Estimation of Total Sediments Load for Makhoul Dam Reservoir

Abstract

The problem of sediment accumulation in dam reservoirs is considered one of the most important problems facing these large projects. The present study estimated the total amount of sediment from the Tigris and Lower Zab Rivers that will enter annually into the reservoir of the Makhoul Dam, which is currently under construction on the Tigris River in Iraq. Field and laboratory measurements were conducted to estimate the bed load of the two rivers using the Helley-Smith device, in addition to estimating this sedimentary load using five empirical equations. The filtration method was used to estimate the suspended load of the two rivers by taking samples and examining them weekly for one year. The results showed that the bed load of the two rivers using the Helley-Smith device was less than 1% of the suspended load. When calculating the bed load using the five applied equations, the results varied, as the Meyer-Peter, Schoklitsch, and Casey formula achieved unacceptable results, while the results of the Kalinske equation were good, as it estimated the bed load for the Tigris River to be 7.6% and for the Lower Zab River to be 10.9%. The results of the Einstein equation were also good, where the bottom load for the Tigris River was estimated to be 2.4% and the Lower Zab River 11.8%. The average of the results of the two equations was taken to represent the bed load and added to the suspended load. Also, the results showed that the highest value of the suspended load was during April for the Tigris and Lower Zab Rivers. The total sediment load of the Tigris River reached 2875461 tons annually, and the Lower Zab River reached 1503739 tons annually. In other words, the total sediment load of the two rivers entering the Makhoul Dam reservoir amounted to 4379200 tons annually, or the equivalent of 3368615 m3 annually.