Seattle sewer lines installed in the early to mid-20th century simply can’t handle stormwater runoff during severe rainstorms. A $262 million project near Georgetown will change that reality for the up to 70 million gallons of polluted stormwater that currently flows into the Duwamish River during severe rainstorms.

The new Georgetown Wet Weather Treatment Station aims to protect water quality in the river by treating the stormwater runoff that currently flows directly into the river. It signifies the first of eight projects that will complete King County’s four-decade work to control the combined sewer outflow that still occurs in parts of Seattle.

King County Executive Dow Constantine said during the groundbreaking ceremony recently that the project will protect the river for the next century.

The U.S. Environmental Protection Agency selected the Georgetown project as one of a dozen nationwide to qualify for low-interest loans through its Water Infrastructure Finance and Innovation Act Program. King County’s project qualifies for $134.5 million in loan funding.

King County’s Wastewater Treatment Division conducted community outreach throughout the design phase to ensure the $262 million project reflects local character. The sustainable design includes a green roof and cisterns to filter and collect stormwater. New trees aim to improve air quality in an area of Seattle with one of the highest asthma rates. The station will also have space for school programs and environmental education.

Added design elements include special lights along the building to alert those nearby when the station is working; the ability to see inside through the fencing and open design of the building; and colored pipes to show the water’s path through the station.

King County expects the project to take five years to construct. Already Titan Earthwork has completed site preparation and demolition to prep the site for construction. King County awarded the treatment station construction contract to Flatiron West Inc.

Follow Tim Newcomb on Twitter at @tdnewcomb.