Water Code § 6028
CHAPTER 2. General Provisions
No action shall be brought against the state or the department or its agents or employees for the recovery of damages caused by the partial or total failure of any dam or reservior or through the operation of any dam or reservoir upon the ground that such defendant is liable by virtue of any of the following:
(a) The approval of the dam or reservoir.
(b) The issuance or enforcement of orders relative to maintenance or operation of the dam or reservoir.
(c) Control and regulation of the dam or reservoir.
(d) Measures taken to protect against failure during an emergency.