Jack D. Fellows


Remotely sensed digital data (Landsat CCT) has proven an efficient and cost effective means of defining land cover information required in hydrologic modeling. However, an organization such as a county government finds great difficulty in collecting and integrating regional ancillary data (aerial photos, soils, etc) with digital remote sensed data.

A computer-based information system allowing engineers to create, access, integrate, and maintain a multi-parameter geographical data base which provides information required by the Soil Conservation Service hydrologic models is described. Land cover, soils, and elevation data are stored as arrays of cells referenced to USGS quad sheets.

A typical scenario involves the analysis of the impact of proposed land cover changes on the runoff hydro graph. In the interactive mode, the user inputs the location of an outfall cell. Enhanced picture processing algorithms applied to elevations determine the watershed area and stream network. The system routes the data contained within the watershed through the model for an input rainfall. The user receives a peak discharge, statistics, and maps describing the watershed. Proposed changes are input to produce a present/proposed hydrologic comparison.

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