الخلاصة:
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.
