I heard on the radio several years ago that there was a plan (in the 50s if I remember correctly) to dam the Golden Gate and drain some of San Francisco bay. Was this actually true and how seriously was this contemplated?
It was called the Reber Plan. https://en.wikipedia.org/wiki/Reber_Plan
There's an excellent multi-part series called "Saving the Bay" about the history of the bay. They run it on public television from time to time.