Determination of Nonsignificance
Total Page:16
File Type:pdf, Size:1020Kb
Department of Natural Resources and Parks Wastewater Treatment Division King County Community Services and Environmental Planning .201 S. Jackson St., MS KSC-NR-0505 Seattle, WA 981 04-3855 Phone 206-684-1 71 4 FAX 206- 684-1 278 DETERMINATION OF NONSIGNIFICANCE TITLE OF PROPOSAL: University Slough Wastewater Overflow Mitigation Project-Phase C DESCRIPTION OF PROPOSAL: The ICing County Wastewater Treatment Divisioil (WTD) proposes to complete the third phase of a three-phase project initiated in response to a May 2008 sewer spill into University Slough. During investigation of the sewer spill, WTD learned that during storm events combined storm water and sewage could enter a stream transfer pipe designed to carry Ravenna Creek flow to University Slough. WTD immediately implemented Phase A of the project, which consisted of inserting a plug into the Ravenna Creek stream transfer pipe when wet weather was expected. Phase A continued until mid-2010. Phase B, which took place during summer 2010, involved extending the Ravenna Creek stream transfer pipe and making other modifications to the stream transfer system to ensure that Ravenna Creek flow could travel coiitinuously through an isolated stream pipe to University Slough without risk of cross- contamination with sewage. This Determination of Nonsignificance (DNS) addresses Phase C of the project, which would consist of the installation of three large logs with root wads in University Slough as mitigation for Phases A and B of the project. Phase C would be constructed sometime between July and September of 201 1 and take approximately two weeks to complete. LOCATION OF PROPOSAL, INCLUDING STREET ADDRESS, IF ANY: The proposal is located in northeast Seattle at the University Slough drainage canal between NE 45th Street and NE Clark Road, just south of University Village Shopping Center. The site is located in Section 16, Township 25N, Range 4E. Responsible Official: Pam Elardo, P.E. PositionITitle: Division Director, King County Wastewater Treatment Division Address: Date: Proponent and Lead Agency: Resources and Parks Contact Person: Sue Meyer, Senior Enviroilmental Planner King County Wastewater Treatment Division 201 S. Jackson St., MS KSC-NR-0505 Seattle, WA 98 104; phone: 206-684-1 17 1 ; e-mail: [email protected] Issue Date: March 14, 201 1 The lead agency for this proposal has determined that it does not have a probable significant adverse impact on the environment. An environmental impact statement (EIS) is not required under RCW 43.2 1C.O30(2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. This information is available to the public on request. (XI This DNS is issued under WAC 197-1 1-340 (2); the lead agency will not act on this proposal for 14 days from the issue date. Comments must be submitted by March 28,2011. Submit comments to Wesley Sprague, Supervisor Community Services and Environmental Unit, Icing County Wastewater Treatment Division, 201 S. Jackson St., MS KSC-NR-0505, Seattle, WA 98104-3855. [XI The King County Wastewater Treatment Division has submitted a pennit application to the Washington State Department of Fish and Wildlife, thus there is no administrative appeal of this DNS pursuant to RCW 43.21C.075, WAC 197-1 1-680, KCC 20.44.120 and King County Public Rule 7-4-1. The rule may be viewed at http://wtvw.kinecountv.~ov/o~_e_~tiondpolicies/~leslutil~ut7411~r.as~~,or contact Sue Meyer at 206-684-1 171 or sue.meyer@,kingcounty.gov to obtain a copy. [Statutory authority: RCW 43.2 1C.110. 84-05-020 (Order DE 83-39), $197-1 1-970, filed 2110184, effective 4/4/84.] King County Department of Natural Resources and Parks Wastewater Treatment Division King Street Center, KSC-NR-0505 201 South Jackson Street Seattle, WA 98104 Environmental Checklist for the University Slough Wastewater Overflow Mitigation Project-Phase C March 1, 201 1 Prepared in compliance with the State Environmental Policy Act (SEPA) (RCW 43.21C), the SEPA Rules (WAC 197-1 I), and Chapter 20.44 King County Code, implementing SEPA in King County procedures. This information is available in accessible formats upon request at 206-684-1 280 (voice) or 71 1 (TTY). ENVIRONMENTAL CHECKLIST A. BACKGROUND 1. Name of proposed project, if applicable: University Slough Wastewater Overflow Mitigation Project-Phase C 2. Name of applicant: King County Wastewater Treatment Division (WTD) 3. Address and phone number of applicant and contact person: King County Wastewater Treatment Division 201 South Jackson Street, MS: KSC-NR-0505 Seattle, WA 981 04-3855 CONTACT: Sue Meyer, Water Quality Planner, Telephone: 206-684-1 171, Email: [email protected] 4. Date checklist prepared: March 1.201 1 5. Agency requesting checklist: King County Wastewater Treatment Division 6. Proposed timing or schedule (including phasing, if applicable): The proposed project is being constructed in three phases: Phase A was implemented in May 2008 and continued until mid-2010. A State Environmental Policy Act (SEPA) environmental checklist and determination of nonsignificance (DNS) were issued for Phase A in September 2008. Phase B of the project took place during Summer 201 0. A SEPA environmental checklist and DNS were issued for Phase B in March 201 0. Phase C of the project, which is the proposal described in this document, would be constructed sometime between July and September of 201 1 and take approximately two weeks to complete. The activities associated with each phase are generally described in Section A.ll. 7. Do you have any plans for future additions, expansions, or further activity related to or connected with this proposal? If yes, explain. SEPA Checlclist Uni\lel,.r.ity Slotigh Wastewater Overflow Mitigation P~,oject Yes. King County would continue to maintain the native plant buffer in and adjacent to the project area that was planted as mitigation for the 2008 wastewater overflow into University Slough. 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. Ravenna Creek Storm Drainage Project SEPA Environmental Checklist and Nonsignificance (DNS), December 1990 * Ravenna Diversion Structure Modification Project-Phase A SEPA Environmental Checklist and Determination of Nonsignificance (DNS), September 2008 Ravenna Creek Stream Transfer Pipe Extension Project-Phase B SEPA Environmental Checklist and Determination of Nonsignificance (DNS), March 1 I, 2010 Water quality sampling was performed by WTD in the Ravenna Creek system between December 2008 and July 2009 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. None known. 10. List any government approvals or permits that will be needed for your proposal, if known. The project would require a permit from the Army Corps of Engineers and a Hydraulic Project Approval from the Washington Department of Fish and Wildlife. 11. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. (Lead agencies may modify this form to include additional specific information on project description). In 2004, King County day-lighted a section of Ravenna Creek in the southeast comer of Ravenna Park. The County also redirected a portion of the creek flow that was conveyed by the combined sewer system to the West Point Treatment Plant in Magnolia to University Slough. During investigation of a May 2008 sewer spill into University Slough, WTD learned that during storm events combined storm water and sewage could enter the stream transfer pipe that was designed to carry the diverted Ravenna Creek flow to University Slough. The County responded to this incident with the three-phased project that is described in the following paragraphs. Phase A of the project was implemented immediately after the May 2008 sewer spill into University Slough. It consisted of inserting an inflatable plug into the Ravenna Creek stream transfer pipe (which carries Ravenna Creek flow to University Slough) when wet weather was expected. The purpose of Phase A was to prevent sewage and March 1, 201 1 Page 2 SEPA Checklist Unii~er-sitySlough kVastevvater Overflow Mitigation Project storm water from entering the stream transfer pipe during the time that a permanent solution to the problem was designed and constructed (Phase B). Phase B of the project took place during summer 201 0. It involved extending the Ravenna Creek stream transfer pipe and making other modifications to the stream transfer system to ensure that Ravenna Creek flow could travel continuously through an isolated stream pipe to University Slough without risk of cross-contamination with sewage. Phase C of the project is the proposal evaluated in this environmental checklist. It involves the installation of three large logs with root wads (called "large woody debris" or "LWD") in University Slough as mitigation for the temporary rerouting of Ravenna Creek flow to the combined sewer system instead of University Slough during Phases A and B of the project. Placement of LWD in the Slough would create fish habitat and promote biological diversity. The LWD would consist of three cedar or fir logs with root wads that would be placed in the Slough and its buffer as shown on the attached Site Plan. Each of the logs would be approximately 20 feet long and approximately 16 to 20 inches in diameter at breast height. The bank-side end of each log would be embedded in the ground and anchors would be used to permanently secure the logs in place.