The Effect of Land-Use Changes on Flood Hydrograph (Case Study: Abolabbas Basin)

The purpose of this study is to evaluate the land use changes on flood hydrograph at Abolabbas basin during the period of 1990-2009. In this paper, the techniques of Remote sensing, Geographic Information System (GIS) and HEC-HMS hydrologic model was used to achieve the purpose intended. At the first step, Landsat satellite images used for the preparation the land use maps of 1990 and 2009, Then images were classified using artificial network algorithm with fine accuracy in eight class of land use. Then these land use maps with the hydrologic soil map were integrated using GIS tools to produce CN maps of 1990 and 2009. The HEC-HMS rainfall-runoff model using of the SCS-CN method for estimating runoff in Abolabbas basin was calibrated and validated for 4 storms occurred at study area. Results of the simulation showed that changes in land use that occurred in the direction the reduction in the level of forest and increased level of rangelands and residential areas has caused peak flow and flood volume during the study period increased 5.5 and 5.1 percent, respectively. On the other hand the results showed, this land use change not affect on the time of peak in flood hydrograph.