Construction work on the long-planned Knickerbocker Floodplain Restoration Project will begin in July on Thornton Creek. Last night at the Knickerbocker Natural Area (NE 100th Street and 20th Avenue NE), staff at Seattle Public Utilities (SPU) and the Parks Department met with neighbors to update them on the work. The project will relocate about 600 feet of Thornton Creek, create a 1.5 acre vegetated floodplain, and upgrade the pedestrian bridge over the creek. The new floodplain will store more water, wood, and sediment during storms and provide benefits to properties further down the creek (e.g. less flooding). It will also improve the habitat for fish and wildlife in the creek.
Some construction work will begin in June, while work in the creek will take place during July 1st and August 31st in an effort to protect fish populations. During that time, the creek will be diverted into two 12″ pipes, and the pedestrian path across the area will be closed for those two months. Once the new 80 foot bridge is installed, access will be reopened in time for the school year to begin.
The two and half million dollar project is a joint effort between the two Seattle departments (SPU & Parks) that have purchased parcels over the past several years. Some of the wetlands creation is being paid by Sound Transit as mitigation for construction at Northgate of the Link Light Rail station. After the contractors finish their work this summer, both departments will be responsible for maintaining the floodplain.
Just a mile east of Knickerbocker, another section of Thornton Creek is being updated when 35th Avenue NE is closed at Meadowbrook beginning Monday to install a larger bridge over the creek. The Seattle Times describes the project.