South Heron Lake TMDL Implementation: Phase 3

Historically, the Heron Lake watershed was wetland prairie with saturated, organically rich soils, perfect for farming. Wetlands were tiled and drained to increase the amount of farmable land. Excess water is directed to ditches or streams, which can cause erosion. These landscape changes contributed to water pollution, which has had a drastic impact on North and South Heron Lake (SHL), once key migratory waterfowl habitat.

The purpose of this project is to reduce phosphorus entering SHL, which does not meet state standards for this pollutant. Too much phosphorus in a waterbody creates harmful algal blooms and decreased levels of dissolved oxygen, making it difficult for fish to live, aquatic plants to survive, and unpleasant for recreation. To address this, the Heron Lake Watershed District (HLWD) and Jackson Soil and Water Conservation District (SWCD) are partnering with landowners to implement projects to reduce phosphorus in the SHL watershed.

Efforts are focused on County Ditch 3 (CD3), which flows into Okabena Creek and then SHL and Judicial Ditches (JD)14 and JD3, which also outlet into SHL. Projects include 15 alternative side inlets (ASI) on CD3, 4 on JD14, and a 4.2 acre wetland on JD3, providing an annual phosphorus load reduction of 2258 pounds, which equates to a 6.1 percent total reduction for the SHL watershed. These systems are in varying stages, ranging from approval of the preliminary engineering report (PER) to completion of the final engineering report (FER).

The projects in this proposal build upon recent successes, including an existing Clean Water Fund Multi-purpose Drainage Management (MDM) grant and an EPA 319 grant. The HLWD has been selected to receive a Small Watersheds Focus Grant to implement practices in the SHL watershed over the next several years. These efforts, coupled with the support of BWSR through this grant, will make meaningful progress towards reaching the 79 percent reduction goal for phosphorus.