(a) The commission shall cooperate with the authority to:
(1) make investigations and plans; and
(2) to the extent provided by Subsection (b), approve investigations and plans for improvements provided by the authority.
(b) This section applies only to commission approval of plans that are appropriate under general law.
(c) Except for a plan regarding the use of water that is permitted by the state, a plan for improvements adopted by the federal government controls.