Water Providers Check Their Seismic Fitness
Water providers around the region work everyday to keep clean and safe water flowing 24/7. This section of the website will highlight projects our members are working on to ensure that our region’s water system is robust, properly maintained, and there when you need it.
The Pacific Northwest, and the greater Portland metro area, isn’t usually thought of as disaster prone. But, in the world of water, emergencies come in all different shapes and sizes.
It is for this reason that the Regional Water Providers Consortium and its water provider members are focused on planning for events – small and large – that could impact local water supplies. Water providers work diligently to ensure that their water system can deliver you the water you need, when you need it 24 hours a day, 365 days a year. In addition, water providers are completing seismic upgrades and other projects to make water systems more resilient. Read about some of these projects below:
- The City of Gresham is in the process of developing a system-wide seismic resiliency plan that it will use to prioritize future projects such as installing earthquake resistant piping on critical mains and existing pump station retrofits. In addition, the City recently completed two seismic retrofits of its Gabbert Reservoir and Cedarville Pump Station, and will begin retrofitting its Hunters Highland Reservoir in 2017.
- The City of Beaverton is in the process of updating its Water Master Plan, which includes providing baseline data to guide the city’s future analysis of its seismic resiliency. The new combined ASR5/Sorrento facility will be built to be seismically resilient.
- The Joint Water Commission (serves all or portions of the Cities of Beaverton, Forest Grove, Hillsboro, and the Tualatin Valley Water District) completed a backup power facility at their water treatment plant in March 2016. The facility now contains two 2.5 megawatt diesel generators, capable of powering the water treatment plant at 50% capacity (37.5 million gallons per day). The building foundation, fuel tank, and electrical conduits are auger-cast pile supported and designed to withstand the 9.0 Cascadia Subduction Zone earthquake. The backup power facility provides power from the raw water pump station, through the water treatment plant, and to the finished water pump stations. The generators can also be dispatched by Portland General Electric to send power back to the grid to offset peak loading.
- West Slope Water District is in the process of seismically upgrading one of its storage tanks so that it meets current seismic code for a major earthquake.
- The City of Portland is finalizing its Water System Seismic Study. The study assesses the seismic performance of PWB’s water system in a Magnitude 9.0 earthquake on the Cascadia Subduction Zone. The system evaluation criteria for seismic performance are based on the target states of recovery outlined in the Oregon Resilience Plan.
New pump station and reservoir increase capacity for Sunrise Water Authority
The Sunrise Water Authority is about half way through two projects that will significantly increase its distribution system's capacity. The increased capacity is designed to meet the City's current growing demand - the city is rapidly expanding both in terms of new homes and commerce - and to meet a 20-year future demand with adequate fire and operational storage.
Located in the heart of the city, the project is comprised of two main parts - first, adding a pump station, and second, adding new reservoir for storage. The pump station is scheduled to be completed by mid-July 2016, and will have a final capacity of 2,700 gallons per minute and will serve the largest and newest reservoir within Sunrise’s distribution system. Next year, Sunrise will complete the second project by building a new four million gallon reservoir.
The total construction cost for both projects are estimated at just under $7,000,000 and together they will increase the system's overall capacity to serve a peak of 15 million gallons per day.
Tualatin increases its storage capacity with new reservoir
The City of Tualatin is mid-way through constructing a one million gallon water storage reservoir which, when completed early next summer, will more than double the amount of water available for the southeast Tualatin.
Located at the City's Frobase reservoir site, the project also includes installing mechanical mixers in both reservoir tanks. The new mixers will result in improved water quality and ensure that water moves from the tanks and through the distribution system more efficiently.
The project will also allow a higher level of resiliency and system flexibility for the city. The storage reservoir is being built to seismic standards and will allow the City to perform preventive maintenance activities on the reservoirs such as cleaning, inspecting, and painting them. The total cost of the project is about $1,000,000.00.
Lake Oswego Tigard Water Partnership Prepares for the Big Quake
With recent studies predicting a major earthquake occurring in the Pacific Northwest sometime within the next 50 years, the Lake Oswego Tigard Water Partnership is taking steps to ensure the survivability of its drinking water system. By requiring each of its new water supply facilities to be designed to remain functional after a large earthquake, the Partnership is improving its odds of bouncing back quickly from a significant seismic event. Here are several design features that will help keep water flowing soon after an earthquake:
- A new, reinforced concrete river intake pump station on the Clackamas River is anchored to basalt bedrock with 14 ground anchors. It also features retractable fish screens to protect against river debris and a fully redundant electrical supply from Portland General Electric (PGE), which keeps power flowing if the primary supply is out.
- Critical treatment facilities and pipelines at the new water treatment plant are supported by 1,110 feet-deep reinforced concrete piles to keep them in place during shaking. This facility also features a fully redundant electrical supply from PGE.
- The new, large-diameter water pipelines are made from steel with each joint double welded for added strength. This design is based on the performance of similar large pipelines that survived earthquakes in Japan.
- The new 3.5 million gallon reservoir utilizes seismic cable connections between tank walls and a foundation specially designed to move without cracking or leaking. Pre-stressed concrete is also used to increase resiliency as well as seismically-activated closure valves on inlet and outlet pipes, which protect against tank emptying should connecting pipes be damaged.
- The new Bonita pump station is also designed to be resilient against large seismic events, featuring discharge pumps with their own foundations and flexible couplings. These design features allow the pumps to move independently from the building during an earthquake. In addition, the building utilizes reinforced masonry shear walls that prevent crumbling.
With these new features, businesses and residents in Lake Oswego and Tigard will be protected by one of the most resilient water supply systems in Oregon.
The Partnership continues to make good progress, and most major facilities and pipelines will be ready for operation in 2016. Here are a few key milestones the project recently reached:
- Almost 9 of the 10.5 miles of pipe have been installed from Gladstone to Tigard
- The new river intake pump station is complete and in operation.
- The new water treatment plant in West Linn is 70 percent complete. Final completion is expected in early 2017.
- The new Waluga Reservoir is complete and in operation.
- The new Bonita Pump Station in Tigard will be completed next month and commissioning into service will begin soon.
Water Providers Collaborate on Washington County Supply Line Projects
Three water providers - Tualatin Valley Water District (TVWD), City of Tualatin and the Portland Water Bureau - are working together on two projects on the Washington County Supply Line (WCSL) which delivers 60 million gallons of water from the Portland Water Bureau to west side wholesale customers.
First, TVWD and the City of Tualatin are partnering together on an emergency pump station for the WCSL. The trailer-mounted portable pumps can be used to redirect up to 10 million gallons of water a day via the WCSL from TVWD’s Wolf Creek service area to TVWD’s Metzger service area and the City of Tualatin in the unlikely event water supply from Portland is disrupted due to an emergency or natural disaster. Second, Portland Water Bureau took advantage of the construction window to upgrade the meter that measures the amount of water that they sell to a portion of TVWD’s service area.
By working together, the water providers were able to develop an important back-up water supply using existing infrastructure, improve resiliency, and achieve cost savings by coordinating construction projects.
City of Gresham’s Gabbert Reservoir Seismic Retrofit Project
The Gabbert Reservoir is a 200,000 gallon steel tank used as part of the City of Gresham’s water distribution system. It was originally constructed in 1969 without much though given to the impact of earthquakes.
In 2014, the City retrofitted the reservoir to withstand forces generated by a Cascadia Subduction Zone earthquake by installing 60-foot long steel rods that are anchored in bedrock and 2-inch thick steel anchor chairs to the reservoir. Retrofitting the reservoir enabled the City to save approximately $500,000 as compared to the cost of constructing a new reservoir. And now, Gresham has a more resilient water system to serve its customers.