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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.

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Updated: August 24, 2020

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What's happening now 

During COVID-19, the Water Bureau continues to work on critical infrastructure projects like Washington Park Reservoir. Projects like this contribute to the economy and support our workforce. We are closely following OSHA, the governor’s and the CDC’s safety guidelines to keep our crews and their families safe.

During the summer and fall of 2020, the Water Bureau is pouring concrete sections of the reservoir roof, applying a water proof membrane and building a hillside at the worksite.

SW Sacajawea Boulevard traffic closure August 30 - September 4 for tower crane removal

Hard work by our contractor during the past few months means that they are ready to dismantle one of the two tower cranes at the work site. The tower crane will be dismantled into smaller parts by two smaller mobile cranes. Removal of the different crane parts via tractor trailer will require several trips.

What to expect:

  • Street closure timeline: SW Sacajawea Boulevard between SW Park Place and SW Sherwood Boulevard will be closed to all traffic all hours shortly after noon on Sunday, Aug. 30 to 7 a.m. Friday, Sept. 4. This closure applies to vehicles, bicycles, and pedestrians.
  • Early morning mobilization: Tractor trailers will begin arriving at approximately 5 a.m. Monday, Aug. 31. The mobile cranes that are used to dismantle the tower crane will arrive early to allow for orientation and for the operators to set up.
  • Restricted pedestrian/bike access: While bike and pedestrian access will not be allowed on SW Sacajawea Boulevard, the multi-use path on SW Lewis and Clark Way will be open for travel in both directions. People with bicycles will be required to walk along SW Lewis and Clark Way.
  • Delays: Expect traffic delays on SW Lewis and Clark Way and SW Sherwood Boulevard as trucks maneuver into position.
  • What you can do: Local residents and visitors to the park should watch for signs, plan extra time for trips, and consider alternate routes and modes of transportation to get to destinations.

The second crane will come down later this fall.

Concrete Pours

Managing the placement and curing of concrete at the Washington Park Reservoir Improvement Project is a delicate act, particularly during the warmer months. As concrete is placed and begins to cure, its temperature heats up. During warm weather, it can heat to temperatures that cause damage to the finished concrete. Also, to make sure that the concrete we pour stays consistent, we arrange for upwards of 35 truckloads to be poured and pumped one right after another. We start early in the day in order to control the heat levels so that the finished concrete is strong, and to make sure that we can finish our pour in one long day.

We expect to complete our large roof pours in the coming month, followed by several smaller pours for minor elements of the reservoir, including stairs, curbs and vents. We will also soon begin applying a waterproof membrane to the roof.

Here's what to expect with the remaining concrete pours:

  • Pours per week: Twice-weekly pours Wednesday and Thursday through the end of August, then weekly pours taking place through October
  • Location: The remaining roof pours will take place on the northern end of the reservoir. After that, pours for the more minor elements will take place in various locations around the reservoir.
  • Start time: 2:30 a.m. on warmer summer days, later on cooler days
  • Number of trucks for roof pours: 35
  • Typical number of trucks for minor pours: Ten or less
  • Truck Routes: Trucks arrive via SW Park or SW Jefferson (same as before)

Stabilizing an ancient landslide

In the area that was formerly Reservoir 4, crews are continuing work on a reinforced soil slope. They are layering rock, geotextile (plastic fabric), and engineered fill (a specialized mix of soils) to build up the hill. This will also provide drainage to prevent water from destabilizing the new slope and existing landslide. The combination of different materials allows crews to build a steeper hillside that will look similar to what was here before construction of the original reservoir in 1894. 

Trail and other closures

Madison Trail: Our contractor is accelerating their process to finish their work by this fall. That means they are carrying a higher volume of materials overhead an sending more traffic along Madison Trail. The trail will remain closed to keep people safe and to reduce the inconvenience of intermittent openings and re-closures. We expect this work to be complete and the trail to re-open by early fall. We apologize for the inconvenience. We're hoping our neighbors will put up with the temporary inconvenience knowing that it allows us to complete some of our more impactful work like concrete pours and crane lifts sooner than anticipated.

Other park closures: Explore Washington Park added a COVID-19 resource page to their website with updated maps and information about openings, closures and safety suggestions at

See photos of work performed in our most recent e-newsletter HERE.

Noise Permit extension: Information HERE

To see a map of the construction site, click HERE.

Watch a video showing how the elements of the new reservoir fit together within the footprint of the historic reservoir HERE.

Project Overview

Including the project description, map and schedule

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Community Outreach History

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