The country’s largest man-made reservoir, Lake Mead, has dropped to such a historically low level that Las Vegas water officials have completed the process of turning on a pump station that will allow Southern Nevada to retrieve water, even under extreme conditions.

The move — to turn on the pump station full bore — is an indication of how low Lake Mead has fallen over the past decade and serves as a bulwark against the possibility of Las Vegas losing physical access to its water as regional issues on the Colorado River become increasingly dire.