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e . Land Erosion and Sedimentation Two levels of land surface erosion analysis have been developed for application in the pilot study. The basic level is to compute land surface erosion potential for each grid cell within the study area. The data variables uf land use. slope and soil erosion index will be automatically retrieved from the data bank and formatted for use in erosion potential calculations. The computatiuns will be performed by the STORM program for alterna- tive land use patterns and the results displayed in computer graphic format. The Soil Conservation Service. Universal Soil Loss Equation technique is used to compute land sur- face erosion potential. The second level of erosion analysis will track the movement of sediment eroded from each cell and determine its ultimate deposition location. The erosion computations are performed as above and the material is then transported using a simplified transport model that moves material from cell to cell. The result will be presented as a graphic dis- play of the annual rate of erosion or deposition on a cell-by-cell basis. SUMMARY e The Corps of Engineers has performed pilot studies that develop flood hazard, flood damage and environmental information for existing and alternative future development patterns as a continuing planning service to local government agencies with land use management responsibilities. Spatial data management techniques have proven to provide the technical capability to perform the comprehensive assessments quickly and systemati- cally. The overall process of data collection and encoding to create a data bank, and processing to interface with modeling computer programs has been found to be rational and achievable although tedioos and requiring particular attention to detail. The tech- niques used are generally modest extensions (although somewhat automated) of tradi- tional analysis methods familiar to most analysts serving the Corps planning function. ACKNOWLEDGMENTS The investigation reported herein was perform~d for the U.S. Army Engineer District, Savannah, by the Hydrologic Engineering Center. The study was performed under the direction of the writer with special contributions by R. Pat Webb, Computer Systems Analyst, and Michael W. Burnham, Civil Engineer of the Planning Analysis Branch. Dale Burnett, Chief, Special Assistance Branch, assisted by Marilyn Hurst. Engineering Technician, provided valuable hydrologic analysis assistance. Water quality and erosion analysis is performed under the direction of Tony Thomas, Chief, Research Branch, by Jess Abbott fOJ storm water quality analysis, R. G. Willey for in.stream quality and Michael Gee. for surface erosion transport. Support by the HEC Director, Bill S. Eichert, and other HEC staff contri. buted to the success of the project. . LITERATURE CITED ; Environmental Systems Research Institute, AUTOMAP II Users Manual, 60 pp. Franzini, et al., 1971. Urbanizations Drainage Consequences. Journal of the Urban Planning and Development Division, Proceedings of ASeE, December, pp. 217.237. Institute for Water Resources. Honey Hill, A Systems Analysis for Planning the Multiple Use or Con- trolled Water Areas.lWR Report 71.9, p. 403. The Hydrologic Engineering Center, 1976. Annual Report. Davis, California, 50 pp. e 17 "-