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REQUEST FOR COUNCIL ACTION Date: 12/10/2012 Item No.: 7.i Department Approval City Manager Approval Item Description: Approve an Agreement between the City of Roseville and Capitol Region Watershed District for the Villa Park Wetland Restoration Project Page 1 of 2 B ACKGROUND 1 The Villa Park Wetland System (VPWS) is a cons tructed wetland system located upstream of Lake 2 McCarrons. The VPWS was de signed to provide stormwater quality treatment prior to its discharge to Lake 3 McCarrons. The VPWS consists of eight treatment components and receives stormwater runoff from a 753-4 acre, fully developed urban watershed, which is appr oximately 70 percent of the total 1,044-acre watershed 5 tributary to Lake McCarrons. 6 Data has been collected since the 1980s to monitor th e water quality treatment effectiveness of the VPWS. 7 In 2009, the Capitol Region Watershe d District (CRWD) completed the Villa Park Wetland Management 8 Plan (VPWMP). Water quality data analyses comp leted for the VPWMP suggest that VPWS components 9 have accumulated sediments and phosphorus and are a net source of phosphorus for Lake McCarrons. The 10 VPWMP concluded that management for removing or immobilizing the sources of phosphorus in the VPWS 11 is a priority for protecting Lake McCarrons. 12 A water quality model of the VPWS was created for th e VPWMP to evaluate various management options 13 and their effects on phosphorus removal. Several ma nagement options were evaluated based on cost, 14 estimated phosphorus removal, expected design lif e, and maintenance costs. The recommended 15 management option is dredging the VPWS to reduce watershed phosphorus loads. 16 CRWD received a loan in late 2009 from the Minnesota Clean Water Partnership for implementation of the 17 dredging portion of the recommended management option, which is referred to as the Villa Park Wetland 18 Restoration Project. 19 The recommended method of dredging the VPWS is hydr aulic dredging. A hydraulic dredge is about the 20 size of a pontoon boat. A boom is lowered into the sedi ment to loosen the bottom material, and a suction 21 hose attached to the boom pulls in the loosened sedime nt/water slurry. The slurry is then pumped into a 22 geotextile tube for dewatering. Geotextile tubes ar e large fabric tubes approximately 60 feet in 23 circumference and 100 feet or more in length. The openings in the geotextile are fine enough that sediments 24 are unable to pass through. The water, however, is able to slowly seep through the fabric. The sediment 25 within the geotextile tubes is allowed to dry and conso lidate for several weeks. Then, the tubes are cut open 26 and the sediment is hauled away. 27 CRWD and Roseville Public Works and Parks and Recreati on staff have met to coordinate the schedule of 28 this project in conjunction with improvements to Villa Park as a part of the Parks and Recreation Renewal 29 Program. As a part of this project , the warming shelter will be removed to provide space for the geotextile 30 tubes. Once the project is complete, Parks and R ecreation will be able to move forward with their 31 improvements. This schedule will minimize the amount of time that part or a ll of the park will be 32 unavailable for programming. 33