STEELE COUNTY MEDFORD RAIN GARDENS. Water of Concern Cannon River TMDL. Impairment Turbidity. CWL Funding by Category

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1 STEELE COUNTY MEDFORD RAIN GARDENS Water of Concern Cannon River TMDL Impairment Turbidity CWL Funding by Category Technical Assistance Funds SSTS Funds Engineering $40,000 Hired Positions Total TA Funds $40,000 Implementation Funds AgBMP Loans Bonding Funds Leveraged Dollars Total Imp. Funding Total CWL Funding CWL Accelerated Grants $266,060 $266,060 $306,060 PROJECT CONTACT Stefan T. Gantert, P.E BWSR Contact Matt Drewitz Project Number: 7R60C / 7R60S Overall Project Description (abstract) This project is a storm water runoff control project, located in the Cannon River Watershed of the Lower Mississippi River Basin, designed to reduce pollutant runoff from the Medford Schools site. The site was originally developed with one (1) dry pond which provided very little water quality treatment. Sediment in downstream ditches and runoff from this highly impervious site were common complaints from local landowners. This project consisted of the construction of four (4) rainwater gardens, tree planting, and native plantings. The main goal of the project is to improve the water quality of the runoff from the site before it discharges to the Straight River, which in turn flows into the Cannon River. Improved water quality throughout the Straight and Cannon river watersheds is a major initiative of the state, local governments, and environmental groups. This project is also intended to be the focus of educational and training opportunities, not only for students and teachers, but also for the general public, local officials, builders, and contractors. Prepared by Board of Water and Soil Resources Fiscal Year Clean Water Legacy Project Page

2 Conservation Implemented Name of Conservation Practice(s) Installed Storm water system control ponds Number or Linear Feet Installed Four (4) - detention basin, bioretention basin, and two (2) rain gardens Estimated Pollutant Load Reduction (include units) Reduction in Total Suspended Solids (TSS) leaving the site (1.66 acre-ft of water quality treatment volume) and 51% Phosphorus removal (62 lbs/year to 30 lbs/ year) Total Cost $259, Conservation Planning Activities Name of Plan(s) Written Landowners Contacted Plans Written Total Cost Types of Identified Identified Implemented Not Applicable Contributing Partners: (List or copy from restoration implementation plan) Partner Description Project Contribution Leveraged Funds Medford Schools Site for improvements Land na Steele County Minnesota BWSR Engineering and project management Clean Water Legacy Technical Assistance and Bonding Funds Staff na Funding $306,060 CWL Accelerated Grants Page 2

3 Project Informational/Educational Activities Type of Activity Newsletters, Brochures, Posters, Etc. Work with Kid Groups Tours, Demos, Etc. Presentations Given Presentations by guest speakers Other MECA Workshop June 2008 The Minnesota Erosion Control Association (MECA) workshop was held at the Medford School in June of 2008 to present information about the Clean Water Legacy Grant. The workshop included presentations from various sources that followed the project from start to finish. There were also demonstrations on the products used and how they were placed. Examples include a demonstration on the vegetation that was placed and a bare tree root planting demonstration. The final plantings were completed in the Spring of 2009 and consisted of around 150 tress of different species. The Medford School sees future educational opportunities in their biology, agricultural technology, and industrial technology classes. They are redefining their curriculum in these areas to incorporate learning opportunities offered by the storm water complex. Examples include a greenhouse to create new plantings for the site, classifying and labeling the trees, and other activities in the years to come for all grades (K - 12). The Medford Schools see this as a great opportunity to teach students the effect of controlling storm water and preventing erosion. At the same time, the complex has created new habitat for a variety of insects, birds, and animals for them to study. Project Outcomes: detail specific project outcomes that work towards meeting Restoration (total maximum daily load studies) and Protection (local water plans) water quality goals Estimates of impervious areas were calculated using topographic survey and aerial photography. Estimates of hydrologic parameters and hydraulic performance were estimated using hydraulic software. In general, the design goals are as follows. 1. The project receives runoff from an existing sub-watershed of 50.7 acres (9.9 acres of impervious). 2. The project reduces the amount of total suspended solids (TSS) leaving the site. The project includes 1.66 acre feet of water quality treatment volume, roughly equivalent to 2.0 inches from impervious surfaces. 3. The project is sized to treat and discharge a rainfall event just under the 5 year recurrence. 4. The project reduces the amount of phosphorous in runoff leaving the site. As estimated by the software, the phosphorous removal is 51% on an average annual basis, reducing the 62 pounds/year inflow to 30 pounds/ year in the outflow. The majority of phosphorous removal is due to the reduction of TSS in the outflow. 5. The project reduces peak water surface elevations and peak outflow from the site as shown below: Table 1 Storm Water Wetlands Peak WSE Comparison Summary Type II 24 Hour Rainfall Event Recurrence Pre-Project Peak Water Surface Elevation (WSE) (ft) Post Project Peak Water Surface Elevation (WSE) (ft) 2-Year Year Year Table 2 Storm Water Wetlands Peak Outflow Comparison Summary TypeII 24 Hour Rainfall Event Recurrence Pre-Project Peak Outflow Culvert Outlet (cfs) Post Project Peak Outflow Culvert Outlet (cfs) 2-Year Year Year CWL Accelerated Grants Page 3

4 Project Photos, Additional Maps, or Conservation Practice Existing Site Before Construction Looking North Storm Water Ponds Following Grading Looking Southeast CWL Accelerated Grants Page 4

5 Project Photos, Additional Maps, or Conservation Practice Existing Site Before Construction Looking West Completed Storm Water Ponds Looking West CWL Accelerated Grants Page 5