The article linked above provides a dynamic map of relatively recent US droughts. As the map sequence suggests, the west-southwest part of our country suffers from a deficit of water resources. We can see this in reservoir levels that trend lower, groundwater extraction that amounts to water mining, and over-allocation of resources such as the Colorado River (ask if you want further explanation of any of these).
There are at least three other parts to the story, though, beyond the past 20 years of on-again, off-again drought. The first involves how much precipitation the area receives in non-drought years. Are those years only average or are do we ever have enough above-average years of precipitation to begin to catch up on the deficit? Of course, we need to look at a much longer history than 20 years to define average. Second, the article mentions human-induced climate change as a big factor influencing the past 20 years, but this may not be much of an effect in the larger scheme of things. We have evidence that severe multi-year, even multi-decade droughts occurred several times in the American Southwest over past millennia, and most of this had nothing to do with human-induced climate change. Third, how can we properly understand the situation so that we can try to manage or mitigate it?
This a fascinating, multidimensional area to study, yet with immensely practical implications. I touched on some of the local practicalities earlier (see my “Questions, We Have Questions about Water” post), but this has regional and larger aspects as well. More to follow…
One thought on “How Long of a Drought?”
Seems to me that the southwest US had a large influx of people moving into the area over the last 75 years or so. The weather in the area is some of the best in the country. California was wise to build dams and aqueduct systems back in the 1960s to better manage floodwaters. Unfortunately, state water management systems have not been able to keep up with the growing demand from both farms and people. At some point things ARE going to change. Whether we actively manage the change or it is forced upon us. Our legislators might not have the ability to work together to do anything about it. Nevertheless, people will ultimately grow tired of being told they need to conserve water, letting their precious investments in landscaping die. Farmers will grow tired of running out of water and watching their crops die. Eventually people will move elsewhere. We already see this in the number of people leaving California for other states to pursue better jobs, lower taxes, lower gas prices, etc.
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