Total Maximum Daily Load For Turbidity, Lower Gar Lake, Dickinson County Iowa, December 2002

(2002) Total Maximum Daily Load For Turbidity, Lower Gar Lake, Dickinson County Iowa, December 2002. Natural Resources, Department of

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Abstract

The Federal Clean Water Act requires the development of a total maximum daily load (TMDL) for the pollutant(s) that causes a water body to be placed on the State of Iowa impaired waters list [303(d) list]. Lower Gar Lake is on the 1998 impaired waters list due to turbidity that creates a condition only partially supporting its aquatic life designated use. The 1998 assessment report echoes the 1994 and 1996 reports in its evaluation of the lake; the primary cause of the poor water quality is shallowness and the resultant re-suspension of nutrients and sediments. Lower Gar Lake is at the end of a system of important natural lakes of glacial origin and is a high priority for water quality improvement. This document consists of a single TMDL for turbidity designed to provide Lower Gar Lake water quality that fully supports its designated uses. Sediment and adsorbed phosphorous delivered from the watershed and re-suspended from the lake bottom are targeted to address the turbidity impairment.