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921.
L. J. Lane M. H. Diskin D. E. Wallace R. M. Dixon 《Journal of the American Water Resources Association》1978,14(5):1143-1158
ABSTRACT: Significant errors in estimating surface runoff and erosion rates are possible if a watershed is assumed to contribute runoff uniformly over the entire area, when actually only a portion of the entire area may be contributing. Generation of overland flow on portions of small semiarid watersheds was analyzed by three methods: an average loss rate procedure, a lumped-linear model, and a distributed-nonlinear model. These methods suggested that, on the average, 45, 60, and 50% of the drainage area was contributing runoff at the watershed outlet. Infiltrometer data support the partial area concept and indicate that the low infiltration zones are the runoff source areas as simulated with the distributed-nonlinear model. 相似文献
922.
923.
The EPA Storm Water Management Model was used to model the effects of urban and agricultural development on storm water runoff from uplands bordering a Louisiana swamp forest. Using this model, we examined the effects of changing land use patterns. By 1995 it is projected that urban land on the uplands bordering the swamp will increase by 321 percent, primarily at the expense of land currently in agriculture. Simulation results indicate that urbanization will cause storm water runoff rates to be up to 4.2 times greater in 1995 than in 1975. Nutrient runoff will increase 28 percent for nitrogen (N) and 16 percent for phosphorus (P) during the same period. The environmental effects of these changes in the receiving swamp forest are examined. 相似文献
924.
R. R. Schoof W. O. Thomas W. M. Boxley 《Journal of the American Water Resources Association》1980,16(2):348-352
ABSTRACT: Winter Creek is a tributary of the Washita River in south-western Oklahoma. The Soil Conservation Service installed floodwater retarding structures which controlled runoff from 56 percent of a 33-square-mile (8550-hectare) gaged drainage area. Application of a hydrologic model to the flood peaks indicated that the structural treatment reduced the flood peaks an average of 61 percent. The Winter Creek channel has narrowed and deepened since the structural treatment was applied. The severe bank erosion occurring before treatment has been arrested and sediment yield from the watershed has been reduced 50 to 60 percent. In some reaches of the channel there has been a dense growth of trees in recent years. 相似文献
925.
Peter E. Black 《Journal of the American Water Resources Association》1980,16(4):615-620
ABSTRACT: Intensive temporal sampling of rainfall, surface runoff and subsurface drainage, and stream flow upstream and downstream of a suburban mall parking lot yielded expected patterns in time and space. Variations in temperature and conductivity showed strong dilution effects, while patterns of nine elemental concentrations in surface runoff showed a flushing effect early in the storm, following by dilution. Heavy nitrate loads in surface runoff were apparently from rainfall, not surficial sources. For the magnitude of storm studied and the existing study site, local impact on stream flow and water quality, like the run-off itself, is rather ephemeral, and dissipates after about five hours. 相似文献
926.
927.
Larry C. Tennyson Carl D. Settergren 《Journal of the American Water Resources Association》1980,16(3):433-433
ABSTRACT: A bromide tracer was used to evaluate percolate water and ion movement in the upper 1.2 m of soil at a proposed sewage effluent irrigation site located in the Missouri Ozarks. Two plots representing Doniphan silt loam and Crider silt loam soils were sprinkler irrigated with local ground water at a rate of 7.62 cm/week from June through August 1976. Soil water potential, percent soil moisture by volume, and background levels of bromide in soil water, ground water, and precipitation were measured at the study plots. Bromide exchange properties and saturated hydraulic conductivity of the soils were determined in the laboratory. During two selected time periods, irrigation water, was spiked with NaBr (5.0 mg/l Br). Bromide movement through the upper profile was quantified by soil water samples and post-sampling neutron activation analysis. Soil moisture was near saturatin in both soils when the Br tracer was applied. Bromide concentrations above background levels (0.023 mg/l Br, Doniphan silt loam and 0.016 mg/l Br, Crider silt loam) were detected within 2.60 hours at 0.9 m in the Doniphan soil and within 3.75 hours at that depth in the Crider soil. The rate of Br movement in the profile was greater in both soils than the measured saturated hydraulic conductivity, Bromide concentrations above background levels were present in soil water from the study plots for a minimum of 21 days after irrigation with the Br tracer. 相似文献
928.
Ashim K. Bhattacharya Robert S. Broughton 《Journal of the American Water Resources Association》1979,15(3):671-683
ABSTRACT: A water balance model was developed to predict daily water table depths in some corn fields with or without subsurface drainage systems, using pertinent soil and water properties and weather data. The model outputs were compared with the recorded data of observed water table depths. Some statistical parameters such as the mean, standard deviation, the coefficient of correlation, the sum of the squares of deviations, and a nonparametric statistical test were used to study the extent of agreement between the observed and the predicted water table depths. No significant difference was found between the distributions of the observed and the predicted water table depths at the 99% confidence level. The study was conducted on some sand and clay soils of the Ottawa-St. Lawrence Lowlands region in Canada where there is a cool, moist climate and poor natural drainage. 相似文献
929.
William Whipple Joseph V. Hunter 《Journal of the American Water Resources Association》1979,15(4):1096-1105
ABSTRACT: Estimates were made of petroleum hydrocarbon pollution loadings reaching the Delaware Estuary by determining storm event loadings of hydrocarbons from four storm sewers, draining areas of different land uses. Although refinery effluents constituted the largest source of petroleum pollution in 1975, it appears that after completion of currently required treatment processes urban runoff will be the largest remaining source of petroleum pollution. The petroleum in urban runoff resembles used crankcase oil in composition and contains toxic chemicals such as polynuclear hydrocarbons. Further research is clearly desirable. Remedial programs to control such pollution may be warranted on the basis of information now available. 相似文献
930.
Frederick W. Bond Donald L. Chery Eugene S. Simpson 《Journal of the American Water Resources Association》1979,15(6):1640-1652
ABSTRACT: Recent developments in the numerical solution of the governing partial differential equations for overland and channel flow should make possible physically based models which predict runoff from ungaged streams. However, these models, which represent the watershed by sets of intersecting planes, are complex and require much computer time. Parametric models exist that have the advantage of being relatively simple, and once calibrated are inexpensive to use and require limited data input. In this study, a procedure was developed for calibrating a parametric model against a physically based model, utilizing base areas of one acre and one square mile, with the expectation that base areas can be combined to model real watersheds. Simulation experiments with the physically based model showed that, for the one-acre base area, the dominant parameter (cell storage ratio, K) related to the slope and friction of the planes, whereas for one square-mile areas, the dominant parameters (K plus a lag factor, L) relate to channel properties. These parameters decreased exponentially as rainfall intensity increased. 相似文献