Agenda - Council - 09/26/2006 - Laserfiche WebLink

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Site Plan Review: GMI Expansion August 31, 2006 Revised: September 22, 2006 Page 3 of 4 Drainage and Grading: A grading, drainage, erosion control, and utility plan has been prepared for this expansion by Charles W Plowe PE and dated August 7, 2006. In general the plan provides drainage from the expanded parking lot into a newly created detention pond which overflows into protected wetland 675 W which is located immediately northwest of the subject property. Staff offers the following comments on the plan: • The grading plan shows the roof drainage being discharged onto the north side of the building; however the architectural plan does not show any downspouts or scuppers on this the profile view of the building. Runoff from the existing building is being discharged to the east side of the building. A drainage swale has been proposed to convey roof drainage to the north and then to the west through a shallow drainage swale. Staff is requesting additional cross sections of this swale to ensure that it can meet the criteria of having a minimum 1 % slope and the side slopes are no steeper than one foot vertical to four feet horizontal. A shallow swale on the north side of the building may likely fill with snow and become ineffective from preventing the runoff from spilling . onto the adjacent property to the north. Staff recommends reconsideration of providing a storm sewer to handle this drainage. • It is recommended that a second catch basin be provided on the east side of the driveway to intercept runoff from the parking lot and to prevent it from flowing into the County highway ditch. If this catch basin is not added, verification that no storm water is reaching the County highway ditch should be verified before the release of the project surety. • A retaining wall is proposed between the two northernmost loading docks. A safety railing needs to be specified on the top of this wall. The normal and 100 year water elevations should be added to the plan to the wetland. • It is unclear were the discharge from the detention ponds flows. Arrows on the plan suggest that it runs over the trail. Contours need to be added to the plan between the detention pond discharge and the receiving wetland. A piped outlet might also be considered in lieu of the swale. • A permit for the Lower rum River Water Management Organization will be required for this expansion. Loading Docks: City Code requires one loading dock for the first 10,000 square feet of floor space and one loading dock for every additional 25,000 square feet of floor space. The proposed expansion shows 2 loading docks and 1 drive -in access. REU Number: This property is subject to a storm water utility charge. The increase in the amount of impervious area will increase this charge. The city will determine the amount of the increase upon review of the final construction plans. It should be noted that the creation of a detention pond on the site allows the property owner to apply for a credit toward this charge. The property owner may wish to apply to the City for consideration of this credit.