Flood plain regulations established to comply with requirements of Section 8411 shall meet the following criteria:

All public agencies shall comply with flood plain regulations established to meet the requirements of Section 8411. For the purposes of this section, “public agencies” includes the state or any department or agency thereof.

Within any area classified “designated floodway” by the department or board after completion of a federal project report the appropriate public agency shall establish the necessary flood plain regulations within one year following notification by the department or board. The state shall not pay any of the cost of lands, easements, and rights-of-way associated with the flood control project as set forth in the project report of the federal agency unless flood plain regulations for the designated floodway are adopted in accordance with the requirements of this chapter.

The department or board shall review the adequacy of flood plain regulations established by a public agency to meet the requirements of Section 8411, and shall notify the appropriate public agency in the event the flood plain regulations are determined by the department or board to be inadequate to comply with the requirements of Section 8411. The department or board may recommend any provisions necessary to provide adequate flood plain regulations. Any such public agency shall within 180 days of receipt of the notice from the department or board, adopt new flood plain regulations. Upon their adoption a copy of such flood plain regulations shall be sent to the department or board.

Flood plain regulations adopted pursuant to Section 8412 shall take effect 60 days from the date of adoption by the public agency and shall be deemed to meet the requirements of Section 8411 unless the department or board determines that such flood plain regulations are not adequate to comply with the requirements of Section 8411. If the department or board makes such a determination, it shall so report to the public agency and shall recommend such regulations or modifications of the regulations of the agency, which it determines are necessary.

If a public agency fails to adopt flood plain regulations pursuant to Section 8411, or fails to adopt new flood plain regulations within 180 days of receipt of the department’s or board’s notice pursuant to Section 8412, or fails to adopt or modify such regulations in the manner determined as necessary by the department or board pursuant to Section 8413 within 90 days of receipt of the department’s or board’s notice pursuant to Section 8413, the local flood control agency having jurisdiction over the project area may adopt flood plain regulations for the designated floodway necessary to comply with the requirements of Section 8411. Such flood plain regulations adopted by the local flood control agency shall take effect 30 days from the date of their adoption and shall be enforced by the public agency and have the same force and effect as if adopted as flood plain regulations by the public agency.

No public agency shall revise flood plain regulations established to meet the requirements of Section 8411 or shall grant a variance from such regulations without the consent of the department or board and of the local flood control agency having jurisdiction over the project area.