Bathymetry of Lake Manatee, Manatee County, Florida, 2009

Lake Manatee, located in central Manatee County, Florida, is the principal drinking-water source for Manatee and Sarasota Counties. The drainage basin of Lake Manatee encompasses about 120 square miles, and the reservoir covers a surface area of about 1,450 acres at an elevation of 38.8 feet above NAVD 88 or 39.7 feet above NGVD 29. The full pool water-surface elevation is 39.1 feet above NAVD 88 (40.0 feet above NGVD 29), and the estimated minimum usable elevation is 25.1 feet above NAVD 88 (26.0 feet above NGVD 29). The minimum usable elevation is based on the elevation of water intake structures. Manatee County has used the stage/volume relation that was developed from the original survey in the 1960s to estimate the volume of water available for consumption. Concerns about potential changes in storage capacity of the Lake Manatee reservoir, coupled with a recent drought, led to this bathymetry mapping effort.