WASHINGTON (AP) — The Interior Department is proposing to award one of the first contracts for federal water in perpetuity to a powerful rural California water district that had long employed Secretary David Bernhardt as a lobbyist.

Conservation groups are demanding fuller disclosure of financial terms and an environmental review of the proposed deal for the California's Westlands Water District, the nation's largest agricultural water supplier. The water district serves some of country's wealthiest and most politically influential corporate farmers.

Bernhardt served as a lobbyist for Westlands until 2016, the year before he joined Interior, initially as deputy secretary.

"The Interior Department needs to look out for the public interest, and not just serve the financial interests of their former lobbying clients," said Rep. Jared Huffman, a Democrat from California.

Responding to questions, Interior spokeswoman Carol Danko said the handling of the Westlands' contract was delegated entirely to California staffers of the Bureau of Reclamation, which is under the Department of Interior.  The agency will make a final decision after the legally mandated public comment period, she said.

Doug Obegi, a senior attorney at the Natural Resources Defense Council, said the handling of the contract raises concerns Interior "is trying to give Westlands a sweetheart deal."

Bernhardt's past lobbying work — much of it for industries with business before Interior — has led environmental groups and Democratic lawmakers to accuse him of lack of transparency and the appearance of conflict of interest in his work at the agency.

As a lobbyist, he was involved in negotiations on a contentious 2016 federal law that made the Westlands' proposed deal possible, allowing water districts to lock up permanent contracts for water from California's federal water project.

The 2016 law had been sought for decades by water districts in California, where frequent droughts sometimes led to water rationing and dying crops. It reshaped the federal handling of water in the U.S. state with the largest economy.

Environmental groups say a permanent deal would let California's water contractors forgo future negotiations before the public and environmental groups, further threatening the survival of some of the endangered native fish and other wildlife that also need the water.

Interior's Bureau of Reclamation posted notice on its website Oct. 25 of the proposed contract and the 60-day public comment period, which ends over the Christmas holiday. Other water districts are lining up behind Westlands to negotiate their own permanent contracts.

Westland's contract would give it permanent claim to enough water to supply more than 2 million California households, although federal suppliers in practice typically divvy up water each year based on available supply. The water comes from the federal Central Valley Project, a massive, federally built network of dams, tunnels and canals that pipes water from greener Northern California to farms and cities of the more populated south.

The 2016 law allows Westlands and other water districts to lock in the water contracts for good if they repay the federal government for their share of the Central Valley Project's costs.

Interior said in its statement Thursday that Westlands owes the federal government $480.7 million. Environmental groups say the rural California water district has been seeking to bargain down the payback amount, and want to see what the contract obliges Westlands to pay.

Danko, the Interior spokeswoman, said the proposed deal would result in the government being paid back a decade early.