FARMINGTON — A proposal to open Lake Nighthorse to boaters is worrying a San Juan County water rights group.

San Juan Water Commission members expressed concerns at their meeting Wednesday morning that recreation on the lake, which serves as a reservoir for the Animas-La Plata project, could contaminate the water.

The lake is located southwest of Durango.

"The water commission is not opposed to recreation," said Randy Kirkpatrick, the commission's executive director. "We're concerned about the multiple layers of influence."

Although Lake Nighthorse is a large reservoir, the water does not flow in and out each year like it does at Navajo Lake, Kirkpatrick said. This has led to concerns on the water commission that fuel leaks and other pollutants could contaminate the water.

The U.S. Bureau of Reclamation, a federal agency under the U.S. Department of the Interior, owns the land around Lake Nighthorse but is looking for a partner to provide services if the area is opened for recreational use, he said.

The city of Durango has been approached by the federal agency to annex the land, Kirkpatrick said.

Bureau of Reclamation officials could not be reached for comment on Thursday.

The proposed annexation would allow Durango police to provide law enforcement service to the area around Lake Nighthorse, said Cathy Metz, Durango's director of parks and recreation, in a Thursday phone interview.

"The lake's only 1.5 miles from the city limits, so it makes sense," she said. "Water quality is a major discussion. There are seven owners of that water. We're in the process of buying into it as well. I think we have very similar goals as the (water commission)."

A proposal for a marina that would provide on-the-water fueling for boaters was struck down in the interest of water quality during community discussion, Metz said.

"Our thought is to have an opportunity to fuel on the property, away from the reservoir," she said.

Although the water commission expressed some concerns about the annexation, Metz said that the land could be de-annexed.

The land could be de-annexed if the area were to become a state park, and administration of the land would be taken over by a state agency, she said, giving a hypothetical example.

If an annexation deal is reached, the lake could be open for recreation as early as 2014, Metz said.

Kirkpatrick said he remains optimistic that a balance can be struck between water quality and recreational use.

The lake, which serves as the water reservoir for the Animas-La Plata Project, fulfills a water rights settlement with the Ute Mountain and Southern Ute tribes and will help supply water to southwestern Colorado and northwestern New Mexico.

"The (Animas-La Plata) project is going well," Kirkpatrick said. "This is just one more step in a long journey we began in 1956."

Greg Yee can be reached at; 505-564-4606. Follow him on Twitter @GYeeDT.