摘要:

ABSTRACT:An heuristic iterative technique based upon stochastic dynamic programming is presented for the analysis of the operation of a three reservoir ‘Y’ shaped hydroelectric system. The technique is initiated using historical inflow data for the downstream reservoir. At each iteration the optimal policies for the downstream hydroelectric generating unit are used to provide relative weightings or targets for operation of upstream reservoirs. New input inflows to the downstream reservoir are then obtained by running the historical streamflow record through the optimal policies for the upstream reservoirs. These flows are then used to develop a new operating policy for the downstream reservoir and hence new targets for the upstream reservoirs. The process is continued until the operating policies for each reservoir provide the same overall system benefit for two successive iterations. Results obtained from the procedure are compared to the results obtained by historical operation of the system. The procedure is shown to develop operating policies which give benefits which are as close to the historical benefits as can be expected given the choice of the number of storage state variab

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00815.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:The Southern Blue Ridge Province, which encompasses parts of northern Georgia, eastern Tennessee, and western North Carolina, has been predicted to be sensitive to impacts from acidic deposition, owing to the chemical composition of the bedrock geology and soils. This study confirms the predicted potential sensitivity, quantifies the level of total alkalinity and describes the chemical characteristics of 30 headwater streams of this area. Water chemistry was measured five times between April 1983 and June 1984 at first and third order reaches of each stream during baseflow conditions. Sensitivity based on total alkalinity and the Calcite Saturation Index indicates that the headwater streams of the Province are vulnerable to acidification. Total alkalinity and p11 were generally higher in third order reaches (mean, 72 μeq/θ and 6.7) than in first order reaches (64 μeq/θ and 6.4). Ionic concentrations were low, averaging 310 and 340 μeq/θ in first and third order reaches, respectively. A single sampling appears adequate for evaluating sensitivity based on total alkalinity, but large temporal variability requires multiple sampling for the detection of changes in pH and alkalinity over time. Monitoring of stream water should continue in order to detect any subtle effects of acidic deposition on these unique resource sy

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00816.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:A stochastic programming framework is developed to evaluate the economic implications of reliability criteria and multiple effluent controls on nonpoint source pollution. An integrated watershed simulation model is used to generate probability distributions for agricultural effluents in surface and ground water resulting from agricultural practices. Results from the planning model indicate that reliability and multiple effluent constraints significantly increase the cost of nonpoint controls but the effects vary by control alternative. The analysis indicates that an evaluation of multiple water quality objectives can be an important planning tool for designing nonpoint source controls for innovative programs to promote cost‐effective water quality regulatio

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00817.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:Stepwise multiple regression analysis was used to develop models predicting the summer peak biomass ofAphanizomenon flos‐aquae, Anabaena flos‐aquae, Oscillatoria agardhii, andMicrocystis aeruginosain four Swedish lakes. These analyses suggest that while epilimnetic total phosphorus concentration is the principal predictor of their peak biomass, other factors such as station mean depth, water temperature, total nitrogen, and total CO2concentration are also import

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00818.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:A deterministic hydrologic model, encompassing the hydrologic regime and all water uses, is developed by integrating empirical hydrologic relationships. The Brandywine Basin, located in southeastern Pennsylvania and northern Delaware, is used as an example to demonstrate this modeling effort. The basin is divided into 19 subwatersheds to account for the spatial variation of resource characteristics. The output of the model is the response of the hydrologic system to various inputs such as precipitation, land use characteristics and policy decisions. This modeling effort is applicable to watersheds similar to the Brandywine Basin in size, and once the model is developed and validated, can be applied continuously in the management and planning of water resources such as predicting the hydrologic effects of proposed projects and simulating hydrologic information.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00819.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:This paper describes the formulation and application of a ground‐water hydraulic management model to determine the optimal development and operating policies of a regional aquifer in the Eastern Province of Saudi Arabia. The hydraulic response of the aquifer system is represented by a simulation model that is linked to an optimization management model using response functions. Yearly optimal ground‐water extraction rates over a planning horizon of 15 years are determined for four scenarios, each reflecting alternative ground‐water development policies. The results are presented in the form of tradeoff curves, relating drawdowns to optimal pumpage, which may enhance the decisionmaker's ability to select the best development policy from a set of alternatives. The results illustrate how various optimal management schemes can be devised to increase the total withdrawal from the aquifer while preventing excessive de‐w

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00820.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:Values of dry biomass of corn, sugarcane, sorghum, rice, taro, millet, cotton, cowpeas, soybeans, and velvet beans as related to the evapotranspiration (ET) were studied. The linear regression model was sufficiently accurate to establish the crop dry biomass and ET relations. A water‐use efficiency index (WUE), which is defined as the additional crop dry biomass per unit ET, is used in this study. The WUE were grouped into high, medium, and low categories. The WUE varied from greater than 35 kg ha‐1/mm for the high category, between 15 and 35 kg ha‐1/mm for the medium category, and less than 15 kg ha‐1/mm for the low category. Application of the established model to the Everglades Agricultural Area, Florida, showed that the regional El can be predicted from the known regional crop yields. The crop yield and ET relations could be used as a potential tool to improve water resources planning and management practices for crop pro

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00821.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:The technology of urban stormwater management has far outpaced its actual application in new urban development. This article documents that implementation gap, but shows that state and local governmental measures, particularly storm drainage regulations, can lead to improved performance in the private sector. Although state stormwater management programs are in their infancy, they are already having a measurable effect in stimulating the adoption of local governmental programs to manage urban storm water. Pioneering state programs in Maryland, New Jersey, and Pennsylvania, described in this article, provide models for states contemplating the formulation of stormwater management programs.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00822.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:A procedure to determine optimal irrigation scheduling strategies under rotational water delivery systems is presented. The methodology involves integration of water delivery amount and frequency, irrigation management strategies, evapotranspiration sequences and crop‐evapotranspiration‐production functions to arrive at an optimal irrigation strategy. Application of the methodology to a farm in the service area of Western Yamuna Canal (India) where a two‐stage system of rotation, one among the irrigation channels and the other among the farmers, is in vogue, reveals that maximum production is obtained with water application in a rotational manner (RI) rather than with irrigation in every or alternate supply periods. Increase in mean water supply which can be effected through improvement in on‐farm conveyance and application systems, has a greater effect on yield than decrease in variance of the supply. Benefit cost analyses indicates that precision land leveling is more cost effective in increasing water supply as compared to water‐cour

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00823.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT:Naturally occurring and man‐made structures can be used for enhancing the development of riparian zones. Naturally occurring structures are cienagas, beaver dams, and log steps. Man‐made structures include large and small channel structures and bank protection devices. All these structures affect streamflow hydraulics and sedimentation and can create a more favorable environment for riparian zone establishment. However, when they are used improperly, they can be destructive to existing riparian zones. Since stream processes are generally slow, long‐time spans may pass before the effects of management action, good or bad, become visible. Also, the effects of large dam installations may appear a long distance downstream from the dam. Therefore, investigations must be of a wide scope. Interactions between riparian site, channel, and streamflow may be so complex that an interdisciplinary approach is req

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1987.tb00824.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY