LAKE ILO NATIONAL WILDLIFE REFUGE - Pretty little Lake Ilo will be a muddy hole in a few days.

Her waters are going fast, running down Spring Creek toward Beulah and clear to the Gulf of Mexico.

It's a trip of many weeks and many rivers for water impounded in the heart of Dunn County. And it's the second time in the refuge's 70-year history the lake has been drained.

This time, the lake's very mission as a National Wildlife Refuge has been threatened by an infestation of carp.

Last time the lake was dry, in the early '90s, the old dam was breached so that a new spillway, dam and outlet works could be constructed.

Digging where the lake was, archaeologists assembled one of the largest collections of Paleo-Indian artifacts found on land managed by the U.S. Fish and Wildlife Service.

The lake was restored in 1996 but over the years since, a healthy water system became less so.

The fat carp are greedy plunderers. They root up the aquatic vegetation that supports the miniscule invertebrate that ducks and waterfowl love to feed on, said Wade King, biologist for the National Wildlife Service.

That's set off a depleting chain reaction. Only 600 ducks were banded at the refuge last month, compared to thousands not many years ago. A small lake once notorious for trophy-caliber northern pike now yields only a few, small pike.

The carp will be poisoned next month once they're corralled into a relatively small pool. The dead carp and species such as bullhead and suckers will become opportunistic meals for skunks, coyotes, gulls and whatever else wanders by for a tasty snack.

The poison affects fish gills, but won't harm birds or animals that eat the dead fish, King said.

It won't be pretty. What's happened to the refuge isn't pretty either.

Refuge manager Kory Richardson says it's one of those dirty jobs that have to be done.

The drained lake means all birds will be impacted to some degree, he said. More than 300 species, from a colony of blue herons that occupy the penthouse branches of tall trees, to dramatic marsh hawks that swoop through the cattail sloughs, check in at the refuge during the year.

He's hoping for a wet winter and spring so the water comes back in a season. The lake is fairly shallow and only covers about 1,000 acres.

Lake Ilo impounds and covers the former confluence of Spring Creek, from the northwest, and Murphy Creek, from the southwest.

The earlier archaeology confirmed the confluence was used for 11,000 years by Northern Plains Indians for its good hunting and because the Knife River flint quarry is only a few miles west.

More than 58,000 artifacts - many small chips left from flaking the hard flint into tools and weapons - were recovered by archaeology teams that dug and sifted through squares of soil. Those artifacts are now stored with the State Historical Society. Casts of significant pieces are at the refuge headquarters and the Dunn County Museum.

Richardson worries that the low water may cause people to scavenge Lake Ilo for artifacts.

He's put up warning signs - it is a big-time federal offense to loot artifacts from federal property - and plans to patrol the property with help from other federal agencies.

Richardson said he's ready for looting, but he doesn't really expect it.

"I don't believe it's a situation where the stuff is laying around," he said. "By and large, it's buried pretty deep and people aren't going to be able to fill up their pockets."

Barry Williams, an archaeologist with the National Wildlife Service, said he'll take the opportunity to look around in an official capacity.

He'll look not so much for artifacts, but to see what's been down cut and eroded by the lake in the years since.

"There won't be a shovel put in the ground," he said. He will collect an exposed stylized artifact if he stumbles onto one: "I think the majority of stuff has been collected already," he said.

Protecting the archaeology is important, but Lake Ilo is first and foremost a refuge, a safe place for nature's creatures to breed, brood, nest and rest.

King said the agencies will wait for the water to come back and restock the lake with perch and northern pike.

"It'll be a couple of years before the fishing is back," King said.

Hopefully the birds and waterfowl won't long behind.

(Reach reporter Lauren Donovan at 888-303-5511 or lauren@westriv.com.)