چکیده:
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
خلاصه ماشینی:
The aim of this research is to study the hydraulic characteristics of the Simineh River and the processes governing it using the integration of the HEC-RAS model within the ArcGIS software environment through the HEC-GeoRAS extension, in order to simulate the hydraulic parameters of that river with a watershed area of 3726 square kilometers.
In this research, based on flow discharge measurement data at existing hydrometric stations in the study area, required cross-sections, and other necessary information, a reach of the Simineh Rud has been simulated and investigated (Young et al.
So far, many studies have been conducted regarding floods, but the study of simulating the river channel path in the Simineh Rud catchment area is the first research that uses satellite imagery and the HEC-RAS model integrated with GIS in the research 1-Chang et al.
Termini 2 (2021) simulated the pattern of changes in the bed of the Tagliamento 3 River in Italy by combining information obtained from satellite images, field photos, hydrological data, and the HEC-RAS model.
The results of this research showed that the HEC-RAS model has a good simulation effect for flood prevention and control and can be used in applying the best management method in the catchment area.
Simulation results using the HEC-RAS hydraulic model in the curved section (Figure 7) showed that the water level changes on both sides of the river bend are close to 50 centimeters, and the flow velocity has a direct relationship with the distance from the river bank, such that the maximum flow velocity of 2.
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