Cal. Wat. Code § 205
The department may join associations of representatives of other States which have been established for not less than 10 years and which have for their purpose the promotion of reclamation and irrigation and cooperation between the several States and the Federal Government in matters relating to reclamation and irrigation. The department may collaborate and cooperate with other members of the association selected in accordance with the constitution and by-laws of such association, relative to matters of public interest to the State within the scope of the activities of such association. The department may, from any of its funds available for the purpose, make expenditures for the pro rata share of the expenses of such association attributable to California and for the services performed by such association for the State.
Ca. Water Code § 205