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Portland Water Bureau

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1120 SW Fifth Ave, Suite 600, Portland, OR 97204

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Washington Park Reservoir Improvements Project

  • Washington Park Reservoirs 3 & 4 The Washington Park reservoirs are part of an historic district that includes the reservoirs and gatehouses.

  • Reservoir 3 The community proposed concept for the Reservoir 3 site includes a dynamic water feature on the top of a 15-million gallon underground reservoir.

  • Reservoir 4 The community proposed concept for the Reservoir 4 site includes a low-land habitat and water feature on top of overflow and dechlorination tanks. Reservoir 4 will be decommissioned and disconnected from the water system in 2020.

  • Reservoir Signage Notices such as these are posted to remind park visitors not to throw objects into the open reservoirs.

Washington Park Reservoir Improvements Project logo 


Click here to keep up to date on the Washington Park Reservoir Improvements Project's progress.

The Portland Water Bureau provides drinking water to more than 950,000 people and strives to provide the highest quality water to enhance the public health and safety, and contribute to the economic viability and livability of the Portland metropolitan region. The goal of the Washington Park Reservoir Improvements Project is to provide increased reliability of stored drinking water at the City’s Washington Park Reservoirs and to protect the water supply.

Project Background
The Washington Park Reservoir Improvements Project will replace Reservoir 3 with a 15-million gallon underground tank and update the existing Washington Park Reservoir 4 to serve as an overflow and stormwater retention facility, including a de-chlorination. In addition, due to a historic landslide to the west – dating back to a slide during the original construction in 1894 -- to the project will stabilize the hillside and isolate the reservoir from moving soil.

This entire project will be completed by 2020.

Historic Designation
The Washington Park Reservoirs Historic District was listed on the National Historic Registry on January 15, 2004. This means that the proposed work is regulated as in a historic district under City Titles 33.445.300, 33.445.320 and 33.846.  The area for the project includes Portland Water Bureau facilities that are both inside and outside the Reservoirs Historic District.


Project Area
The project work will be located at 2403 SW Jefferson St. in southwest Portland. The area is roughly bounded by SW Jefferson St. near the TriMet tunnel and Madison Trail on the east, by SW Lewis and Clark Circle on the north, by SW Oxford Road on the west and by fencing in the woods within Washington Park on the southwest and south. The project area surrounds and includes the two Washington Park reservoirs and related piping, vaults and pumping facilities, and landscaping that are operated and maintained by the Portland Water Bureau.

Reservoir 3 holds approximately 16.4 million gallons of water when full and Reservoir 4 holds 17.6 million gallons. These reservoirs are an essential part of the water system serving areas west of the Willamette River in the city.  The pumping facilities on the site ensure water can reach high elevations in the west hills.

The reservoirs, dams and gatehouse were constructed in 1894, with accessory structures completed slightly later. The area is landscaped with a variety of ground covers, trees and shrubs consistent with the reservoir location within Washington Park.  Several of the operational and decorative structures and elements within the Reservoirs Historic District are considered to be “contributing structures” in the National Historic Listing. The project area in the Reservoirs Historic District is surrounded by a chain link fence (the boundary of the Reservoirs Historic District is contiguous with or is just outside this fence in most locations).

Outside the Reservoirs Historic District, the project area includes vaults and piping that are in paved areas near Portland Water Bureau facilities or along Madison Trail, and pavement and gates on Madison Trail.  Madison Trail serves as a maintenance road for the Portland Water Bureau and Portland Parks & Recreation, and as a bike and pedestrian path within the park. It is not a public right of way. Several public walkways and trails traverse the project area outside the Reservoirs Historic District and intersect Madison Trail.

The Arlington Heights Neighborhood is to the north and west of the project area, and Goose Hollow Neighborhood is to the east.

Project Design
The project proposes to build a new below-ground reservoir in the same general footprint as the existing upper Reservoir 3, with a reflecting pool on top. Part of Reservoir 4 needs to be filled to stabilize the hillside above. The reservoir will be disconnected from the water supply and the remaining water body will include a lowland habitat area/bioswale and a reflecting pool. The public will have more access to the area and aesthetic design amenities will improve the visitor experience and understanding of the site.

Proposed project
Proposed project 

Upper Reservoir 3's proposed improvements Lower Reservoir 4's proposed improvements
Upper Reservoir 3 (left) and lower Reservoir 4's (right) proposed improvements.

Public Involvement Opportunities
The project team is currently working on finalizing design and permitting for the project. As more is known and major milestones approach, the project team will continue to provide updates to key stakeholders, including Neighborhood Associations. Type III and Type IV permitting processes involve hearings that are open to the public and will allow time for public comment. Visit the Project Updates page for the latest information.

Visit the Community Involvement page for a summary of the engagement activities during the visible features design process, including Community Sounding Board meetings and public open houses. 

Additional Information
For information about this project, check out the Frequently Asked Questions or contact Lindsay Wochnick, Public Information, at 503-823-3028.

Thank you for your patience and cooperation as the Portland Water Bureau works to improve the city’s century-old water system.  

Project Updates