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, G!een C, ompany <br /> <br />April 15, 2004 <br />File: 812622 J-0240 <br /> <br />Mr. Scott Harlicker <br />Senior Planner <br />City of Elk River <br />13065 Orono Parkway <br />Elk River, MN 55330 <br /> <br />RE: PULLMAN PLACE <br /> <br />Dear Mr. Harlicker: <br /> <br />As you are aware we have had a number of meetings with the developer and their representatives <br />regarding Pullman Place project. We have come to resolution on all of the issues relative to site <br />plan development, hydrant placement, and firefighting needs. However at this point we have not <br />received revised plans showing any of the issues we have discussed and resolved in plan form. <br /> <br />We have received revised drainage calculations from John Oliver and Associates and have <br />completed a review on them. At this point the drainage calculations are not approvable because of <br />a number of issues still unresolved. These issues are as follows: <br /> <br />· The grading plan shows a storm sewer entering the northeast detention pond with an invert <br /> of 886.0. The storm sewer intake located immediately upstream from the pond shows two <br /> inverts, 887.6 and 883.4. The lower invert is 2.6 feet lower then the pond inlet. This <br /> difference in structure elevations needs to be resolved. <br />· The normal Water level (NWL) of the 883 for the pond should provide an average water <br /> depth for the pond of three feet. This requires that the cumulative storage volume of the <br /> dead storage provided by the surface area of the NWL contour should show an average <br /> depth of three to eight feet. <br />· The high water level (HWL) for the ponds do not match. The pond is modeled as one pond <br /> which is correct since there is an equalization pipe between the two ponds. This means that <br /> the pond HWL's should be relatively close. <br />· The flared end section discharging into the pond in the southwest corner of the property is <br /> shown to have an invert of 883.0. This does not match the contours of the pond where the <br /> flared end section is shown. <br />· The southeast pond outlet is proposed to tie into the existing intake at an invert elevation of <br /> 882.8. The Elk River Station plans show this intake to have an invert of 883.21. This is 0.41 <br /> feet higher of the proposed connection elevation. It is also 0.21 feet higher then the pond <br /> outlet elevation. This discrepancy needs to be resolved. <br /> <br />Ltr -041504-Halicker <br /> <br /> <br />