Eight Mile Lake flood could be catastrophic for hatchery

As previously reported in the Echo, a major flood on the Icicle Creek is possible in the coming months due to failure of the dam at Eight Mile Lake, which could send an additional 20,000 CFS down the creek, which would already be in flood stage.
The potential failure is due a fire last fall above the watershed of Eight Mile Lake, which burned all the trees, brush and grasses above the lake. The resulting snow melt could overwhelm the earthen dam there.
The historic high flows on Icicle Creek are about 15,000 CFS. Leavenworth National Fish Hatchery Complex Manager Dave Irving said he was only recently made aware of the potential flood.
“I know it was brought to our attention at one our recent Icicle Work Group meetings, because of the fire up there and the potential of runoff which could fill Eight Mile Lake and there could be some flooding with that,” Irving said. “It’s not like I’ve known it for a year or those kinds of things. The reconstruction of the dam has been talked about in the Icicle Work Group for quite sometime. The flooding is only a recent topic.”
Irving said, when talking about a flood, the number one concern is the impact on people, whether someone getting hurt or killed and then any kind of damage that would occur to property.
“When you start talking about the hatchery, we have people that live on site, so as the water comes down Icicle Creek and begins to flood the open area, you have people’s homes and property. Our concern would be people’s lives,” Irving said. “Beyond that, we have fish here on station, anything that would happen with that water, any kind of silt and material that’s caught up in that flood would probably plug up the intake up river. That would plug the water coming into the hatchery. Without that water, the fish on station would probably die.”
Depending on when the flood occurred, LNFH has two year classes of fish on station. There are fish are almost 18 months, smolts, which will be released toward the end of April. There are also fish spawned last fall that they will not be releasing until April 2019.
“Those are two year classes of fish, both are 1.2 million fish. We would lose both those year classes and that would affect those fish that return over the span of time, two, three, four, five years and more of fish that would come back,” Irving said. “That would affect our ability to have brood stock for spawning fish into the future, but harvest levels of fish coming back as well. There’s impacts to property and impact to fish themselves.”
The potential impacts would be catastrophic if that flood came before they released this year’s fish.
“We have to have the water. We have water coming into the hatchery all the time. The fish that are here have to have that constant flow of cold, clear, oxygenated water, which comes in the form of three different types of water coming into the hatchery, water from the stream down the pipeline, which is surface water,” Irving said. “We have well water. And during the summer, we have the water we bring down from the snow lakes. All that is essential for the fish in the hatchery. Just the like fish in the stream, those fish have to have a constant flow of water.”
If the stream flow was cut off, there is only a certain amount of water in the wells, he said. That is not enough for the number of fish they have on station. If they had a little bit of time, he said, they could just release the fish and get them into the stream.
“After sitting down with the Department of Ecology and getting with their experts on the flood time, you have 60 minutes between the time the flood would occur at Eight Mile Lake and it would get to the Wenatchee River,” Irving said. “There’s no real time there to do anything. Most likely, if that flood were to occur, and you have 20,000 CFS coming down, we would lose all the fish on station.”
The fish could be wiped out by the plugged intake or by water sweeping through the hatchery grounds. Irving said he does not know if the water would rise high enough to get into the hatchery grounds.
“I don’t have the expertise on what those levels of water will be coming down the canyon, in terms of how much it would spread out. At the Icicle Work Group, water up to 10 feet deep. I have no expertise on that. It may spread out and not get to the hatchery,” Irving said. “If the debris plugs up the intake, that would have an immediate impact on station. In all the raceways we have here, that’s where the water comes from. The well we have would not be able to keep the raceway full, so all the fish on station would be without water and they would die.”
If the flood water were to sweep the hatchery grounds, there would be enough debris and dirt in the raceways to suffocate the fish, so that would be a disaster too. If the intake were plugged, in all likelihood, it could not be un-plugged very quickly.
“The intake is about a mile upstream, which is 30-inch diameter pipeline...with all the debris that would come down there with rocks and stuff, it would be hard job to unplug that. Not only would it be silt and small material, but I’m sure there would be bigger material,” Irving said. “Once it clogged into that pipe, I don’t know how long it will take that to get unplugged. It may never get unplugged. That would be a major job. You may have to dig up the pipeline if it was filled up with lots of cobble, silt and logs. It’s not like you could auger that out.”
Irving said there are not many precautions they can take in anticipation. Although they have dealt with high water issues in the past.
“We do have silt and logs that come down. We watch that. At the intake, we have metal racks there that catch that material. We go up and check those everyday, especially when you have higher runoff, so you can pull that material off,” Irving said. “When it gets caught up against our structures here, if it starts to pile up, it creates even more of a log jam. We watch that, and even with that, it can cause some damage.”
Generally, with runoff, the peak flow can get up to 10,000 or 15,000 CFS. Irving said they really watch that and pull the material off with a front end loader.
“If you were to have an immediate flood like that, it would dangerous to go out and do something during that time. It would be an immediate flood, so I’m not sure there is anything you could do to prepare for it. I don’t know how you can be ready for those types of things,” he said.
At the very least, with 60 minutes warning, Irving said they could get their people out, which is the number one concern. He said they have been working with the Chelan County Sheriff’s Office, providing them information on who is there. Plus, there is a point of contact.
Irving said they put their heart and soul into taking care of the fish.
“If we had to get people off station immediately, we would have to do that. If the fish die, that’s a sacrifice that would have to be made,” Irving said. “There’s not much you could do to save the fish. If you had some time, you release those fish out into the Icicle Creek and hope they survived as the water flushed down into Wenatchee. With only 60 minutes, that’s a hard thing to do.”
Irving said they are getting ready to release fish at the end of the month. It takes about two days to release 1.2 million fish. It would be pretty hard to do in 60 minutes, he said.
The most likely flood time would be in June, during the high water period, but the flood could come early if there is a rain event.
“You’re looking at the potential for a flood anytime. It could be a rain-on-snow event. We’re releasing these fish here before runoff starts. Most likely, we’ll get that year’s class out. So the only fish on station are those younger fish that we are keeping until the next year. If there was a flood event, we would only lose that one year class,” Iving said. “We’re hoping nothing happens. We’re hoping somehow there are some fixes that can occur to alleviate a potential flood.”
Ian Dunn can be reached at 548-5286 or editor@leavenworthecho.com.