Evaluation of Himeran Reservoir Sedimentation by Using HEC-HMS Software

Abstract

ABSTRACT Hemrin dam is an important dam located on the course of the Diyala river. The sediment problem has greatly effect on Hemrin dam and its reservoir. Simulation for sediment entering and deposition in Hemrin reservoir was done using Hydraulic Engineering Center-Hydrologic Modeling System (HEC-HMS 4.1 software). Several input data were used for simulation such as precipitation data for the basin , watershed characteristic, geometric boundary for Diyala river and Hemrin reservoir and water release from Hemrin reservoir. The calibration processes for the model was done by using field measurement data for water discharge from Diyala river and good agreement was reached. The adopted period for simulation was 34 years started from 1981 up to 2014 and the result obtained show that the average annual sediment discharge load to Hemrin reservoir is( 3.43x106 ton) while the average annual sediment deposited is (3.25x106 ton) , the results show that the peak sediment discharge load occurred in November 1984.The simulation suggest that about 49.5% of mass of sediment deposited as clay while the all sediment load out from reservoir as clay. While the silt formed 40.3% of mass of sediment deposited while the sand and gravel are 8.9% and 1.3% respectively. The results prove that there is a strong link between precipitation depth in the basin and sediment entering to Hemrin reservoir. The sensitivity analysis was done by using cover factor and soil erodibility factor for sub basins in the watershed and this processes show that these two factor have large effect on sediment entering and deposition in Hemrin reservoir.