OASIS, Calif. — Signs of once grandiose dreams dot the shoreline of the Salton Sea, dried up like the dead fish that bob ashore from time to time. This lake, the largest in California, was once supposed to be the Riviera of the West, a playground for stars like Frank Sinatra, Jerry Lewis and Desi Arnaz.

But the Salton Sea, created by accident 40 miles south of Palm Springs, has been shrinking for decades now, while the saline content continues to rise — it is roughly 50 percent saltier than the Pacific Ocean. Waterfront homes built more than a generation ago sit abandoned and boarded up, on a labyrinth of streets where only a couple of houses on each block are occupied.

But California does not give up easily on its dreams, so yet another ambitious development is poised to rise beside this vanishing sea.

Government officials have approved plans for a town that would eventually grow to nearly 40,000 people, with enough businesses and jobs to support the residents. Supporters of the project say it is the most sustainable development being planned in the state, but the town, known as Travertine Point, would be more than 20 miles from any existing town.