Remote sensing and GIS database for runoff curve number change assessment

Remote sensing and Geographical Information System (GIS) are excellent tool s for acquiring and managing spatially distributed data. The USDA Natural R esource Conservation Service (NRCS) Curve Number method incorporating GIS t echniques and remotely-sensed data were used in this study for assessing th e runoff curve number (CN) change, The S-65A sub-basin in the Kissimmee Riv er Basin, FL was used as an example to demonstrate the feasibility of appli cation. The GIS database as obtained from both Landsat Thematic Mapper (TM) images and Digital Orthophoto Quarter Quadrangle (DOQQ) data which was fur ther processed using Arcview and ERDAS Imagine software. A grid of curve nu mbers was generated based on land use for 1990 and 1995, The results showed that not only were both TM images and DOQQ data applicable for assessing t he land use changes and CN variation in the S-65A sub-basin, but also the l and use change in this 5-yr study period caused an increase of CN value by about 8%.