BILLINGS — In an effort to kill off invasive Asian clams, the water levels at Lake Elmo State Park in Billings have between eight and 10 more feet to drop before the water body is completely empty, said Bob Gibson, Montana, Fish, Wildlife and Parks Communication and Education Program Manager on Wednesday.
“We want any of the invasive Asian clams that are in here to freeze, starve and dry up here in the winter. And that, we hope, will eradicate them," Gibson said.
So far, between six and eight feet of water has been drained from the lake and large sections of the lake bed have been exposed.
"This is the only place in Montana that they’ve been found and we want to keep it that way. We don’t want them to accidentally get downstream, into the Yellowstone River and every place that it goes," Gibson said.
The lake is fed by water from the Billings Bench Water Association canal system and water levels have been dropping at the man-made 61-acre lake since Sept. 1.
The water association ends service on Oct. 15, then it's full steam ahead to let the lake drain completely, Gibson said. Every season, the water level fluctuates by two or three feet depending on the irrigation need, but the lake hasn't been down this low in at least 30 years, Gibson said.
The last major drain to Lake Elmo was around the 1970s or 1980s to repair a headgate, Gibson said.
On Wednesday, crews were seen digging a trench from the headgate near Lake Elmo Drive to deeper water to allow for better drainage.
“When we get down to eight feet or 10 feet or more, the lake doesn’t drain as well. So we’re back over here now digging out a channel from the deep part of the lake to that headgate so the water will continue to run there," Gibson said.
It's likely pumps will have to be used to get the remaining water out, Gibson said. The water can be pumped downstream or upstream, with no fear of further spreading the clams, because the water will dry up and the clams will freeze and die just the same, Gibson said.
"Any water that goes back up there will go into the ditch and will dry up and freeze during the winter or will go out onto farm fields where it will dry up and freeze during the winter,” Gibson said.
While dry, access to the lake bed is open to the public, but people are asked not to comb the beach for treasurers, use a metal detector or dig in the lake bed. It's against state law to disturb or remove topsoil in state parks.
Gibson said the law is more focused around state parks like Bannack, the ghost town that was the site of the state's first major gold discovery in 1862. But there still may be historic artifacts at Lake Elmo.
“We don’t want people even coming around thinking that they are doing the right thing by picking up old beer cans and beer bottles and things like that, because we don’t want anything accidentally to illicitly get out of here," Gibson said.
The wildlife department will likely organize a trash pick up to remove legitimate garbage from the lake bed once it's drained, Gibson said.
People are asked not to remove any clams that they happen to find either. There is a clam species native to Lake Elmo that look very similar to the invasive Asian clams, Gibson said.
They take a trained biologist's eye to tell apart, and it would be a shame to introduce a new invasive species to the Yellowstone River or some other water body, even by accident.
"We’re trying to dry them up. The other problem is people who have picked up the ones who they think are native, put them in a bucket and try to take them down to the Yellowstone River. You accidentally get one of these clams into the Yellowstone River, it defeated all of what we are trying to do here," Gibson said.
The clams cause problems by clogging up irrigation or municipal water pipes. They can grow and attach around the inside of pipes, but also bury into sandy lake and riverbeds.
Gibson said when biologists first found the clams near the boat launch on the north side of the lake in 2019, they were only found in the first inch or two of mud.
“It’s not like they are burrowing down six feet. So we think that a good, cold winter and a little frost going into the lake bed, into the mud will freeze, starve and dry them up and that will kill them all," Gibson said.
Another problem with the Asian clams is that they have the potential to hurt the local ecosystem and food chain, Gibson said. The clams are filter feeders, straining plankton and microorganisms from the water to eat. The clams could take plankton from other native wildlife, possibly lowering populations of larger fish up the food chain.
“It can eventually affect the fish life in the lake or anywhere it goes," Gibson said.
The dry lake will allow easy access for construction crews to add some new park amenities, worth about $500,000. Work has already started on a hand-launch boat ramp near the Montana Fish, Wildlife and Parks office on the south end of the lake.
A welcome addition for users of the 1.4 mile walking trail around the lake will be a newly constructed path around the section near Lake Elmo Drive. The section is currently steep, rocky and close to the road, which has a winding S curve for vehicles.
Billings resident Clark Finch, 74, said he's excited for the new 8-foot-wide section of walking path. He said it will be nice for him and his 158-pound Anatolian shepherd, Max, to be farther away from traffic during their four weekly walks around the lake.
“There’s many times when I walk there, people are driving by, you know how it is nowadays with their face down in their phone. And you’re right alongside the road. So moving the trail away from the road. Then you look at the power lines there, there’s a lot of fishing line. So it will be on the other side. It will be much safer, it’s going to be awesome," Finch said.
The construction will also add a rock fishing jetty to the south side of the lake that is accessible to wheelchairs so people can fish deeper water. The feature will also have underwater fish habitat constructed at its base for young bass and perch to grow.
More outcroppings to deeper water will be added to the northeast side of the lake as well.
When the lake is filled back up next irrigation season, eventually all of the wildlife that's in the Yellowstone River will work its way to Lake Elmo, like suckers and carp, Gibson said.
The wildlife department will likely stock additional fish, like catchable trout, perch, bass, catfish and panfish.
“Those little sunfish and things like that, that’s the start of the food web that we need for the bigger fish to eat littler fish. Then we will have places for all of those other fish to spawn and to naturally reproduce. We’ll continue to stock them and enhance that fishery as we need to. As we find out what’s reproducing, what’s not and how things are working," Gibson said.
Lately, the bird watching at Lake Elmo has been great, Gibson said. The low water has concentrated the fish to a more central location, encouraging fish-eating ducks like the merganser to feast.
The gulls have had a tenancy to wait and try to steal fish from the ducks. That, mixed with an occasional osprey or kingfisher sighting in the morning makes for a pretty entertaining slice of wildlife.