عنوان مقاله [English]
Iran is one of dry region in the world. Except the Caspian sea borders and the range and the elevations of Alborz and Zagros, this country often have a dry climate with a little precipitation. The collect rainwater method for different purposes has been used for the long time in Iran. This research has been done for Kalat basin, and conduct to check the appropriate way to determine the location for collecting rainwater. At the first step, the basin was divided to smaller sub basins by GIS software. Then for a period of 18 years (1991-2010) the need of water plant was calculated by Cropwat software. The assumption was that the cropping pattern of all of sub basin was the same pattern with basin area. Then due to lack of rain station, to calculate runoff in the spring, the curve number method was used (SCS). After estimating the runoff created in upstream of any sub basin, by comparing the net irrigation needs in downstream lands with the runoff created in upstream, a convenient location to collect rainwater, was suggested. Eventually, it became clear that it is possible to add 46 percent to irrigation lands.