Thirsty folks from California and the Southwest wanting more water to be piped in to feed their water intensive crops and lawns in the desert. I'm sure that'll go down well in outlying regions. Maybe change in meteorological patterns and population levels hitting critical mass without the attendant infrastructure are bad for water levels. Aquifers are depleted. Rainfall is reduced. There's no more snowmelt to bank on as that savings account has been drained. Wildfires, drought, and rising sea levels will displace significant numbers of people. Agriculture will shift north and east. I think California peaked a few years ago.