DIFFERENCES IN RESERVOIR BATHYMETRY, AREA, AND CAPACITY BETWEEN DECEMBER 20–22, 2005, AND JUNE 16–19, 2008, FOR LOWER TAUM SAUK RESERVOIR, REYNOLDS COUNTY, MISSOURI

On December 14, 2005, the embankment of the upper reservoir at the Taum Sauk pump storage facility, Reynolds County, Missouri, catastrophically failed and flooded the East Fork Black River, depositing debris and sediment in Johnson’s Shut-Ins State Park, the lower Taum Sauk Reservoir, and downstream in the Black River. Bathymetric surveys conducted December 20–22, 2005 and June 16–19, 2008 documented the bathymetry of the reservoir after the failure and documented the subsequent excavation of sediment and debris from reservoir. The U.S. Geological Survey, in collaboration with Roux Associates Inc., conducted the bathymetric survey in 2008 to prepare a current bathymetric map for the lower reservoir, to establish a current elevation-area and capacity table, and to determine reservoir area and capacity differences between the 2005 and 2008 bathymetric surveys.

Approximately 350,000 data points were collected in the 2008 survey and approximately 311,000 data points were collected in the 2005 survey. The bathymetric surface was contoured from the edited data points using geographic information system software, and the contours were cartographically edited to create bathymetric maps. The bathymetric surfaces were converted to a 1-meter gridded data set, then the bathymetric surface difference map was computed by subtracting the 2005-surface grid from the 2008-surface grid.

The elevation difference map shows areas of change between the two bathymetric surfaces of the reservoir bottom. Most changes can be attributed to the removal or redistribution of material in the lake following the excavation of the debris deposited during the flood event. At the full pool elevation of 750 feet, the 2008 reservoir volume was 620 acre-feet greater than the 2005 reservoir volume while the surface area increased by 3 acres.