Agenda Packets - 1998/04/06 - Laserfiche WebLink

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Storm Drainage • The originally proposed storm wa 96 drainage system for the reconstruction of Highway g Y g y included a regional storm water pond to be constructed adjacent to the northwest shore of Round Lake. This concept would require trunk sewer along Highway 96 from approximately Keithson Drive to the proposed ponding site. The conceptual storm drainage plan works for Layout#1, the at- grade intersection,however significant modifications to the concept plan may need to be made to accommodate the proposed bridge in Layouts#2, #3 and#4. In the bridge alternatives, Highway 96 is lowered significantly creating a relatively flat profile grade which in turn causes difficulties in conveying large volumes of storm water over long distances. In addition, an existing 60 inch diameter storm sewer outfall from the TCAAP site crosses Highway 96 just west of the proposed bridge and drains into Round Lake. The original plan allowed for clearance of the Highway 96 storm sewer over the TCAAP outfall line, however with the lower profile of Highway 96 required for the bridge crossing, the two storm sewers intersect each other. For these reasons, it is likely that a regional storm water pond (for Highway 96 drainage) will need to be constructed in the vicinity of the Highway 10 and Highway 96 interchange in layouts #2, #3 and#4. The preferred location of the pond would be in the southwest or southeast quadrant of the interchange however other quadrants may be feasible as well. The pond would require approximately 0.5 to 0.75 acres of land depending on adjacent slopes. • Ramp Metering/HOV Based upon discussions with Bob Brown of MnDOT State Aid, it is unlikely that the north access ramps for the Highway 96/Highway 10 interchange would be required to be metered or include HOV facilities. These ramps would be considered "temporary"in that upon redevelopment of the TCAAP site, a new interchange at Gateway Boulevard would be constructed and the north ramps removed from Highway 96. If ramps were built to the south, they would be viewed as permanent facilities and likely would be considered for metering and or HOV provisions by MnDOT. TCAAP Property Acquisition We anticipate that the process to acquire property from the federally owned TCAAP site will require over two years. Mike Fix from TCAAP has been shown preliminary drawings of the proposed access ramp in the northeast quadrant of the intersection. Mr. Fix stated that he had no objection with the alignment and taking of property but warned that it may be difficult to acquire the necessary area in time to construct the roadway in 1999 or 2000. If the council decides to proceed with layout#2 or layout#3, immediate coordination with the U.S. Army will be necessary to begin the process of acquisition. A possible alternative to impacting the TCAAP property would be to construct a loop in the southeast quadrant of the • 14