Machine drills 3-mile tunnel under Lake Mead — PHOTOS | Local Nevada

The American and Italian flags hang from the front of a tunneling machine that just finished drilling a three-mile tunnel underneath the bed of Lake Mead and into a water intake structure placed at the bottom of the reservoir in 2012. Courtesy (Southern Nevada Water Authority)

View from the rear of the tunnel bore machine, looking back down three miles of tunnel already constructed at the third intake tunneling project at Lake Mead Tuesday Sept. 16, 2014. Intake No. 3, as it is officially known, is the Southern Nevada Water Authority's $700 million answer to a mounting dilemma: Roughly 90 percent of the valley's drinking water is drawn from Lake Mead through two existing intake pipes. (Mark Damon/Las Vegas Review-Journal)

John Entsminger, left, general manager of the Southern Nevada Water Authority, and Jim Nickerson, second from left, project manager for Vegas Tunnel Constructors, with visitors at the tunnel bore machine during a tour of the third intake tunneling project at Lake Mead Tuesday Sept. 16, 2014. Intake No. 3, as it is officially known, is the Southern Nevada Water Authority's $700 million answer to a mounting dilemma: Roughly 90 percent of the valley's drinking water is drawn from Lake Mead through two existing intake pipes. (Mark Damon/Las Vegas Review-Journal)

Tour of the third intake tunneling project at Lake Mead Tuesday Sept. 16, 2014. Intake No. 3, as it is officially known, is the Southern Nevada Water Authority's $700 million answer to a mounting dilemma: Roughly 90 percent of the valley's drinking water is drawn from Lake Mead through two existing intake pipes. (Mark Damon/Las Vegas Review-Journal)

Bronson Mack, left, public information officer for Southern Nevada Water Authority, describes the tunnel bore machine during a tour of the third intake tunneling project at Lake Mead Tuesday Sept. 16, 2014. Intake No. 3, as it is officially known, is the Southern Nevada Water Authority's $700 million answer to a mounting dilemma: Roughly 90 percent of the valley's drinking water is drawn from Lake Mead through two existing intake pipes. (Mark Damon/Las Vegas Review-Journal)

A worker walks through a tunnel roughly 400 feet below ground at Lake Mead near Las Vegas Wednesday, June. 12, 2013. The Southern Nevada Water Authority will use the tunnel to link a third intake, still under construction, to the existing intake system. (John Locher/Las Vegas Review-Journal)

A Vegas Tunnel Constructors "shifter" operates a remote control device that moves concrete tunnel sections into place behind the boring machine during construction of the third intake tunnel at Lake Mead on Tuesday Sept. 16, 2014. (Mark Damon/Las Vegas Review-Journal)

A Vegas Tunnel Constructors "shifter" operates a remote control device that moves concrete slabs into place behind the boring machine as the Southern Nevada Water Authority leads the Review-Journal on a tour of the still under construction third intake tunnel taping the water of Lake Mead outside of Las Vegas on July 31, 2013. (Jason Bean/Las Vegas Review-Journal)

The Southern Nevada Water Authority leads the Review-Journal on a tour of the still under construction third intake tunnel taking the water of Lake Mead outside of Las Vegas on July 31, 2013. (Jason Bean/Las Vegas Review-Journal)

Workers work in a tunnel roughly 400 feet below ground at Lake Mead near Las Vegas Wednesday, June. 12, 2013. The Southern Nevada Water Authority will use the tunnel to link a third intake, still under construction, to the existing intake system. (John Locher/Las Vegas Review-Journal)

A worker is raised from a tunnel system at Lake Mead near Las Vegas Wednesday, June. 12, 2013. The Southern Nevada Water Authority will use the tunnel to link a third intake, still under construction, to the existing intake system. (John Locher/Las Vegas Review-Journal)

A Vegas Tunnel Constructors worker helps stage the concrete slabs that are to be put in place behind the boring machine as the Southern Nevada Water Authority leads the Review-Journal on a tour of the still under construction third intake tunnel taping the water of Lake Mead outside of Las Vegas on July 31, 2013. (Jason Bean/Las Vegas Review-Journal)

A circle of bubbles and ripples appear on the surface of Lake Mead early Wednesday afternoon, marking the moment an underground tunneling machine broke through into a water intake structure at the bottom of the lake more than 200 feet below. (Courtesy of the Southern Nevada Water Authority)

The American and Italian flags hang from the front of a tunneling machine that just finished drilling a three-mile tunnel under Lake Mead and into a water intake structure placed at the bottom of the reservoir in 2012.

Workers from Vegas Tunnel Constructors, a subsidiary of Italy-based construction giant Impregilo, guided the massive machine to within three millimeters of its intended target.

The circular groves in the foreground were made by the machine’s cutters on a piece of concrete that was pushed along by the tunneler Wednesday as it punched through into the then-water-filled intake structure.

The intake has since been capped and drained to allow workers inside to finish building the new straw that should begin delivering lake water to the Las Vegas Valley by this summer.

Information for this report was provided by the Southern Nevada Water Authority.