LAS VEGAS — For the second time in a decade, the feds are warning that if water interests in Arizona, California and Nevada can’t find a fix for the Colorado River’s problems, the interior secretary will find it for them.

Deputy Interior Secretary Michael Connor implied that was the department’s position in a talk Friday to hundreds of water officials, farmers and others gathered in Las Vegas for the 70th annual conference of the Colorado River Water Users Association. After his speech, Connor came right out and said it in response to a reporter’s questions.

Connor talked of the need to prevent Lake Mead, about 25 miles south of Las Vegas, from falling to dangerously low levels — potentially low enough to force Draconian cutbacks in water deliveries to cities and Indian tribes in Arizona, as well as to farms. The solutions haven’t been easy to find, in large part because they would require water users, particularly cities and farms in Arizona and California, to accept smaller cuts in water deliveries soon to stave off more severe cutbacks later.

The lake has dropped more than 120 feet since 2000. It’s expected to close 2015 at 1,082 feet elevation, 5 to 6 feet lower than a year ago. The first shortage in the river would be declared at 1,075 feet, but its effects would be far less drastic than shortages declared at lower lake levels that Conner raised concerns about.

Tucson has a stake in Lake Mead because it depends more on Colorado River water than any other Arizona city that takes Central Arizona Project water from the river for drinking. Tucson is also at the end of the CAP pipeline, which has made many water officials here over the years think they could be more prone to cutoffs than other Arizona cities, although there’s no hard evidence that’s the case.

The risk is now up to 30 percent that Mead will drop to potentially dangerous levels in five years, Connor said.

“In the first six months of 2016, we have to see progress, coming together” among leaders of the three Lower Colorado River Basin states, Connor said after his talk. “I’m optimistic at the progress that we’ve made so far, but we need to be very transparent about the risks we face and think through solutions. We feel it’s very important to stay on track and get it resolved.”

He said that by the time of next year’s conference, he hopes the states will have reached agreement and that his boss, Interior Secretary Sally Jewell, will come to celebrate. If not, he said, he or Jewell may have to carry out “contingency planning” to manage the river.

Conner took essentially the same position that former President George W. Bush’s first interior secretary, Gale Norton, took in 2005 when she wrote a letter to the states warning that she would impose a solution if the states couldn’t find one. Two years later, the seven states negotiated an agreement setting guidelines for what levels of water shortages would be declared at different lake levels and how the states would share shortages.

Back then, the lake level was much higher and the risks much lower, Connor and other officials noted last week.

At the time, authorities felt the risk of the lake dropping to 1,020 feet in five years was 3 percent, he said. Now, due to continued drought and the availability of more advanced computer models, the risk is 11 percent of dropping below 1,020 in five years if climate change isn’t considered, and 30 percent if it is, Conner told the group.

“We’re committed to continuing negotiations into 2016 and thinking creatively how to implement actions to protect Lake Mead elevations,” he said.

Afterward, Colorado water users association President David Modeer said no one involved in Southwest water issues wants to see the feds impose a solution. But that may be an appropriate action “if we can’t solve it,” said Modeer, a retired CAP general manager and before that Tucson Water’s director.

“We’ve always recognized that if we can’t find cooperative agreements to address falling reservoirs, someone else will step in, and that will be the (Interior) secretary,” Modeer said.