the water supply for seven out of every ten people that live in the state of nevada. so we need to know that we have secure access. reporter: so 600 feet below ground, and three miles along a dark narrow tunnel beneath lake mead, engineers have found a solution, seven years in the making, at a cost of $817 million. each and every time i come down with shock and awe. it is truly an impressive sight. reporter: this is the end of the tunnel and this is the critical point. up above us, 40 feet, is the hemisphere cal cap. think of it as a giant bath plug. above that the waters of lake mead. and in a few weeks time, that plug will be lifted and those waters will flood this tunnel. and because it s quite literally at the bottom of the lake it will guarantee water supply for thirsty las vegas even as those sinking lake levels threaten to leave the two much older water intake tunnels above the water
journey deep beneath the waters of lake mead. how can nevada keep tapping into the waters of lake mead even when the levels sink to historic lows. 600 feet down, and three miles along the dark narrow tunnel, the culmination of a 7-year, $1817 million 817 million project. above that the waters of lake mead. in a few week s time that plug will be lifted and the water will flood the tunnel. because it s at the bottom of
extraordinary. reporter: 600 feet down and 3 miles along a dark narrow tunnel. the culmination of a 7-year, $817 million project. this is the end of the tunnel and this is the critical points. you above us 40 feet is the catch. think of it has a giant bathtub. above that waters of lake mead. and in a few of weeks time that plug will be lifted and the waters will flood the tunnel. it will guarantee the water supply for this i las vegas. even as it leaves the other two turns above water line useless. it s the economic engine to the state of nevada. this is a responsibility we
600 feet down and three miles along a dark narrow tunnel. the culmination of a seven-year, $817 million project. this is the end of the tunnel, and this is the critical point. up above us, 40 feet is the hemispherical cap. think of it a giant bath plug. above that lake mead. and in a few weeks time that plug will be lifted and those waters will flood this tunnel. because it s at the bottom of the lake, it will guarantee the water supply for thirsty las vegas even as sinking lake levels threaten to leave the other two much older water intake tunnels above the water line and effectively useless. when you consider the fact that we re responsible for providing water to 2 million people and 40 million annual visitors to the economic engine of the state of nevada, this is a responsibility that we don t take lightly.
the water supply for seven out of every ten people that live in the state of nevada. so we need to know that we have secure access. reporter: so 600 feet below ground, and three miles along a dark narrow tunnel beneath lake mead, engineers have found a solution, seven years in the making, at a cost of $817 million. each and every time i come down with shock and awe. it is truly an impressive sight. reporter: this is the end of the tunnel and this is the critical point. up above us, 40 feet, is the hemisphere cal cap. think of it as a giant bath plug. above that the waters of lake mead. and in a few weeks time, that plug will be lifted and those waters will flood this tunnel. and because it s quite literally at the bottom of the lake it will guarantee water supply for thirsty las vegas even as those sinking lake levels threaten to leave the two much older water intake tunnels above the water