STATE ENVIRONMENTAL POLICY ACT (SEPA) DETERMINATION OF SIGNIFICANCE (DS) AND REQUEST FOR COMMENTS ON SCOPE OF ENVIRONMENTAL IMPACT STATEMENT (EIS) Proposal: Electron Hydro LLC Lead Agency/Proponent: Pierce County Planning and Public Works Date of Issuance: August 3, 2026 Application Number: 1010260 Agency Contact: Tony Kantas, Senior Planner, 2401 S 35th Street, Tacoma, WA 98409, (253) 798-2789 /tony.kantas@piercecountywa.gov Applicant: Electron Hydro, LLC Attn: Thom Fischer, 1800 James Street, Suite 201, Bellingham, WA 98225, thom@electronhydro.com Location of Proposal: 30020 Lookout Road East, within Section 3, T 16N, R 6E, W.M., in Council District #3. Within the Puyallup River High Intensity and Conservancy shoreline environments designations, and within Rural 20 and Designated Forestland zoning designations. Tax Parcel Number(s): 0616032001, 0617343000, 0617331003. Description of Proposal: The project proposes improvements to an existing 26-megawatt hydropower facility located within the shoreline jurisdiction of the Puyallup River. The proposal includes construction of a bladder diversion and spillway system, as well as a fish and sediment exclusion facility, as described in the revised SEPA Checklist dated September 2, 2025, and the accompanying application materials. The proposal also includes a request for after-the-fact approval of a sediment basin/habitat pond and a concrete stairway that were constructed without the required permits. The subject application was submitted in response to the revocation of a Shoreline Substantial Development Permit (Application No. 858766) previously issued by Pierce County. The revoked permit addressed only certain components of the current proposal and did not include a fish exclusion facility designed to prevent fish from entering the hydropower facility flume. The original application that was subsequently revoked generated no comments expressing concern. In contrast, the current application has received significant comments from agencies indicating that the proposal may result in significant adverse environmental impacts, including potential unique or uncertain impacts, consistent with WAC 197-11-330(3)(e)(iv). EIS Required. The lead agency has determined that this proposal is likely to have significant adverse impacts, including unique or unknown impacts, on the environment (WAC 197-11-330(3)(e)(iv)). Accordingly, an Environmental Impact Statement (EIS) is required pursuant to RCW 43.21C.030(2)(c) and will be prepared. The environmental checklist, along with comments submitted by the Washington State Department of Fish and Wildlife and the Puyallup Tribe of Indians identifying probable significant environmental impacts associated with the proposal, may be reviewed online at the Pierce County website. These impacts include potential significant adverse impacts on river temperature, sediment management, upstream and downstream fish migration, fish mortality, and water quality. The specific comments received indicating the subject proposal may have a probable significant environmental impact are as follows: • Comment letter from Puyallup Tribe of Indians and attachments, dated February 3, 2026. • Comment letter from State of Washington Department of Fish and Wildlife, dated February 6, 2026. • Comment letter from State of Washington Department of Fish and Wildlife, dated May 29, 2026. • Comment email from Washington State Department of Ecology, dated June 8, 2026 • Comment letter from SWCA Environmental Consultants, dated June 26, 2026 1. The lead agency has preliminary identified the following areas for discussion in the EIS (WAC 197-11-444): • Surface water movement/quantity/quality • Habitat for and numbers of diversity of plants, fish, or wildlife • Fish or wildlife migration routes • Public water supplies • Releases or potential releases to the environment affecting public health, such as toxic or hazardous materials • Historic and cultural preservation, including treaties, tribal rights, interests, and resources. • Built environment • Maintenance • Erosion 2. The lead agency has preliminary identified the following alternatives for discussion in the EIS: • Proposed Action: As described in the revised submitted SEPA Environmental Checklist, dated September 2, 2025, and supporting application material. • Alternative 1: An alternative approach to producing energy without probable significant environmental impacts. • No action alternative: Do not install the diversion bladder system or implement the associated bladder system improvements outlined in the proposed project description and maintain an open river system as required by the Federal Courts, until all local, state and federal permits are obtained. Scoping. Agencies, affected Tribes, and members of the public are invited to comment on the scope of the EIS. You may comment on alternatives, mitigation measures, probable significant adverse impacts, and licenses or other approvals that may be required. The method and deadline for providing your comments is August 24, 2026. Comments can be provided as follows: By email to: Tony Kantas at tony.kantas@piercecountywa.gov/ In writing to: Tony Kantas, Planning & Public Works, 2401 S 35th Street, Tacoma WA 98409. Issue Date August 3, 2026 / Comment Deadline: August 24, 2026 IPL0363330 Aug 5 2026