| Sediment and driftwood management in reservoirs is a long-term issue for maintaining dam functions. In 2017, one gate of the Susobana Dam in Nagano became uncontrollable because sediments and submerged wood clogged the bottom outlet. This case demonstrates that extreme sedimentation can cause a problem related to submerged wood around bottom outlets in terms of reservoir management. Therefore, in order to understand the dynamics of submerged wood in a reservoir, we discussed a method for detecting submerged wood using Narrow Multi-Beam sonar (NMB) and the process for submerged wood to occur in a reservoir. As a result, we were able to detect submerged wood under a log boom in reservoirs and experimentally clarified the different process of density change over time between driftwood and greenwood. |
