Funds heretofore appropriated to the Department of State under the heading "International Boundary and Water Commission, United States and Mexico" shall be available for the purposes of sections 277d-1 to 277d-5 of this title: Provided, That authorizations under said sections shall apply only to projects agreed upon by the two Governments in accordance with the treaty of February 3, 1944.
22 U.S.C. § 277d-5