A simplified GIS-based SCS-CN method for the assessment of land-use change on runoff

The purpose of this study is to evaluate the impact of land-use alteration over years on potential runoff volumes for the Gaza Strip. The runoff curve number (CN) is an important factor to calculate the runoff volume in the standard Soil Conservation Service (SCS) method. The standard SCS-CN method takes too much time when calculating and analyzing composite curve number in hydrologic modeling. Therefore, GIS was coupled with HEC-GeoHMS which includes land topography to produce more accurate CN and runoff volumes for the Gaza Strip catchments. The uniqueness of the developed approach is its simplicity and inclusiveness of influential parameters for accurate CN prediction. Results show that land-use changes over time play an important role in CN number and runoff volumes. Moreover, the use GIS with HEC-GeoHMS and SCS-CN methods provides a quick and accurate method of calculating CN and runoff volumes when compared with the rational method.