Utah and Nevada water regulators are close to a deal splitting their shared Snake Valley aquifer and potentially allowing the Southern Nevada Water Authority to pipe its portion 285 miles south to Las Vegas.

Utah Department of Natural Resources Director Mike Styler confirmed that negotiations are proceeding and likely to produce a draft agreement by August or September. He wouldn't discuss the details, but said any deal would protect Utah's water users, wildlife and air quality.

Environmentalists and those who live around the aquifer on the state line west of Delta want Utah and Nevada to back off. They fear the Las Vegas water project could dry up the valley around Great Basin National Park, limiting development and sending dust storms toward Utah's Wasatch Front.

But Styler said an agreement spelling out the states' shares is the best protection.

"I really believe that, absent this agreement, each state could be engaged in a drilling war and the ultimate losers would be the people of the Snake Valley," he said.

Officials in White Pine County, Nev., based in Ely, wrote to Gov. Jon Huntsman Jr. last month asking him to hold off on any agreement until the Southern Nevada Water Authority produces detailed groundwater studies as part of its permitting process in 2011. Utah's deputy water engineer, Boyd Clayton, wrote back July 9, saying study results likely would not affect the agreement.

Once the states produce a draft accord, Styler said, they will conduct public hearings in both states before signing it. Lt. Gov. Gary Herbert, who likely will be Utah's governor by then, approves of the direction of the deal, Styler said. A spokesman for his transition team said Herbert still is gathering information.

Meanwhile, environmentalists have launched an e-mail and postcard campaign asking Herbert to stop the deal. They want to wait for the science, said Steve Erickson, Utah organizer for the Great Basin Water Network.

"There's no urgency for an agreement," Erickson said. "The Nevada state engineer won't even hear the case [for a pipeline] for two years."

Styler said the reason to press on with a deal will become clear once his agency makes the details public.

"[Opponents] have some unfounded belief that this is a giveaway," Styler said, "and it's actually very protectionist."