The Secretary is authorized to negotiate for and enter into a contract for the termination of the existing lease of the Hoover Power Plant made pursuant to the Project Act [43 U.S.C. 617 et seq.], and in the event of such termination the operation and maintenance, and the making of replacements, however necessitated, of the Hoover Power Plant by the United States, directly or through such agent or agents as the Secretary may designate, is authorized. The powers, duties, and rights of such agent or agents shall be provided by contract, which may include provision that questions relating to the interpretation or performance thereof may be determined, to the extent provided therein, by arbitration or court proceedings. The Secretary in consideration of such termination of such existing lease is authorized to agree (a) that the lessees therein named shall be designated as the agents of the United States for the operation of said power plant; (b) that (except by mutual consent or in accordance with such provisions for termination for default as may be specified therein) such agency contract shall not be revocable or terminable; and (c) that suits or proceedings to restrain the termination of any such agency contract, otherwise than as therein provided, or for other appropriate equitable relief or remedies, may be maintained against the Secretary. Suits or other court proceedings pursuant to the foregoing provisions may be maintained in, and jurisdiction to hear and determine such suits or proceedings and to grant such relief or remedies is conferred upon, the United States District Court for the District of Columbia, with the like right of appeal or review as in other like suits or proceedings in said court. The Secretary is authorized to act for the United States in such arbitration proceedings.