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Motion: Bob Johnson moved, Paul Ellefson seconded, to approve Permit #02-52. Motion carried. Permit 02-53; Joe's Sporting Goods -Little Canada Motion: Roger Lake moved, Paul Ellefson seconded, to approve Permit #02-53. Motion carried. Monthly Enforcement Report During September, 15 notices were issued to address the following violations on permit sites: repair silt fence (8), sweep streets (3), stabilize site and revegetate areas (5), repair inlet protection (4), and repair rock construction entrance (5). 5. PROJECT STATUS REPORTS Website Maintenance Following his May 1st recommendation to switch to a new website provider, Cliff reported that the site transfer work is almost finished. He hopes that the switch to the GovOffice.com server will resolve the website update problems we have been experiencing. Website maintenance training will occur next week. Carver Subwatershed Infiltration Study Earl Bancroft gave a presentation on the outcome of the study that began in February to achieve the Carver Lake SLMP objective to infiltrate the first 0.25 inches of stormwater runoff to reduce nutrient levels. The District's goal is to maintain Carver Lake's rating as a "swimmable" lake. Staff considered the following alternatives from the Met Council's Urban Small Sites BMP Manual: • rainwater gardens • infiltration basins (larger scale rainwater gardens) • infiltration trenches (similar to Kline Volvo site) The feasibility for each alternative was evaluated based on criteria such as: • Physical issues: average slopes, percolation rates, infiltration rates, groundwater depth, depth to bedrock, utility locations, and foundation locations • Non-physical issues: public acceptance (its location in someone's yard), and the need for maintenance agreements with either homeowners association or local unit of government Staff had difficulty finding suitable areas within the three Carver Lake subwatersheds, since most of the area has steep slopes, intense development (duplexes and four-plexes), small yards and setbacks resulting in limited open area, and utilities placed on both sides of the road. Only a few areas were found with potential for infiltration basins, and treatment would only benefit a few acres per site. Focus shifted to the southeast Subwatershed, and staff concluded that this area had the most potential and could be retrofitted with underground infiltration trenches along street curbs. Each trench would be designed to treat runoff from afive-acre area and infiltrate within two days. Staff commented on the large number of cul-de-sacs in this area, and discussion was held on their potential to help achieve the District's infiltration objectives. Earl felt they would be suitable for pervious pavement, an innovative technology that hasn't yet been used in Minnesota. He estimated the surface life at five to six years, compared to 20 or more years for traditional pavement materials. Discussion was also held on the potential to convert the center portion of cul-de-sacs into an infiltration system and to consider it as a backup system in the event that the pervious pavement system fails. Earl's presentation was intended to assist with the 2003 budget planning process. He recommended that that the District proceed with the construction of one street infiltration trench system and two pervious pavement systems. The District would first have to coordinate with the City of Woodbury to identify and respond to their concerns before proceeding with design and installation. These systems would be trial sites to be monitored for effectiveness and cost benefit before the District adds more throughout the southeast Carver Lake subwatershed. Cliff stated that the budget already contains a $400,000 placeholder (Budget Line 56). Earl will distribute figures for review and consideration at a later date. Page 2 October 2, 2002 RWMWD Minutes