The rain and cooler temperatures of the week of September 21 to 27, 2014, were a signal to fish, that it is almost time for them to swim upstream! The summer dry-season is over, and in-water work at The Confluence on Thornton Creek must finish by the end of September in compliance with state regulations on habitat for fish.
With creek work finishing now, construction will continue on the flood plain area being created on the east side of 35th Ave NE adjacent to Meadowbrook Pond, and on rebuilding of the 35th Ave NE roadbed. Westwater Construction is the private contractor working on this project designed by Seattle Public Utilities along 35th Ave NE at NE 107th Street in Meadowbrook.
Meadowbrook Pond is not a “park” but is a Seattle Public Utilities facility with the functions of containing floodwaters and filtering sediments out of the water. The sediments settle in the pond and are dredged out by vacuum trucks in a cycle of routine maintenance every few years. As the creek then continues its flow eastward to its outlet on Lake Washington at Matthews Beach, excess sediments will not be carried along downstream, which would cause the creek and outlet to become silted up and blocked.
Both branches of Thornton Creek, north and south, were temporarily diverted during summer 2014 construction to improve and enlarge the creekbeds at the point of The Confluence where the creek branches join and flow into Meadowbrook Pond. Seattle Public Utilities reported that recent rainfall which caused higher water in the creek, allowed observation of how newly-installed log structures and rock weirs are working. In addition to improvement of fish habitat, creek improvements are designed to help sediments move through the channel into Meadowbrook Pond.
Work is progressing on-schedule at The Confluence site, including the continued closure of 35th Ave NE at NE 107th Street through the end of November 2014 while the roadway is rebuilt. A huge cut was made across the road to install much larger culverts for the south branch of the creek to pass under 35th Ave NE on its way to Meadowbrook Pond. Now a bridge-like structure is still under construction to rebuild the roadway over the new culvert.
Extensive digging can still be seen on the east side of 35th Ave NE at NE 107th Street, where a flood plain is being created to increase the capacity for water even more.
Seattle Public Utilities Thornton Creek reports of the monitoring of the water quality can be found at this link.