Sauk Lake – North Bay Implementation Plan

The Sauk Lake North Bay TMDL Study addresses nutrient impairments for the North Bay of Big Sauk Lake (DNR #77-0150-02) located in the Upper Mississippi River Basin in Todd County, Minnesota. The goal of the North Bay TMDL study was to quantify the pollutant reduction needed to meet State water quality standards for nutrients, specifically total phosphorus, for deep lakes in the North Central Hardwood Forests (NCHF) ecoregion. The numeric water quality standard for total phosphorus concentration is a summer average of 40μg/L. Most recent data indicates that the Sauk Lake-North Bay has a summer average total phosphorus concentration of approximately 60μg/L (2002-2007) and does not meet the standard. The TMDL assessment relied upon analyses of flow and stream sampling (FLUX), lake modeling (BATHTUB), and regression equations developed by the MPCA. The specific sources of nutrients, target reductions from each source, and strategies to achieve the reductions will be discussed further in this implementation plan.