Notwithstanding section 507 of this title, if the Secretary, in her judgment, determines that additional project benefits, including but not limited to additional conservation storage capacity, are necessary and in the interests of the United States and the project and are feasible and not inconsistent with the purposes of this subchapter, the Secretary is authorized to develop additional project benefits through the construction of new or supplementary works on a project in conjunction with the Secretary's activities under section 506 of this title and subject to the conditions described in the feasibility study, provided a cost share agreement related to the additional project benefits is reached among non-Federal and Federal funding participants and the costs associated with developing the additional project benefits are allocated exclusively among beneficiaries of the additional project benefits and repaid consistent with all provisions of Federal Reclamation law (the Act of June 17, 1902, 43 U.S.C. 371 et seq.) and acts supplemental to and amendatory of that Act.