Sediment Management at Naodehai Reservoir

The sediment management at Naodehai reservoir on the Liu River in China is discussed in this study. The Naodehai reservoir was operated as an uncontrolled flood detention reservoir from 1942 to 1970. It has been operating in such a scheme as storing clear water in dry season and sluicing muddy water at free flow or low water level in flood season since 1971. The equilibrium status of erosion and deposition in the reservoir was reached in early 1970s. The process of the sediment movement in the reservoir is erosion in the flood season and deposition in dry season since 1971. This mode of operation has enabled the reservoir to maintain 80% of its original storage capacity after 60 years of operation. The major negative impact of the reservoir operation mode is silt deposition in the downstream channel. The downstream deposition causes the riverbed rising and decreases the flood discharging capacity of the river channel. The measures such as water and soil conservation in the upper basin, revetments and groynes in the downstream river channel have been executed to reduce the deposition.