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Green and resilient

Decisions made early on by the Lake Oswego-Tigard Water Partnership were designed to make the project energy efficient, environmentally responsible and earthquake resistant


SUBMITTED PHOTO - The Lake Oswego-Tigard Water Partnership's water treatment plant boasts a solar array with 110 panels that generate up to 32 kilowatts of power. When generating capacity exceeds demand at the plant, the excess is delivered back into the utility grid.  A year and a half shy of its projected completion date, the Lake Oswego-Tigard Water Partnership received a rebate check for more than $82,000 from Energy Trust of Oregon.

The check was in recognition of the project’s use of energy-efficient equipment — specifically the upgraded variable-frequency drives at its River Intake Pump Station that now require much less energy to pump water from the Clackamas River.

“It’s been nice to see (efficiency efforts) come to fruition, even though the project’s not yet done,” said Jordan Imlah, the partnership’s citizen information coordinator.

Those efforts are part of the $254 million project’s multi-pronged approach to reducing its overall carbon footprint, integrating the reuse of materials and protection of natural resources while putting a premium on seismic resiliency not only at the river intake station in Gladstone but also at the Bonita Pump Station in Tigard, a water treatment plant in West Linn, a new reservoir in Lake Oswego and along more than 10 miles of welded-steel pipeline.

“There were several objectives we knew we wanted to achieve,” says Joel Komarek, the project’s director.

First: longevity.

“We wanted the design (of the entire project) to be robust enough, and to incorporate robust materials, so that it would last 75 years or longer,” he said, adding that the partnership also wanted to ensure the project was consistent with Lake Oswego’s “strong sustainability ethic.”

One of the best examples of that effort can be found at the partnership’s water treatment plant in West Linn, where 110 large solar panels are projected to generate up to 32 kilowatts of power — enough to literally keep the lights on, and then some. “When we’re not using as much energy,” Komarek said, “the extra gets sent back into the grid.”

At the water treatment plant, “we knew we wanted to design features that minimized energy use for artificial lighting, heating and cooling,” Komarek added, “and to incorporate design features that didn’t require the construction of expensive storage and conveyance systems.”

Adding to the water treatment plant’s efficiency is a new system of using existing water to cool the plant, employing a heat exchanger to take advantage of cooled water “to act as a heat sink and thereby reduce our cooling needs,” Komarek said.

Meanwhile, fish screens have been installed at the pump station in Gladstone for the safety of local species, as well as to protect the pumps from being damaged by free-floating debris that might result from a catastrophic event. In fact, all of the partnership’s facilities were designed to withstand worst-case earthquake scenarios — another facet of sustainability.

“In a large seismic event, one of the most important things a city can do is make sure its community has water for sanitation and drinking and fire-suppression,” Komarek said. “So we wanted to make sure (the system) would continue to be able to produce water.”

That means safeguarding manpower as well.

“For our water treatment operators, if they’re in that building when the shaking starts, (we want to ensure) that their lives are not at risk, and that they can remain in and continue to operate the building,” Komarek said.

In the project’s design phase, that necessitated consulting the International Council on Codes, the American Society of Civil Engineers and a variety of engineering firms that have conducted forensic studies of areas of the world where large-scale earthquakes have proved devastating — Japan and Christchurch, New Zealand, for example — to learn from their successes and mistakes.

“What we chose to do, even though we knew it was going to add a premium to the cost of construction, was self-select important (design elements) that are consistent with those used for essential facilities, like hospitals and police stations,” Komarek said.

It wasn’t cheap, of course: Komarek pointed out, for example, that double-welded lap joints on all of the system’s pipes came with an added $1 million price tag.

“In most cases for steel pipe design, it’s typical and more customary to just use a single-joint weld,” he said. “But to add that second weld to every joint increases the ability of the pipe joint to remain intact” — and ensures that water will continue to flow to Lake Oswego and Tigard.

Similarly, each critical structure at the water treatment plant, including the pipelines, is supported by a foundation of 1,100 concrete piles that are drilled and cast and anchored to the site. That’s a $3 million design decision, Komarek said — and the safest option.

“It makes sure that even when the shaking occurs, even when surrounding soils might settle or liquify, that all the structures on top of the piles remain in place and operable and occupiable,” Komarek said.

Similar measures are in place at the Bonita pump facility, where two energy sources provided by Portland General Electric are meant to guard against a complete power outage. And closer to home, the Waluga Reservoir 2 in Lake Oswego is outfitted with “seismic cable connections,” Imlah said.

“They’re inside of the concrete, which helps the foundation move without cracking the walls, so there’s some give with it,” he explained. “It’s pre-stressed concrete, which helps prevent cracking as well.”

Another resiliency measure in place at Waluga 2: In the event that something breaks along the pipeline, an activated closure valve would automatically close to prevent drainage from the reservoir.

Not all of the partnership’s sustainability measures are in anticipation of doom, gloom and scarcity, however. In West Linn, garden roofs, bioswales and ponds — as well as pervious driveways and sidewalks — reduce stormwater runoff and replenish groundwater. Crews have recently removed invasive species like poison oak and blackberry bushes from all around the reservoir in Lake Oswego, allowing native trees and other indigenous flora — all of which require much less water and maintenance — to truly flourish.

An added bonus?

“Since they’ve cleared the site, we’ve seen an increase in deer,” Imlah said.