On the Hydraulic Simulation of River Simineh using HEC-RAS and ArcGIS Software,

The purpose of present research work is to study the hydraulic properties of River Simineh and its process using HEC-RAS model, in a combination with ArcGIS software using HEC-GeoRAS extension to simulate the hydraulic parameters of river having a catchment area of 3726 km2. For that mean, since multi-dimensional models require long time and high cost in river bends, by using a combination of satellite images and HEC-RAS model a multi-dimensional simulation was prepared. Among those, 58 cross-sections are considered along the river lane that main data required in this research are elevation maps, satellite images, boundary conditions and River Simineh hydrometric stations. The results showed that at the upstream of river, the discharge was 316.3 m3/s and water level was 12.85 m, and at the downstream the flow rate and water level are 313.6 m3/s and 11.52 m, respectively. On the other side of the river bend, the water level variation is around 50 cm and the flow velocity is directly proportion to a distance from the river bank; so that the maximum flow velocity of 2.2 m/s occurred at a distance nearby 1.5 m. To verifying the model, a statistical parameter of NSE coefficient for the water level and flow depth were 0.805 and 0.845, respectively; which shows the accuracy of model. Those results indicate a high accuracy of HEC-RAS model in hydraulic simulation of River Simineh flow. Also, simulations prepared in GIS background have significant impacts on the accuracy of outputs