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K:\020552-000\Admin\Docs\3. Phase 4_Cost Estimating\Hugo North Start Cost Estimating 052223.docx 178 E 9TH STREET | SUITE 200 | SAINT PAUL, MN | 55101 | 651.286.8450 | WSBENG.COM Memorandum To: Shayla Denaway, City of Hugo From: Roxy Robertson, WSB Cc: Tony Havranek Mark Erichson Date: May 22, 2023 Re: North Star Wetland Bank Development Cost Estimate WSB Project No. 020552-000 Introduction The City of Hugo is interested in creating a wetland bank along the west side of Hwy 61 at the North Star Elementary School. The wetland banking process generally consists of the following application steps prior to approval from regulating agencies (Board of Water and Soil Resources (BWSR), Wetland Conservation Act (WCA), and Army Corps of Engineers (USACE)). 1. Draft Prospectus (Scoping Document) 2. Prospectus (Concept Plan) 3. Draft Mitigation Banking Instrument (MBI)/Final MBI (Full Application) Initial assessment phases of this project resulted in the completion of the existing vegetation surveys, 2022 hydrology monitoring, a draft prospectus application, and coordination with the Technical Evaluation Panel (TEP) and interagency review team (IRT). The draft prospectus included a proposal to restore approximately 19 acres of wetland, rehabilitate approximately 98 acres of wetland, and provide approximately 5 acres of upland buffer for a total wetland bank area of 123 acres with a credit potential of around 70 credits. We removed the acres in the northwest corner of the parcel to avoid the need for two conservation easements. At this point, the city may move onto the Prospectus step of the application process for the wetland bank bu t has requested that WSB evaluate the proposed costs for development and construction of the wetland bank to determine cost and benefits of the project. Wetland Bank Concept WSB developed two concepts in the draft prospectus that utilize slightly different construction methods to restore hydrology. 1. Option 1 Wetland hydrology would be restored by construction of 2-3 ditch plugs in the western and central north-south lateral ditches. Ditch plugs consist of clay core trenches compacted with construction-grade clay topped with topsoil and vegetation. Ditch plugs are keyed into the banks to prevent water from moving around them at high flows. One ditch plug would be constructed at the intersection of the eastern lateral ditch and the east-west main ditch channel. Two to three plugs would also be constructed in the southern ditch. An outlet control structure (OCS) with a set elevation would be installed at the southwestern edge of the parcel where the ditch connects to JD 3.