Hydrological Risk Assessment of Old Dams: Case Study on Wilson Dam of Tennessee River Basin

This case study presents a risk analysis reassessment for the oldest dam in the Tennessee River basin-the Wilson Dam-based on postdam flow data. The hydrologic risk of old Wilson Dam was computed from historical flow data (spanning pre and postdam periods) and reservoir volume at the dam site. Additional flow data not previously used in the design phase of the dam helped to update more robustly the probability of flood occurrence that exceeded a particular return period during the life of a dam. The generalized extreme value (GEV) distribution was fitted to historical peak flow (at the dam site) and annual maximum reservoir volume using the L-moment method. This reassessment approach has wide application in reservoir water and safety management for aging dams. The study underscores the need for a review of risk analysis for aging dams that have extensive postdam flow data, particularly in the United States. Furthermore, this case study also demonstrates the unique value of the L-moment method in incorporating postdam flow data for more robust risk analysis. DOI: 10.1061/(ASCE)HE.1943-5584.0000410. (C) 2012 American Society of Civil Engineers.