Status
As of May 2013
Phase: Design
City Staff have identified the locations where LID improvements will be made. First priority improvements will be constructed, and pending available funding, second priority improvements will be constructed. Below is a map showing the locations for the proposed improvements.
LID Improvement Map
Individual Property PDF Maps
10th Avenue NE Improvements
10th Avenue NE and Serpentine Place Improvements
12th Avenue NE Improvements
NE 180th St Improvements
Overview & History
This sub-basin experiences drainage problems because of residential development and the overflow from an undersized stormwater pond located in a closed depression. Pump Station #25, associated with the stormwater pond, contributes flow downstream to residential neighborhoods in Shoreline and Seattle that experience flooding during large storm events.
The North Fork, Pump Station #25 (North Fork Sub-basin) is approximately 158 acres and is located at the headwaters of the Thornton Creek Basin and is located in the City of Shoreline. Thornton Creek basin is a highly urbanized basin with poor water quality and frequent flooding along the length of the Creek, both in the open channel reaches and the piped sections. Thornton Creek is listed as an impaired water way.
This project will look at ways to improve water quality and provide flow control within this sub-basin. The retention and infiltration of runoff through the use of Low Impact Development (LID) stormwater features will improve hydrologic function in the upper watershed, reducing the volume of runoff that reaches the pond and Ronald Bog and provide water quality treatment where none currently exist. LID is a stormwater management strategy that emphasizes conservation and use of existing natural site features integrated with distributed, small-scale stormwater controls to more closely mimic natural hydrologic patterns in residential, commercial, and industrial settings (Low Impact Development Technical Guidance Manual For Puget Sound, 1995).
The project will include public involvement during the design phase. Sub-basin evaluation and public involvement will be conducted during the first half of 2012. Construction is expected spring 2013.
In January 2011, the City was awarded $630,000 in state funds from the Washington State Department of Ecology’s Stormwater Retrofit and LID Grant program.
Surface Water Master Plan
Rain Garden Brochure
2005 LID Technical Guide Manual for Puget Sound