Tunneling under Lake Mead in search of much needed water

Lake Mead in Boulder City, Nevada is a major source of water and power for millions of people in Arizona, California and Nevada. Las Vegas draws 90 percent of its water from the lake. But the ongoing drought has caused the lake to fall to record low levels and it is currently 60 percent empty.

"It really reaffirms the seriousness of the drought that we are in," Bronson Mack from the Southern Nevada Water Authority told CBS News' Chris Martinez.

With conditions getting so bad, city leaders decided to build a 3-mile long tunnel deep below the lake, which will start drawing water from its deepest point by the end of this summer.

"The construction of this third intake and eventually new pumping station will help secure southern Nevada's access to its water resources in Lake Mead," Mack said.

The lake also powers the Hoover Dam and helps generate electricity for millions. As water levels drop, officials are concerned that the turbines won't work.

"We're replacing about a quarter of the turbine runners to make sure they can continue to generate power even if the lake were to continue to fall," said Terry Fulp from the U.S. Bureau of Reclamation.

If conditions don't improve by the end of the year, officials warn they may need to cut water supplies to residents.

"This is the worst 16-year drought we've ever seen," Fulp said.