THPC Headpond Bathymetry-Sedimentation (Laos)

DSI was contracted by Statkraft Energi, AS, to conduct an assessment of the historical sedimentation and develop updated bathymetry of the existing Theun Hinboun Power Company’s Headpond. The Headpond is a relatively small run-of-river reservoir with storage of only 52 million m3. Therefore, sedimentation in the Headpond can have significant impacts on operations and the life of the project. With the construction of the Nam Theun 2 (NT2) project just upstream of this project, it was even more critical to evaluate the historical and future sedimentation impacts. The NT2 project will essentially eliminate the routine floods coming down the Nam Theun into the Headpond. While these flows also were a major sediment delivery mechanism for the Headpond, they also produced significant bed shears in the Headpond itself. The bathymetric data was collected using a GPS/ADCP data collection system assembled by DSI. In addition to the data collection, THPC staff was trained on the ADCP/GPS data collection system so they could collect the data for future annual assessments. The ADCP data was processed and combined with water surface time series to determine the current Volume-Area-Elevation relationship for Headpond. The following figure shows the final digital terrain model (DTM) generated for the Headpond.