[lazide]

Notably, the California Central Valley is mostly as productive as it is because of fossil aquifers that are starting to reach nearly completely depleted states. The California Aquaduct would still allow some of it, but not nearly to the extent it has. Much of the remaining fossil water is having quality issues (excessive arsenic, salt, etc.).

Arizona is not that far off [https://www.kjzz.org/2023-12-11/content-1865370-groundwater-...].

There is a very real chance both locations will end up ‘reverting to the mean’ in the next 100 years due to lack of sustainable water supplies, which I uh expect to cause significant cultural and political dysfunction, as river driven water supplies are highly variable and don’t have the stabilizing effect that underground aquifers have.

I’m less familiar with Arizona, but in California a big issue with the fossil aquifers is that when drawn down too much, they collapse, and will never be able to be rehydrated. At least not with currently known technology. ~ 28 feet of subsidence so far. [https://en.m.wikipedia.org/wiki/Central_Valley_land_subsiden...].

Modern Day Mesopotamia (at least Iraq) has similar issues - [https://www.nrc.no/news/2024/november/iraq-drought-slashes-s...]. The most stable areas politically (Kurdistan, Baghdad) is also the only area with reliably reachable not-super-deep aquifers (Figure 27 ish), and also not problems with overly saline low quality sub-surface water (see figure 37ish) [https://www.researchgate.net/publication/338393628_Groundwat...].

The north and northeast is the only part of Iraq with subsurface water suitable for normal domestic use without being treated.