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RICE CREEK WATERSHED DISTRICT CLEAN WATER GRANT PROGRAM APPLICATION AND CONTRACT GENERAL INFORMATION Contract Number Individual/Group Other Grant Award AmendmentLi Cancelled Ll A17-08 Individual Yes ❑ No RI Date: Date: APPLICANT INFORMATION Applicant Phone Email City of Centerville 651-503-1834 GBurmeister@CENTERVILLEMN.com Mailing Address City State Zip 1880 Main Street Centerville MN 55038 CONSERVATION PRACTICE/PROJECT LOCATION Physical Address Municipality Trail Side Park- 7145 Main St. Centerville County �[31 ownship Range Section %,% Parcel ID Anoka 22 23 22 233122220013 Nearest lake,stream or wetland that the proposed practice drains to Approximate distance to nearest waterbody Centerville Lake Adjacent PROJECT INFORMATION Project Description(Attach additional sheets if necessary) The Trail Side Park property is located on the east side of Centerville Lake,along the west side of Main St.in Centerville(see map to right). Approximately 350'of shoreline is actively eroding. Natural wave action and wakes from boat traffic are the primary causes of erosion. Sediment and nutrients from the eroding shoreline directly enter Centerville Lake,which is part of the Rice Creek Chain of Lakes. Additionally,a sanitary sewer main within the park is at risk of exposure if erosion continues. For this project,the 350'shoreline is divided into north and south zones based on the shoreline topography. North Zone(Approximately 165')-This zone is characterized by relatively steep shoreline slopes(about 2:1). Currently,these upland slopes are slumping into Centerville Lake as a result of wave action undercutting the toe of the slope. Generally,these slumping soil areas are four to six feet high. The north zone shoreline slopes consist of sandy soils being held in place by weedy forbs and grasses with relatively shallow root systems. The continued erosion of these slopes threatens a paved regional bike path(about 12'east of the OHWL)and Main St(about 30'east of the OHWL). South Zone(Approximately 185')-The south zone is characterized by an approximately 20'wide level area below a steep slope leading up to a bike path and Main St. Shoreline erosion has undercut this level area,resulting in two to three foot high vertical shoreline banks. This erosion has contributed to the loss of about 10 mature trees(24"-50"DBH)in the past five years. A sanitary sewer line parallels the lakeshore along this south zone,generally within 15'-20'of the eroding shoreline. This sewer main,which is about three to four feet in elevation above the OHWL,is at risk of failure if the lakeshore erosion trend continues. Please note that in the past year the City of Centerville had to implement shoreline stabilization measures to protect the sewer main alignment located immediately south of the project. PROJECT DESIGN Trail Side Park is located on the windward side of Centerville Lake and experiences more than a mile of fetch. On windy days,the shoreline is pounded by waves more than a foot high. The Trail Side Park shoreline also absorbs the wakes from recreational boaters,including waterskiing events held offshore from the park. With a goal of long term shoreline stabilization,the Anoka Conservation District proposes installing riprap(the minimal quantity necessary)and native plantings. North Zone(Approximately 165)-The north zone has a slope that is similar to the shoreline to the north of the project.This north zone design consists of laying type IV geotextile fabric under 12"of riprap(the minimal depth feasible for shoreline protection)that is keyed into the lake bottom. Native willow stakes(similar species to the property to the north)will be installed throughout the riprap area. Low growing native shrubs will be installed in a six foot wide zone above the riprap that is currently mowed. South Zone(Approximately 185)-The south zone is heavily used for community events during the summer months(water skiing shows,fireworks viewing,etc.). Thus,a secondary goal in this zone is to maintain the lake view and access docks seasonally installed in this area. Therefore,the south zone design consists of laying type IV geotextile fabric under 12"of riprap(the minimal depth feasible for shoreline protection)that is keyed into the lake bottom. About 550low-growingnative plants(forbs and grasses)will be interplanted in a six foot wide zone upslope of the riprap that is currently mowed. PROJECT BENEFITS Water Quality Stabilization of the Trail Side Park shoreline will provide reductions in total suspended solids,total phosphorus,and other nutrients entering Centerville Lake.As part of the Rice Creek Chain of Lakes system, the water quality benefits will also have downstream benefits to the Chain of Lakes and Rice Creek. Existing Infrastructure Protection Shoreline stabilization will provide protection for the sanitary sewer line within the park,a regional bike path,and Main St. Recreational Use Shoreline stabilization within Trail Side Park will provide continued access to Centerville Lake for community events and general recreational use by the public. ESTIMATED POLLUTANT REDUCTIONS Pollutant reductions were estimated using the Wisconsin NRCS Direct Volume Method in conjunction with BWSR's pollution reduction calculator for stream and ditch erosion. Erosion severity along the shoreline was classified as'severe'because the bank is predominantly bare,with exposed tree roots and fallen trees(see site pictures at end of memorandum). Based on this determination,the lateral recession rate was estimated to be 0.3 ft/yr,which is on the low end of the'severe'range(0.3-0.5 ft/yr). Assuming sandy soils,the estimated soil loss from this 350'stretch of bank with an average 2'eroding face is approximately 11.6 tons per year. This results in an estimated 9.82 pounds of total phosphorus contributed to Centerville Lake and downstream waterbodies annually. Stabilization of the bank will result in 100 percent reductions in these estimated pollutant loads. 2016 C-S application contract.pdf Page 1 of 3 2/05/2016 93