Cal. Wat. Code § 22252.3
In any year in which the board determines that the water supplies of the district will be inadequate to provide water in a quantity furnished in years of average precipitation, the board may specify a date prior to which applications for water for the ensuing irrigation season are to be received. In districts where meters or other volumetric measuring instruments or facilities are not available or are inadequate to measure substantially all agricultural water deliveries, the district may establish annual water requirements in the district for growing each type of crop grown in the district, accept such applications for water based on proposed crops to be grown and acreage of each such proposed crop, and determine the quantity of water apportioned under Sections 22250, 22251, 22252, and 22252.1 expressed in terms of acreage of each type of proposed crop to be served. In such a district, the district may refuse to deliver water to, or assess penalties on, the landowner who uses such water on a greater acreage of such crops than such landowner's share of the estimated available water will bring to maturity based on the requirements established for growing such crops in the district.
In establishing annual water requirements for growing particular types of crops, as authorized in this section, the district, with respect to those crops which ordinarily require periodic irrigation, may designate the number of irrigation runs and the amount of water to be allocated to each such run with respect to each crop and may give the water user water credits measured by the designated irrigation runs with respect to each such crop as to which the water user has notified the district he intends to underirrigate.
This section provides a means of measuring the allocation of water to lands based on the type of crop grown and does not authorize a district to designate the crops to be grown on such land.
Nothing in this section shall prohibit or limit the apportionment of available water to land given preference under Section 22252.1 or this section or to otherwise restrict or limit existing powers of the district to control and provide for distribution of water.
Ca. Water Code § 22252.3