摘要:

ABSTRACT:While significant nonpoint source (NIPS) pollution control progress has been made since passage of Section 319 in the 1987 Water Quality Act, existing federal legislation does not provide for the most timely and cost‐effective NIPS pollution reduction. In this paper, we use findings from the Rural Clean Water Program and other nationwide agricultural NIPS pollution control programs, building on legislative history to recommend a coordinated and efficient direction for agricultural water quality legislation. A collaborative framework should be established to accomplish the goals of the Clean Water Act (CWA), Coastal Zone Management Act (CZMA), and the Conservation Title of the Farm Bill. Valuable elements of the 1990 CZMA amendments that created a coastal NIPS program should be subsumed into the CWA. The CWA should reemphasize use of receiving water quality criteria and standards and should allow states flexibility to tailor basin‐scale NPS program implementation to local needs. Implementation should involve targeting of NIPS pollution control efforts to critical land treatment areas and use of systems of best management practices to address these targeted water quality problems. The 1995 Farm Bill should reorient production incentives toward water quality to support the collaborative framework, implementing ecologically sound source reduction principles. The Farm Bill and the CWA should contain interrelated provisions for voluntary, incentive‐assisted producer participation and fallback regulatory measures. Such coordinated national water quality and Farm Bill legislation that recognizes the need for flexibility in state implementation is supported as the most rational and cost‐effective means of attaining water qualit

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1996.tb04042.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACT:A non‐linear optimization model is applied to the California State Water Project (SWP) and portions of the Central Valley Project (CVP). The model accounts for the major hydrologic, regulatory, and operational features of both projects. The model maximizes long‐term SWP yields over a 70‐year period, using a quarterly time step. The potential for increased yield associated with a proposed facility improvement is evaluated with the model. The proposed facility is an extension of the Folsom‐South Canal, which would allow water to be conveyed from the American River below Folsom Reservoir into New Melones Reservoir on the Stanislaus River or into the California Aqueduct. Model results indicate that extension of the Folsom‐South Canal has the potential to increase SWP yields by 1

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1996.tb04043.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACT:At the Everglades Nutrient Removal project in south Florida, three lysimeters were installed to measure daily evapotranspiration (ET) rates from cattails (Typha domingensis), mixed marsh vegetation, and an open water/algae system. The cattail lysimeter began operation in February 1993. The mixed marsh vegetation lysimeter began operation in January 1994, and the open water lysimeter with occasional algae cover began operation in December 1993. The mean measured ET rate was 3.6 mm, 3.5 mm, and 3.7 mm per day for the cattail, mixed marsh vegetation, and open water/algae system, respectively. High resolution weather data were continuously measured at the site. Six models were applied to estimate daily ET rates of the three systems. The Penman‐Monteith equation best estimated ET of cattail and mixed marsh vegetation, and the Penman Combination equation was most suitable for the open water/algae system. Empirical equations based on solar radiation and maximum temperature produced estimates of daily ET from the three systems that are comparable to models that require many more parameters. In cases where limited data is available, the calibrated simple models can be used to estimate ET from wetlands in south Florid

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1996.tb04044.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACT:The water quality in the Brazos River in Texas is seriously degraded by natural salt pollution in the upper Brazos River. Controlling the natural salt springs and seeps in the Dove Creek area will reduce the chloride concentration in the Brazos River by nearly 45 percent. The brine that is discharged as natural springs and seeps in the Dove Creek area is from two sources: (1) local recharge and (2) deep‐basin. A preliminary design of the brine recovery system was developed in this phase of the study. A three‐dimensional, finite element model to simulate groundwater flow in anisotropic and heterogeneous media under steady state conditions was developed to assist with the design and evaluation of brine recovery systems in the Dove Creek area. Model simulations indicate that a shallow‐well brine recovery system pumping about 56 l/s (2 cfs) of brine will eliminate approximately 45 percent of chloride discharging into the upper Brazos

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1996.tb04045.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACT:Water quality in the Brazos River of Texas is seriously degraded by natural salt pollution. Two thousand tons/day of total dissolved solids emanate from brine springs and seeps in the Upper Brazos River drainage. Approximately 45 percent of the total salt load comes from a relatively small flow in the Dove Creek area. The companion paper demonstrates that a system of wells pumping brine at a constant rate of about 2 cfs from the near surface aquifer should eliminate the brine springs in this area. In this paper, injection into deep brine aquifers is shown to be a feasible brine disposal alternative. Four brine aquifers were determined from the literature to be possible injection zones. Accurate net aquifer thickness maps were generated in a 23 by 14 mile area centered on the Dove Creek area for three of the aquifers from an interpretation of 41 well logs. Constant injection for a project life of 100 years was simulated using the SWIFT/486 software. Modeling suggests that one well would be sufficient to inject the entire disposal volume into either the Strawn or Ellenburger Formation.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1996.tb04046.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACT:It is important to extract and assess low flow recession characteristics for water resources planning in the upper reaches of streams. However, it is very difficult to express synthetically the low flow recession characteristics for a stream flow. In this paper, first a new method of constructing the master recession curve based on the exponential expression is proposed and applied with the restriction that there are no regulation or diversion structures in the upper reaches above the measurement station. Daily precipitation and stream flow were used for the analysis. Second, analysis for a recession constant was conducted and the relationship between the recession constant and low flow and/or geology was qualitatively examined. In conclusion, the application of the proposed method indicated that it is objective and useful for constructing the master recession curve. It became apparent that the recession constant of a master recession curve may be defined as the total index of low flow characteristics. In addition, it was found that baseflow value increases in the order of Paleozoic, Mesozoic, Tertiary, and Quaternary.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1996.tb04047.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACT:A variety of management options are used to minimize losses of nitrogen (N), phosphorus (P), and other potential pollutants from agricultural source areas. There is little information available, however, to indicate the effectiveness of these options (sometimes referred to as Best Management Practices, or BMPs) on basin scales. The objective of this study was to assess the water quality effectiveness of BMPs implemented in the 3240 ha Lincoln Lake basin in Northwest Arkansas. Land use in the basin was primarily forest (34 percent) and pasture (56 percent), with much of the pasture being regularly treated with animal manures. The BMPs were oriented toward minimizing the impact of confined animal operations in the basin and included nutrient management, dead bird composter construction, and other practices. Stream flow samples (representing primarily base flow conditions) were collected bi‐weekly from five sites within the basin from September 1991 through April 1994 and analyzed for nitrate N (NO3‐N), ammonia N (NH3‐N), total Kjeldahl N (TKN), ortho‐P (PO4‐P), total P (TP), chemical oxygen demand (COD), and total suspended solids (TSS). Mean concentrations of PO4‐P, TP, and TSS were highest for subbasins with the highest proportions of pasture land use. Concentrations of NH3‐N, TKN, and COD decreased significantly with time (35–75 percent/year) for all sub‐basins, while concentrations of other parameters were generally stable. The declines in analysis parameter concentrations are attributed to the implementation of BMPs in the basin since (a) the results are consistent with what would be expected for the particular BMPs implemented and (b) no other known activities in the basin would have caused the declines in analysis paramet

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1996.tb04048.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACT:A model for urban stormwater quality was developed in this study. The basis for the model is the process by which pollutants build up on the watershed surface. For the wet climate of the study site, it was assumed that there exists an interval of time over which the pollutant buildup equals the pollutant washoff (no accumulation of pollutant). The buildup model was represented by a linear function of the antecedent dry time. The buildup function was then linked with a pollutant washoff model represented by a power function of the storm runoff volume. Various time intervals for no net accumulation were tested to calibrate the model. The model was calibrated to observed data for two small urban basins in Baton Rouge, Louisiana, and model results were used to analyze the behavior of phosphorus concentrations in storm runoff from these basins over a long period of time.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1996.tb04049.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACT:A method for quantifying fluctuations in time‐series data was developed and tested to aid the process of visualization. The methodology is based on free‐form sliding polynomials and identifies (a) short‐period variability about the mean value, (b) a long‐term trend or cycle, and (c) random errors residual to these two structured components. Consistent results were obtained for designed synthetic data and natural data from seven sites in Georgia. Statistics of fit of the analytical model for the natural data were not significant on a site‐by‐site basis. An unexpected finding for the study was obtained when the statistical results for the seven data sets for temperature were pooled. The smoothing model yielded consistent long‐term trends even though the individual station results were not significant. Also, the correlation coefficients, while low, showed a statistically significant trend toward higher values toward the northwest and away from the Georgia coast line. This study thus supports the concept that multiple‐site, and regionally based, analyses are necessary for the detection of trends. Secondarily, such consistency of results strengthens the conclusion that the proposed smoothing method is an effective procedure in the presence of varying amounts of random content in the na

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1996.tb04050.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACT:The Hanging Gardens are a unique feature of Zion National Park. Knowledge of the source and residence time of water discharging from the Hanging Gardens is necessary to help preserve these features. Ground‐water chemical and isotopic data distinguish the discharge from seeps and springs into two groups, one of low and one of high conductivity. Water with low conductivity likely originates as recharge near the seeps and springs, and it only interacts with the Navajo Sandstone. High conductivity water, on the other hand, originates as recharge on the tops of plateaus to the east, where it interacts with marine rocks of the Carmel Formation. Carbon dating of these ground waters indicates that the low conductivity water is essentially modern recharge, while the high conductivity water was recharged 1,000 to 4,000 years ag

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1996.tb04051.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY