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231.
Donald W. Steffeck Fred L. Paveglio Frank C. Bellrose Richard E. Sparks 《Journal of the American Water Resources Association》1980,16(3):553-555
ABSTRACT: The annual sedimentation rate of lakes and reservoirs is usually not evaluated for changes in depth relative to time. By using a linear regression with depth as the independent variable and annual rate of fill as the dependent variable the effect of changing depths is negated. According to both profile and linear regression analyses, Peoria Lake is filling faster in the more recent of two time spans but Lake Meredosia's increasing sedimentation rate is shown only by a linear regression. The probable cause for increasing sediment loads in the Illinois River is an almost twofold increase in row crop production in Illinois. 相似文献
232.
ABSTRACT: A possible methodology is developed to deal with the problem of designing complex pipeline systems, when they are subject to different rates of demand, and when a hypothesis of the flow distribution in different branches is not allowed. The mathematical algorithm used in linear programming. The problem, which is not linear, is dealt with by means of an iterative method; that is, by starting with a possible solution and inserting at each iteration the solution found in the preceding iteration. By taking as variables of the problem the piezometric heads of the ends for each branch of the network, the piezometric gradients and flows, and by thus considering the diameter as a derived variable, it is possible to isolate the nonlinearity in the cost function of the network. The latter is linearized each time close to the solution found in the preceding iteration. 相似文献
233.
Lewis A. Rossman Frank T. Vanecek 《Journal of the American Water Resources Association》1978,14(4):842-855
ABSTRACT: An improved computational procedure for solving water quality management models containing interacting pollutants and control policies is presented. The method is developed with respect to the specific problem of minimizing the costs of basin-wide thermal and organic pollution control to meet water quality standards. It views the problem in partitioned form where a master problem is used to find cooling levels for thermal polluters while subproblems determine optimal organic pollutant reductions for fixed cooling levels. A gradient based search procedure is used to solve the master problem. Computational results for several river systems are presented. Application of the method to other water quality management models is suggested. 相似文献
234.
Jackie Sellers Ronald M. North 《Journal of the American Water Resources Association》1979,15(1):167-181
ABSTRACT: The “principles and standards for planning water and related land resources” were made effective October 25, 1973. The document was noticeably deficient in suggestions for the necessary implementing procedures to ensure its success. Current implementing procedures are based on an incorrect premise of maximizing a single objective subject to non-quantified constraints. A successful implementation of multiple objective planning requires optimizing simultaneously several competitive goals. A system of goal programming has been developed and applied to decisionmaking situations as a test of its usefulness in planning for multiple objective water resources projects. The result is a project planning process which can be replicated for adjustments in expected resource supplies or demands to provide a tradeoff matrix between economic and environmental objectives as well as traditional functional purposes. This procedure, tested on the Cross Florida Barge Canal, is an integrated analysis of economic and environmental values which may be as effective in implementing multiple objective planning as the “Green Book” was in developing the now inappropriate benefit cost analysis. 相似文献
235.
Thomas D. Chiatovich John W. Fordham 《Journal of the American Water Resources Association》1979,15(2):301-315
ABSTRACT: This study investigated low flow augmentation as a means of meeting inorganic water quality standards for the Truckee River at the California-Nevada state line. A digital inorganic water quality model was combined with a deterministic dynamic reservoir operating model in an iterative process which allowed the optimization of releases subject to selected inorganic water quality constraints as well as downstream demands. Results from model runs with varied flow and river loading data indicate that flow augmentation may be a feasible and relatively inexpensive way of meeting standards for this system except in time of severe drought. 相似文献
236.
Dan M. Wells James D. Mertes B. L. Allen Arthur N. Click 《Journal of the American Water Resources Association》1975,11(4):714-733
ABSTRACT: Several techniques for selecting a least environmental impact corridor have been proposed. Two approaches have been found workable; the computer graphics and the map overlay. This report combines features of both to determine an appropriate routing for a water conveyance canal. The study was conducted by an interdisciplinary planning team. Environmental factors were mapped and weighted on overlay maps. Alternative routes were identified and carefully studied. Several critical environmental implications were noted. Aesthetic factors, out door recreation interpretation, visitor safety and disruption of human and animal travel routes were considered and dealt with. 相似文献
237.
ABSTRACT Both because of its effectiveness and ease in use, linear programming has become progressively popular in water resources planning problems. Yet, the assumptions of linear construction costs can be misleading. Diseconomies of scale in construction can be handled by successive approximations to the cost function but problems with economies of scale yield paradoxical results when piecewise approximations are used. If significant economies of scale exist in only one facility, the solution to problems of this nature can be found using normal linear programming codes by successively adjusting the unit construction cost on that single facility to iteratively work toward the true optimal solution. 相似文献
238.
Chin-shu Liu 《Journal of the American Water Resources Association》1972,8(5):976-986
ABSTRACT. The setting of rule curves for reservoirs or lakes operation requires balancing the flood control storages reserved against the storage requirements for various conservation uses. In this study, a linear programming model is developed to perform single purpose analysis that minimizes flood damages of a multi-lake river system under various initial and input conditions. A flood control utility measure function is arrived from the resulting analysis, and the inclusion of the function in conservation analysis could provide the total functional analysis. The river-system transition function involving time-lags of short duration is described. The function constitutes the basis for the optimization model, and also provides the transformation to reduce significantly the size of the problem. The application to a critical subsystem in the Oswego River System is reported. 相似文献
239.
M. Hossein Sabet Otto J. Helweg 《Journal of the American Water Resources Association》1989,25(5):1047-1053
ABSTRACT: Construction of a “peaking storage tank” may reduce the operational cost of municipal water in the availability of a time-of-use energy rate. A peaking storage tank is used for storing water that is pumped from wells or other sources of supply during off-peak periods when energy costs are less for use during periods of on-peak water demand. The optimal size of a peaking storage tank is that which results in the minimum total cost, which includes both the storage construction cost and the cost of operation of the pumps. The operational cost for a given time-of-use rate is determined by help of a pipe network simulation model solved by the Newton-Raphson technique and a dynamic programming optimization model. A more simplified method is also introduced. Analyses show that low off-peak energy costs make the construction of peaking storage tanks economically attractive and reduce on-peak energy use, which results in electrical load leveling. 相似文献
240.
Interdisciplinary teams have been used in federal land planning and in the private sector to reach consensus on the environmental impact of management. When a large data base is constructed, verifiability of the accuracy of the coded estimates and the underlying assumptions becomes a problem. A mechanism is provided by the use of a linear statistical model to evaluate production coefficients in terms of errors in coding and underlying assumptions. The technique can be used to evaluate other intuitive models depicting natural resource production in relation to prescribed variables, such as site factors or secondary succession. 相似文献