CARSON CITY -- Hours before the start of a state hearing on the Southern Nevada Water Authority's plan to tap groundwater in White Pine County, the U.S. Department of Interior agreed to drop its protests against the $2 billion project.

In the agreement finalized Sunday, Interior officials will team with the water authority on monitoring wells and other protections for federal resources at the northern end of the proposed 250-mile pipeline to Las Vegas.

Water authority General Manager Pat Mulroy said the accord proves that those charged with protecting federal lands in Nevada are "comfortable" with her agency's ability to divert water without harming the environment.

"It means a lot," she said.

The deal was announced Monday morning, just before opening arguments in what was expected to be a three-week hearing before State Engineer Tracy Taylor.

As chief of the Nevada Division of Water Resources, Taylor will decide how much water, if any, the water authority should be allowed to take from Spring Valley, a watershed in White Pine and Lincoln counties that includes about 1 million acres and no towns.

Part of the valley lies within Great Basin National Park.

The National Park Service, U.S. Fish and Wildlife Service, Bureau of Land Management and Bureau of Indian Affairs all signed on to the agreement with the water authority.

With protests from those agencies now settled, some are predicting the all-important state hearing could end as much as a week early.

The protests that remain come from conservationists and White Pine County residents, most of them represented by the Oregon-based Western Environmental Law Center.

Simeon Herskovits, director of the law center's southwest office, criticized the last-minute deal at a noon news conference in front of the Nevada Legislative Building.

"There is nothing enforceable about these agreements," he said. "These are agreements we essentially see as sellouts for political purposes."

Herskovits and other pipeline opponents spoke in front of a prop brought in for the hearing: a 15-foot-tall water bucket covered with banners decrying the project. One sign said, "Water wrongs don't make water rights." Another said, "Don't let Las Vegas destroy Nevada."

Rancher Dean Baker hauled the metal bucket 350 miles from his home in Baker, at the eastern edge of White Pine County.

"These water hearings are interesting," he said, his face shaded by a white cowboy hat. "But they should be about water, not about the politics and the money that keeps coming forward."

Water authority Deputy General Manager Kay Brothers described the monitoring agreement as an early warning system designed to identify the effects from pumping before they damage water resources in the area.

Chuck Petty, chief of the National Park Service's water rights office, said such an approach makes sense because it could take a long time for the effects of groundwater pumping to show themselves.

"It's important for decision-makers to have the information they need well in advance," he said.

Mulroy said that the authority would pay for the monitoring wells and that federal officials would decide where to put them, which will improve the government's ability to protect resources without having to "run to Congress with a tin cup every year."

If the wells show signs of a potentially damaging drop in the water table, the authority would reduce pumping, shift it to other locations or shut it down, Brothers said.

The agreement does not specify the type and severity of impacts that might prompt changes in the water authority's pumping regime.

Baker hotelier Terry Marasco accused federal officials "caving in."

"The National Park Service, an agency which is responsible for protecting the public interest, has developed a toothless document ... that says nothing about a trigger to stop pumping when impacts appear," he said.

After opening statements from attorneys for the water authority and the Western Environmental Law Center, Mulroy delivered the hearing's first testimony.

Later Monday, Taylor heard from Las Vegas Mayor Oscar Goodman, Henderson Mayor Jim Gibson, North Las Vegas Mayor Mike Montandon and Clark County Commission Chairman Rory Reid, who serves as vice chairman of the water authority board.

Goodman said the pipeline project has statewide importance because it will secure the future for the economic engine that supplies Nevada with about 70 percent of its jobs and tax revenue.

In other words, Goodman said, "What's good for Las Vegas is good for Nevada."

Brothers and Ken Albright, the water authority's director of in-state resources, closed out Monday's testimony.

The authority is seeking state approval for 19 groundwater applications it filed in Spring Valley in 1989. The applications represent almost half of the water the agency hopes to pipe to Las Vegas from across rural White Pine, Lincoln and Clark counties.

If developed as planned over the next decade, the pipeline project is expected to supply water for as many as 425,000 homes in Southern Nevada.

Authority officials are scheduled to present testimony through Thursday and finish their case over three days next week.

Friday has been set aside for public input in the hearing room in Carson City and by video link from Ely, Baker and the Sawyer Building in Las Vegas, at Las Vegas Boulevard and Washington Avenue.

The Western Environmental Law Center is to present its case against the Spring Valley applications on Sept. 21 and 22.

That was to be followed by four days of arguments and evidence from the federal government, but that testimony has been scrapped after the agreement announced Monday.

No new closing date for the hearing has been announced.

All of the testimony is being broadcast live in room 4406 of the Sawyer Building. The testimony can be viewed over the Internet, either through a link on the Water Resources Division Web site or under Live Meetings at www.leg.state.nv.us.

The deadline for written comments is Nov. 3.

The state engineer is not expected to issue a decision on the water authority's applications before the end of the year.