Draft Osakis Lake Area Excess Nutrients Total Maximum Daily Load Report

This Total Maximum Daily Load (TMDL) study addresses nutrient impairments for Smith Lake (DNR # 21-0016), Faille Lake (DNR # 77-0195) and Lake Osakis (DNR Lake # 77-0215), located near the headwaters of the Sauk River (07010202) in the Upper Mississippi River Basin in Todd and Douglas Counties, Minnesota. The goal of this TMDL is to quantify the pollutant reductions needed for these lakes to meet State water quality standards for nutrients. The numeric water quality standards for Smith Lake and Osakis Lake, both deep lakes, are a summer average total phosphorus (TP) maximum concentration of 40 ?g/L and 14 ?g/L chlorophyll-a, and greater than 1.4 meter in Secchi depth. The numeric water quality standards for Faille Lake, a shallow lake, are a maximum summer average TP concentration of 60 ?g/L and 20 ?g/L chlorophyll-a, and greater than one meter in Secchi depth. Water quality for all three lakes does not meet deep/shallow lake state standards for nutrient concentrations in the North Central Hardwood Forest (NCHF) ecoregion.