Cal. Health and Safety Code § 117085

The board of supervisors of any county wherein is located a body of water owned by a governmental agency, that is used to supply water for human consumption may by resolution request the governmental agency owning the body of water to open the body of water to public fishing and the surrounding land area for other recreational use. The governmental agency owning the body of water shall thereupon make and file with said board of supervisors an estimate of the cost of preparing a coordinated plan for public fishing in said body of water and other recreational uses in the surrounding land area. The board of supervisors thereupon may deposit with the governmental agency owning the body of water the amount of the estimate not exceeding two thousand five hundred dollars ($2,500), and the governmental agency owning said body of water thereupon shall proceed promptly with and complete the coordinated plan. In event the cost of preparing the plan shall be less than the amount deposited by the board of supervisors, the excess shall be repaid by the governmental agency owning the body of water to the board of supervisors that made the deposit. The plan may provide for development of the area by stages and may exclude from public access structures, facilities or works of the agency necessary in supplying water for human consumption and the portions of the body of water and surrounding land area as may be reasonably required for the protection, maintenance or operation of the structures, facilities, or works. The plan may exclude portions of the surrounding area as are unsuitable for public recreational use. The coordinated plan may also include an estimate of the cost of the capital improvements necessary or convenient for public fishing and recreational uses, an estimate of the annual cost of maintenance and operation of the plan, and a recommendation as to the manner in which the plan may be financed. After completion of the coordinated plan the governmental agency shall promptly make application to the department for an amendment to its water supply permit, that would allow the opening of the body of water to public fishing and the surrounding land area for other recreational use pursuant to the coordinated plan.