City of Spokane final, and largest, CSO Tank Goes On-line

Check out this video to learn about the 3.2 million gallon Combined Sewer Overflow (CSO) tank that lies beneath the popular public plaza along Spokane Falls Boulevard and just north of the Downtown Library. Citizens are reaping more than just the benefits of spectacular Spokane River views.

Called CSO Tank 26, it became operational in August. Essentially, it captures pollutant laced stormwater from rain and snowmelt that use to overflow to the Spokane River when the sewer system was overwhelmed.

Said Kyle Twohig, Director of Spokane City Engineering Services, “In a major storm event, this one line could contribute up to forty percent of the entire amount of flow that would overflow to the river.” CSO Tank 26 now captures the overflow before sending it to the treatment plant once system capacity becomes available.

This is the final and largest of 26 CSO tanks installed by the city. Twohig’s excitement is contagious as he ponders their “huge impact on the health of the Spokane River.”