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761.
Andrew A. Dzurik 《Journal of the American Water Resources Association》1979,15(2):420-425
ABSTRACT: Methods of floodplain management are changing in the United States. There has been a gradual shift in emphasis from “flood control” to “management” of the floodplain. The complexities of multilevel governmental involvement in floodplain management demand an analysis of a new means to coordinate these efforts. It is the intent of this paper to discuss the role of the Corps of Engineers in this area and the problems the Corps has encountered in its endeavors. The occurrence of these problems indicates that there is a need to strengthen the federal role to ensure a comprehensive view of floodplain management. 相似文献
762.
B. N. Lohani Pakorn Adulbhan 《Journal of the American Water Resources Association》1979,15(4):1028-1038
ABSTRACT: Linear programming is the simplest of all the optimization techniques used in regional water quality management studies; but the technique can optimize only one goal. When there are multiple goals with the same or different priorities, goal programming is a useful decisionmaking tool. This paper illustrates the application of goal programming to a regional water quality management problem where the following two goals are considered: (1) minimize the total cost of waste treatment, and (2) maintain the water quality goals (dissolved oxygen) close to the minimum level stated in the stream standards. 相似文献
763.
764.
E. C. Dickey J. K. Mitchell J. N. Scarborough 《Journal of the American Water Resources Association》1979,15(6):1753-1769
ABSTRACT: The application of hydrologic models to small watersheds of mild topography is not well documented. This study evaluates the applicability of hydrologic models described by Huggins and the Soil Conservation Service to small watersheds by comparing the simulated and actual hydrograph for both gaged and ungaged situations. The annual maximum rainfall events plus storms exceeding 2.5 inches from 25 years of rainfall and runoff data for two small watersheds were selected for the model evaluations. These storms had a variety of patterns and occurred on many different watershed conditions. Simulated and actual hydrographs were compared using a parameter which contained volume, peak, and shape factors. One-half of the selected storms were used to calibrate the models. For both models, there were no significant differences between the simulated and actual runoff volumes and peak runoff rates. Parameters obtained during the calibration process and relationships developed to estimate antecedent moisture and to modify tabulated runoff curve numbers were used to simulate the runoff hydrograph from the remaining storms. These remaining storms or test storms were simulated only once in order to imitate an ungaged situation. In general, both the Huggins and SCS model performed similarly on the test storms, but the level of model performance was lower than that for the calibration storms. For both models, the two-day antecedent rainfall was more important than the five-day in determining antecedent moisture and modifying tabulated curve numbers. The time of concentration which resulted in good hydrograph simulations was about three times larger than that estimated using published empirical relationships. 相似文献
765.
Michael L. Shrader Richard H. McCuen Walter J. Rawls 《Journal of the American Water Resources Association》1980,16(1):49-55
ABSTRACT: With the increased use of models in hydrologic design, there is an immediate need for a comprehensive comparison of hydrologic models, especially those intended for use at ungaged locations (i.e., where measured data are either not available or inadequate for model calibration). But some past comparisons of hydrologic models have used the same data base for both calibration and testing of the different models or implied that the results of model calibration are indicative of the accuracy at ungaged locations. This practice was examined using both the regression equation approach to peak discharge estimation and a unit hydrograph model that was intended for use in urban areas. The results suggested that the lack of data independence in the calibration and testing of regression equations may lead to both biased results and misleading statements about prediction accuracy. Additionally, although split-sample testing is recognized as desirable, the split-samples should be selected using a systematic-random sampling scheme, rather than random sampling, because random sampling with small samples may lead to a testing sample that is not representative of the population. A systematic-random sampling technique should lead to more valid conclusions about model reliability. For models like a unit hydrograph model, which are more complex and for which calibration is a more involved process, data independence is not as critical because the data fitting error variation is not as dominant as the error variation due to the calibration process and the inability of the model structure to conform with data variability. 相似文献
766.
Irfan A. Khan 《Journal of the American Water Resources Association》1980,16(4):608-614
ABSTRACT: Feasibility of disposing treated sewage in wells sunk into a partially confined coastal limestone aquifer at Waimanalo in the island of Oahu was investigated using an electric analog model. Electric analog modeling was preferred over digital modeling because of ease with which tides could be generated at the ocean boundary in the form of sinusoidal waves. The results of model operation showed that high permeability, low storativity, and the presence of ocean render the Waimanalo aquifer highly suitable for the disposal of waste water in deep wells. Since the quality of water in the aquifer is already unsuitable for municipal, industrial, or agricultural use, waste water injection will not result in any loss of fresh water supply source to the island. It is also believed that the cost of waste water disposal through the aquifer will be considerably less than that through an ocean outfall. During model development it was discovered that electric analog models can help prepare certain graphs which can be useful for aquifer analysis without any further use of the model. 相似文献
767.
S. F. Shih 《Journal of the American Water Resources Association》1980,16(4):724-727
ABSTRACT: The water budget computation in shallow lakes is complicated because marsh vegetation can transpire large quantities of lake water. Thus, a model including the marsh zone evapotranspiration (WET) was developed to compute the water budget for Lake Okeechobee. Three periods of testing (1969–74), planning (1963–74), and recorded period (1952–77) were used to compare the differences of the sum of storage deviation between the WET and conventional methods (WOET). Results of the WOET method showed that the sum of stage deviations were 87.42 cm (2.868 ft.), 231.80 cm (7.605 ft.), and 284.50 cm (9.333 ft.) in the testing, planning, and recorded periods, respectively. These stage deviations are equivalent in the same order to 29, 76, and 93 percent of the lake volume. In general, the WET method not only was applicable to compute the water budget for the lake but also reduced the sum of storage deviation by about 42, 31, and 49 percent, respectively, in those three periods. The storage deviation in WET method was reduced on an average to about 2 percent each year in all three periods, and the deviations were scattered more randomly than in WOET. 相似文献
768.
769.
Marvin V. Damm 《Journal of the American Water Resources Association》1980,16(5):907-913
ABSTRACT: Simulation of a large stream-aquifer system in Nebraska has been accomplished for the period from 1975 to 2020 to determine effects of controls on ground water pumpage. Three scenarios tested consisted of average annual withdrawals of 15.2 ac-in/ac (FUTURE 1), 14.8 ac-in/ac (FUTURE 2), and 9.8 ac-in/ac (FUTURE 3). The highest quantity represents the historical tendency; while the 14.8 in. figure represents a slight reduction and also represents an equalization of irrigation application efficiencies throughout the area. The lowest figure represents a substantial increase in application efficiency. Comparisons between simulated ground water elevations indicate maximum savings of FUTURE 2 over FUTURE 1 of less than 8 ft. FUTURE 3 ft. FUTURE 3 levels are projected to be a maximum of approximately 13 ft. higher than FUTURE 1's. The relatively small savings from reductions in pumpage result primarily from recirculation effects. Differences between ground water contributions to stream flow are small for all scenarios. These contributions decrease with time and increasing pumpage amounts. Base flow rates at the end of the simulation are approximately 25 percent of those at the beginning. 相似文献
770.
ABSTRACT: This paper first discusses the results of sensitivity analyses conducted on various parameters of the San Francisco Stormwater Model ta version of WREM) and the Penn State Runoff Model in terms of their impact on outflow hydrographs. The parameters considered within a idealized catchment include: basin shape, imperivous fraction, overland roughness and slope: deterntion depth; infiltration capacity; and hyetograph timing. Second, the results for the hypothetical catchment are extended to the lazzard laboratory surfaces (asphalt, grass, roofing material) as a mean of illustrating the need for changes in model structure, as opposed to continued parameter adjustment Finally the effect of altering the scale of hydraulic representation in the surface runoff and sewer transport calculations are demonstrated for two gaged watersheds in Hamburg, West Germany. 相似文献