I am not convinced that these wells carved deep into the rock of Paint Creek were functional. Their proximity to the ceremonial earthworks makes me lean more to them being sacred wells that may have been presided over by a priestess.
Illustrated History of Missouri
Many years ago, in the bed of Paint Creek, in Ross County, Ohio, several deep cavities or wells were discovered, which gave rise to much speculation as to their origin and purpose. I believe they have since been found in many other localities. Mr. Pidgeon states that he discovered four similar ones in the bed of a small tributary of the St. Peters river, varying in depth from eight to twelve feet, from five to six feet in diameter at the bottom and from three to five feet at the top. These excavations were made in the soft slate rock which formed the bed of the stream. To the level top, or rim of the well, a thin flat rock was fitted, with a round or square hole in the center, about twelve inches in diameter. This opening could be closed at will, by a stone stopper perforated with small holes. A short distance below the wells he found one of these stoppers which fitted neatly the larger capstone of one of the wells. At the time of their discovery the depth of the stream which flowed over them was ten inches. Mocking-Bird informed him that these were fish traps, and that many such could be found in other streams, were they not so filled with mud and stones as to escape observation ; and also that they were constructed and used anciently for the purpose of securing a supply of fish for the winter. Large quantities of bait being deposited in them in the fall, the fish would gather there in great numbers, when the stopper would be placed over the mouth, which prevented their escape, and then they could be taken out with a small net as desired. While it is no doubt true that the mound-builders were an agricultural people, it is quite reasonable to suppose, from the fact that their most extensive works are found upon the shores of lakes and banks of rivers, that fish formed no inconsiderable item of their bill of fare.