The Portland Water Bureau and contractor Hoffman Construction Company have started a long-term capital improvement project to update the Washington Park reservoir site at 2403 SW Jefferson Street. The project complies with federal and state mandates, seismically strengthens key water infrastructure on Portland’s west side, and helps ensure a healthy, resilient, and secure water system.
A new 12.4-million gallon, seismically reinforced below ground reservoir will be constructed in the same footprint of existing Reservoir 3 (upper) with a reflecting pool/water feature on top. The new reservoir will preserve the historic drinking water function provided by the original reservoirs and be engineered to withstand ongoing landslide encroachment and potentially catastrophic effects of a major earthquake.
When complete and online, the new reservoir will supply water to Portland’s west side and serve more than 360,000 people, including all downtown businesses and residents, 20 schools, five hospital complexes, more than 60 parks, and the Oregon Zoo.
Existing Reservoir 4 (lower) will be disconnected from the public drinking water system and a lowland wildlife habitat area, bioswale, and reflecting pool will be constructed in the basin.
Construction started Sept. 12, 2016 and will proceed through 2020. A pause is scheduled to occur from 2020 to 2022 to allow soils to settle. From 2022 to 2024, construction of interpretive features, including the two reflecting pools and surface features, will conclude the project.
FIVE MONTHS AT-A-GLANCE
|Install Tree Protection Fencing||Around project site||X|
|Begin Removal of Grand Staircase||Within project site, by Existing Reservoir 3||X|
|Remove Gatehouse 3 Platform||Within project site, by Gatehouse 3||X|
|Remove Plastic Liner||Within Existing Reservoir 3||X|
|Vegetation / Tree Removal||Around the existing reservoirs, by SW Sacajawea Blvd. and SW Sherwood Blvd.||X|
|Removal of Stilling Tank inside Gatehouse 4||Within project site, by Gatehouse 4||X||X|
|Modify Reservoir 4 concrete liner||Within Existing Reservoir 4||X||X|
|Erosion Control (ongoing)||Within project site, by Existing Reservoirs 3 and 4||X||X||X||X||X|
|Fill Reservoir 4 Basin||Existing Reservoir 4||X||X||X||X|
|Construct Upper and Lower Shoring Walls||Within project site, by Existing Reservoir 3||X||X||X||X|
|Install Piping||Under Dam 3||X||X||X||X|
ACTIVITY & IMPACTS
Until March 2018, major earthwork will occur along with the construction of shoring walls and the new underground reservoir. Work during this stage will cause temporary impacts to traffic, parking, and TriMet bus service.
|Current – March 2018|
||Multi-Use Shared Path
SAFETY IS OUR TOP PRIORITY
The traffic control plan in place until March 2018 has been approved by the Portland Bureau of Transportation with input from Portland Parks & Recreation, Explore Washington Park, neighborhood associations, and the community. Please contact us to share any concerns related to the project, including traffic control.
OCTOBER 2016 ACCOMPLISHMENTS
General Site Work
- Tree protection fencing has been installed to minimize impacts during construction.
- Vegetation and trees have been removed from in and around the project site. Of the approximately 210 trees removed, 19 percent (40 trees) are non-native/invasive. Roughly 47 percent (80 trees) of the healthy, non-invasive trees removed will be used in river restoration projects in the Sandy River Basin. These projects will help create pool habitat, increase cover, and improve spawning beds for migrating, spawning, and rearing fish populations. Several trees were also delivered to the Oregon Zoo for use in primate exhibits. After construction is completed, the Water Bureau has committed to plant 20 percent more trees and shrubs than required.
Reservoir 3 & 4 Work
- Existing Reservoir 4 inlet and outlet piping has been disconnected.
- Existing Reservoir 3 Grand Staircase has been partially removed.
- Gatehouse 3 platform has been removed.
- The plastic liner in Existing Reservoir 3, originally installed in the 1970s and later replaced in 2003-2004, has been removed.
- Erosion control at the site is ongoing.
- The Stilling Tank inside Gatehouse 4 will be removed.
- Existing Reservoir 4 concrete liner will be perforated to allow for drainage. As part of the project, existing Reservoir 4 will be removed and buried, making room for a large stormwater bioswale and wildlife habitat area with open water and connecting walkways.
- Existing Reservoir 4 basin will be filled in order to stabilize the historic landslide. Excavated material from Reservoir 3 will be moved inside the project work site to fill Reservoir 4. This will dramatically reduce construction impacts and truck traffic to local neighborhoods.
- Crews will begin construction on the first of two shoring walls, one temporary and one permanent, to protect the site from earth movement and allow for construction of the underground reservoir.
- Under Dam 3, piping will be installed.
KEEPING YOU UP-TO-DATE
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