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 awarded the consultant contract to AltaTerra Consulting, LLC, with subconsultants The Watershed Company and Osborn Consulting rounding up the project team.  The project kick-off meeting took place Wednesday, November 15th, and the first steps of the project, data collection and field investigations, are underway.

Timeline (Updated 20 November, 2017)

December 2017 - February 2018 - Data Review

January/February 2018 - Public Meeting

February - March 2018 - Field Evaluation

Summer 2018 - Project and Strategy Development

Fall 2018 - Community Event Focus Meeting

Fall 2018 - Basin Plan Report Writing

December 2018 - February 2019 - Present Plan to City Council for Adoption


The fee for this project is $178,000.


Links to Pertinent Projects

Other City Basin Plans

Staff Contact