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141.
Krishan P. Singh 《Journal of the American Water Resources Association》1976,12(2):381-392
ABSTRACT. Unit hydrographs derived by using two methods, linear programming and least squares, are compared. Test data comprise rainfall and runoff information from four storms over the North Branch Potomac River near Cumberland, Maryland. The mathematical bases of these methods for unit-hydrograph derivation are explained. The linear programming method minimizes the sum of absolute deviations, and the least squares method minimizes the sum of the squares of deviations. Computer subroutines are readily available for application of these methods. The unit hydrographs derived with the two methods are practically the same for storms 2 and 3, but differ somewhat for storms 1 and 4. However, the reconstituted direct surface runoff hydrographs are similar to those observed with the exception of the hydrograph for storm 4 which had a relatively more non-uniform rainfall excess of a considerably larger duration. 相似文献
142.
D. T. O'Laoghaire 《Journal of the American Water Resources Association》1978,14(4):809-826
ABSTRACT: This paper describes a mathematical model, an algorithm and a computer program that were specially developed to study the problem of a water quality management system undergoing a rapidly increasing environmental stress. The model output will determine the locations, sizes and the timing of construction of new treatment plants plus an overall treatment plant operating policy so that environmental standards are maintained at a minimum cost. The model, as formulated, is a 0-1 mixed integer programming problem which is solved by decomposing it into a capital budgeting problem (solved by Little's branch and bound algorithm) and an operational policy problem (solved by linear programming). The coded algorithm (in FORTRAN 10) has been tested with a semi-realistic example. 相似文献
143.
Gary D. Tasker 《Journal of the American Water Resources Association》1982,18(6):965-970
ABSTRACT: Data splitting is used to compare methods of determining “homogeneous” hydrologic regions. The methods compared use cluster analysis based on similarity of hydrologic characteristics or similarity of characteristics of a stream's drainage basin. Data for 221 stations in Arizona are used to show that the methods, which are a modification of DeCoursey's scheme for defining regions, improve the fit of estimation data to the model, but that is is necessary to have an independent measure of predictive accuracy, such as that provided by data splitting, to demonstrate improved predictive accuracy. The methods used the complete linkage algorithm for cluster analysis and computed weighted average estimates of hydrologic characteristics at ungaged sites. 相似文献
144.
Thomas E. Croley 《Journal of the American Water Resources Association》1974,10(6):1123-1132
ABSTRACT: Water resource development has progressed to the stage where various human factors are now being considered in reservoir design and operation. The introduction of human factor objectives complicates the problem since they are noncommensurate with other objectives and they are difficult to identify quantitatively. Some of the problems that now arise concern the proper methods for consideration of several different, sometimes subjectively identified, objectives in reservoir planning. The classical systems analysis approach to decision making for multiple objective problems is outlined and the inherent difficulties associated with multiple objectives and subjective estimates are identified. Techniques being used in reservoir design and operation are reviewed and discussed. An alternate technique for considering noncommensurate, subjectively identified, objectives, which relates the objectives in terms of real trade-off costs and eliminates the need for a priori estimates of objective worth is then presented. The method is illustrated with three examples, including a reservoir operation problem and a cooling tower design problem. 相似文献
145.
Risk factors for driving into flooded roads 总被引:2,自引:0,他引:2
Motor vehicle-related deaths account for more than half of all flood fatalities in the United States, but to date, very little is known about the risk factors associated with why people drive into flooded roads. Using data from survey questionnaires administered in Denver, CO, and Austin, TX, this paper suggests that people who do not take warnings seriously are more likely to drive through flooded roads, as are people aged 18–35, and those that do not know that motor vehicles are involved in more than half of all flood fatalities. In Denver, people who have not experienced a flood previously and those who do not know they live in flood-prone areas are also more likely to drive into flooded roads. 相似文献
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