A foreign invader that’s made its way into Colorado for the first time has raised concerns for water supplies in the Pikes Peak region, and officials worry the scourge is heading west.

The Colorado Division of Wildlife said Jan. 17 that zebra mussels had been found in Lake Pueblo State Park. The mussels are harmless to humans, but in much of the Midwest, they wreak havoc on water ecosystems, cause headaches for water system managers by clogging pipelines and plague recreational boaters.

Officials here now worry this tiny scourge — each is the size of a fingertip — is moving west. Other than one spot in California, this is the farthest west they have been discovered.

With the mussels widespread in the Midwest, it may have only been a matter of time before they showed up here. Officials say they probably hitched a ride from someone who boated in mussel-infested waters.

“It’s always a possibility, when you have people who are boating and waters that are infested with it,” said Peter Soeth, spokesman for the U.S. Bureau of Reclamation, which owns the reservoir.

But, he said, “You are always holding out hope it won’t happen.”

The appearance is especially problematic for the Pueblo reservoir, because it provides 52 billion gallons of water a year to several cities. The Fountain Valley Conduit pipeline brings water from the reservoir to Colorado Springs, Fountain and Security, and plans are in the works for the Southern Delivery System, a $1 billion pipeline project to carry water 40 miles from the reservoir to Colorado Springs.

“Obviously we would be concerned, especially with their ability to clog the pipelines and the fact they reproduce pretty quickly,” said Natilia Sibert, spokeswoman for Colorado Springs Utilities, which buys water from the pipeline.

The Eastern European zebra mussels were introduced to the U.S. by oceangoing vessels in the late 1980s. They have since spread from the Great Lakes throughout the Mississippi River basin.

The mussels spread by hitching rides on boats, latching onto the sides or surviving in ballast water. Recreational boaters are thought to be a main transportation method.

Once they’re in a body of water, they can drive out native species. They eat the plankton, depriving fish and other mussels of food, and have been known to grow to densities of 700,000 a square meter, covering up native mussels.

Water suppliers spend millions each year clearing pipes and dams of mussels, and boaters have to scrape their hulls and empty bilges of mussels.

Aside from one spot in California, before the recent discovery, the farthest west they had been found was on the Arkansas River in central Nebraska.

Those in Pueblo — two adults and a larva — were found during routine sampling, according to the Colorado Division of Wildlife.

The DOW will bring in a team of divers during the coming weeks to determine how widespread the zebra mussels are, said Gerg Gerlich, chief of fisheries.

“Until we get a determination on the level of infestation, we really don’t know if this is the tip of the iceberg and they have been there for a while,” Gerlich said.

Michael Seraphin, DOW spokesman in Colorado Springs, said officials don’t suspect they moved downstream from Colorado Springs, and don’t expect them to come here — without help.

“It would be very difficult for them to get up to Colorado Springs,” Seraphin said.

But there is concern for the Pueblo State Fish Hatchery, which gets water from the reservoir.

Officials are studying the water there, and have stepped up monitoring across the region. The worry is they could be transported in the water fish are moved in when fish stocking begins in April, Gerlich said.

“We have not found them. We’ve scoured the place and there is no evidence they are in the hatchery,” Gerlich said.

There are no plans for mandatory boating measures at the reservoir, but officials are urging people to use caution.

After leaving any lake or waterway, boaters should clean and dry their hull, drain water from the bilge, inspect the boat inside and out and remove any plant and animal material.

CONTACT THE WRITER: 476-1605 or scott.rappold@gazette.com