A decades-long fight over a plan to pump water from arid and sparsely populated valleys along Nevada's eastern edge and pipe it to thirsty Las Vegas is about to get its first hearing before a federal judge.

Environmental groups and American Indian tribes are expected to tell U.S. District Judge Andrew Gordon in Las Vegas on Monday that a proposed 263-mile (423-kilometer) north-to-south water pipeline just west of the Nevada-Utah state line amounts to a city water grab supported by incomplete and inadequate federal environmental studies.

Southern Nevada Water Authority lawyers are expected to argue that the state's largest metropolitan area and economic hub has to have water, and that the U.S. Bureau of Land Management properly granted rights of way for the pipeline to cross federal lands in 2012.

The environmental review took eight years, the water agency said in a statement characterizing the pipeline and related pumping and storage facilities as a "modest investment in water resources for considerable economic returns that benefit Nevada as a whole."

Southern Nevada uses only 5 percent of Nevada's statewide water resources, the statement said, but is responsible for roughly 70 percent of the state's economic activity.

Rob Mrowka, a senior scientist with the Center for Biological Diversity, evokes fears that remote springs will wither, rare species of plants and animals will die, and arid scrub brush rangeland in the Spring, Cave, Dry Lake and Delamar valleys will turn to dust if Las Vegas is allowed to tap ancient underground aquifers that don't naturally replenish every year.

"Their plan to drain ancient aquifers left by the last ice age would cause significant and catastrophic changes across a section of central Nevada the size of Vermont," said Mrowka, whose organization filed a lawsuit in February 2014 against the environmental findings.

Other lawsuits were filed by plaintiffs including local governments in Nevada's White Pine and Lincoln counties, citizen groups, the Duckwater and Ely Shoshone tribes, and the Confederated Tribes of the Goshute Reservation in Utah.

Water agency officials concede a pipeline built to carry 75,000 gallons (283,900 liters) of water a day from near Ely in White Pine County - a distance comparable to a drive from Las Vegas to Los Angeles - could cost billions of dollars to build.

But they say it may become essential if drought keeps shrinking Lake Mead on the Colorado River. The Las Vegas area, home to 2 million people and host to 40 million visitors a year, currently gets almost all of its drinking water from the vast reservoir behind Hoover Dam.

Attorney Simeon Herskovits, representing the Great Basin Water Network, noted the federal court hearing is the first in a case that has been developing since 1989 in state courts.

Proponents and opponents also are due later this year to respond to an order by a Nevada state court judge in Ely that rejected findings by the state's top water official, Jason King, that enough underground water exists to supply the pipeline.

"Our key argument Monday is that the federal government simply failed to take the hard look required under (the National Environmental Policy Act)," Herskovits said of Monday's proceedings. "In practical terms, there will be no way to replenish or recharge these systems."

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