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The Agua Fria river flows about half a mile away from the site. Although it's rarely above ground, the subsurface flow is the third-largest in the state, and th
by nkoren 9y ago
The Agua Fria river flows about half a mile away from the site. Although it's rarely above ground, the subsurface flow is the third-largest in the state, and there aren't very many people upstream. Arcosanti has a well and gets all its water from there.
Interestingly, the area is dotted with the ruins of numerous large Hohokam settlements; it's obvious that the population was much greater about 600 years ago than it is today. The Hohokam built some pretty sophisticated aqueducts, one of which is located on the Arcosanti property, which brought water up from the river to the settlements on top of the mesa. At the time, it seems that the rainfall pattern was dominated by small but frequent winter storms, resulting in almost year-round surface flow. But a change in the climate about 600 years ago switched the rainfall pattern monsoon-type: dry in the winter, and flash floods in the summer. The Hohokam aqueduct system couldn't cope with this, and their civilisation collapsed. So it's definitely a point worth being concerned about in that environment.
Arcosanti, however, is fine.
- mxuribe 9y agoIf I remember my "history" correctly, actually, the trigger to climate change back at that time was related to pirates (or their diminishing thereof): https://en.wikipedia.org/wiki/Flying_Spaghetti_Monster#Pirates_and_global_warming https://en.wikipedia.org/wiki/Flying_Spaghetti_Monster#Pirat... ;-)
- sbierwagen 9y ago>which brought water up from the river to the settlements on top of the mesa They pumped water uphill?
- nkoren 9y agoNo, they intercepted the water far enough upstream of their settlements. Let's say you have a pueblo on a 200 ft mesa, above a river that's running at a 4% gradient. Your aqueduct needs a 2% gradient to maintain good flow -- the Hohokam were excellent at maintaining consistent gradients over very long distances -- so what you need to do is build a small check dam 200 / (4% - 2%) = 10,000 ft upstream, with the stone aqueduct wending its way "up" the side of the mesa from there. Ruins of these kind of structures can be seen all over the area.