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Kelly Butte Reservoir Project Honored with Concrete Award

Staff accepts Concrete Award
Staff from the Portland Water Bureau, MWH, and Hoffman Construction
accepted the award at an annual banquet.

The Oregon Concrete & Aggregate Producers Association (OCAPA) awarded the Portland Water Bureau’s Kelly Butte Reservoir project a 2016 Excellence In Concrete (EIC) Award.

The awards program began more than 30 years ago and continues today as a way to recognize concrete projects at the forefront of innovation and technology and showcase projects to inspire excellence in concrete design and construction.

Kelly Butte Reservoir 
Kelly Butte Reservoir, November 2015

The Kelly Butte Reservoir project began in late 2012 and was completed in 2016. The project replaced the 10-million-gallon aboveground water storage steel tank built in 1969 with a new, buried 25-million-gallon reinforced concrete reservoir. An overflow basin, multiple vaults, valve structures, access roads, and intricate network of underground piping were also constructed.

To construct the underground reservoir, basin, vaults, valve structures, and concrete encase all water pipes in and out of the facility, 16,000 cubic yards of high-strength concrete (3-5K PSI) was brought and poured onsite. Concrete placement for the structures and piping was required within a maximum of 60 minutes from the time of batch.


The reservoir’s floor and roof, each consisting of 266 20-feet by 20-feet squares, were poured in a checkerboard pattern in order to provide each square 14-days of continuously flowing water cure. The support columns also required a 7-day continuous flow water cure achieved with burlap and an elaborate network of piping and drip sprinklers.

The new underground reservoir consists of a 394 X 296 foot floor and roof, five walls, and 252 support columns. The reservoir has two cells, each with capacity to store 12.5-million-gallons of water. The cells were strategically built to operate independently, allowing for easy cleaning, inspection, and maintenance.

For the project, MWH Global was the structural engineer, Hoffman Construction Company the general contractor, Hoffman Structures the concrete subsidiary to Hoffman Construction Company, and CEMEX the concrete supplier.

The reservoir currently serves all of east Portland and will be a stopover for water supplied to the Washington Park reservoir and southwest Portland area water storage tanks.

The Water Bureau was also honored in 2015 with an EIC Award for the Forest Park Low Tank project which included the construction of a below ground 1.3 million gallon water storage tank and a 1,408 square foot pump station in NW Portland.

For additional information about the project, visit  


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