What about just making it a salt water marsh?
For example, I think that Death Valley would be much more valuable to the human race if it were flooded...
Imagine a Giant Inland Sea, connected to the Pacific by a Shipping Canal.
Much of central California would be flooded yes, but it could become a mecca for international commerce!
The water removed from the ocean to flood the area would lower sea levels so the people in Kirbati, Tarowa, and the other isolate atols in the pacific would be safer from flooding.
Write you congressman and demand that Death Valley be flooded NOW!