For the purposes of this part, the powers, duties, functions, and responsibilities exercised by the department because of federal approval of Michigan’s permit program under section 404(g) and (h) of the federal water pollution control act, 33 USC 1344, apply only to “navigable waters” and “waters of the United States” as defined under section 502(7) of the federal water pollution control act, 33 USC 1362, and further refined by federally promulgated rules and court decisions that have the full effect and force of federal law. Determining whether additional regulation is necessary to protect Michigan waters beyond the scope of federal law is the responsibility of the Michigan legislature based on its determination of what is in the best interest of the citizens of this state.