Agenda - Planning Commission - 02/07/1995

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in the sou[hern portion of the plat has been delineated. It appears that construction of Cobalt (c ,u~rently shown as 150th) will require placement of the pavement ali on one side of the right-~-way in the vicinity of the wetland to avoid construction in the wetland. After avoiding ~at portion of wetland, it appears that the pavement can then swing to the center of the righ.~ of wa,y_ again to avoid removal of trees along the front property line of Lot 12, Block 3, (3orham s Sandy Acres. Barium S~eet exceeds the 600 foot maximum length for dead-end streets; however, this is to be consi]:lered a temporary situation until the property to the north develops. The east/~ 'est street, which will be 149th, has been proposed with an outlet onto Hwy. #47. In ar cordance with comments from Mn/DOT, the closing of of the access north of 152nd on he west side of Hwy. #47 will be pursued in conjunction with the new outlet onto Hwy. #47 as a result of the development of Willow Ridge. It is Staffs understanding that the de, teloper has applied to Mn/DOT for a right of access permit. Also in accordance with prelin tinary comments from Mn/DOT, the developer is proposing to dedicate 50 feet of right-of, way from the centerline of Hwy. #47. Drainage: ~ drainage and grading plan dated January 17, 1995 has been prepared by Ross Abel P.E. iAn area of 4.2 acres located on the northeast portion of the site drains to a proposed Wet pond which would be created in a natural low area on the northeast comer of the site. T~is area would have an overflow which would discharge to a landlocked natural pond imm~ately adjacent to the eastern boundary of the site. The drainage plan should be amended t5 include a high water overflow from this natural pond into a sedimentation basin located on the southeast corner of the site which would in turn overflow into DNR Protected Wetland 659. Wetland 659 has an outlet which begins discharging when its water level}reaches its ordinary high water (OHW) designation into a storm sewer in 149th Avenue wl~,'ch discharges into the Rum River. A 2.3 acre area which drains Cobalt Street south of B~arium Street drains into the man-made sedimentation basin and then to the wetland syltem described above. The remaining 6.7 acres on the northwest portion of the s~te drmnsifrom a storm sewer system constructed in Barium Street to a man-made sedimentation/detention pond located on the northwestern comer of Wetland 659 and then into the abOve-mentioned wetland system. Calculations should be submitted to predict what the inCreased bounce from a 10-year and 100-year storm would have on Wetland 659. Utilities: ~i'he developer is proposing to install the public improvements (streets, storm sewer, sew6r and water) with no f'mancial participation on the part of the City. Sanitary seker shall be extended throughout the plat. A 12-inch interceptor main shah be continued along Barium Street. All other sanitary sewer mains shall be eight inches. Water service shall be extended to the site by extending a 12-inch watermain from where it currently tei'minates on 149th Lane N.W. 1200 feet east of T.H. #47 to the intersection of Barium an~T.H. #47 and then looping this main south along the east side of T.H. #47 into Amber Ridge. The cost of this looping will be credited to the d. eveloper's trunk utilities assessment~. Water service within the subdivision streets shall be- 8-inch mains.