CCP 05-27-1997 - Laserfiche WebLink

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I I . . 'The stQnn water detention requirements for the public right"of-way drainage areas were based .. upon the 100-year, 5-inch rainfall; while RCWD water quality requirements are based upon a I 2.5-inch rainfall. These storm designs result in approximately 1.72 acre-feet of storage required for water quality purposes and 3.44 acre-feet of storage for rate control. A total pond volume of ,I approximately 3.5 acre-feet could be accommodated within the I-acre area presented on Exhibit 7. A more cost-effective alternate for the City of Arden Hills would be to accommodate all, or a I portion of, the storm runoff from the roadways within the individual site ponding requirements. According to the District's storm drainage requirements, individual parcels must provide adequate I storm water detention volume to meet both storm water quality and rate control requirements. Proposed additional volume available within these sites could feasibly reduce the City's overall I requirements for the 3.5 acre-feet of storage. Project costs associated with the recommended storm drainage requirements are estimated at I $474,000, as presented in the cost section of this report. The cost could be reduced by up to $85,000 through the consolidation of storm water treatment/storage areas within individual I parcels, thereby reducing the City's pending requirements and pipe sizes necessary to carry higher flows. Ie Commercial Roadwl\Ys I It has been proposed by City staff to provide an enhanced entry into the Gateway Business District I with some form of upgraded roadwayand/or "boulevard" style design. As a result of those concepts, this section of the report outlines two alternates for the roadway design. As presented I on Exhibit 8, it is proposed to construct the segment of West Round Lake Road from Highway 96 to 13th Street NE as a Municipal State Aid Street, possibly utilizing MSAS funds. The proposed roadway along the Minnesota Transfer rail spur would be constructed as a typical I commercial street, designed in accordance with Arden Hills design standards. I Traffic counts were obtained at the north end of West Round Lake Road during the first week of May, 1997. The two-day, 24-hour counts resulted in average daily traffic (ADT) volumes of I 2,400 vehicles per day, and showed a large volume of high capacity trips as well. Additionally, the traffic generation volumes presented by the developer have been used to project the ultimate I development's trip generation for use in the [mal pavement design. Those projected volumes for Phases I through IV are in the range of 5,000 to 5,200 vehicles per day. With existing volumes Ie of 2,400, and the potential for in excess of 4,000 vehicles per day generated south of the rail spur, an ultimate development ADT in excess of 11,500 vehicles per day could be expected in this area. I Using MnDOT's guidelines for MSAS road design, West Round Lake Road would be classified FEAS-520.089 -7- 520-089-10