LESSONS LEARNED FROM THE FAILURE OF THE TAUM SAUK DAM

摘要

The Taum Sauk Upper Dam breached in the early hours of December 14, 2005, letting loose approximately 1.4 billion gallons of water over a 25 minute period. The dam was a 90-foot high concrete-faced dumped-rockfill dam used as a pumped storage facility. Three independent teams investigated the root cause of this failure. Each found that the root cause was due to overtopping induced slope failure, although specific details of slope failure varied in some respects. Modifications to the project instrumentation followed by deterioration during project operations between December 2004 and December 2005 contributed to the accidental overtopping. The investigators also found that deficiencies in the original design and construction contributed to the failure. Material used to construct the dam was not clean rockfill and foundation preparation in the area of the breach was not completed in accordance with the original specifications. Several important lessons were learned from this incident; 1) the importance of good communications between and within organizations responsible for the safety of dams, 2) the risks of over-reliance on instrumentation versus human interface, 3) parapet walls on top of embankment dams create a heightened hazardous condition, 4) cable supported instruments are prone to vibration failure, 5) staff gage calibrations are a critical aspect of an instrumentation program. Fortunately, the breach did not occur during recreation season. No lives were lost, and lessons learned from the breach of the Taum Sauk Dam should help to prevent similar incidents.