Anacortes approves design modification to eliminate water supply contamination risk

Anacortes approves design modification to eliminate water supply contamination riskThe 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.

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.

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.