Ravenna Creek pipe extension

What you can expect during construction

Project location map (PDF)


New box culvert with pipe extension (PDF)

Construction in the park area will be limited to the southeast portion of the park, with limited street area required for equipment and truck access.

• The ballfield will be closed for use during the summer and fall of 2010. In 2009, King County worked with the community and Seattle Parks to schedule construction after spring tournaments ended. Summer users will be scheduled on nearby alternate fields.
• Excavation in and adjacent to the ballfield will be carried out for up to six weeks. Pumps and generators will be required for dewatering during excavation.
• The new section of transfer pipeline will be constructed by fusing sections of HDPE (plastic) pipe and feeding them into the box culvert. This activity will be carried out in the construction area at the park.
• To protect public safety, there will be some pedestrian and trail detours around the construction area and truck entrance.
• Some street parking will be eliminated temporarily during construction.
• A temporary creek bypass is necessary during working hours and some non-work hours for pipe and structure installation in the box culvert. Surface creek flows in the park will not be affected.
• Work will be carried out during normal construction hours. Longer hours may be required under some conditions.
• Construction on NE 54^th Street will require traffic to be reduced to one lane. People should drive carefully in the area and watch for flaggers. Some parking spaces will be unavailable over a 2-3 week period.

In addition to restoration of construction areas, King County will carry out weed removal and replace failed plantings along the creek .

Creek Diversions to Protect Water Quality During Construction

King County has maintained an inflatable plug in the Ravenna system during the winter periods since 2008, diverting sewer and creek flows to West Point Treatment Plant during the wet weather season. King County’s Hydraulic Project Approval (HPA) will allow the county to maintain the creek diversion during summer 2010 to accommodate construction activities. Ravenna Creek flows through the system to University Slough will be restored when construction is completed.

Improving vegetation in Ravenna Park and University Slough

As part of permit required mitigation, King County will remove invasive weeds from some areas of the Ravenna Creek Daylighting project. The county will also replace some native plants that have died. Volunteer groups have worked many hours to maintain the native plant habitat along the daylighted portion of Ravenna Creek.

In addition to work in Ravenna Park, the county will remove invasive weeds and replace failed plantings along University Slough, from NE 45^th Street to Clark Road. The county restored this area following the sewer spill response in 2008.