When white settlers forayed into what came to be known as the Imperial Valley at the dawn of the 20th century, they found a barren desert in California’s southeastern corner, unpopulated except for a few members of the Kamia clan of the Kumeyaay tribe.

The harsh conditions, however, had a potential upside. With water, the desert could bloom with crops and the water was potentially available from the Colorado River, which flowed to the sea a few dozen miles to the east, on the other side of a massive stretch of Sahara-like sand dunes.

The settlement of the valley was romantically portrayed in “The Winning of Barbara Worth,” a best-selling novel by Harold Bell Wright that later became a silent movie.

A canal was dug, routed through Mexico to skirt the sand dunes, and the Imperial Valley, named for the Imperial Land Co., blossomed. It became a 500,000-acre provider of vegetables, alfalfa and other crops watered at very little cost from the Colorado and nurtured by year-round sunshine.

By being the first organization to tap the Colorado, the Imperial Irrigation District, formed in 1911, obtained the river’s most senior diversion rights. Thus, when allocations were later formalized by a multi-state compact, the IID claimed nearly three-fourths of California share of 4.4 million acre-feet a year, with the remainder going to municipal users in and around Los Angeles.

There have been minor adjustments in allocations over the years, and IID has sold some of its water to other entities, particularly in San Diego County. However, the district has jealously guarded its senior rights, even as the Colorado’s flows dwindled and upstream reservoirs such as Lake Mead and Lake Powell shriveled.

The day of reckoning, however, may have arrived.

The federal Bureau of Reclamation, citing the Colorado’s declining flows and the probability that Mead and Powell cannot be sustained, wants all seven states drawing water from the river to cut back. Years of negotiations have gone nowhere, largely due to IID’s stubborn defense of its rights.

This month, the Bureau of Reclamation raised the stakes of the multi-state poker game, proposing three options: do nothing and let nature take its course, reduce all diversions by the same percentage, or cut back proportionately by water rights.

“The prolonged drought afflicting the American West is one of the most significant challenges facing our country today,” Deputy Interior Secretary Tommy Beaudreau said as he and other officials gathered in a room overlooking Hoover Dam and a much-diminished Lake Mead. “We’re in the third decade of a historic drought that has caused conditions that the people who built this system would not have imagined.

“Everybody understands the significance of the crisis,” Beaudreau added. “I think everybody understands that, as fortunate and thankful we are for the precipitation, that nobody’s off the hook, and that there needs to continue to be unity in trying to develop solutions.”

Federal officials have hinted that if forced to act, they likely would opt for the across-the-board equal percentage reduction in diversions. It would have the greatest negative effect on California overall and the Imperial Irrigation District specifically, and would clearly undercut the senior rights held by the IID and some other diverters – particularly Native American tribes which gained rights relatively late in the 122-year history of the Colorado’s diversions.

Such a move would certainly draw lawsuits from the IID and California water interests, contending that it violates long-established rights.

The release of the three options is widely regarded as a spur to get negotiations going again, but whether it works is very much up in the air.