PC PACKET 120822 - Laserfiche WebLink

Home

Ms. Rachel Juba December 1, 2022 Page 3 Wetlands The Oneka Prairie development requires wetland impact replacement approval to move forward. Based on a Technical Evaluation Panel meeting held on 11/21/22 to review proposed impacts, we anticipate approving wetland impact replacement and boundary and types for Oneka Parkway, but need the applicant to address technical comments provided below. 17. A revised wetland replacement plan has not been provided that accurately reflects the amount of impact for the development nor the construction of Oneka Parkway. 18. The wetland boundaries and types have been approved for the area within the confines of parcel 0703121420001, and a MN Joint Application requesting approval for sequencing/sequencing flexibility and wetland replacement using bank credits for impacts due to the development itself has been noticed (10/27/22)with a 60 day deadline of 12/27/22. 19. A series of wetland impact exhibits have been submitted by the applicant's team. A figure dated 11-18-22 was submitted on 11-18-22 by Anderson with the correct wetland boundaries drawn. This exhibit was distributed to the Technical Evaluation Panel (TEP) and used for the TEP meeting held on 11/21/22. The most current wetland impact exhibit is dated 11-29-22 and was used for this review. 20. A revised wetland replacement plan identifying all impacts as discussed at the 11/21/22 TEP meeting needs to be submitted in a timely fashion to allow for review; no submittal has been received to date. The 11/29/22 wetland impact exhibit does not include impacts for rip-rap and grading within wetland D/E, outlot A in the northwest corner. 21. A determination needs to be made in regard to the use of retaining walls near wetlands. The TEP indicated that it would be OK to not use retaining walls to prevent additional wetland impact due to the quality of the wetlands. The TEP is requesting a table that shows the amount of impact with and without retaining walls to see the difference it would make. 22. The wetlands on site are most likely a combination of surface water and groundwater fed. Proposed grading and development will alter surface hydrology which may result in regulated impacts to on site wetlands. The TEP would like to see a figure showing existing hydrology (surface flow), the size of existing and proposed watersheds (catchments), and the volume of hydrology routed to wetlands under existing and proposed conditions. 23. Stormwater ponds adjacent to wetlands need to be lined to ensure no horizontal flow from the wetland to the pond resulting in wetland drainage. 24. Initial modeling shows a reduction in the hydrology elevation in some wetlands. This would be considered and impact and would need to be mitigated for. Adding this additional impact may put the amount of wetland impact for the development over the 0.5 acre threshold for the US Army Corps. 25. All stormwater/point hydrology needs to have pretreatment(quality not volume) prior to discharging to any wetland. FES 108 and 309 appear to direct untreated stormwater to wetland D/E. 26. All inverts need to be above the defined wetland boundary elevations so as not to cause drainage of the wetlands. S:\Users\R_Juba\DEVELOPMENT PROJECTS\Oneka Prairie\Preliminary Plat\Engineers Memo and Red-lined Comments\LTR-rjuba-Oneka Prairie Preliminary Plat- 120122.docx