Zackuse Basin Plan

Project Description

The Zackuse Creek basin drains approximately 240 acres in the west portion of the City of Sammamish. The primary overland drainage conveyance in the basin is Zackuse Creek, which drains to Lake Sammamish and is located just south of and parallel to Louis Thompson Road in the City of Sammamish. Stormwater runoff from developed neighborhoods flows into Zackuse Creek via numerous culverts, ditches and outfalls along Louis Thompson Road. Although there are some undeveloped parcels in the Tamarack neighborhood, the basin is mostly fully developed and the neighborhoods would generally be classified as mature suburban neighborhoods.

The historic Tamarack neighborhood is somewhat unique to the City; roads are private and there is no public stormwater infrastructure. Stormwater runoff flows uncontrolled over land or in ditch-and-culvert systems west and south through the neighborhood, causing erosion and flooding issues. Non-attenuated flows from Tamarack and other basin neighborhoods may contribute to elevated peak flows in Zackuse Creek, causing erosion and landslide concerns in the creek ravine itself.

The purpose of this project is to develop a basin plan for the Zackuse Creek basin that will aid the City in identifying and prioritizing short and long term actions to improve the overall health of the basin. The plan will include evaluation of flooding, erosion, water quality, and fish and wildlife habitat problems in the basin under existing and future predicted conditions. The plan will also include recommendations, prioritization and planning level cost estimates of capital improvement projects (CIP), maintenance and operations activities, and programmatic measures including education and outreach to correct, mitigate, or avoid these problems.  

Project Updates

The City has selected three consultants to interview with the City on 5 and 6 September:

Herrera Environmental Consultants


Tetra Tech

Timeline (Updated 17 August, 2017)

July 27, 2017 - RFQ/PA Release

August 10, 2017 - Deadline for questions

August 22, 2017 - SOQ/PA Due to the City

August 28, 2017 - Notify short-listed firms

September 5-6, 2017 - Consultant interviews

September 8, 2017 - Notify successful consultant

September 08-22, 2017 - Select consultant and negotiate SOW and contract

October 17, 2017 - Present consultant selection to City Council 

October 19, 2017 - Anticipated project start

June 2019 - Basin plan adopted by City Council




Links to Pertinent Projects

Other City Basin Plans

Staff Contact