11/07/94 - Laserfiche WebLink

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C~se SUNWOOD DRIVE N.W. By: City Engineer Steven Jankowski Background: On October 5, 1994, Ryan Schroeder, Pete Raatikka, who is preparing the alignment for Sunwood Drive N.W., and I met with DNR officials in St. Paul to discuss two environmentally sensitive areas for the proposed roadway. As you will recall, the proposed right-of-way crosses Wetland gl 14P, just westiof the Wood Pond Hills subdivision, and Wetland #673W, just west of Sunfish Lake Boulevard~N.W. Both of these wetland crossings are unavoidable. We had proposed crossing both of~ these wetlands with an 84-inch arch pipe along the edge of each side of the wetland and two~r ten-foot by six-foot box culverts located in the middle of the wetland. We were told by DNR repl'esentatives that this crossing proposal was unacceptable and suggested that we propose some altgrnative crossing configurations of these two wetlands. Attached are two possible alternatives to the original crossing configuration for these environmentally isensitive areas. The attached sketches illustrate these alternatives. The general alignment of Su~wood Drive N.W. is illustrated on the enclosed sketch entitled "Sunwood Drive Alternate Alignment". The environmentally sensitive areas for Wetlands #114P and #673W are located in the area described at Detail A and B respectively. Alternative gl: This alternative is illustrated by Figures A- 1 and B- 1 and is the original proposal submitted to DNR for crossing the ~environmentally sensitive areas. We have been advised that this proposal is unacceptable. It has been included to provide a baseline to compare the subsequent alternatives. Alternative #2: /- This alternative is illustrated by Figure A-2 and B-2 and consists of filling halfway across each of these wetlands an~ bridging the remaining half. It offers a less costly compromise to a full bridge across each of these wetlands which we have assumed would be acceptable to DNR. Wetland replacement would still be proposed to compensate the area of the wetland filled. This alternative retains the same horizontal alignment as alternative gl. This alignment was considered the best from the standpoint of engineering and safety. Alternative #3: This alternative ii; illustrated by figures A-2 and B-3. The half bridge concept is retained for the Wetland gl 14P.. However, the alignment of the roadway crossing Wetland #673W has been relocated approximately 150 feet to the north to avoid bisecting this relatively small protected wetland into twolequal halves. The Wetland #673W crossing would consist of fill with a single equalizer culvert.~- DNR reviewers felt this alignment would have a smaller impact on the wetland. This alignment dOes create undesirable impacts on the horizontal roadway alignments. It creates a reverse curve neat the intersection with Sunfish and a skewed angle at the intersection of Sunwood and Sunfish. #/