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October 29, 1993 John Peterson Page 2 of 3 It was noted by Commissioner Deemer at the October, 1993 Planning and Zoning Commission meeting that an existing wood bridge currently spans the I7 foot wide ditch at a location approximately 80 feet south of the common lot line between Lots 5 and 6. Commissioner Deemer suggested that it would be possible for Krypton Street to be extended as a through street by bridging the ditch at this location. In reviewing the Developer's proposed grading plan, I have concluded that bridging County Ditch 43 is possible. The advantages associated with platting Krypton Street N.W. as a through street would include the elimination of the cut-de-sac, which is in excess of our maximum allowable length. A second advantage would be that sufficient area would appear to be available for an additional lot. The primary disadvantage associated with the through street would be primarily the increased cost for constructing the required bridge. Assuming that it would be the position of the Minnesota Department of Natural Resources (DNR) that there be no reduction in the width of the existing channel, a box-culvert type bridge, spanning a length of 20 feet could cost in the neighborhood of $100,000 to construct. This element of the improvements alone would add $7,700 per lot to the cost of the subdivision improvements. This would approximately double the per-lot cost of improvements on an average sewered and watered lot in the City of Ramsey. In addition, the City would be responsible for maintaining, and eventually, replacing this box culvert bridge at the end of its useful life. Finally, this bridge would require a permitting process with the DNR which would add rime and expense to the platting process. It should be noted that the above discussion of costs associated with bridging the ditch are highly dependent upon the type of structure ultimately allowed by the DNR. For example, ff the DNR were agreeable to a large diameter concrete culvert, the above costs would be significantly reduced. I will attempt to solicit additional input from DNR regarding this issue prior to the meeting. Wetlands: DNR Wetland #114-P is located on the property. The ordinary high water level (OHW) in indicated to be 858.1 feet Any work which changes the course, current or cross section of this wetland will require a DNR Protected Waters Permit. This project should be reviewed by the Lower Rum River Water Management Organization (LRRWMO) for compliance with their standards. Grading and Drainage: The chief grading concern will be the protection of the surrounding wetland from erosion and sedimentation resulting from the development. Silt fence has been specqfied for selected areas. The LRRWMO will address the adequacy of the proposed erosion control. The grading plan, as proposed by the Developer, would have all nm-off conveyed to the northeast, down Krypton Street N.W., where it would be collected by catch basins and transmitted to an existing sedimentation pond constructed in the Wood Pond I-lills subdivision. The overflow from this sedimentation pond flows into Protected Wetland 114-P. If Krypton Street N.W. was constructed as a through street, the proposed storm sewer would probably not be required, as the existing catch basin on the terminus of Krypton Street N.W. would likely be adequate to handle a small amount of additional pavement that would drain to it. However, additional catch basins and sextimentation ponds would need to be constructed near the ditch crossing.