Wupatki is a very dry place even by the standards of the Southwest, with annual precipitation averaging about 8 inches. Human habitation in such an arid landscape is therefore highly dependent on capturing as much available moisture as possible. It appears that the prehistoric inhabitants took advantage of the volcanic ash laid down over the area by the eruption of Sunset Crater in AD 1064 for farming purposes since it acted as a mulch, retaining water from the summer rains that would otherwise have evaporated in the heat and strong winds. For other purposes such as drinking, cooking, and construction, however, water trapped in the soil isn’t very useful, so other sources needed to be found. As at Chaco Canyon, which is similarly dry, some of this water would have come from a few springs in the area, especially in the dry season, but it would also have been useful to capture as much of the runoff from the summer rains as possible. Due to the geology of the Wupatki area, this water could only be used for floodwater farming in a very few places, but there were other ways to take advantage of it.
One such way was apparently shown by a discovery made by two National Park Service archaeologists in the 1940s. While out evaluating sites for stabilization needs, Albert Schroeder and Philip Van Cleave found some potsherds on the ground in sufficient number to make them think that they might be reconstructible into something approaching the original vessel. They picked up the sherds and dug a bit into the ground beneath them to see if there were any more. Sure enough, just under the surface of the ground there was a whole ring of sherds in place, indicating the presence of a broken but substantially complete jar that had apparently been deliberately buried. They excavated it and took some pictures, and Schroeder wrote up a short article on the discovery for American Antiquity which was published in 1944.
The jar was of the ceramic type Moenkopi Corrugated, which Schroeder dates to AD 1075 to 1275. This is unfortunately a quite wide date range, encompassing almost the entire period of substantial prehistoric occupation of Wupatki, so it is not possible to say at what point during the occupation the jar was buried. From its position, however, Schroeder was able to determine that it was likely placed to capture runoff from the summer rains. It was buried in the sand underneath one of the sandstone ledges that are so common at Wupatki, so one possibility is that it was placed to capture runoff from the ledge. Indeed, it seemed that the part of the ledge above the jar naturally collected runoff from a wide area of the sandstone outcrop. At the time Schroeder and Van Cleave found the jar, however, the water pouring off the ledge fell somewhat short of where the jar was. Schroeder suggested that there may have been some erosion in the period between the time the jar was buried and the time it was found, such that at this time of placement the ledge extended further out and the runoff may have poured directly onto the jar. If this was not the case, however, the jar was probably buried with the sand level with or a bit higher than the rim, so that runoff from the sandy ground around the jar rather than the ledge above would flow into the jar.
Either way, it seemed apparent to Schroeder that the purpose of the jar was likely to collect water, which makes sense in such an arid environment. He admitted to being somewhat unsure of the details of his proposal, and he did not venture any theories as to what the water would have been used for or why a jar was used in this way to collect it. Obviously the amount of water in a single jar would not have been much for agricultural purposes, so I suspect the water was used for household use. To be so used, depending on how close the household in question was (which Schroeder unfortunately did not mention), the jar could either have been dug up after filling or left in place. In the latter case, the water could have been taken out with a ladle and transferred to a canteen or some other sort of vessel for transportation.
I don’t have any sort of major point to make about this paper, but it’s interesting as an example of the kinds of adaptations people make to harsh environments. Wupatki would have been a hard place to live in prehistoric times, but people gave it their best shot.
Schroeder, A. (1944). A Prehistoric Method of Collecting Water American Antiquity, 9 (3) DOI: 10.2307/275790