Agenda - Planning Commission - 04/01/2004

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Alpine ~?oods ?reliminary .Plat Review March 2d, 2004 2of4 removal limits. This plan must be amended to identify trees to be removed and to remain on the plat as well as their species. Wetlands: A substantial portion of the property is wetland. A wetland delineation report has been submitted; staff will be prepared to comment on this report at the Planning Commission meeting. TNs report will also need to be submitted to the Lower Rum Privet Water Management Organization for verification. Drainage: A drainage and grading plan has been prepared by Mark K, retchrner PE of Passe Engineering. Th/s plan proposes to construct two ponds located on the north and south ends of the development. All street surfaces, except for the southerly 200 feet of Vanadium Street (the north/south street), and the furore residential structures on the east Side of Vanadium Street will drain to these ponds prior to overflowing into DNP,, protected wetland 734W. A review of tltis grading and drainage plan has been made and the following comments are offered: 1. Calculations have been submitted sho~ving the 10-year and 100-year event for sediment ponds A and B. However no information is presented for wetland 734 which is riparian to ten of the subdivision lots. The 100-year flood elevation needs to be established for this wetland and the lowest floor structure elevations must be a rain/mum of one foot above this elevation. Staff is also recommending that the house pads be located at least 2 vertical feet above the edge of the delineated wet[and. 2. Four existing residences are proposed to remain within the new subdivision. Existing iow floor and at ~ade elevations should be added for these structures to the Fading plan. 3. Proposed front comer elevations should be added to allow verification of adequate overland drainage from individual [ors. In particular, Lots 6 & 7 of Block 4 should be evaluated to insure that a mirfimum g-fade of one percent exists over ali tufted areas. 4. A table specifying house type, garage elevation, minimum floor and abrade elevations, 100-year flood elevations and front and backyard slopes must be added to the grading plan. 5. The southernmost 200 feet of Vanadium Street drains onto 153rd Lane and westward to its intersection with Xenon Street. TNs is a low point where water remains in the ditch until it percolates into the.sandy soil. In view of th_is situation, a catch bas/n should be added at the intersection of Vanadium and 15? Lane to collect the runoff from the south 200 feet of Vanadium Street as well as the portion of I57 Lane to mitigate this situation. 6. A permit must be obtained from the Lower Rum River Water Maintenance Orgarfization to insure the adequacy of the storm water system and erosion control measures. Streets: The street system for this development has been detailed on a three-sheet set of plans. Staff offers the tbllowing comments: 1. Street names must be added to the preliminary and final plat documents. Staff suggests the following names to be consistent with the Anoka County grid system: Vanadium Street NW; Uranium Street NW; 154~h Circle or Court NW; and 155~h Lane NW. 2. Sidewalks are required on one side of every through street. No sidewalks have been proposed on the plan submitted. 3. The typical section of the street cross section should be modified to show a street width of 31 feet from back of curb to back of curb. 32