(a)(1) Pending adoption of the plan by the center, it shall be unlawful for any person to erect, maintain, suffer, or permit any structure, dam, obstruction, deposit, clearing, or excavation in or on the stream corridor which will adversely affect the efficiency of or restrict the capacity of the watercourse or flood plain, appreciably increase runoff or flood heights, adversely affect the control, protection, allocation, or utilization of the water and related land resources of the stream corridor, harmfully obstruct or alter the natural flow of flood waters, or harmfully increase erosion, siltation, or water pollution. In order to prevent undue hardship, the center may, prior to the adoption of the plan by the center, issue a letter or written statement signed by the executive director of the center ruling with respect to any proposed land or water use in any political subdivision that none of the above-listed adverse effects will occur as a result of the proposed use. Nothing in this subsection shall apply to a political subdivision that, on June 30, 1973, has in effect a flood plain ordinance and a sediment control ordinance.

(2) Pending adoption of the plan by the center as to any land brought within the stream corridor after March 1, 1983, it shall be unlawful for any person to engage in any land-disturbing activity in or on such land within the stream corridor which will adversely affect the efficiency of or restrict the capacity of the watercourse or flood plain, appreciably increase runoff or flood heights, adversely affect the control, protection, allocation, or utilization of the water and related land resources of the stream corridor, harmfully obstruct or alter the natural flow of flood waters, or harmfully increase erosion, siltation, or water pollution. In order to prevent undue hardship, the center may, prior to the adoption of the plan by the center as to any land brought within the stream corridor after March 1, 1983, issue a letter or written statement signed by the executive director of the center, ruling with respect to any proposed land-disturbing activity in or on such land that none of the above-listed adverse effects will occur as a result of the proposed use.

(3) Pending adoption of the plan by the center as to any land brought within the stream corridor on or after July 1, 1998, it shall be unlawful for any person to engage in any land-disturbing activity in or on such land within the stream corridor which will adversely affect the efficiency of or restrict the capacity of the watercourse or flood plain, appreciably increase runoff or flood heights, adversely affect the control, protection, allocation, or utilization of the water and related land resources of the stream corridor, harmfully obstruct or alter the natural flow of flood waters, or harmfully increase erosion, siltation, or water pollution. In order to prevent undue hardship, the center may, prior to the adoption of the plan by the center as to any land brought within the stream corridor on or after July 1, 1998, issue a letter or written statement signed by the executive director of the center, ruling with respect to any proposed land-disturbing activity in or on such land that none of the above-listed adverse effects will occur as a result of the proposed use.

(b)(1) After adoption by the center of the plan or any portion thereof or any amendment thereto, it shall be unlawful within those areas regulated by the plan or any portion thereof or any amendment thereto for any person to engage in any land-disturbing activity in or on the stream corridor which will be incompatible or inconsistent with the plan or any portion thereof or any amendment thereto. A proposed land or water use shall be deemed to be not in compliance with the plan unless and until the governing authority of the political subdivision issues a certificate for the proposed use pursuant to Code Section 12-5-445.

(2) The governing authority shall, before referring the application to the center pursuant to Code Section 12-5-445, require the applicant to furnish such detailed information on the proposed land or water use as the governing authority shall reasonably request and as required by the plan and rules and regulations adopted pursuant to this part.

(3) Any land-disturbing activity shall be done strictly in accordance with the certificate issued under this part. Any substantial change or modification of a proposed land-disturbing activity for which a certificate has been issued shall require a new certificate, which must be issued in accordance with the requirements of this part.

(4) The governing authority shall adopt ordinances, regulations, or procedures as necessary to assure that any land-disturbing activity is conducted in compliance with the plan and the certificate.

(c) The governing authority shall give public notice of and shall hold a public hearing before issuing or denying any certificate under this Code section. Written notice of the public hearing shall be mailed to the applicant and to the owner at least ten days prior to the hearing. The form and procedure for such hearings shall be determined by the governing authority involved, provided that all interested persons shall be afforded adequate notice of such hearings and an opportunity to be present and express their views. The information required under paragraph (2) of subsection (b) of this Code section shall be filed in final form and be available for public inspection prior to such hearing.

(d) The governing authority shall delineate and clearly label the stream corridor on the zoning map and the official map of such governing authority.