Tucked in the U.S. Senate's tax and climate package is $4 billion for drought resiliency – money that comes at a critical time as the West grapples with dwindling supply from the Colorado River, depleting reservoirs and a drier climate that's causing the worst wildfires the region has seen this century.

The funding would benefit Colorado and the six other basin states that rely on the Colorado River to quench the thirst of their residents and keep economies moving.

U.S. Sen. Kyrsten Sinema, Arizona's senior senator who sought the funding, succeeded in persuading her colleagues to support it, her office told Colorado Politics.         

“Through her negotiations, Senator Sinema successfully ensured the budget reconciliation package accomplishes two main goals: it helps Arizona's economy grow and compete and it boosts drought and climate resources for Arizona and the entire American West," Hannah Hurley, Sinema’s spokesperson, said.

Sinema was her party's last holdout, and her decision to support the package allows the Biden administration to push ahead with key pieces of its domestic agenda.

Crucial to Sinema's support is securing money for Arizona, her home state that sits at the epicenter of the West's water woes. Millions of Arizonans get their drinking water from the Colorado River, delivered through the Central Arizona Project aqueduct.

And perhaps more than other other states, Arizona, which has junior water rights, faces a bigger quandary.

In June, the U.S. Bureau of Reclamation told the basin states to come up with a plan within 60 days to conserve between 2 million and 4 million acre-feet of water next year to protect the power generators at Lake Powell and Lake Mead. The bureau's announcement caught some by surprise, and the basin states, which otherwise had cooperated in the past in taking significant and often painful actions to conserver water, appear less inclined to play nice this time around.   

The upper basin states - Colorado, Utah, Wyoming and New Mexico — already said they have no plans to make additional cuts to water use next year to meet the Bureau of Reclamation's demand. Instead, the upper basin states insist the lower basin states (Arizona, Nevada and Southern California) do the cutting.

But even if those states — Arizona gets the most of the three — agreed to give their most of their annual allocation from the Colorado River, it wouldn't satisfy the federal demand to save 4 million acre-feet of water.

The $4 billion that Sinema secured could ease some of that pain and it might even help bring the states to the negotiating table.  

The sum will fund activities to mitigate the effects of drought in the basin states, including paying for temporary or multi-year voluntary reduction in water use, system conservation projects, and ecosystem and habitat restoration projects, according to a draft of the legislation.