7.6. A. & B. SR 06-06-2005 - Laserfiche WebLink

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3 calculations will be in compliance with city qodes. The storm sewer system will be designed to provide lateral connections for site development of each lot to pick up storm water runoff internally. The proposed street design includes a low point near the common lot line between lots 7 and 8. The conceptual drainage design will provide for an overland overflow route between lots 7 and 8. A drainage easement will be place on this overflow route to provide for the 100 year rainfall event. The proposed storm sewer improvements are shown as Exhibit 5. General Sitework Mass site grading will bring the street to subgrade elevation and wil establish basic drainage patterns on the individual lots. As lots develop, site specific grading plans will need to be prepared to establish site drainage patterns. Due to the existing overhead power line and the grade along the north line, a retaining wall will need to be constructed along the north lot line of Lot 1. Wetlands The wetlands on the site were delineated during the development of Twin Lakes Road. The majority of the existing wetlands surrounds a drainage ditch that conveys drainage from Klievers Marsh through the site. Additionally on Lot 1 there is a wetland along the remnants of a drainage ditch that flowed from the Elk River Business Park into the main drainage ditch. The remnant drainage ditch on Lot 1 no longer conveys drainage and splits Lot 1 into two pieces. The area on Lot 1 west of the remnant ditch is not accessible from the north, west or south sides. The only feasible access to the western portion of Lot 1 is across the remnant ditch and because of this limited access it is necessary to fill this wetland in order to make reasonable use of the property. A Technical Evaluation Panel (TEP) review of this proposal will be necessary. The proposed wetland fill is shown on Exhibit 6. VI. PHASING The Northstar Business Park can be developed in multiple phases. The first phase would begin at the intersection of 175th Avenue and Twin Lakes Road. For purposes of discussion it is assumed that phase one would consist of approximately 750 feet of street and utilities, this would allow for the development of three proposed lots: 5, 6 & 7 and possibly Lot 4. A fire hydrant should be added at the phase break to allow for flushing since the watermain loop would not be complete. A temporary storm water pond could be constructed on proposed lot 8 to receive the storm water from the first phase, until future phases are completed. The temporary pond would discharge into the existing drainage ditch which flows to the expanded regional storm water pond. A temporary cul-de-sac would be installed to provide a vehicle turn around. Sanitary sewer is not affected by phasing, as it flows to the intersection of 17Sh Avenue and Twin Lakes Road. Site grading of the entire site and expansion of the regional storm water pond should be done as part of the initial phase to minimize additional costs associated with phasing and balance the site earthwork quantities. The proposed phasing plan is shown on Exhibit 7. Phasing should reduce the initial investment by the City and will defer the cost associated with future phases.