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The City of Portland, Oregon

Portland Water Bureau

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Washington Park Reservoir Improvement Project

  • Project Updates Stay in the know about project progress! Sign up to receive emailed updates.

  • Upper Reservoir - Pump House View The new reservoir is engineered to withstand ongoing landslide encroachment and seismic events.

  • Serving Portland Since 1895 When completed, the new reservoir will provide service for at least another 100 years.

  • Lower Reservoir 4 - Downtown View A lowland wildlife habitat area, bio-swale, and reflecting pool will be constructed.

  • Supplying Water to Portland's West Side Serving more than 360,000 people, 20 schools, three hospital complexes, 60 parks, and major attractions.

  • Upper Reservoir 3 - Grand Staircase View The new reservoir, in the footprint of the historic Reservoir 3 (upper), features a reflecting pool at ground level.

  • Washington Park Reservoir Improvement Project A new 12.4-million gallon, seismically reinforced underground reservoir.

  • Lower Reservoir 4 - Powerhouse View Existing Reservoir 4 (lower) will be disconnected from the public drinking water system.

Take the Virtual Tour


Updated: November 13, 2018

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What's Happening Now

Crews continue working on the drilled shaft foundation and are averaging two completed shafts per day. Each completed shaft is drilled, the drilled spoils hauled to Reservoir 4 site, a rebar cage placed inside the drilled hole and then the hole filled with concrete. In this process communication and planning is vital, and requires weekly and daily coordination meetings, and then onsite communication using voice, hand and radios signals.

Crews also continue fabricating rebar cages at the old Reservoir 4 site, which are then trucked up to the new reservoir as needed.

Work also continues in the pump houses and gatehouses. The upper gatehouse is being repurposed to house the pumps and other machinery needed to recirculate water for the reflecting pools that will be built during the final stages of this project. The pump houses continue to be refitted with new mechanical and electrical equipment and wiring.

Other work includes replacing old pipe and installing new pipe. It’s a very busy and confined site!

Check out the newest videos uploaded to the virtual tour:

In case you missed it, here is an interesting piece by KGW. The drone footage it pretty spectacular.

WHAT'S NEXT? - NIGHT WORK, December 2018 - November 2019 (more information HERE)

Concrete will be poured for the floor slab, support columns, walls and roof of the new reservoir. Due to the size and volumes of concrete deliveries, they will begin in the early morning, in some cases as early as 2:30 am and will continue through the day, with new concrete trucks arriving approximately every 3 - 5 minutes. Concrete deliveries should be completed before 6 pm but on site work will continue beyond that time to complete the finishing work.

The reservoir floor slab will be poured in 12 sections. Each section will be poured in a single day. For the first four slab sections, there will be 30-40 days between each of the pours. Pour frequency will increase after that, as walls, columns and roof are poured atop completed slab sections. While it is anticipated that there will be several days between pours, there may be limited short term cases where pours will occur daily.


To see photos and learn more about activities on-site over the past month, check out the monthly update HERE.

Concrete & Rebar

The Washington Park Reservoir Improvement Project is a big project and uses A LOT of materials, particularly concrete and steel rebar.  3,000 truckloads of concrete will be used during the lifetime of the improvement project! That is a total of 30,170 cubic-yards, or 120 million pounds, along with 7.4 million pounds of rebar, long and straight and coiled stacks.

The original reservoir was made of concrete poured over the existing carved out landscape with some rebar thrown in here and there. The new one is a highly engineered structure being built to current standards and reinforced with rebar every few inches. The rebar being used today is more than twice the thickness of any used in the original construction.

Just as rebar and its application have evolved since 1894, so has concrete and its formulation. Shotcrete used on this project is a special mixture that is thicker than usual and contains fibers. This allows it to adhere to the wall surface. For the drilled shafts, walls, floor slab, and columns a high strength structural concrete is being used.

Did You Know?

The Bull Run Water Drainage Area is 102 square-miles in area, receives 80-170 inches of precipitation annually, and provides water to almost 1 million Oregonians, or about 1 in every 4 people. There are more than 205 species of birds, mammals, reptiles, amphibians and fish, and close to 94.4% of the area is forested. Up to 77.3% of the area is Old - and medium-growth trees. Non-forested land is mostly made up of steep, unvegetated slopes and bodies of water. There are also five summits over 4,000 ft.


Community Outreach History

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Project Overview

Including the project description, map and schedule

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Traffic Impacts

Beginning April 2, 2018