A useful automated rainfall-runoff model for engineering applications in semi-arid regions

This research develops a useful GIS-based automated Semi-Distributed Time–Area model (SDISTA) that is intended for engineering applications in semi-arid regions. SDISTA is a simple model that reconsiders the time–area technique using an improved approach that deals with each grid cell as a completely independent hydrologic unit. Travel times through the grid cells are estimated using a spatially varied grid-based Manningʹs formula that relates the hydraulic radius at each grid cell to the characteristics of its upstream catchment area and excess rainfall depth. SDISTA is tested in this research on cases from semi-arid regions including Sinai Peninsula. The results show that SDISTA can be as accurate as HEC-1/HEC-HMS using a very dense network. SDISTA is fully automated and requires minimum effort from the user which is very favorable for engineering applications. The most attractive feature of SDISTA is its ability to automatically delineate and simulate any number of catchment areas simultaneously on digital elevation models.