Does Hills Creek dam make you nervous? (Portland, Eugene: earthquake, living)

[jinx98521]

This may sound rediculous, but.. Upon considering a move to Oakridge oregon, I came across Hills Creek dam. Does living so close to the dam make anyone else nervous? In the event of an earthquake, landslide, or any other natural disaster that could cause dam failure, it would completely wipe out Oakridge, Eugene, Springfield, and so many other towns. Of course, The people closer to Eugene/Springfield would have more time to evacuate, but still... Am I just being paranoid here? Does anyone else worry about the safety of their family while living so close to a major dam?

[Nell Plotts]

That dam has an Emergency Action Plan. Both the Corp of Army Engineers and the town of Oakridge should have copies.

The easy solution is to locate above the level of the reservoir.

Many dams were built before the risk of serious earthquakes were well understood but in all honesty the faults are located well off the Oregon coastline and the chance, IMHO, of dams failing for that reason isn't large. Heck, the failure of the Bonneville Dam would scour Portland metro. If we experience that level of earthquake all our bridges and most buildings would fail.

[Metlakatla]

There aren't many places to live "above the reservoir" there. It's higher in elevation than Oakridge proper, and residential dwellings are pretty much non-existent there until you get up past Willamette Pass. It's right on the edge of a National Forest.

http://projects.registerguard.com/we...ounty.html.csp

[bler144]

It would be a concern, sure, but realistically 'house fire' is still far more likely as a family emergency, and auto accident is a more likely cause of death.

[Billy_J]

An earthquake is the earth moving back and forth. Like a railroad car rolling forward and backwards on the rails.

Foundations of a house, which are attached to the earth, typically move back and forth with the earth. (It is the structure above the foundation which breaks - because it can't keep up with the earth's movements.)

Same with a dam. It is attached to the earth and also moves back and forth with an earthquake. So not to worry!

And they intentionally tried breaching dams in WWII. They had a very difficult time doing so because the concrete is so thick!

Other than that, when was the last time you heard about a dam breaking?

[Metlakatla]

Plenty of times...

The Johnstown Flood: the Worst Dam Failure in U.S. History - ABC News

That said, I'd actually worry more about living farther down the mountain than Oakridge if I were going to worry about the dam breaking. Although can won't be able to find housing "above the reservoir," you can driver there pretty quickly, and there are several roads besides Highway 58 that you could take.

[Nell Plotts]

In the NW the Teton Dam failed at first fill in the 1970s. Here is what happened in response: Safety of Dams Program, Bureau of Reclamation

[DCLS1957]

There's an old video on you YouTube called "Dams Disaster" posted by Largest Dams channel. It talks about dam safety and highlights the Hills Creek Dam in the video. Even though this video is old, it's one of my favorites about dam safety.

[texasdiver]

Here is what it looks like when a dam collapses.

Yes this is Brazil and different standards. But it was all caught on video and the footage is stunning:

https://www.nytimes.com/interactive/...-collapse.html

[Larry Caldwell]

I have a friend who retired from Oregon Water Resources Management. I asked him about the Hill Creek dam, and this is what he said:

It's a dam big pile of rocks? Seriously it's over 300 feet tall and the crest is a half mile or so. It's not the newest of the Willamette Valley projects but kinda in the middle it was finished in 61 so it did survive the the big one. It's operated as a flood control project so The rule curve for fill is weighted more for event captures and release until spring generally I wouldn't expect sustained full elevation until late April, early May. The regulating outlets and the hydro plant can release a lot of water. The emergency spill way is hardened with concrete it would be a serious event for water to be going over that. Pretty recreation in the summer. Google Willamette Project teacups to see where it fits size wise. If Cougar and Green Peter have water they're tapped before the boating reservoirs.

In other words, it's not normally full in winter, and is used to capture storm surge. Then they fill it up in the spring for recreation and irrigation water. Failure seems to be unlikely. "The big one" was the '64 Christmas Flood, our most recent 100 year event.