There's quite a history of boat racing on the Salton Sea (even recently). The extremely high salinity of the water apparently makes it "the fastest water on earth".
Several years ago, I read a Mario Andretti biography and he talked about many of the Indy drivers of the day (1960/70s) racing boats there - probably part of the Salton City 500, but not sure. Maybe Dave B. knows more about this.
Here's an article from Sports Illustrated that talks about Mickey Thompson, Chuck Daigh, and even Astronaut Gordon Cooper racing at the 500.
Desert Full of Motorboats 1964