2019-12-09-minutes-public-works-study-session

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V**//CENTURY FWEST E N G I N E E R I N G p- E' S 4 • KIrrITAs COUNTY— State Environmental Policy Act (SEPA) Checklist. It was anticipated that the County would issue a Determination of Non -Significance (DNS) or Mitigated DNS. • WASHINGTON DEPARTMENT OFFISH AND WILDLIFE —Hydra u I ic Project Approval. 3. WHAT HAS CHANGED/ISSUES WITH THE CURRENT SCOPE OF SERVICES Since the current scope of services was approved, two unanticipated issues have come up. 3.1. WETLAND IMPACTS Issue: Initial wetland delineations and preliminary design of the proposed improvements identified a larger wetland impact than originally anticipated based upon NWI maps, triggering a Section 404 Individual Permit rather than a Nationwide Permit. The threshold for wetland impacts to be covered by the Section 404 Nationwide Permit applicable to this project is 0.5 acres. The Draft Wetland Delineation Report, conducted under the original scope of work, identified 37 separate wetlands within the direct study area. Preliminary design of the proposed improvements identified over 8 acres of wetland impacts and over 13 acres of wetland buffer impacts. As such, our regulatory permit lead from the Corps of Engineers Seattle Regulatory District has confirmed that the project will need to obtain a Section 404 Individual Permit, which will require a greater level of both design and justification to ensure that impacts can be more accurately calculated, reported, and mitigated. Further, the permit application will require an alternatives analysis under Section 404(1)(b) which demonstrates that different alternative project designs were considered that avoid and minimize impacts to aquatic resources to the greatest degree possible. In addition, the Washington Department of Ecology (Ecology) will require an Individual Section 401, Water Quality Certification. Wetland mitigation is now anticipated to be larger in scale and would require identification of suitable off-site mitigation alternatives, for at least a portion of the mitigation. Identification of suitable off-site mitigation areas would need long lead-times due to property availability and negotiation of conservation easements. As a result, the project schedule is critically tied to the processing of the Section 404 Individual Permit; therefore, addressing wetland impacts and mitigation strategies is the critical path as the airfield project environmental assessment progresses. As such, the 25 percent design level provided for in the current scope is not sufficient based on the current project needs. Additional effort is needed to more accurately determine items such as: • Project design alternatives that mitigate flood issues, and minimize impacts to aquatic resources; • Documentation of where wetland fill has been avoided and minimized to the degree feasible; • Cut and fill quantities, locations of impact, and sources, including drainage improvements associated with flood mitigations; • Development of wetland impact overview plans and sections; • Identification and feasibility of off-site wetland mitigation areas within the same watershed; • Site assessment and wetland delineations for selected off-site mitigation area; • Cultural resources assessment of off-site wetland mitigation area; • Development of a wetland mitigation report and conceptual plan; Bowers Field Airport Environmental Assessment Page 3 Advanced Design Needs for NEPA Analysis November 27, 2019