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Letter to SRF 03-30-2011March 30, 2011 Jeffrey Olson SRF Consulting Group, Inc. One Carlson Parkway, Suite 150 Minneapolis, MN 55447 -4443 RE: TEP Comments regarding WCA Replacement Plan Application for proposed T.H. 41Trail and Underpass Project Mr. Olson, After review of your application for wetland replacement as associated with the proposed T.H. 41 Trail and Underpass Project, the City of Chanhassen has the following comments: • Please supply a purchase agreement for the wetland credits signed by both parties. At a minimum, a resolution passed by the County Commissioners or County Park Board. • The purchase agreement for wetland credits states that the impacts and wetland bank to be drawn from are in different major watersheds. The Board of Water and Soil Resources shows a minimum of eight available wetland banks in the same major watershed. Please address the reason for not using these banks. • Wetland 5: This is a DNR Public Water. Please indicate the OHW relative to the fill being placed for trail construction. • Wetland 8: The proposed alignment goes directly through the center of the wetland. It is likely that this alignment will result in impacts beyond the immediate footprint of the trail. This should be reviewed and discussed. • Wetland 8: Do alternate alignments exist? Based upon the presentation at the public review process for the trail alignment, the original preferred alignment involved entering Lake Minnewashta Park north of the currently proposed alignment. This alignment into the park would not require any wetland impacts. Please discuss this alternative. • Wetland 22: Given that this wetland is a flow through seep, bisecting the wetland with a trail has a strong likelihood effecting hydrology and resulting in additional secondary impacts downstream. Impacts to this wetland should be avoided either through realignment of the trail or the use of a raised boardwalk. In addition, the following TEP members have submitted the comments listed below: Jack Gleason. Department of Natural Resources - I would like to reiterate that 'wetland 5' is DNR Public Water Wetland 10 -132W, and the Ordinary High Water Level (OHWL) of it is 995.8 ft. It appears as if the alignment and work required to construct the trail will not occur below the OHWL. A retaining wall is proposed immediately adjacent to this wetland. Please be advised that if the retaining wall or associated fill is placed at or below the OHWL, a DNR Public Waters Work permit may be required. State rules do not allow placement of fill in Public Waters. The DNR Commissioner can waive this prohibition if a road or trail is proposed by a government agency, and the prohibition would prevent or restrict the project or create a major conflict with other public purposes or interest and there is no other feasible or practical alternative to the project that would have less environmental impact and the public need for the project rules out the no -build alternative. The County would have to provide compelling supporting documentation justifying any such Public Water Work application. Regarding the trail along Lake Minnewashta, the trail may increase runoff volumes. We encourage the City to request storm water management BMPs, such as buffer strips, to help mitigate for the increase in impervious surface coverage in the shoreland area in order to protect water quality. Greg Graczyk, Carver SWCD Wetland 20: It seems very possible to shift the trail to the south to avoid impacts. We have at times taken into consideration the preservation of desirable trees as a valid sequencing discussion point. Further documentation of this should be noted. Wetland 22: If I remember correctly, this area was originally missed on the delineation and included after our TEP review of the site. It appeared at the time of the review that this is a seep type area. If I am thinking of the correct area, I have some concerns of the functions of this area post construction. In particular the downstream leg. Potentially some design details at this area may be helpful (subcut depth, base materials, compaction, etc. etc.) Wetland 8: The replacement plan should include some additional discussion as to why the use of Ches Mar Farm Road couldn't be used. There may have to be some filling off of the ditch off the road to get down to a more level grade but it appears the grade of the trail behind the houses (looking at contours) will put the trail above the designed maximum of 8.33 %. Once again it also appears that there may have to be a significant amount of desired tree removal to utilize this route. This is understandable but should be discussed. Ken Powell, BWSR • Per previous TEP review and City approval, the wetland boundaries are appropriate for review of the replacement plan. • Project purpose and need has been adequately identified. • The no -build alternative explanation in the application is short on details. I would expect some discussion of the "master plan" or other document(s) that this project is in conformance with. There is a vague reference to "plans ", but nothing specific is discussed. In addition to the no -build alternative, WCA rules require a discussion of a second wetland avoidance alternative (not just any alternative). This should be an alternative that avoids wetland impacts. While this may not be entirely possible, I suspect that with some major rerouting and redesign that there is an alternative that would impact at least very little wetland. I also suspect that such an alternative probably creates problems related to park use, safety, costs, etc. Such a discussion should be part of the application and part of the argument for the proposed plan. • The application does not discuss any specific wetland avoidance and minimization measures taken for areas where most of the impacts are proposed. For example, there is a fair amount of impact associated with Wetland 20 (Figure 4A). An obvious question would be why the trail cannot be shifted south to avoid or minimize wetland impact. For Wetland 8 (Figure 41)), there is no discussion of why the trail continues through the middle of the wetland rather than go to either side. I assume there are issues with existing homes, etc., but this needs to be explained. Also, how was the impact through this wetland minimized? Was a boardwalk or bridge considered? Were the side slopes steepened and how much? I support the use of wetland bank credits for the replacement, but I would note that technically the application is not complete unless it includes a signed (by both parties) purchase agreement or application for withdrawal. That provides the evidence for the commitment to use said wetland bank for replacement. The application in my copy is not signed by either party. Minnewashta Park north of the currently proposed alignment. This alignment into the park would not require any wetland impacts. Please discuss this alternative. Please respond to all comments and make any appropriate changes necessary to the application by April 15th, 2011. A decision will be made at the April 25, 2011 Chanhassen City Council Meeting and Public Hearing. If you have any questions or should require additional information please contact Terry Jeffery at 952.227.1168 or by E -mail: tjeffery0ci.chanhassen.mn.us Sincerely, CITY OF CHANHASSEN Terry Jeffery, Water Resources Coordinator