The department may cooperate with any county, city, state agency or public district on flood control and other water problems and when requested by such county, city, state agency or public district, may enter into cooperative agreements to prepare plans and specifications, construct, or maintain and operate projects or expend money in behalf of such county, city, state agency or public district, to accomplish the purposes of Chapters 1 and 2 of this part.
Ca. Water Code § 12611