Agenda - Planning Commission - 11/04/2010

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Preliminary Site Plan Review -Suite Living at The COR October 28, 2010 Page 5 of 7 Additional BMP's should also be considered and investigated to provide for some rate control and lessen the need for downstream piping/structure sizing, and reduce the volume of water leavingthe site. With the proposed coordinated storm sewer effort between this project and the Residence at the COR to the east; private cross drainage easements will be required to outline responsibilities of each entity as it relates to ownership, maintenance, etc. Are the proposed stubs along the east side of this property . adequately sized to handle the proposed runoff from this project (building, paved areas, etc.)? Please identify overflow routes for all the "ponding areas" around catch basins; explaining drainage patterns and overflow routes should one or more of these basins become clogged and/or frozen. Adequate • freeboard should. be provided to protect private property from the potential for flooding. A maintenance will be required for the overall system to ensure timely maintenance and performance to the intended design. A stormwater analysis using EPASWMM or equivalent software that provides dynamic routing and evaluates surcharge impacts inust be prepared. Please explain how the proposed site storm sewer connection to the west will be made to the existing public system in the right-of-way. Are the receiving structures adequate in size and downstream capacity to accept the runoff from this project? 'All impacts to existing infrastructure for curb cuts and utility connections (streetlights, hydrants, catch basins, streetscape, roadways, etc.) must also include a relocation/restoration plan, not just notes calling out the removals. Notes and details must be added showing impacts to the structures and roadways, methods of connections, and mitigation/restoration; including sawcutting, coring, closures, timing, etc. Is there any dewatering required for this project? If so, the appropriate permit must be secured from the DNR, and the City will want to review the dewatering plan prior to implementation. No dewatering activities can occur until the required permit is secured and submitted for review. Additional permits that will be required include, but are not limited to, an NPDES construction permit from the MPCA (which includes a SWPPP plan), LRRWMO, right-of-way, and City contractor's license. A SWPPP plan will be required. for this project, which may be able to be accomplished by a subdivision transfer of the existing master TOWN CENTER project or development of a stand-alone site specific plan. Additional inlet protection should be added to the existing downstream structures located within the public streets that may be impacted by site runoff, additional•silt fence locations should be added to the plans to adequately protect erosion concerns onto the public streets, and the rock construction entrance should be relocated to Civic Center Drive. The following erosion control notes should be added or amended on the plan set, or included in the SWPPP: • Any impacts to City streets (wet tap and curb cut locations) should be brought to grade with class 5 by the end of the work day and paved within 24 hours. • The contractor should have a sweeper on site or available within 3 hours. All material tracked onto City streets must be removed immediately upon discovery, or as directed by the City . Engineer. • Installation of silt fence and other down gradient sediment protection measures shall be completed and inspected prior to commencement of any site activities. A detail sheet must be added to the -plan set and include all infrastructure proposed; including but not limited to manholes, catch basins, gate valves, hydrants, curb, paving sections, pipe installation, etc. Current City details for all improvements proposed within the right-of-way must also be included. 53