Cal. Water Code § 36577

In lieu of assessing all land pursuant to its cash value as set forth in Section 36571 or the county assessed value pursuant to Section 36575, the board may provide for an alternative method of valuation based upon the benefits bestowed on the land by directing the assessor to, and the assessor shall thereafter, adopt as the assessed value of all land in the district an amount determined by the board pursuant to Section 36578.