The pipes that carry water from the east to west side of the Willamette River are more than fifty years old and will probably not survive a major earthquake. This could leave Portland’s city core without reliable water for six months or more. The Willamette River Crossing Project will deliver water to the west side of the river, even after an earthquake. Investment in this project makes sure that we can fight fires and provide water to critical facilities like hospitals. The project is key to our region’s ability to recover economically after an earthquake.
The Portland Water Bureau has worked for the past several decades to increase the number of water supply facilities that can withstand earthquakes. Reservoirs at Kelly Butte and Powell Butte on the east side, and the future reservoir at Washington Park on the west side were all designed to meet current seismic standards. The Willamette River Crossing is the next step in strengthening our system to make it more earthquake-resistant, and critical for bringing water to the west side.
The project budget is $88 million. As part of the Water Bureau’s Capital Improvement Program, this project is funded by revenue bond proceeds paid back with the utility ratepayers’ fund.
Work schedules can change for many reasons including weather, traffic and problems with tools, machines or supplies. Sometimes we need to stop between different types of work and start again later.
Once construction starts, work hours are expected generally to be between 7 a.m. to 5 p.m., Monday through Saturday. However, some work will take place overnight between 6 p.m. and 6 a.m. We will coordinate overnight hours with affected property owners, businesses, tenants, and transportation agencies. Work schedules are subject to change to due contractor availability and weather.
Much of the work will take place in parking lots on the east and west side of the river, with some of the work taking place on surface streets on SE Stephens and SE Harrison between SE 7th and 10th Avenues.
Project timeline and phases
The project has two distinct but overlapping phases: exploration/design and construction. For example, geotechnical exploration during the design phase provides information to inform design but also includes construction elements that will be used during the water main installation. During construction, the project design will be confirmed at each step and may be revised based on newly discovered conditions.
The project is currently in the exploration/design phase. Along with utility locates, site exploration and soil testing, this phase includes conducting a geotechnical probe which will provide essential information on how the geology beneath the river will impact the construction. Geotechnical probes directly push tools and sensors into the ground using hydraulically powered percussion — a bit like a jackhammer. Conducting the pilot bore – the geotechnical probe – will help us determine the best tools to use for the future pipeline, and the best path across the river.
Fall 2019, Design Phase 1: Pre-construction Activities
- Soil sampling: On the east and west sides of the river, crews dug in the street, sidewalk, and public right-of-way to find the exact location of underground utilities and assess conditions at the site. After completing exploration, we restored the right-of-way with similar materials as needed.
- Preparing “Block J” (1720 SW Naito Parkway): Crews fenced off the parking lot at SW Naito Parkway between Harrison and Market to prepare for the geotechnical probe. They will dig a hole 20 to 30 feet deep in the parking lot and place the equipment for the geotechnical probe into the hole.
Winter-Spring 2020, Design Phase 2: Westside connection and geotechnical investigation
Westside connection: Several years ago, the Water Bureau installed a large water pipe called the “Westside Header” on the west side of the Willamette River. This 5,000-foot long water pipe receives water from the east side of the river, then carries that water to the pipe system along the west side of the river. During this phase, crews will add a connection to the Westside Header to get it ready for the new Willamette River Crossing.
Public impacts: Traffic will be temporarily diverted as crews dig a trench in SW Naito Parkway between Market and Harrison Streets.
Geotechnical investigation: We need to know what’s underground before we go “full bore.” Drilling a pilot bore – a geotechnical probe – will help us identify the types of soil and rock deep underground. This will help us determine the best path beneath the river. A 12-inch diameter probe will drill a pilot hole from the parking lot on the west side, along the proposed pipe alignment to the east side. Crews will not have to disrupt traffic by digging a trench because the probe will be steered while underground. As the probe bores its way along the pipe alignment, its computerized drill bit will send information to the surface about what it encounters.
Caption: The geotechnical probe will follow the same path as the Horizontal Directional Drill.
Fall 2020-Spring 2021, Construction Phase 1: Eastside connection, eastside shaft, and microtunnel
Eastside connection: Just as the Willamette River Crossing pipe will need a connection to the Westside Header (mentioned above in Design Stage 2), it also will need a connection to the eastside water pipes that bring water towards downtown from Powell Butte Reservoir. This work will occur at the same time as construction noted below. This work is depicted as Open Trench work in the diagram below.
Public impacts: There will be lane closures during this stage as we dig trenches along SE 7th Avenue between Stephens and Harrison, and on SE Harrison from 7th to 10th. There will be road and lane closures during this stage.
Eastside shaft: We will build an 80-foot-deep, 50-foot-diameter shaft (hole) in a parking lot near SE Water Ave. and Clay St., half-way between the east and west side connections. The shaft will be used to begin digging a microtunnel to the east and the horizontal directional drill to the west. Workers in the shaft will connect the long string of pipe we store in the microtunnel with the pipe we install using Horizontal Directional Drilling.
Public impacts: The area will experience increased truck traffic as trucks remove soil from the shaft and the hole we dig as we build the microtunnel.
Microtunnel: The microtunnel is a small tunnel boring machine. The machine will dig a hole nine feet in diameter, similar to, but much smaller than the 58-foot-diameter machine that excavated the Alaska Way Viaduct in Seattle, Washington). Our construction team came up with an innovative idea build this microtunnel between SE Water and 7th Avenues so that we can store a 1,900 -foot- long section of water pipe deep underground instead of digging a trench that would severely disrupt neighborhood traffic and businesses.
Winter 2021-Fall 2022, Construction Phase 2: Horizontal Directional Drilling (HDD)
Horizontal Directional Drilling (HDD): Once the shaft and the microtunnel are complete, HDD will be used to dig a 1,800-foot-long hole beneath the Willamette River. This hole will be kept full of thick mud to keep it open until a water pipe can be installed in it. The HDD hole will start in Block J on the west side of the river and end in the eastside shaft. It will take 4-5 months to enlarge the HDD hole enough to fit the new water pipe into the hole.
Public impacts: Trucks removing soil excavated by the HDD at Block J on the west side of the river may temporarily block traffic.