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The City of Portland, Oregon

Portland Water Bureau

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Water Bureau Utilizes the Off-Peak Season Effectively

Around September of every year, the demand for water supply begins to decrease.  By the first of November, the Portland Water Bureau moves into winter demands, also known as the “off-peak” season.

This normal and expected decrease in water demand allows the Water Bureau Operations Group to take facilities out of service that typically run 24/7 in the peak demand period. The Operations Group then shifts gears into a maintenance mode to effectively utilize the off-peak period.

The Water Bureau’s off-peak period is from November 1 to March 31. This is the ideal time for Operations to perform critical maintenance on pumps, tanks, valves, and the transmission system. During this time, engineering projects are scheduled that require portions of the system to be out of service. Due to the large amount of work and short timeframe, the Operations and Engineering groups partner closely to effectively utilize this off-peak period. Members of the Operations Analysis group maintain an active spreadsheet to track all the different projects and monitor for critical scheduling conflicts. 

This year has shaped up to be a busy one for the Operations Group. There are several large capital improvement projects in construction, including the Powell Butte and Kelly Butte Reservoir projects. There is also an internal pipeline inspection of the Washington County Supply Line (WCSL), several corrective maintenance projects, and the regularly scheduled off-peak activities.

Left: An electrician installs a GridBee submersible mixer in the Linnton Tank in NW Portland. Right: An industrial painter cleans the reservoirs at Mt. Tabor.

One of the regularly scheduled off-peak tasks is the cleaning of tanks and reservoirs. Operation engineers and industrial painters clean the in-service open reservoirs at Mount Tabor and Washington Park a minimum of twice a year.

Industrial painters patch cracks on the interior face of the Mt. Tabor reservoirs.

All of our closed storage tanks are on a rotating five-year cleaning schedule. This off-peak period, the Water Bureau has 17 tanks scheduled for cleaning, including the 50-million gallon Powell Butte 1 reservoir.

Left: An operating engineer III (left) and an operating engineer trainee work to replace a ball valve at the Westwood Tank in SW Portland. Right: A team performs maintenance on a flow valve at Westwood Tank.

In addition, there are several special projects this year, including the installation of three tank mixing systems to help address water quality issues, installation of a new standby generator at Calvary Pump Station, replacement of the more than 50-year old Westwood ball valve that has reached end of life, tank leak repairs at Vermont Hills 4 and 5, various pump and motor rebuilds, and the shutdown of the WCSL for internal inspection.

Dan Allison
Water Operations


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