Sec. 4. LIMITATIONS. (a) Nothing in this Act shall be construed as authorizing any state agency or political subdivision to regulate the discharge of dredged or fill material in the navigable waters of the state in any manner different from or inconsistent with the requirements of Section 404.

(b) Nothing in this Act shall be construed as authorizing any state agency or political subdivision to regulate the discharge of dredged or fill material in the navigable waters of the state:

(1) by the corps of engineers;

(2) by persons operating under contract with the corps of engineers;

(3) when the corps of engineers certifies that such discharge is incidental to a project undertaken by the corps of engineers or persons operating under contract with the corps of engineers, and that such incidental discharge was announced and reviewed at the same time and under the same conditions as such project; or

(4) by cities which own and operate deepwater port facilities, or by navigation districts or port authorities, or by persons operating under contract with such cities, navigation districts, or port authorities, when such discharges are part of or incidental to a navigation project to be paid for with public funds or when such navigation project is to be owned by such cities, navigation districts, or ports.

(c) Nothing in this Act shall be construed as authorizing any state agency or political subdivision to regulate the discharge of dredged or fill material in the navigable waters of the state in any manner unless and until an agreement as described in this Act is validly entered into and in effect.

(d) Nothing in this Act shall be construed as authorizing any state agency or political subdivision to exercise any authority under this Act except in accordance with an executive order of the governor.

(e) Nothing in this Act shall be construed as authorizing any state agency or political subdivision to regulate the discharge of dredged or fill material in the navigable waters of the state in any manner different from, or inconsistent with, the agreement described in this Act.

(f) Nothing in this Act shall be construed as affecting any application for a permit from the corps of engineers to discharge dredged or fill material in the navigable waters of the state if such application is received by the corps of engineers or postmarked before the effective date of the agreement described in this Act.