5C, 2013 Pavement Management Program - Resolution Receiving the Feasibility Report and Ordering the Public Hearing for Improvement

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Storm Water Management Best Management Practices (BMPs) such as, infiltration basins, bio-filtration basins, rainwater gardens, underground filtration cells, filtration strips and constructed wetlands are proposed to improve water quality treatment, volume and rate control of storm water runoff in the area. These BMPs will be designed to meet Rice Creek Watershed District (RCWD) and Minnesota Pollution Control Agency(MPCA)requirements. Overland street drainage and drainage from the limited storm sewer system currently flows into the Johanna Marsh wetland. Upgrades to the storm drainage system which include treatment, volume control and rate control measures are recommended to decrease pollutants in storm water runoff discharging into Johanna Marsh and, subsequently, Lake Johanna. A. RCWD Volume Reduction Requirement Storm water management will include volume reduction requirements for new and/or disturbed impervious areas created by the project. Volume reduction requirements are based on approximately 4.8 acres of reconstructed impervious areas created by the proposed neighborhood project as well as connected impervious areas draining into streets. Based on current RCWD Rule C5(f) utilizing a local street classification, the volume reduction requirement is 0.8 inches off all disturbed plus added impervious areas and those impervious areas connected to the streets. Connected impervious areas include applicable roof, driveway and patio area with runoff draining directly into the street right- of-way. Existing street widths are irregular throughout the neighborhood due to the poor pavement conditions and frequent patching. The proposed project, with the addition of concrete curb and gutter, will provide consistent street widths throughout. However, an overall impervious surface decrease is anticipated post-reconstruction. For the purposes of calculating a volume control requirement, the impervious surface assumptions are based on current street edge locations as outlined on an aerial photograph. The total RCWD volume reduction requirement based on 2012 RCWD rules is as follows: - Impervious Area(Disturbed+ Connected+New) = Regulated Area [square feet] 117,568 sq ft+ 90,704 sq ft+ 0 sq ft= 208,272 square feet - Regulated Area [sf] x 0.8 inches x 1/12 ft/inch= Volume Reduction [cubic feet] 208,272 sq ft x 0.8 inches x 1/12 = 13,885 cubic feet Meetings with RCWD staff in May 2012 indicate that RCWD is considering rule changes to a volume reduction requirement consistent with other Twin Cities area metropolitan watershed districts. It is anticipated that the infiltration requirement will increase from the current rules applicable to this project. 8