Estimation of Silt Sediments in Dewerige Dam Reservoir Mayssan province

Abstract

The study deals with amount of sediment yield in flooding condition in reservoir of Dewerige dam .Since the Dewerige River is seasonal river, therefore the study achievement during dry season. The study aims to calculate amount of siltation which accumulated in reservoir and its impact on reservoir storage capacity, thus reducing economic life time of the dam. Topographic map (dwg file) considered the base map .The final field survey in field work during January 2017 was measured thickness of siltation in reservoir. By chosen cross-sections area in channel of Dewerige River based on Trapezoidal rule the volume of siltation can be calculated. Finally, siltation volume used to calculate: rate of sediment, economic life time of the dam, sediment yield and specific sediment yield in reservoir of Dewerige dam. Deposition of sediments in reservoir assumed as 514000 m3 during designing stage report of Ministry of Irrigation, the general commission of dams and reservoirs, nevertheless the study proved sediment yield is 8242950.6 m3 /y that is a very big amount of sediment for a small dam reservoir. Economic life time take into account during designing stage was 50 years, while the economic life time depend upon this study is 3 years.