Sec. 24. (a) This section does not apply to the following:
(1) The adoption of rules restricting construction within the one hundred (100) year flood plain.
(2) The acquisition of conservation easements under IC 32-23-5.
(3) The investigation of alleged violations of the Indiana flood control laws.
(b) A power of the commission may not be exercised upon any of the following:
(1) A river included in the natural, scenic, or recreational river system under IC 14-29-6 or the river's associated one hundred (100) year flood plain.
(2) A nature preserve under IC 14-31-1.