Tumwater to construct 3-million-gallon reservoir

On Tuesday, February 20, Tumwater City Council approved a service provider agreement with RH2 Engineering, Inc. to design a 3-million-gallon reservoir.

The reservoir will be located approximately southeast of The Preserve and sited on a city property along 93rd Avenue in Thurston County.

RH2’s contract is for $1,658,845 which will cover three design phases. The first phase will deal with the design of the water tank and an access road from 93rd Avenue.

Engineering Services Manager Bill Lindauer explained that due to the elevation difference between 93rd Avenue and the project site, the access road will curve as it winds to the reservoir.

The second design phase will focus on a 9,500-foot water main extension on 93rd Avenue from Kimmie Street to Snowdrop Avenue. The last design phase will deal with extending the water main from the reservoir to Old Highway 99.

Lindauer said that though there are existing water main segments in the surrounding area due to new developments over time, the water system from 93rd Avenue currently needs to be connected with the water system on Old Highway 99. A large component of the project outside the construction of the reservoir will be to connect the two water mains.

The water mains' extensions will allow the water system from 93rd Avenue to connect with Old Highway 99.

According to the agreement, RH2 will subcontract HDR Engineering for pre-design and permitting services, Sage Geotechnical for geotechnical services, and Sitts & Hill Engineers for topographic survey.

Water Resources Director Dan Smith said that the reservoir was first conceptualized in the city’s 2010 water system plan as a 2.5-million-gallon reservoir before the city’s 2021 water system plan recommended the construction of a 3-million-gallon reservoir.

Smith also mentioned that the full cost of the project could go upwards to $30 million.