Optimising hydropower potential with a comprehensive reservoir sedimentation study

To harness the country’s hydropower resources, a power corporation in Asia commissioned DHI to carry out reservoir sedimentation studies for a proposed construction of a new hydropower plant. By analysing the reservoir's sediment dynamics using numerical modelling, DHI provided valuable insights into the reservoir sedimentation patterns over time. These insights are crucial for ensuring both efficient and sustainable operations of the hydropower plant, minimising environmental impact and supporting long-term ecological balance.

Challenge

The new hydropower plant will be constructed on a river with an elevation of almost 800 m. With a depth of 850 m and length of 6.8 km, this was a major project that needed careful planning of the design and operation mechanisms. As such, it was critical for our client to get a comprehensive understanding of sediment characteristics – including its inflow, distribution and potential impact on the reservoir.

Solution

Using client data, DHI conducted a numerical modelling study of the reservoir conditions in MIKE 11 (now MIKE+ Rivers) and MIKE 21C. The data was analysed, validated and corrected before using as input for the study. This approach ensured that the study results provided an accurate representation of the reservoir's actual conditions. Our modelling helped to assess the loss of reservoir storage over time, determine the time taken to reach equilibrium level, identify the optimal flushing strategy as well as highlight the necessity of a separate desilting basin.

Results

The hydropower study yielded valuable insights into the reservoir sedimentation patterns over time, offering a clear understanding of how sediment accumulation would impact reservoir operations. It provided crucial estimates of safe discharge levels, ensuring that the hydropower plant could maintain optimal performance without risking structural damage or operational inefficiencies. Additionally, the study helped finalise essential construction parameters, including crest and intake levels, which are vital for the successful and sustainable operation of the new hydropower facility.