Meeting will update Scoggins Dam neighbors on potential new site that could flood their property
About 30 property owners near Scoggins Dam east of Hillsboro are still wondering if their homes will be flooded by a new dam that's not only better equipped to hold up against a major earthquake but designed to hold more water as well.
The short answer is still maybe.
The current dam at Henry Hagg Lake near Gaston provides water for much of Washington County, supplying local businesses, farms and about 400,000 people.
For 15 years, county, city and state leaders have been discussing dam upgrades that could improve safety and storage as population projections skyrocket.
Project leaders held a meeting with surrounding property owners in October 2015 to discuss the two main options for upgrading the dam, said Mark Jockers of Clean Water Services: Strengthen and raise it at its current site or move it to a new site downstream.
The downstream-dam option would require a much smaller, less costly dam — only 1,000 feet wide, rather than the current 2,500-foot wide dam — because it would be located in a narrower part of the valley.
But it would inundate the Stimson Lumber Mill and nearby property owners.
The other option would strengthen and raise the dam in its current location. Various dam strengthening options have been considered since 2007, when scientists discovered the likelihood of a 9 magnitude or greater earthquake hitting the Pacific Northwest and federal Bureau of Reclamation (BOR) officials realized they needed to upgrade the dam's seismic protection.
An earthquake of that magnitude would flood surrounding areas and could spread floodwaters as far as Washington, Clackamas and Multnomah counties, given that Scoggins Creek (and Hagg Lake's water) run into the Tualatin River, which winds through all those areas.
A plan to bolster the current earthen dam by widening its crest and adding huge amounts of soil to its east wall turned out to be so expensive, project leaders decided to look again for less expensive options, Chris Regilski, BOR's Pacific Northwest Region Dam Safety Liaison, told the News-Times in 2015.
The agency did a value-planning study to consider a number of new ideas, working with Clean Water Services (CWS), which has been pondering how to upgrade Scoggins Dam for nearly 15 years to increase the local water supply.
In 2016, Congress reauthorized Reclamation's Safety of Dams program to include other benefits such as additional water storage.
By late summer or fall of this year, project leaders will drill the foundation rock at the downstream location to determine if the structure is well suited to host a dam. Tom VanderPlaat of CWS said it will likely be one to two years before they have a good understanding of the proposed area that would host the downstream dam. "It's not a fast process," he said. "We need a wide variety of studies to make a big decision."
VanderPlaat will be answering questions and updating the public at a meeting at 7 p.m. March 22, at the Scoggins Valley Church, 50085 S.W. Scoggins Valley Road.
"I appreciate that I'm frustrating their lives in a very direct way and I never say I understand because I don't have someone trying to make me potentially move my home," said VanderPlaat, adding that any property owners who had to move would be compensated. "I'm trying to provide information as timely as possible so people can make the life decisions they need to make."