Investigation of sediment depositions in the Dak Uy reservoir, Kon Tum province using field survey aproach

Abstract

    This paper presents the investigation of sediment deposition in the Dak Uy reservoir, Kon Tum province after 41 years (from 1977 to 2018). Firstly, the Sontek M9 ADCP, with 9 multiple sensors, is used to measure the flow characteristics and bed elevation in 13 given cross-sections in the reservoir. Then, the obtained bed elevation is combined with the bathymetry, which was used for designing the reservoir, in order to determine (i) quantitatively sediment deposition in the reservoir, (ii) the longitudinal distribution of sediment deposition in the reservoir, and (iii) the lateral distribution of sediment deposition in the all 13 given cross-sections. The results clearly show that the total volume of sediment deposition in the reservoir after 41 years is of about 3.005  106 m3 , approximated 78.7% of dead volume of the reservoir. The longitudinal distribution of sediment is the delta, with the the depostion height varies from 0 to 4.06 m. The maximum deposition height occurs at the cross-section located at the distance of 60 m from the main dam. In term of sediment deposition in the 13 given cross-sections, the height of sediment deposition after 41 years varies between 0 and 10.0 m, with the maximum value appeared at the location y = 875 m in the crosssection MC3 (and at the longitudinal distance of 1140 m from the main dam). Finally, relevant issues of sediment deposition in the Dak Uy reservoir is also discussed.