摘要:

ABSTRACT:Recent federal legislation strengthened nonpoint source pollution regulations and helped to support and standardize pollution control efforts. A comprehensive review of current state and federal programs for forest areas reveals a substantial increase in agency water quality protection activities. These new efforts emphasize monitoring to assess the use and effectiveness of best management practices (BMPs). Recent monitoring reveals that BMP use is increasing and that such use typically maintains water quality within standards. However, information is generally lacking about the cost effectiveness of BMP programs. Carefully designed and executed monitoring is the key to better specification of BMPs and more cost effective water quality protection. (KEY TERMS: water quality; nonpoint source pollution; water law; watershed management; forestry; best management practices.)

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1993.tb01500.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:Land application of sewage sludge requires careful monitoring because of its potential for contamination of surface water and ground water. A rainfall simulator was used the investigate the effects of freshly applied sludge on infiltration, and on runoff of sediment and nutrients from agricultural crop lands. Rain was applied to 16 experimental field plots. A three‐run sequence was used to simulate different initial moisture conditions. Runoff, sediment, and nutrient losses were monitored at the base of each plot during the simulated rainfall events. Sludge was surface applied and incorporated at conventionally‐tilled plots and surface applied at no‐till plots, at rates of 0, 75, 150 kg‐N/ha. Steady‐state infiltrability increased as a result of sludge application, although the no‐till practice was more effective in increasing the infiltrability than the sludge application. No‐till practices greatly reduced runoff, sediment, and nutrient losses from the sludge treated plots, relative to the conventional tillage practices. Incorporation of the sludge was effective in reducing nutrient yields at the conventionally‐tilled plots. This effect was more pronounced during the third rainstorm, with wet initial conditions. Peak loadings of nutrients appeared during the rainstorm with wet ini

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1993.tb01501.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:Air temperatures are sometimes used as substitutes for stream temperatures. To examine the errors associated with this procedure, linear relationships between stream temperatures, T, and air temperatures, Ta, recorded for 11 streams in the central U.S. (Mississippi River basin) were analyzed. Weather stations were an average 42 miles (range 0 to 144 miles) from the rivers. The general equations, Tw= 5.0 + 0.75 Taand Tw= 2.9 + 0.86 Tawith temperatures in °C, were derived for daily and weekly water temperatures, respectively, for the 11 streams studied. The simulations had a standard deviation between measurements and predictions of 2.7°C (daily) and 2.1°C (weekly). Equations derived for each specific stream individually gave lower standard deviations, i.e., 2.1°C and 1.4°C, respectively. Small, shallow streams had smaller deviations than large, deep rivers. The measured water temperatures follow the air temperatures closely with some time lag. time lags ranged from hours to days, increasing with stream depth. Taking into account these time lags improved the daily temperature predictions slightly. Periods of ice cover were excluded from the anal

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1993.tb01502.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:A mathematical model is developed to optimally schedule long‐term stormwater infrastructure rehabilitation activities. The model is capable of considering multiple rehabilitation projects and is driven by overall cost eensiderations. Rehabilitation activities are scheduled based on perceived reliabilities and future deterioration expected within the specified planning horizon. Future growth within the stormwater drainage basin is incorporated using chance constraints that limit the likelihood that a stormwater discharge exceeds system conveyance capacity. Model structure and development are discussed, and a hypothetical example using a drainage network is presente

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1993.tb01503.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:Nitrogen inputs to, and outputs from, a 55‐acre site in Lancaster County, Pennsylvania, were estimated to determine the pathways and relative magnitude of loads of nitrogen entering and leaving the site, and to compare the loads of nitrogen before and after the implementation of nutrient management.Inputs of nitrogen to the site were manure fertilizer, commercial fertilizer, nitrogen in precipitation, and nitrogen in ground‐water inflow; and these sources averaged 93, 4, 2, and 1 percent of average annual nitrogen additions, respectively. Outputs of nitrogen from the site were nitrogen in harvested crops, loads of nitrogen in surface runoff, volatilization of nitrogen, and loads of nitrogen in ground‐water discharge, which averaged 37, less than 1, 25, and 38 percent of average annual nitrogen removals from the site, respectively. Virtually all of the nitrogen leaving the site that was not removed in harvested crops or by volatilization was discharged in the ground water.Applications of manure and fertilizer nitrogen to 47.5 acres of cropped fields decreased about 33 percent, from an average of 22,700 pounds per year (480 pounds per acre per year) before nutrient management to 15,175 pounds of nitrogen per year (320 pounds per acre per year) after the implementation of nutrient management practices. Nitrogen loads in ground‐water discharged from the site decreased about 30 percent, from an average of 292 pounds of nitrogen per million gallons of ground water before nutrient management to an average of 203 pounds of nitrogen per million gallons as a result of the decreased manure and commercial fertilizer applications. Reductions in manure and commercial fertilizer applications caused a reduction of approximately 11,000 pounds (3,760 pounds per year; 70 pounds per acre per year) in the load of nitrogen discharged in ground water from the 55‐acre site during the three‐year perio

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1993.tb01504.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:Modem management concepts were used to increase the efficiency and productivity of a large and complex water resource study conducted on two Delaware River components of the National Wild and Scenic Rivers System. The study analyzed the hydraulics of a 120 mile reach of the river using Rhodamine WT dye injected under medium‐flow, low‐flow steady‐state, and low‐flow‐surge wave flow conditions. The study benefited from a decentralized management structure that used informal teams to attain quality control objectives, to overcome study difficulties, to secure substantial interagency cooperation, and to maximize limited financial and staffing

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1993.tb01505.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:Ten pairs of snow sensors were analyzed to investigate the feasibility of predicting snow water equivalent at high‐elevation, telemetered snow sensor sites from lower‐elevation sensors. The need for this analysis stems from an agreement between the California Department of Water Resources and the USDA Forest Service to temporarily allow snow sensors in California's wilderness areas so that a predictive relationship can be developed. After 10 or 15 years, the agreement calls for the sensors to be removed. Initial efforts to aprioriselect sensor pairs were based on proximity, colocation within a basin, and annual precipitation amount, but regression yielded poor fits (R2<0.65) and high standard errors in eight of the ten cases. Analysis of the results suggested that eleva‐tional similarity was the most important selection criteria, and that all available sensors near the target site should be analyzed via a regression screening. Using elevation for selection and the regression screening, five sensors that initially had poor fits were reanalyzed. Each of the five sensors was paired with between two and five new sensors, and R2values improved between 27 and 46 percent. Various data smoothing and editing algorithms were evaluated, but they rarely resulted in improved

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1993.tb01506.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:This paper presents a parameter sensitivity study of a two‐dimensional flow and transport model of a contaminated site. Hydrogeological and site data from previous investigations were used for calibration. The USGS contaminant transport model (MOC) was used.After flow calibration to establish a reference model, parameters were varied to examine the effect each had on predictions of a contaminant plume. Hydrogeological parameters and a step size parameter were incrementally varied individually. Each result was compared to the reference model output to evaluate changes in concentration values and contaminant plume configuration.The study indicated that a generally predictable trend can be established for some parameters not affected by pumping or similar high stresses. Ranges were identified to relate concentration error or plume change to the amount of parameter error. Some parameter perturbations produced distorted model responses at high stress locations. Porosity and anisotropy were found to be the most influential of the model parameters studied on the plume predictions. (KEY TERMS: ground water hydrology; hydrogeology; pollution modeling; water quality; model calibration

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1993.tb01507.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:The Montana Department of Natural Resources and Conservation developed a hydrologic model to help analyze the effects of allocating water for consumptive and instream uses in the upper Missouri River basin of Montana. The model, a PC‐based FORTRAN program, uses a mass‐balance approach to compute monthly streamflows, reservoir operations, hydropower production, and irrigation and municipal water uses throughout the 54,000 square mile basin for a 59‐year base period. Simulation results are presented as monthly mean and percentile‐exceedence values. The model was run for baseline conditions and six hypothetical water‐allocation alternatives. Results were used by staff resource area specialists to assess potential impacts to water quantity and distribution, water rights, water quality, stream channel form, fisheries, wildlife, recreation, hydropower production, and economics. These analyses were presented to the public and the decision‐making board in an environmental impact statement (EIS). Though, in many instances, the model did not allow for detailed, site‐specific analyses, the model was an important tool and its simulation results formed the hydrologic basi

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1993.tb01508.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:A model of comprehensive environmental monitoring process with integral quality assurance is presented. This model views the monitoring process as iterative cycles of a series of elements: design, plan, protocols, preparation, field liaison, sample collection, sample handling, laboratory analysis, data transmission, data validation, data approval, data provision, statistical analysis, and reporting. Quality assurance is linked to each element, not just to laboratory analysis. The program of quality assurance ensures that environmental monitoring data are compatible with the project goals, are comparable between various sampling agencies, and maintain a high degree of scientific credibility. The key characteristics of the overall quality assurance process are detailed documentation, timely resolution of problems, regular reporting, and routine independent audits.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1993.tb01509.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY