Department of Natural Resources and Parks PRESORTED Wastewater Treatment Division STANDARD King Street Center KSC-NR-0503, 201 S. Jackson St. U.S. POSTAGE , WA 98104-3855 PAID SEATTLE, WA PERMIT NO. 836 TRANSFER PIPE EXTENSION PROJECT Summer 2009 King County to Extend the Ravenna Creek Stream Transfer Pipe The King County Wastewater Treatment Division is extending the pipeline that conveys Ravenna Creek downstream from RavennaRAVENNA-ECKSTE Park. ToIN PARK protect public health and the environment, a section of pipeline will be added to isolate the stream and prevent potential sewer overflows into University Slough.

RAVENNA CREEK PIPELINE KEEPING EXTENSION PROJECT THE PUBLIC INFORMED COMMUNITY MEETING COWEN PARK

September 10, 2009 RAVENNA This map shows the 6:30-8:30 p.m. PARK proposed project area. As project design Ravenna Eckstein Community Center progresses, King County

6535 Ravenna Ave NE Project Location will provide more Seattle, WA 98115 detailed information about project scope and schedule.Updates to agencies and community members

BURKE GILMAN TRAIL will be provided as RAVENNA CREEK PIPELINE EXTENSION PROJECT construction plans are developed. Some COMMUNITY MEETING impacts can be expected during construction. September 10, 2009 RAVENNA People will have 6:30-8:30 p.m. WOODS opportunitites to ask Ravenna Eckstein Community Center questions and provide comments. 6535 Ravenna Ave NE Seattle, WA 98115 You can find contact information on the King County is hosting a community meeting to back page and check provide the public with an opportunity to learn the project Web page about the Ravenna Creek Pipeline Extension for updates: Project. Construction is expected to occur in www.kingcounty.gov/ 2010 and may affect park use during the summer environment/wtd/ months. You can meet project staff, ask questions, Construction/Seattle/ and provide the team comments and concerns. RavennacCkPipe Extension.aspx All are welcome to attend. Light refreshments will be served. For people needing special accommodations, please contact Monica Van der Vieren at 206-263-7301 or [email protected]. ating Re a Cre sou astew ter Alternative formats available rces from W Printed on recycled stock. Please recycle. GCIU 1202M Produced by King County DNRP, WLRD, GIS/VC & Web Unit 206-263-7301 or TTY Relay: 711 0907Ravennanews.indd skrau Project scope

King County proposes to isolate This project is currently in early stages of Why is this project needed? Ravenna Creek flows within a design. Construction is expected to occur pipe that will travel through the during the summer of 2010 to coincide A 2004 King County daylighting project diverted Ravenna Creek flows from the box culvert that currently conveys with lower sewer and stream flows. Some county wastewater treatment plant in Magnolia to the University Slough. During creek flows. The box culvert may preconstruction investigation may occur investigation of a May 2008 sewer spill into University Slough, King County receive sewer overflows during during summer 2009; people may notice determined that installing an additional section of pipe to the stream transfer heavy storms. After this project is activity in during that time. pipeline will prevent flows from the sewer system from combining with creek flows completed, normal creek flows will during heavy rains. be able to travel through the system to University Slough without risk of King County and Seattle Public Utilities worked together to evaluate a range of cross-contamination with sewage during Local Combined Sewer Line solutions. Together the county and SPU identified this project as the most cost- periods of heavy rain. No change in effective way to isolate stream flows and maintain system capacity. normal stream flows would result from this project. Lake City Tunnel (King County Sewer) Sewer overflows would continue downstream in the box culvert to the Creek Diversions to Protect Water Quality during the county’s Laurelhurst Trunk and on to the 24th Ave Diversion King County will maintain an inflatable plug county’s West Point Treatment Plant. Structure Wet Weather Season in the Ravenna system from fall 2009 until RAVENNA CREEK construction is completed in 2010. The plug diverts sewer and creek flows to West Point Treatment Plant during the wet weather Underground Pipe season. King County installed the plug after identifying the problem in late 2008 and Lake City BOX CULVERT Regulator receiving a Hydraulic Project Approval (HPA) CROSS-SECTION 54th Street Diversion Structure from Department of Fish and Wildlife (WDFW). The plug was removed Laurelhurst Trunk (King County Sewer) June 18, 2009.

BOX CULVERT WITH PIPE LEGEND EXTENSION UNIVERSITY Sewer Over ow During Heavy Rain STREAM SLOUGH Extended Transfer Area Want more information? FLOW OVERFLOW N Sewer Pipeline Contact Monica Van der Vieren at 206-263-7301 or Stream Flow [email protected] with:  Questions, comments, concerns  Requests for email or hard copy updates as the project develops Check the project Web site for updates Schedule www.kingcounty.gov/environment/wtd/Construction/Seattle/  Project design - 2009 RavennaCkPipeExtension.aspx  Procurement (contracting) - late 2009/early 2010 For background on the Ravenna Creek Daylighting Project, see the Seattle Parks and Recreation Web site:  Construction - summer 2010 www.seattle.gov/Parks/proparks/Projects/RavennaCreekatRavenna.htm ating Re a Cre sou astew ter rces from W