Page - 345 - in Book of Full Papers - Symposium Hydro Engineering

Table 5 Forecast of the Reservoir Storage Capacity Loss for the Reservoir Sedimentation over the Years Project Results Designed Storage Capacity of the Reservoir Normal Water Level (m) 994 Storage below NWL (10,000 m3) 92000 Water Level (m) 982 Dead Storage Capacity (10,000 m3) 66300 Adjusted Effective Storage Capacity (10,000 m3) 25700 Calculation of the Measured Section in 2014 Normal Water Level (m) 994 Storage below NWL (10,000 m3) 30124 Dead Water Level (982m) (m) 982 Dead Storage Capacity (10,000 m3) 11756 Effective Storage Capacity (10,000 m3) 18369 Sedimentation Forecast Sedimentation Period (Yrs) 5 10 20 Residual Storage Capacity below NWL (10,000 m3) 29655 29185 28264 Residual Dead Storage Capacity (982m) (10,000 m3) 11483 11203 10624 Residual Effective Storage Capacity (10,000 m3) 18172 17982 17640 Note: The calculated storage capacity of the surveyed sections in 2014 is the main stream storage capacity calculated by the section method, which does not include the storage capacities of tributaries. It satisfies the requirements for storage capacity loss forecast, and has a certain difference with the storage volume calculated by the contour method in 2014. 5. CONCLUSIONS AND SUGGESTIONS Most sections of the Manwan HPP are covered by the luxuriant vegetation, and the main sources of sediments mainly are: ① The sediment in the upstream flows into the Manwan Reservoir; there are large populations and farmlands around the Gonglang River, thus the water and soil loss is quite serious; ③ Some gullies in the reservoir area are covered by little vegetation, therefore the sediment flows into the main stream through the tributaries and the rainwater. Sediment of the whole reservoir is mainly deposited below the dead storage capacity. The Xiaowan HPP was impounded in 2009, which greatly 345