Author(s): Sayed Reza Alvankar; Farzaneh Nazari; Bahram Saghafian; Hossain Sedghi
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Keywords: Sediment yield; Reservoir sedimentation; Semi-arid Regions
Abstract: The average annual sediment production from a catchment depends on many factors such as climate, soil type, land use and topography. Survey data of many reservoirs in Iran which are mostly located in semi-arid regions, shows that sediment yield is actually more than predicted by sediment rating curves or other empirical formulas developed in other countries. High intensity of rainfall after dry season in semi-arid region, deliver high amounts of sediment into the reservoirs. Underestimation of sediment yield in reservoirs cause them to be filled with sediment much sooner than expected. For example reservoir survey data in Minab dam in southern part of Iran with drainage area of 10000 Km2 and mean annual discharge of 8. 5 m3/s, shows that 14. 5% of reservoir capacity is lost during 10 years of operation. In this research, by utilizing 19 reservoir survey data in Iran, a relationship between average annual sediment yield rate against drainage area size is developed. The result of sediment estimation by this formula is about 3 to 6 times of the value estimated with similar relationship which have been developed in the United States.
Year: 2007