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.
The City sent the RFQ/PA to select consultants on 27 July, 2017. Selected consultants receiving the City's RFQ are as follows:
PBS Engineering and Environmental
Herrera Environmental Consultants
Osborn Consulting, Inc.
Questions about the RFQ/PA were due 10 August, 2017. No questions were received from prospective consultant.
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