The following terms wherever used in this subchapter shall have the following respective meanings:

“Project Act” shall mean the Boulder Canyon Project Act [43 U.S.C. 617 et seq.];

“Project” shall mean the works authorized by the Project Act to be constructed and owned by the United States, exclusive of the main canal and appurtenances mentioned therein, now known as the All-American Canal;

“Secretary” shall mean the Secretary of the Interior of the United States;

“Firm energy” and “allottees” shall have the meaning assigned to such terms in regulations promulgated before July 19, 1940, by the Secretary and in effect on July 19, 1940;

“Replacements” shall mean such replacements as may be necessary to keep the project in good operating condition beginning June 1, 1937, but shall not include (except where used in conjunction with the word “emergency” or the words “however necessitated”) replacements made necessary by any act of God, or of the public enemy, or by any major catastrophe; and

“Year of operation” shall mean the period from and including June 1 of any calendar year to and including May 31 of the following calendar year.