Cal. Wat. Code § 108
It is hereby declared to be the established policy of this State that in the development and completion of any general or co-ordinated plan prepared and published by the Department of Water Resources or any predecessor thereof or successor thereto, all uses, including needs of the area in which the water originates, of water shall be given consideration.
Whenever the Legislature authorizes the construction or acquisition by the State of any project which will develop water for use outside the watershed in which it originates, the Legislature shall at the same time consider the authorization and the construction or acquisition of such other works as may be necessary to develop water to satisfy such of the reasonable ultimate requirements of such watershed as may be needed at the time the export project is authorized or as will be needed within a reasonable time thereafter. The authorization with respect to such additional works may provide for state acquisition or construction, in whole or in part, of any such additional works, or financial assistance to other entities in connection with the acquisition or construction of such works, or a combination thereof.
Ca. Water Code § 108