OVERVIEW OF THE 2005 TAUM SAUK UPPER RESERVOIR FAILURE, REYNOLDS COUNTY, MO

The upper reservoir of the Taum Sauk Pumped Storage Project failed catastrophically on the morning of Dec 14, 2005 due to the malfunctions on the reservoir’s instrumentation system, which allowed the pool to overtop the parapet wall (the upper reservoir did not have a spillway). This overflow scoured the wall’s rockfill foundation, causing the wall to collapse and unleash a much larger outflow. The resulted flood rapidly eroded a 680 foot wide breach in the rockfill embankment and stripped the mountainside of vegetation and residuum down to bedrock. This material, along with crushed rockfill, reinforced concrete, HDPE liner fragments, and steel rebar was deposited in the popular Johnson’s Shut-ins State Park, located about one mile away and 700 feet below. Post failure measurements suggest that the peak outflow was around 289,000 cfs. The reservoir drained in approximately 12 minutes.

The flow left a path of destruction and debris, obliterating a campground and other facilities within the state park. The flow and its associated debris were largely contained when the flood reached the lower reservoir, which had been pumped down to fill the upper reservoir the previous night.

Although there were five injuries, there were no deaths. Consequences could have been far worse had this occurred during a busy summer weekend at Johnson’s Shut-ins State Park, when upwards of 800 campers and park employees might have been sleeping in the path of the flow, most of whom would have been killed.