Assessment of SCS-CN Model in Runoff Estimation Case Study: Amir-Kabir (Karaj) Dam Watershed

The volume of runoff arising from rainfall in river basins is given special attention by researchers in the various parts of water resources management. So far, a variety of procedures have been devised and used for estimating the volume of runoff arising from rainfall. Most of such procedures are either based on classic statistical methods or the results obtained from other basins. Nowadays, remote sensing and GIS techniques provide a better use of these models. The Soil Conservation Service (SCS) has devised a method for runoff calculation which is based on curve number computation. The present study implemented the above model in the watershed of Karaj (Amir-Kabir) Dam by means of Geographic Information System (GIS) techniques, and came to the conclusion that using the weight model in curve number calculation allows for the entire factors effective in runoff production to be considered,thus leading to a more accurate estimation of the runoff arising from rainfall.