Clearwater Construction & Management LLC, of Spokane, is the apparent low bidder for an $813,000 project to install a new sewer overflow basin near the Spokane River in northwest Spokane.

The 28-by-165-foot concrete tank, called a combined sewer overflow, will detain both wastewater and storm water during heavy storms or melt off to eliminate overflows into the Spokane River, says Steve Hansen, a senior engineer for the city of Spokane. During those surges, the new tank will release flows slowly by pipe to the city's Riverside Park Water Reclamation Facility, just downstream from where the tank is being put in.

The tank will be installed on city property overlooking the T.J. Meenach Bridge, near the corner of York Avenue and Nettleton Street, Hansen says.

The project is being mandated by the Washington state Department of Ecology as part of an effort to clean up the Spokane River and reduce overflows of wastewater into it, he says, adding that the tank is the third one that's being installed as part of that effort. More tanks will be installed in the future, but Hansen says he's not sure how many more will be put in.

He says the city's wastewater treatment plant can accomodate only a certain amount of excess stormwater from the city's sewer system during a storm surge, and when there is more water than it can handle, that wastewater flows directly into the river.

"The goal is to continue to improve what goes into the river," Hansen says.

Approximately 10,200 cubic yards of soil will be excavated as part of the project, and 329 linear feet of sewer lines will be placed to carry water to and from the basin.

Work on the installation of the basin is expected to begin sometime next month, and will take between five and six months to complete. Construction on the project will occur throughout the winter as weather permits, he says.

Money for the project will come from the city's wastewater treatment fund.