Simulation of Collecting Urban Runoff in Dry Areas, Case Study Eslamshahr

The aim of this research is to simulate the collection of runoff due to irregular rainfall regimes and ‎the ‎total occurrence of annual rainfall in dry areas. Simulation has been done using hydrological models ‎in ‎Islamshahr city with a dry climate. The data includes all the layers related to surface and ‎subsurface ‎urban infrastructures for collecting runoff, which is prepared from spatial data sources in ‎ArcGIS ‎Software. The research method for calculating runoff in Islamshahr is the SCS (CN) model during ‎‎2005 and ‎‎2011. In this regard, first, the direction and collection of runoff were determined based on ‎elevation data ‎and field observations. Then the amount of runoff produced in each evaluation basin and ‎the ‎geometry of its channels were calculated with the atmospheric runoff simulation Swale model ‎in ‎SWMM software. The combination of the SCS (CN) model in the production of runoff and the ‎Swale ‎model in the SWMM environment has provided a new way to collect runoff at the best point ‎of ‎concentration of runoff so that the maximum runoff produced in basins 3 and 4 And there are 5 ‎Islamshahr ‎because the runoff from the upstream basins is also added to it, so it is a suitable outlet for ‎collecting ‎runoff. Also, in terms of reducing runoff, the Swale model reduces the vulnerability potential of ‎Islamshahr in ‎the face of the risks