43 U.S. Code § 618f - Repayment of advances for flood control
The first $25,000,000 of advances made to the Colorado River Dam Fund for the project shall be deemed to be the sum allocated to flood control by section 617a (b) of this title and repayment thereof shall be deferred without interest until June 1, 1987, after which time such advances so allocated to flood control shall be repayable to the Treasury as the Congress shall determine.
Source(July 19, 1940, ch. 643, § 7,54 Stat. 777.)