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 (location map). A bathymetric survey conducted December 20-22, 2005, documented the bathymetry of the lower Taum Sauk Reservoir after the upper reservoir failure (Rydlund, 2006). After subsequent excavation of sediment and debris from the lower reservoir by Ameren Union Electric (UE), the U.S. Geological Survey (USGS), in collaboration with Roux Associates Inc., conducted a bathymetric survey of the lower Taum Sauk Reservoir on June 16-19, 2008, to prepare a current (2008) bathymetric map (fig. 1) for the lower reservoir, establish a current (2008) elevation-area and capacity table, and determine reservoir area and capacity differences between the 2005 and 2008 bathymetric surveys.