Seattle Public Utilities share the following information on Wednesday about a coming six month closure of 35th Avenue NE next to Nathan Hale High School.

Beginning as early as May 5, part of 35th Avenue Northeast will be closed for approximately six months while the city’s longest creek is reshaped to prevent chronic flooding and restore habitat for threatened salmon and other species.

For years, the confluence of the North and South branches of Thornton Creek, just east of 35th Avenue Northeast, has been prone to flooding. High waters have frequently inundated nearby homes, Nathan Hale High School and Meadowbrook Community Center and closed the road to traffic.

To fix the problem, Seattle Public Utilities (SPU) will remove an undersized culvert under 35th Avenue Northeast and realign the existing creek channel through a new two-acre flood plain. The wider channel and flood plain connection will help native fish habitat by spreading out and slowing the peak flows of Thornton Creek.

Additionally, the project will construct a new bridge under 35th Avenue Northeast slightly north of where the creek currently runs.

To perform the work, it will be necessary to close a section of 35th Avenue Northeast, between Northeast 110th Street and Northeast 105th Street, for about six months. 35th Avenue Northeast will be open only to local access traffic, including access to the Meadowbrook Community Center from the south.

Traffic will be detoured from 35th Avenue Northeast to Lake City Way Northeast via Northeast 110th Street and Northeast 95th Street. Detour signs will be in place prior to the closure.

Southbound Metro buses (Route 64 and 65) will be detoured to Lake City Way Northeast via Northeast 110th Street and Northeast 95th Street. Northbound Metro buses will be diverted to Sandpoint Way Northeast via Northeast 95th Street and Northeast 110th Street. As the closure date approaches, more information will be found at http://metro.kingcounty.gov/alerts/.

Historically, the Thornton Creek Confluence Reach was 170 acres of partially forested wetland that included most, if not all of the low-lying property now occupied by the Meadowbrook Playfield, Nathan Hale High School and Meadowbrook Pond west and east of 35th Avenue Northeast.

SPU is working with federal scientists (U.S. Fish and Wildlife Service and NOAA Fisheries Science Center) to measure project performance by comparing existing conditions with post-construction changes in flood plain storage, habitat conditions and biological response (abundance and diversity).

Along with the ecological benefits of restoring stream and flood plain processes to the Thornton Creek Confluence Reach, the project will reduce the City’s operating costs at nearby Meadowbrook Pond by reducing the frequency of dredging needed at the Pond (currently averaging every three to five years).