Knickerbocker Floodplain
The Knickerbocker floodplain site is a section of the South Branch of Thornton Creek in Northeast Seattle. This project will relocate several hundred feet of the creek and create a 1.5 acre vegetated floodplain. This increased storage capacity will provide benefits to downstream stream-side properties and improve the habitat for biological communities within the creek. A new pedestrian bridge over the creek will be built as well.
Project Updates
Final (100%) Design Drawings (pdf)
SEPA Checklist (pdf)
SEPA DNS (pdf)
A community meeting was held on Thursday, November 15 from 6:30 to 8:00 p.m. at Sacajawea Elementary School (9501 20th Ave. N.E.) to present the project’s 90% design.
An informal question and answer session was held on Tuesday, July 17 from 6:30 to 7:30 p.m. at the project site near N.E. 100th St. and 20th Ave. N.E.
Project Details
The Floodplain Project is located near the intersection of NE 100th St. & 20th Ave. NE.
The project’s major elements are:
- Replacing a six-foot-wide rockery-lined straight stream channel with a meandering channel 15 to 20-feet-wide.
- Excavating a 30 to 100-foot-wide floodplain
- Removing invasive plants
- Installing over 100 pieces of large wood, native riparian plantings and stream gravels
- Planting the riparian zone (the stream bank) with native vegetation
- Replacing the existing pedestrian bridge in the 20th Ave. N.E. right-of-way
- Monitoring the project area for physical and biological conditions over time and testing the project’s effectiveness
Project Schedule
The project design work was completed in 2012, and construction is tentatively scheduled for June – September, 2013.
Contact Us
For additional information, contact Arnel Valmonte, SPU Project Manager, at (206) 615-1438 or arnel.valmonte@seattle.gov.