Nathan Denzin:
Can you look at a dam and say, "That's about to fail," or, "That's sturdy"?

Mark Erickson:
It's harder than that, just looking at it. You know, these dams have history. They were, they've been well documented since I would say the mid 1980s, so as you're walking around structures during flood events, you pick up on details that show themselves, whether it's downstream seeps or settling, unusual settling. We've went through and investigated the pipes internally, so we know that data. That's just all part of the dam inspection process that we do and documentation for DNR.

Nathan Denzin:
Right. But you couldn't just walk up to the dam when it's dry and say, "I don't know, that looks sketchy," or, "That looks safe to me."

Mark Erickson:
That'd be a lot harder to do that. I mean, if there was a glaring weakness, it might be that it's already too late.

Nathan Denzin:
Right. I want to talk a little bit more about the danger that they would pose too. Is there a different danger level between overtopping and breaching? Like, is one more dangerous than the other or do they both pose a similar threat?

Mark Erickson:
Well, I would say overtopping would be, you would be storing more water. You'd have a bigger pool that would flow down the valley. You know, a breach can happen at any pool level really, but as you increase your pool depth, that's when the breach becomes more dangerous downstream. It's more water you're holding back. This dam and another dam did overtop in the 2018 event, so what that means is that we had a three-foot pipe, concrete pipe, going through this structure that was running full bore with 35 feet of head on it, and we had a grass ramp where that dozer is, and that grass ramp spillway was flowing full, and it still couldn't keep up to the rain coming down the valley, and it overtopped the whole structure.

Nathan Denzin:
Yup. So, that's a lot of, I mean, that's an insane amount of water.

Mark Erickson:
Yeah, and the storms that are tracking are getting more severe and pushing these structures to their limits, and they're hydraulically not capable for some of those bigger events.