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A case study is presented of a hydrologic investigation of the Red Run Drain-Lower Clinton River watershed, an area near Detroit, Michigan, that has undergone urbanization since the 1940's. The purpose of the study was to determine peak-discharge frequencies at gaged and ungaged locations for existing and future conditions. Population density was used as an indicator of urbanization in relationships defining unit hydrograph parameters and hydrologically significant impervious area. Input parameters for a single event rainfall-runoff simulation model (HEC-1) were developed to reflect watershed conditions in the years 1940, 1950, 1960 and 1975. The input parameters were verified by reconstructing observed flood events that occurred at these points in time. Sets of synthetic winter and summer storm hyetographs were input to HEC-1 to develop a series of curves for two gaging stations that relate peak discharge to magnitude of synthetic storm for each watershed condition. The curves were used to transform the series of recorded annual peak discharges at each gage to a stationary series that reflects 1975 watershed conditions. Discharge frequency estimates were then developed for ungaged locations using winter and summer synthetic storms that were assigned exceedance frequencies consistent with actual exceedance frequencies at the gaged locations. Projections of future population density were the basis for developing HEC-1 input parameters representing year 2000 and 2025 watershed conditions. Estimates of peak discharge-frequencies for the future conditions were made at the gaged and ungaged locations using the methods described above. (Author).
The application of the Soil Conservation Services (SCS) urban hydrology techniques is made to four watersheds. The parameters of the methods are obtained from standard SCS guidance and from calibration of watershed model HEC-1 using the SCS method. A modified method of determining these parameters is also recommended to SCS. Runoff parameters are then used with design storms to illustrate the differences in frequency curves which may result. (Author).
Water resources planning at the federal level is comprehensive multi-purpose multi-objective planning. The increasing complexity of issues, planning alternatives, and evaluation criteria have spawned an ever growing need for increased data and associated analysis procedures. The increased number of such models, both demanding and generating large amounts of data, have stimulated awareness of the need for planning oriented data management systems. This paper describes recent activities of the Corps of Engineers Hydrologic Engineering Center in data management for water resources planning studies.