43 U.S.C. § 507

Except as provided in section 509b of this title, construction authorized by this subchapter shall be for the purposes of dam safety and not for the specific purposes of providing additional conservation storage capacity or of developing benefits over and above those provided by the original dams and reservoirs. Nothing in this subchapter shall be construed to reduce the amount of project costs allocated to reimbursable purposes heretofore authorized.