Separate components of the flood flow using the distributed hydrological WetSpa model in Ziarat- Gorgan watershed

There are many ways for flow hydrograph separation. .Base flow as a component of river flow, which reacts to precipitation, includes interflow and ground water flow. The spatially distributed hydrological WetSpa model calculates discharges and hydrograph at any point of the basin and gives 3 components of flow separately i.e. surface runoff, interflow and groundwater. In this study, the WetSpa model has been applied for flow simulation and hydrograph separation in the Ziarat river basin. In order to apply the model, hourly hydrometeorological data for a period of four years (2007-2010) including rainfall, evapotranspiration, temperature and discharge are used as inputs. Additionally, three main maps of the digital elevation model, soil map (texture), and landuse are also applied and converted to digital formats. The result of the simulation shows a good agreement between the simulated hydrograph and the observed one. The water balance components for the entire simulation period is given as well as for a flood event. In this mountainous forested watershed, the basflow forms the major part of the flow. As for the studied flood, it has formed 97% of the flood volume. . Forest and vegetation affect each of these components differently.