Harry Truman actually said...
It has been my understanding that Reclamation projects, historically, have been based on the principle that the construction costs to the Federal Government would be repaid, without interest, in 40 years, plus, in some cases, a 10-year development period.
Context
Letter to Secretary Krug Upon Signing Bill Relating to the Completion of the Provo River Reclamation Project
03/28/1948