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Department Approval "�f- Item Description: BACKGROUND f�� � REQUEST FOR COUNCIL ACTION Date: 6/9/14 Item No.: 7.d City Manager Approval ��7�- Authorize Acceptance of Cost-Share Funds and Approve Cost-Share Agreement for Dellwood Street Drainage Improvements Over the years, residents of Dellwood Street north of County Road B have experienced street flooding and other drainage concerns during intense rain events. Extreme rain events have occurred over the past several years, including July 16, 2011, and June 21, 2013, that caused flooding in the street, as well as private property damage. City staff has completed a study of the storm sewer system in the Dellwood Street - Sherren Street area to analyze the existing drainage and localized flooding issues. The study also identified potential improvements that would reduce the level of flooding. The proposed improvements include the installation of an underground infiltration pipe netwark at the intersection of Sherren Street and Dellwood Street. This will allow for some storage and infiltration that will alleviate some local flooding and surcharging of storm sewers from the 6-acre drainage area. A smaller infiltration trench will also be added on Dellwood Street south of Sherren Street, which will be connected to the larger underground storage vault to the north. Existing starm sewer pipe will be removed and an infiltration trench will be added along two backyards at 2271 and 2263 Dellwood Street to minimize some ponding issues that are created by the 4 acre drainage area and lack of slope. The pipe will be constructed the same as the street systems to allow far maximum storage and infiltration. There will be one rain garden installed in a residential back yard at 2246 Dellwood that collects �� water from a 2 acre drainage area, mainly from backyards. The rain garden will minimize the area and duration of ponding by allowing water to infiltrate. A pipe will also be installed to connect the rain garden to the infiltration trench in the street to provide an overflow. Staff applied for funding from the Ramsey-Washington Metro Watershed District (RWMWD) through its Cost-Share Program. This funding is available to assist municipalities located within the RWMWD to incorporate water quality improvement Best Management Practices (BMPs) into redevelopment, roadway and storm sewer improvement proj ects. Only projects that are not part of a permit requirement are eligible for this funding. The RWMWD Board has reviewed the City's application, and has approved this project for funding. POLICY OBJECTIVE This area is listed as a problem area in the City's Comprehensive Surface Water Management Plan (CSWMP.) One of the goals from the City's CSWMP is to provide flood protection for all residents and structures as well as protect the integrity of conveyance channels and storm water detention areas. This project is also consistent with City water quality goals. Page 1 of 2