As used in this subchapter—

(a) The term "Federal reclamation laws" shall mean the Act of June 17, 1902 (32 Stat. 388), and all Acts amendatory thereof or supplementary thereto.

(b) The term "Secretary" shall mean the Secretary of the Interior.

(c) The term "project" shall mean any reclamation or irrigation project, including incidental features thereof, authorized by the Federal reclamation laws, or constructed by the United States pursuant to said laws, or in connection with which there is a repayment contract executed by the United States, pursuant to said laws, or any project constructed or operated and maintained by the Secretary through the Bureau of Reclamation for the reclamation of arid lands or other purposes.

(d) The term "construction charges" shall mean the amounts of principal obligations payable to the United States under water-right applications, repayment contracts, orders of the Secretary, or other forms of obligation entered into pursuant to the Federal reclamation laws, excepting amounts payable for water rental or power charges, operation and maintenance and other yearly service charges, and excepting also any other operation and maintenance, interest, or other charges which are not covered into the principal sums of the construction accounts of the Bureau of Reclamation.

(e) The term "repayment contract" shall mean any contract providing for payment of construction charges to the United States.

(f) The term "project contract unit" shall mean a project or any substantial area of a project which is covered or is proposed to be covered by a repayment contract. On any project where two or more repayment contracts in part cover the same area and in part different areas, the area covered by each such repayment contract shall be a separate project contract unit. On any project where there are either two or more repayment contracts on a single project contract unit or two or more project contract units, the repayment contracts or project contract units may be merged by agreements in form satisfactory to the Secretary.

(g) The term "organization" shall mean any conservancy district, irrigation district, water users' association, or other organization, which is organized under State law and which has capacity to enter into contracts with the United States pursuant to the Federal reclamation laws.

(h) The term "division of a project" shall mean any part of a project designated as a division by order of the Secretary or any phase or feature of project operations given a separate designation as a division by order of the Secretary for the purposes of orderly and efficient administration.

(i) The term "development unit" shall mean a part of a project which, for purposes of orderly engineering or reclamation development, is designated as a development unit by order of the Secretary.

(j) The term "irrigation block" shall mean an area of arid or semiarid lands in a project in which, in the judgment of the Secretary, the irrigable lands should be reclaimed and put under irrigation at substantially the same time, and which is designated as an irrigation block by order of the Secretary.