Use of Satellite Data in Urban Hydrologic Models

The study investigates the use of computer-aided analysis of LANDSAT multispectral data in estimating percentage of imperviousness and associated land uses needed in urban hydrologic modeling. An interactive computer was used to delineate seven land use classifications in the 132-sq mi (342-sq km) Maryland portion of the Anacostia River Basin from LANDSAT data. The land-use distributions compared favorably with those of an earlier study which obtained the same information through analysis of aerial photographs having a scale of 1:4800. The LANDSAT data were used to estimate the basin imperviousness as 25.1% while the aerial photographic study had given 23.5%. Comparisons between the photographic and LANDSAT imperviousness estimates are made for subareas within the Anacostia Basin as small as 0.14 sq mi (0.36 sq km). Approximately 94 man-days were required to complete the land-use analysis using the aerial photographs while less than 4 man-days were required to accomplish similar tasks using the LANDSAT data.