State Avenue construction tackles pollution problem in Olympia

The construction along State Avenue in Olympia is intended to benefit drivers, pedestrians and the environment.

Slated for completion in the spring, the State Avenue Stormwater Retrofit project will upgrade the street with safety features while reducing pollution in Budd Inlet.

With more than 13,500 vehicle trips daily, State Avenue is one of the most heavily traveled arterial roads in Olympia that lacks water quality treatment, according to the city. Stormwater runoff from State Avenue currently drains untreated into Moxlie Creek, which empties directly into Budd Inlet’s East Bay.

The project targets nine blocks of State Avenue between Central Street and East Bay Drive. Crews will install filtration units to capture and treat the stormwater runoff from the road. Manufactured by a company called Filterra, these units will be between the curb and the sidewalk. The system also incorporates shrubs and landscaping into the design.

The system is built to remove pollutants such as oil, phosphorus, nitrogen, metals and other suspended solids. The treatment can reduce pollutants up to 93 percent depending on the substance, according to the company, which has published results online.

“We prioritized this project because the (stormwater) discharges more or less into Budd Inlet without any treatment,” said Eric Christensen, water resources engineer for the city.

The state Department of Ecology has previously reported that Moxlie Creek discharges high levels of dioxins — chemical contaminants that are industrial byproducts. To help improve water quality, the department awarded the city a Water Pollution Revolving Fund Loan worth $619,485. The city will repay the 20-year loan with annual payments of $40,097, according to a staff report.

The stormwater treatment dovetails with an asphalt overlay and paving project for State Avenue. Work began in late October, and the entire project is slated for completion in March or April 2015, said Brett Bures, project manager for the city.

Crews will wait until the weather warms up in the spring before finishing the paving portion, Bures said. The project includes removal of 19 trees that had been damaging sidewalks. Crews will plant 29 new trees that are more suitable for urban environments, said Bures, listing species species such as chanticleer pear, crabapple, ivory silk lilac, black gum, aristocrat pear and crimson spire oak trees.

The contract was awarded to Quigg Bros. Inc. for $1,743,289. As part of the project, crews will also build several curb extensions called “bulb-outs.”

“Bulb-outs provide a shorter crossing distance across intersections,” Bures said. “They also act as a traffic calming device because they protrude into the lane and provide a safer walking surface and path for the pedestrian.”