In this subchapter:
(1) “Lake” means an inland body of standing water, including a reservoir formed by impounding the water of a river or creek but not including an impoundment of salt water or brackish water, that:
(A) has a storage capacity of more than one million acre-feet; and
(B) is owned in whole or part by a political subdivision of this state, including a special-purpose district or authority.
(2) “Lake area” means the area within 5,000 feet of where the shoreline of a lake would be if the lake were filled to its storage capacity.