This subchapter applies only to a feeding operation confining cattle that have been or may be used for dairy purposes, or otherwise associated with a dairy, including cows, calves, and bulls, in a major sole source impairment zone. In this subchapter, "major sole source impairment zone" means a watershed that contains a reservoir:
(1) that is used by a municipality as a sole source of drinking water supply for a population, inside and outside of its municipal boundaries, of more than 140,000; and
(2) at least half of the water flowing into which is from a source that, on the effective date of this subchapter, is on the list of impaired state waters adopted by the commission as required by 33 U.S.C. Section 1313(d), as amended:
(A) at least in part because of concerns regarding pathogens and phosphorus; and
(B) for which the commission, at some time, has prepared and submitted a total maximum daily load standard.