The existing NE 90th St stormwater pond treats the runoff from the 90th St stormwater basin before it drains into the Sammamish River. It was constructed in 2000 and currently provides about two thirds of the water quality treatment required by today’s regulations. The pond works by allowing sediment to settle out of the stormwater before it enters the Sammamish River. Over the last 20 years, significant sediment has accumulated, filling up a portion of the pond. The City will be removing the accumulated sediment from the pond during the summer of 2023.
The project will also construct some improvements to the site to help with pond operations. These improvements include a rebuilt maintenance access and installation of a new valve to separate the pond from the stormwater trunk line in 90th Street. This work will make it easier for City stormwater crews to maintain the system.