Ottertail River TMDL Water Quality Improvement Projects to Reduce Turbidity Phase V
Projects and Practices 2016: Laws of MN 2015 First Special Session Chapter 2, Article 7, Section 7
The TMDL study identified uncontrolled runoff into the drainage ditches and stream bank erosion as the greatest contributors to the pollutant of concern. The practices installed as part of this project will reduce erosion and sedimentation to the county ditch and river by an estimated 1,375 tons/year, or 20% of the total reduction needed to meet the goals of the Lower Otter Tail TMDL Implementation Plan. In addition, the project will reduce Phosphorus loading by 1,870 lbs/yr.
LOCAL LEVERAGED FUNDS
The Otter Tail River is impaired for turbidity. This project involves the installation of 45 side-inlet structures into Wilkin County Ditch 3-2 and 7-1 and 22 acres of buffer strips along the entire systems. Eleven miles of continuous berm will also be constructed along the ditch. When installed these water quality practices will become a permanent part of the ditch system and will be maintained by the ditch authority. These ditches outlet to the Otter Tail River just upstream from Breckenridge, MN. Together these water quality BMPs will reduce sediment loading by 1,375 tons/year. This is about 20% of the total reduction needed to meet the goals of the Lower Otter Tail TMDL Implementation Plan. In addition, this project will reduce Phosphorus loading by 1,870 lbs/year. A TMDL study was conducted on the Otter Tail River by MPCA in 2006. Water quality monitoring was conducted by the USGS, MPCA and the Wilkin SWCD. Water quality data indicated that the Otter Tail River was impaired for turbidity due to sediment loading. The USGS estimated that the annual sediment load at the sampling site in Breckenridge, MN was 40,400 tons/year. MPCA determined that this annual sediment load would need to be reduced by 17 percent (6,868 tons/year) in order for the river to meet acceptable water quality standards. Since 2007 the Wilkin County has been working with landowner to install water quality BMPs into the county ditches that drain into the Otter Tail River. At this time all county ditches, except for CD 3-2 and 7-1 have had water quality BMPs incorporated into them. Work completed to date includes: over 40 miles of county ditches with sediment controls (side inlets) and over 300 acres of buffer strips. Retrofitting CD 3-2 and CD 7-1 will complete this phase of the TMDL Implementation Plan. This work will be done in cooperation with Wilkin County Landowners, Buffalo Red River Watershed District, Wilkin County and the Wilkin Soil and Water Conservation District.