Up to 8 million gallons of water sits perched above the northbound lanes of Highway 217 just south of the Sunset Highway interchange.

By design, however, this perch is anything but precarious.

The Tualatin Valley Water District is wrapping up construction on the state-of-the-art Ridgewood View Park Reservoir and Pump Station, built to withstand a catastrophic earthquake and keep on delivering drinking water from its hilly neighborhood throughout the sprawling district.

“It’s built to last at least 100 years,” said Nick Augustus, TVWD’s project manager.

The $30 million project includes rebuilding and improving Ridgewood View Park, which sits alongside the water reservoir and even uses its surface for tennis and pickleball courts.

The new reservoir and pump station have been in operation since last month and the park should be finished before its West Slope neighbors and the wider community gather Sept. 20 to celebrate the project’s completion.

The project took two years to build and replaced a 5 million gallon tank that had been at the site since the early 1970s, when the Wolf Creek Water District served the area before a later merger created TVWD. The project also replaces a nearby pump station and added more than a mile of 24-inch welded steel pipe that ties it into the existing water system.

The original tank’s ceiling beams were beginning to fail when the district took that reservoir out of service in late 2011 and began planning its replacement, Augustus said.

The larger tank has five sides so that the district could increase storage capacity but still stay within existing property lines, he added. From there, the reservoir can take in water from current and future sources and deliver up to 11 million gallons a day — more than its entire capacity.

The sophisticated pump station is fully automated and equipped with valves to receive and distribute water under vastly different amounts of pressure in the hilly region, Augustus said. A backup generator will keep the water flowing during power outages. One of the largest nearby customers is Providence St. Vincent Medical Center, where the need for water during emergencies is critical.

Bringing the larger reservoir and pump station online will help the district keep up with demands in the growing district, especially during periods of increased water usage like those the district saw during the exceptionally hot summer of 2015.

“This will definitely help with that,” Augustus said.

The Ridgewood View project has been awarded the Institute for Sustainable Infrastructure’s Envision rating system’s Gold Award for its sustainable design. The water and park districts were the first in Oregon to receive this award for building environmentally friendly features into the project, including large rain gardens that collect and filter natural runoff from atop the massive reservoir.

The Ridgewood View reservoir is the most costly project in TVWD history, but it’s a record that is not expected to stand long.

The district and partners are in the process of planning a much larger Willamette Water Supply Program, which includes a massive amount of infrastructure including two new 15 million gallon reservoirs on Cooper Mountain, where the water delivery system takes advantage of gravity.

Even before construction of the Willamette project ramps up fully, TVWD is starting to plan for a new project to replace another aging 5 million gallon reservoir. That tank is on Southwest Grabhorn Road, also in the Cooper Mountain area south of Aloha.

Such projects are designed to increase the capacity and reliability of the district’s water system, but they come with a cost.

Last week, the district’s board of directors approved a rate increase that will add about $10 to a typical residential customer’s bimonthly water bill, the district’s funding source for such infrastructure improvements, said district spokesman Alex Cousins.

Ridgewood View Park improvements

During the two-year construction project, Ridgewood View Park has been torn up and closed to the public.

That will change in the coming weeks as workers put the final touches on the park property, those changes coming largely at TVWD’s expense for taking the Tualatin Hills Park & Recreation District facility out of service.

The new park that opens later in September will show vast improvements from the old one that was most recently open in 2014. The enhancements were based in large part on community requests, Cousins said.

The new park again will have tennis courts with a commanding view from atop the water reservoir, but now, those courts also will accommodate a couple of games of pickleball on courts that overlap one of the tennis courts. (Players must bring their own pickleball nets and other equipment.)

At ground level, the new park will feature a much larger playground, including a larger structure on a safer SMARTE artificial surface and a more natural play area that uses boulders and logs from the project site.

One of the most anticipated additions is a new bocce court near the entrance. The Italian ball sport is gaining followers across the Portland area, where courts can be tough to come by. THPRD also is developing more bocce courts elsewhere to help meet this demand.

There also is a new covered picnic structure, a seasonal portable toilet, a nicer parking area off Southwest Ardenwood Street, and an improved trail system through the woods, connecting with Ridgewood Elementary School to the south. A new bridge spans a periodic creek that collects rain runoff during storms and is known as Ephemeral Stream.

“The redeveloped park gives the neighborhood a wider variety of amenities,” said Bob Wayt, spokesman for THPRD. “We realize the lengthy closure of the park was an inconvenience, but we hope the neighbors will agree the wait was worth it.”

Project Celebration

The Tualatin Valley Water and Tualatin Hills Park & Recreation districts are inviting the community to celebrate the completion of a new water reservoir and pump station and the reopening of an improved Ridgewood View Park.

When: 5-7 p.m. Tuesday, Sept. 20

Where: 10001 SW Ardenwood St., just east of Highway 217 and south of U.S. 26 (use street parking or park at Ridgewood Elementary School)

What: Pump station tours at 5:30 p.m., dedication at 6 p.m., food catered by nearby 808 Grinds (Hawaiian café), kids’ activities, sports demonstrations and more.