Anacortes approves design modification to eliminate water supply contamination risk
City of Anacortes, Washington · Meeting date: May 18, 2026 · Published: May 26, 2026
The city council has greenlit a contract add-on for HDR Engineering to design an air gap and duckbill valve for the Whistle Lake Road Pipe Arch, securing a vulnerable relief point in the city's water transmission network.
Key points
- The Anacortes City Council unanimously approved a $2,926 contract modification with HDR Engineering, bringing the total design contract to $60,033.
- The design update will add an air gap and duckbill valve to the Whistle Lake Road Pipe Arch.
- The existing pipe arch, which serves as a hydraulic relief point, currently lacks an air gap or screening, presenting a contamination risk to the municipal water supply.
Full report
The Anacortes City Council has unanimously approved a contract modification with HDR Engineering to address a potential contamination risk in the city's water transmission infrastructure. The action, passed via the consent agenda at the council's May 18, 2026, meeting, authorizes an additional $2,926.42 for the Whistle Lake Road Pipe Arch Modifications design project.
The city's older water transmission line utilizes a pipe arch as a relief point for excess hydraulic grade. As pressure increases in the pipeline, water gradually overflows the arch and is discharged into a storm drain following dechlorination. According to city documents, the existing structure currently lacks an air gap or screening mechanism, leaving it vulnerable as a potential source of contamination for the municipal water supply.
To mitigate this risk, HDR Engineering will modify the project's design to incorporate a dedicated air gap and a duckbill valve. The contract modification brings HDR's total not-to-exceed fee to $60,033.42. The design services are being funded through municipal rates and user fees, drawing from an earmarked project budget of $550,000.
The modification extends the contract's period of performance to May 16, 2026. The council approved the measure without discussion as part of its routine consent calendar.
This summary was generated by AI based on the source document and may contain errors.
Source: City Council Meeting, City of Anacortes