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®OUP <br />VXIN1 RAMWmria6ruNNros <br />June 1, 1989 <br />City of Mounds View <br />2401 Highway 10 <br />Mounds View, MN 55112 <br />Attn: Mari Saa='_on <br />Dear Mary: <br />222 EASIL177LE SANAVA ROAD, ST PAUL MINNESOTA 55117 612 48A.0272 <br />RE: MDUNOS VTF.W MINMEcnMh <br />SILVER VIEW PARK TRAIL CULVERT <br />SEH FILE NO: 87154 <br />We have completed our preliminary design and cost estimates for <br />the two alternative culverts you, Ric Minetor, and I discussed on <br />May 23. The :wo alternative culverts are briefly described as <br />follows: <br />48" corrugated metal pipe - 60 feet plus aprons <br />This option will result in a 5 year design flood level of <br />900.7. The berm/trail across the culvert would need to be <br />constructed to a 902 elevation to allow for some freeboard. <br />A 100 year storm would need to overflow the berm through a <br />notch at elevation 801.0. The material necessary to <br />construct the 9' high berm is available upstream in the <br />drainageway. Placing this fill impacts the cost. We <br />estimate the installed cost of the culvert and berm <br />materials and installation to be $6,500. <br />Corrugated Metal Box Culvert, 9'8" wide by 2'7" high <br />This alternative suggested by Ric appears to be highly <br />3esirable. The 5 year storm is easily passed within the <br />structure, if constructed at a grade of 1.25$, while the 100 <br />year storm only needs a grade of 3.5%. This alternative <br />would not require an overflow of the berm for the 100 year <br />storm. The resulting berm height is 899. The length,of the <br />structure necessary would be 40 feet, with no formal aprons. <br />It would then have the appearance of a small bridge. We <br />estimate that innte1ta41n ni this at' ctu will generate <br />its own fill for cover over the top. Therefore, the <br />installation price of the structure itself is the only cost <br />factor. We estimate the insta. led cost of this structure to <br />be S13,000. <br />