Cal. Water Code § 56055

If the district board approves and adopts the report of the engineer or engineers, the board shall order the engineer or engineers to prepare precise plans and specifications for the work contained in said report. Said precise plans and specifications shall be in conformity with the general plans and specifications contained in said report as approved by the district board unless the district board by a four-fifths vote adopts a resolution declaring that the public interest requires a modification of or departure from the general plans and specifications, which resolution shall contain a statement of the manner in which the modification is required or departure is to be made.