Rights of way for ditches, canals, or reservoirs heretofore or hereafter approved under the provisions of sections 946 to 949 of this title may be used for purposes of a public nature; and said rights of way may be used for purposes of water transportation, for domestic purposes, or for the development of power, as subsidiary to the main purpose of irrigation or drainage.
(May 11, 1898, ch. 292, § 2, 30 Stat. 404; Mar. 4, 1917, ch. 184, § 2, 39 Stat. 1197.)