No provision of this division, or of any order, rule, or regulation of the state board or of any district, is a limitation on:
(a) The power of any local or regional authority to declare, prohibit, or abate nuisances.
(b) The power of the Attorney General, at the request of a local or regional authority, the state board, or upon his own motion, to bring an action in the name of the people of the State of California to enjoin any pollution or nuisance.
(c) The power of a state agency in the enforcement or administration of any provision of law which it is specifically permitted or required to enforce or administer.
(d) The right of any person to maintain at any time any appropriate action for relief against any private nuisance.