Lake Corporation headquarters taking shape
Drivers on McVey Avenue have likely noticed a new structure taking shape at the Lake Oswego Corporation headquarters next to the Oswego Lake dam. The framework is in place on a new two-story marina and office building, and it will soon be followed by a new boathouse.
Both structures are being built as part of a project to expand the Lake Corp.'s headquarters and ensure that it can survive a Cascadia-level earthquake so that the corporation can maintain control of the dam in the aftermath.
The project was originally scheduled to be completed by Memorial Day. Things are running behind, but Lake Corp. Manager Jeff Ward says there's a very good reason for that.
The original plan was simply to build second stories on top of the previous marina and boathouse buildings, but when crews began to strip out the walls late last year in preparation for construction, they found significant structural problems in both buildings.
"When we got in there, we had to tear them all the way down," Ward says. "Everywhere we went, we just discovered stuff."
Some of the problems were simply due to natural wear and tear on the aging buildings, and others stemmed from errors in the original construction. The boathouse was built in 1942, and Ward says the marina was added at some point in the 1950s or 60s — long before the full danger of a Cascadia-type earthquake was publicly known.
"They were built more like clubhouses," he says of the two buildings.
The marina's foundation was salvageable with some maintenance work, but it turned out that the boathouse foundation would have to be rebuilt entirely. One side of it rested on the dam itself, which is embedded into bedrock and is quite sturdy, Ward says. But the other side was essentially just built on platforms, and it turned out those platforms rested on 20 feet of sand.
To ensure that the new foundation could withstand an earthquake, crews had to drive pilings 20 feet down to reach the basalt layer under the sand, then pour a new foundation on top. That part of the project was recently completed, Ward says, with construction on the boathouse framing set to begin this week.
The expanded scope of the work resulted in a significant delay to the project, not only because of the construction time but also because the new plans had to be re-approved by the Development Review Commission.
The original buildings had some exemptions to normal zoning rules in order to be located at the edge of the water, but they only applied to those specific structures. Even though the replacements will occupy essentially the same footprint as their predecessors, the corporation had to apply for new exemptions.
The new requirements also created a large cost increase, but Ward says the Lake Corp. board understood the need in order to be prepared for an earthquake.
"The boathouse, that was spendy," he says. "We had a significant cost overrun on it, but you couldn't not do it. The good news is, it's not going to go anywhere now."
In addition to being earthquake resistant, the new buildings will include rooftop solar panels and a battery backup system for the computers that monitor the dam, so officials can maintain control in the event of a power outage. (In an emergency, Ward says, the dam can also be lowered mechanically without electricity.)
Ward says he now expects the construction to be finished at some point in the summer, but the corporation plans to have the boat launch ramp at the site up and running within the next couple of weeks, along with the fueling station.
Lake Corp. staff have been working out of a temporary office in Foothills during construction, but Ward says once the boat ramp opens, they'll try to have one person on site to monitor launches.
"You'll be able to pull a rig in and back a boat down the ramp," he says. "That's the main thing."
The timing also works out because mid-April is right around the time when Oswego Lake is expected to reach nearly full capacity after slowly refilling for the past several months. The lake was partially drained last fall as part of a regular procedure to give lakefront homeowners a chance to inspect their docks and other water's edge installations.
The lake can be refilled relatively quickly by allowing water from the Tualatin River to flow in through the Oswego Canal, but Ward says the corporation timed this year's drawdown so that the lake could be slowly refilled by rainwater and still be full before the summer.
The usual fill level is 98.6 feet, he says, but 98.3 is the minimum for normal use, and he expects the lake to reach that point after the rain this week. Allowing it to refill naturally will give the corporation a leg up in fighting algae this summer, he says — the Tualatin River shows comparatively higher levels of pH, which fuels algae growth.