Thornton Creek Alliance
THORNTON CREEK Currents
Every month, TCA mails its professionally compiled and edited newsletter, Thornton Creek Currents, to its members. It's a source of information on the organization and on happenings in the watershed--not only issues, but events and opportunities. Currents also provides a forum for its members. Each month, we will try to post one article from Currents on this web page, in hopes that you will consider joining TCA, so you can receive the newsletter in its entirety as well as become an active TCA member!
Northgate “Water Quality Channel” Making Progress
By John Lombard
Design for the “Thornton Creek Water Quality Channel” on the south lot of Northgate has reached the 30% stage. Seattle Public Utilities is seeking a Master Use Permit for the project, with work scheduled to begin this June.
On February 3, the Northgate Stakeholders Group wrote to Mayor Greg Nickels and the Seattle City Council to praise work on the project so far. Despite some concerns, TCA (represented on the Stakeholders Group by Cheryl Klinker and me) supported this statement.
In November and December, we met several times with Seattle Public Utilities about a variety of concerns we had with the project. SPU had changed the design dramatically from the original concept shared with the Stakeholders, which would have taken nearly all of the flow from the pipe underneath the south lot and daylit it through a series of bridges. The bridges were also to act as weirs, backing higher flows up for water quality treatment and some detention.
SPU determined that design was infeasible, saying it would lead to regular flooding at 1st Ave. NE and NE 100th St. (a crucial intersection for the Metro Park and Ride) and would be much more expensive than previously estimated, in part because of poor soils on the site.
The new design leaves more stormflow in the pipe than before; the baseflow and smaller stormflows would be diverted just through the lower half of the open space. The upper half would receive water from a different source—a drainage system serving 20 acres of development to the south.
TCA’s concerns included: Was SPU’s increased cost estimate reliable? Would flow from the 20-acre drainage system dry up in the summer? Would the revised design for the pipe diversion still look and act like a creek? Were its water quality features over-engineered? Would it be fish passable? Had the pedestrian experience on the site been compromised?
Overall, we believe SPU has satisfactorily addressed these concerns. At our urging, they hired an outside “value engineering” consultant to review costs and work with the design team to address these issues and others. They brought back Peggy Gaynor, the primary designer of the original proposal, as a full member of the design team, particularly to address our concerns about creek functions and the visual experience. They added a pedestrian connection to NE 100th St. that many community representatives were seeking.
This is a complicated, expensive project, with a tight schedule that must be synchronized with private development on the remainder of the south lot. TCA will continue to track it closely. If you have questions, please let me know, at email@example.com.
You Can Be a Steward
A steward can be the solo "garden type" who likes to work individually, or the "workparty leader" type who likes to develop projects and lead groups to implement them. All site stewards, new or old, need to register with Bob Spencer to ensure you and your volunteers are insured and will be his first contact regarding your chosen site. He plans to meet with you, discuss your goals for your projects, and find out how he can support you. Both Bob and Theresa have funds to support events at your sites, so we encourage you to call Bob Spencer soon at 206 684-4163. Thanks and congratulations to all who made this program a success, volunteers and staff. TCA thanks you formally; the results are there for all the world to see.