California Code, Public Resources Code - PRC § 5093.55

Other than temporary flood storage facilities permitted pursuant to Section 5093.57, no dam, reservoir, diversion, or other water impoundment facility may be constructed on any river and segment thereof designated in Section 5093.54;  nor may a water diversion facility be constructed on the river and segment unless and until the secretary determines that the facility is needed to supply domestic water to the residents of the county or counties through which the river and segment flows, and unless and until the secretary determines that the facility will not adversely affect the free-flowing condition and natural character of the river and segment.