California Code, Water Code - WAT § 8401

(a) A large portion of the state's land resources is subject to recurrent flooding by overflow of streams and watercourses causing loss of life and property, disruption of commerce, and interruption of transportation and communications, all of which are detrimental to the health, safety, welfare, and property of the people of this state.

(b) The public interest necessitates sound development of land use, as land is a limited, valuable, and irreplaceable resource, and the flood plains of this state are a land resource to be developed in a manner which, in conjunction with economically justified structural measures for flood control, will result in (1) prevention of loss of life, and (2) prevention of economic loss caused by excessive flooding.

(c) The primary responsibility for planning, adoption, and enforcement of land use regulations to accomplish flood plain management rests with local levels of government.

(d) It is the policy of this state to encourage local levels of government to plan land use regulations to accomplish flood plain management and to provide state assistance and guidance therefor as appropriate.