Sec. 310. (a) "Watershed", for purposes of IC 14-25 through IC 14-29, means an area:
(1) from which water drains to a common point; and
(2) for:
(A) a watercourse, that is measured to the mouth of the watercourse; and
(B) any part of a watercourse, that is measured to the farthest downstream point in question.
(b) For purposes of IC 14-13-2, "watershed" has the meaning set forth in IC 14-13-2-3.8.
(c) For purposes of IC 14-30.5, "watershed" has the meaning set forth in IC 14-30.5-1-10.