There's a new player in the fight over a controversial proposal to pump groundwater just outside a national monument in the Mojave Desert: pop star Sia Furler.

The best-selling singer-songwriter, who owns a home in Palm Springs and got married here a few years ago, tweeted Friday night at California Senate leader Kevin de León and another senator, urging them to "Please #preserveCA and let the CAleg vote on #AB1000." The bill would require a state environmental review of Cadiz Inc.'s plan to pump as much as 16.3 million acres of groundwater per year in the middle of the desert, just outside Mojave Trails National Monument, and sell it to Southern California cities.

Conservation groups say the Cadiz project would threaten natural springs and wildlife in the national monument, which was created by President Barack Obama last year. The company disagrees, arguing its pumping project wouldn't harm the environment.

The Trump administration has taken steps that could speed Cadiz's approval, most recently undoing an Obama-era legal opinion, which critics say could help clear the way for the company to pipe groundwater out of the desert. Trump's Interior Department may soon try to shrink the national monument, which conservationists fear could make it easier for the Cadiz project to move forward. The department's second-in-command is David Bernhardt, who until recently worked alongside Cadiz chief executive Scott Slater at the law firm Brownstein Hyatt Farber Schreck, which owns shares in Cadiz Inc.

READ MORE: Conservationists slam Bernhardt as 'walking conflict of interest'

It wasn't immediately clear how the Cadiz controversy caught the attention of Sia, who wowed crowds at the Coachella Valley Music and Art Festival last year with her trademark theatrics and hit songs like "Chandelier" and "Elastic Heart." The singer's publicist didn't respond to an email seeking comment Saturday evening.

The bill Sia tweeted about, AB 1000, would require California officials to conduct an environmental review of Cadiz's proposal, and of any other projects that would transfer groundwater away from desert lands in the vicinity of national monuments and other protected spaces. Supporters include Gov. Jerry Brown, who said the bill is needed because California’s desert landscapes "may be the most fragile ecosystems of all."

Cadiz spokesperson Courtney Degener said Sia's tweet "reflects a desperate attempt by the proponents of AB 1000 to use an uninformed celebrity to kill thousands of good paying union jobs, block reliable water supplies and undermine California's stringent environmental permitting process."

The tweet "reflects how out of touch the proponents of AB 1000 are with working California families — those who suffer most when job opportunities lack and infrastructure improvements are endlessly delayed," Degener said in an email.

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AB 1000 looked dead earlier this month after it was blocked by the Senate Appropriations Committee through a controversial procedure in which the powerful committee chairperson and legislative leaders can kill bills with no public explanation.

But the legislative session doesn't end until this Friday, and Cadiz opponents are urging Senate leader Kevin de León — a Los Angeles Democrat who's portrayed himself as a leader of the California resistance to President Trump — to revive the anti-Cadiz bill.

Sia's tweet called for de León and Sen. Ricardo Lara, D-Bell Gardens — who chairs the appropriations committee — to let the Legislature vote on the bill.

"No more fronting for Cadiz in SanBernardino!" the pop star wrote on Twitter, referring to the fact that the land the company owns is in San Bernardino County.

Sia isn't the first celebrity to weigh in on Cadiz.

The band Edward Sharpe and the Magnetic Zeros also tweeted at de León and Lara this month, urging them to "Pls protect the Mojave from Cadiz & @realDonaldTrump!" James Valentine, the lead guitarist for the band Maroon 5, posted a similar tweet, as did "Arrow" cast member Paul Blackthorne and "Parenthood" actor Jason Ritter.

David Lamfrom, director of the National Parks Conservation Association’s California desert program, said the Cadiz issue started "getting around to progressive-minded people in LA" when the Los Angeles Department of Water and Power's board voted to support AB 1000. The bill's author, Democrat Laura Friedman, hails from Glendale.

De León hasn't commented publicly on Cadiz, but Lara has. In a recent statement, he noted that the groundwater project has already gone through an environmental review under the California Environmental Quality Act, which survived legal challenges. The lead agency on that review was the Santa Margarita Water District in Orange County, which has a signed contract with Cadiz to buy a portion of the groundwater it pumps.

Lara said demanding an additional review would create a problematic precedent.

"California has the highest environmental review standards in the country and this particular project has gone through significant consideration," he said. "Making an exception for one particular case will create precedent for the Legislature to block other controversial projects."

The anti-Cadiz bill is also opposed by dozens of water agencies, local governments, labor unions and business groups, including the Association of California Water Agencies, the Southern California Association of Governments, the California Chamber of Commerce, and the Inland Empire Economic Partnership, among others.

Cadiz is waiting for Trump's Interior Department to review a 2015 decision that its water pipeline requires an additional federal permit, which the company contends it does not.

Sammy Roth writes about energy and the environment for The Desert Sun. He can be reached at sammy.roth@desertsun.com, (760) 778-4622 and @Sammy_Roth.