On Lake Mead, boat seller Jason Davis manoeuvers his craft towards Hoover Dam, where thousands of tonnes of concrete loom over the water in graceful modernist lines, and a ring of mineral deposits shows where the water level used to be.
For him, the lake is not just a battery for the huge generators in the dam, but a waterscape whose beauty and peacefulness are worth protecting.
"You know, people who haven't been here don't appreciate it," he says as a sunset rages in the desert sky above.