The Willamette River Crossing Project will strengthen Portland’s water system and keep water flowing to the west side – even after an earthquake.
If a major earthquake struck Portland today, the city core wouldn’t have reliable water for six months or more. That’s because the water mains (pipes) crossing the Willamette River are more than 50 years old and they are in liquefiable soil – soil that has a lot of water and will shift and move like liquid during an earthquake. Those pipes probably wouldn’t survive a big quake. That means no water to drink and flush toilets, no water flowing to fight fires and no water to help people in critical facilities like hospitals. It also means billions of dollars of economic damage to the whole state of Oregon.
What is liquefaction?
Liquefaction happens when vibration in soil, like when an earthquake makes the ground shake, causes the soil particles to lose contact with one another. As a result, the soil behaves like a liquid. Watch a video to learn about liquefaction here.
The River Crossing Project is part of our commitment to preparedness. Installing an earthquake-resilient water pipe deep under the Willamette River will help deliver water to the west side and downtown after an earthquake. This water pipe is the next step in strengthening our system and keeping water flowing.
We’ve thoroughly studied potential locations for the new crossing. The study pointed to the areas outlined in orange. The west connection for the new pipeline will be near RiverPlace and SW Naito Parkway. The east connection point will be near SE 10th Avenue and Harrison Street.
We're Digging Deep: Here's Why
We’ll combine horizontal directional drilling and microtunneling to bury pipe deep in bedrock under the Willamette River. Crews won’t work in the river which will reduce impacts to shipping, recreation, and fish habitat. Crews will also store 1,600 feet of pipe in a tunnel deep underneath the busy commercial zone on the east side before feeding it under the river. This means less impact on businesses, traffic and the public.
Whats Happening Now
We need to know exactly what’s underground before we go “full bore”—so first we’re collecting data from a geotechnical probe, or Geoprobe. This will allow us to map the types of soil and rock along the proposed crossing route.
A Geoprobe machine looks like a tractor with a large ladder. What looks like a ladder is actually a rig that probes soil. Instead of drilling, the Geoprobe hydraulically pushes tools and sensors up to 200 feet below the surface.
The Geoprobe will provide samples along the drill path for geotechnical engineers to analyze. It can also record data from underground tests:
- Conductivity: how electricity passes through the soil.
- Pressure: soil characteristics, such as grain size and strength.
The samples and test data will help us map what’s underground, to chart the best way so that we can proceed beneath the river.
What to Expect: Traffic and Noise
- Temporary/intermittent lane closures on SW Naito Parkway: Temporary lane closures will be in effect on the right lane of northbound Naito Parkway as crews move equipment on and off the site. Closures will take place 9 a.m. to 3 p.m., Monday - Saturday.
- S Harbor Drive (Southbound): Temporary lane closures will be in effect on the southbound Harbor Drive and streets that approach Harbor Drive as crews move equipment on and off the site. Closures will take place 9 a.m. to 3 p.m., Monday - Saturday.
- Equipment noise will be approximately 90 decibels. (A power lawn mower is approximately 100 decibels.) Over a period of six weeks in July and August, geotechnical investigation and drilling will generate noise, Monday to Saturday, both days and nights. The loudest tasks will be completed before 10 p.m.
Please allow extra time for travel and respect work zone safety cones, detours, and flaggers.Learn more about the WRX project at portlandoregon.gov/water/wrx.