Page - 543 - in Book of Full Papers - Symposium Hydro Engineering

150㎥/s and 200 ㎥/s) were very similar, though the flushed out sediment volume was about 10% higher for Q = 200 ㎥/s. This means that 85% of the total MP water storage capacity of 687,000㎥ were restored. After the flushing, the deposits in front of the power intake were cleared down to the original bed. Table 7. Volume Balance of Flushed Deposits in the MP for Load Case Load case MP volume (m3) Initial deposit volume (m3) Erosion Residue Volume (m3) Percentage of eroded volume Residual deposits (m3) Residual MP volume Q 150m3/s, 1day flushing 687,000 200,000 (100%) 88,000 44% 112,000 84% Q 200m3/s, 1day flushing 96,500 48% 103,500 85% Fig 9. The Initial Condition(left) and Hydraulic Flushing of Built up deposits with 150㎥/s after 14 Hours of Flushing Through the Fully Opened Underway Spillway Gate 4. CONCLUSION The area where the Patrind project is located is highly influenced by sedimentation due to eroded soil in the Himalayan Mountains. In order to manage sedimentation effectively, topographic and geological investigations, as well as several numerical analyses and physical model investigations were conducted. Through this process, the project adopted the OHDS technique, bypass tunnel and natural sand trap(MP), to prevent sediment inflow into the intake. In addition to applying OHDS, stability against sedimentation was further enhanced through turbine coating. The Patrind Hydropower Plant has been in operation since November, 2017 and hydrological monitoring and flushing effect analyses are scheduled to be conducted at the end of the dry season, March 2018, to confirm OHDS appropriateness. 543