, high water table, and highly developed canal system) cause significant interactions between ground water and surface water systems. Interaction processes involve infiltration, evapotranspiration (ET), runoff, and exchange of flow (seepage) between streams and aquifers. These interaction processes cannot be accurately simulated by either a surface water model or a ground water model alone because surface water models generally oversimplify ground water movement and ground water models generally oversimplify surface water movement. Estimates of the many components of flow between surface water and ground water (such as recharge and ET) made by the two types of models are often inconsistent. The inconsistencies are the result of differences in the calibration components and the model structures, and can affect the confidence level of the model application. In order to improve model results, a framework for developing a model which integrates a surface water model and a ground water model is presented. Dade County, Florida, is used as an example in developing the concepts of the integrated model. The conceptual model is based on the need to evaluate water supply management options involving the conjunctive use of surface water and groundwater, as well as the evaluation of the impacts of proposed wellfields. The mathematical structure of the integrated model is based on the South Florida Water Management Model (SFWMM) (MacVicaret al., 1984) and A Modular Three‐Dimensional Finite‐Difference Groundwater Flow Model (MODFLOW) (McDonald and Harbaugh, 19

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03336.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY