The city is flowing along with its booster chlorination system project, which is aimed at strengthening its water supply system and improving system operations for water quality control.

At its July 20 meeting, the Mercer Island City Council took the next step with the project’s development by voting to award a bid to Woodinville’s Harbor Pacific Contractors, Inc. to construct the permanent booster disinfection system for the city’s reservoir and main pump station.

Council also voted to authorize City Manager Jessi Bon to execute a contract with Harbor Pacific Contractors, Inc., in an amount not to exceed $2,115,642, which is the contractor’s total submitted bid.

“This is obviously a very significant project in terms of complexity and cost, and over the past several years it’s been a priority project of city council to ensure safe potable water for Island residents,” said Mayor Benson Wong, who noted that Public Works chief of operations Jason Kintner, utilities engineer Rona Lin and sustainability program analyst Ross Freeman played key roles in leading their staff in advancing the capital project.

Councilmember Lisa Anderl said the Public Works department was thorough in constructing the agenda bill. She looked to the past in addressing the city’s future needs.

“I will tell you that not too many people remember much about what happened in 2014, but everybody remembers the E. coli scare. I think this is a great investment in our infrastructure and I’m grateful to city staff for pulling it along to get this far,” Anderl said.

According to the agenda bill, construction is scheduled to begin in October of 2021 with expected completion by August 2022, but the project may extend an additional six months depending on availability of supplies due to the pandemic. The Washington State Department of Health approved the project design on June 14, 2021.

On the sustainability front, the project is expected to feature a host of approaches, including the recycling of asphalt pavement grindings for use in future construction projects; removal and replacement of the city’s oldest, unlined cast iron piping; usage of low-flow pumps and more.

Construction at the city’s main pump station — located between 88th and 89th avenues southeast at Southeast 43rd Street — will include installation of a sodium hypochlorite generator system, and a mixer in each of the reservoir tanks to prevent tank stratification and allow the chlorinated water to mix uniformly, according to the agenda bill. Other aspects of the robust construction docket will include interconnecting water mains on 89th Avenue Southeast, and removing a pair of pressure-reducing valve (PRV) vaults and installing a new PRV station and a flow-meter station in the 9700 block of Southeast 40th Street.

Low responsible bidder out of three contractors, city staff noted that Harbor Pacific Contractors, Inc. has constructed comparable water utility projects for other agencies, including Clallam County Public Utility District and the city of Bellevue.

The project’s total cost is $3,284,770, which includes contingency, final design, construction support, project management and inspection services. The city’s total approved budget for the project is $3,505,000.