Cal. Wat. Code § 1005
Nothing in this division shall be construed as depriving any city, city and county, municipal water district, irrigation district, or lighting district of the benefit of any law heretofore or hereafter passed for their benefit in regard to the appropriation or acquisition of water. Any right to the water of any stream which flows along a boundary of the State and which is the subject of an interstate compact to which the State is a party, to the extent such right relates to quantities of water which the United States has, under the authority of an act of Congress, contracted to deliver to any municipal corporation, political subdivision, or public district in the State, from storage constructed by the United States on any such stream, shall not be subject to any requirement or limitation provided by law relating to the time within which the construction of works for the use of such water shall be commenced, carried on, or completed, or within which such water shall be put to use, or relating to the continuity of use of such water; and water contracted to be delivered from such stream, shall be reserved to the contractor therefor without diminution by reason of the contractor's failure to apply such water to use during any period, and shall not be subject to appropriation by any other than such contractor.
Ca. Water Code § 1005