Any idea how much of the Ogallala is paleowater and how much is from rainwater?
DB2
Recharge rates on the aquifer vary, depending upon where you look.
Recharge in the aquifer ranges from 0.024 inches (0.61 mm) per year in parts of Texas and New Mexico to 6 inches (150 mm) per year in south-central Kansas.[15]
The recharge rate of the Ogallala aquifer has been estimated to average about one half inch per year (“Ogallala Aquifer ,” 2014).
I know a farmer out there. He is a photographer in my circles. He is a nutty guy. Hates the entire idea of organic. Not an honest bone in his body. Getting someone like him not to drill wells will be impossible.
I have seen him have a two year old’s meltdown on the topic of organic foods. Likes to fry his steaks in butter and finish them in the oven. Thing is he does not know when to stop eating steak.
I can remember way back in the early 1980’s reading that the Ogallala Aquifer was destined to dry up. Back then, the Sunday edition of the Detroit Free Press was a great read, in depth articles on topics from around the country, and the world, and they printed articles about the Ogallala in danger of drying up.
I’m not trying to imply that the Aquifer isn’t in danger of going dry, but it’s been warned about for over 40 years, maybe longer.
But the cited water experts in Kansas most definitely know more about its capacity than I do, just jogged a memory about this same story long ago.
“…since widespread pumping began around 1940, much of the Ogallala has lost at least 30%”
30%/80 = 0.4% per year
This would imply the aquifer has some 175 years to go. Then it will be back to rain-fed agriculture and cattle grazing.
DB2
That is the average recharge rate. Some parts of the aquifer are much lower–or same/higher. The only ones really monitoring the level of the aquifer are NOT the farmers but the federal govt or, in rare locations, local govt bodies set up to specifically monitor the rare resource they are using up. Once the water is gone, so is the local economy.
No, your calculation assumes you can drain the aquifer to 0. Like oil production, the lower the percent left in the ground the harder it is to produce. There is no “magic number” as to what the minimum is, in some areas it’s higher, in some it’s lower.
There comes a point where it is uneconomic to produce because the volumes trickle off. Depending on geology, in some areas the water is holding the rock cracks open, once the water is remove the ground subsides and there is nowhere for the “recharge” water to go; this effect can accelerate over time, just like a mine collapse can be smaller or larger.
Surface waters may contaminate acquirers as they recharge due to runoff of pesticides, fertilizers, etc. and as the “reservoir” becomes smaller the residues become proportionately larger. There are other issues as well, but the most persuasive is that once it’s gone it’s gone and can take hundreds of thousands, perhaps millions of years to redevelop, assuming it ever does.
Anyone who has had a well go dry is more aware of the dangers than someone who hasn’t; the supply is not endless and (like oil) there is a limit. Some things can be increased in supply: wheat, soybeans, etc. but acquifer isn’t one of them, at least not in any ecological sense.
This would imply the aquifer has some 175 years to go, on average.
Well, it reverts back to WW2 levels – assuming no changes in agricultural genetics. The seed companies will be glad to develop more drought resistant crops.
At any rate, to avoid drawing down the aquifer usage must go back to rain-fed levels. This would also mean low levels of water usage.
Since the aquifer is going to be drawn down then it becomes a matter of when and how the benefits are distributed – more benefit over the next century or less over several centuries.
DB2
Water rights have been an issue in the west from the first settlers. This is nothing new. Climate change puts it in the news again.
If supplies are decreasing decisions are needed. Otherwise mother nature will take care of it. Some agriculture will become unprofitable. Some cities may become ghost towns. The economic impact could be significant.
A smart investor might buy up deserted land in hopes that climate change is cyclical.
This works if you are investing for your great-great-*10-grandchildren. Because when climate change is cyclical, it tebds to cycle over centuries, not over decades.
Db’s calculation also assumes an equal rate of depletion over the course of 40 years. I bet it is being depleted at an accelerating rate due to climate change and population growth though I do not plan to look it up.
Probably true, which means the aquifer will only last, say, 100 years instead of 175. The question remains, do we use the benefits of the stored water over the next century or do we move (some) of the benefits into future centuries?
DB2
It’s hard to speculate about the rate of acceleration without evidence. It could be 100 years as you speculate, or 75, 50 or 25 for all I know. Plus, we are looking at this one aquifer in isolation. What is the cumulative effect of multiple aquifers drying out at an accelerating pace due to climate change and population growth?
Whichever, the question posed above still remains.
The Ogallala is unusual in that it has a large amount of paleowater which is basically a fixed, one-time use resource. It can provide benefits over 25, 50, 100 years (depending on the pumping rate) but the total benefit is fixed.
The is also some recharge from rainwater, and like all water usage it is important to live within one’s means. Cities in the dry southwest have learned how.
Water officials in San Diego, though, say they are not worried. “We have sufficient supplies now and in the future,” said Sandra Kerl, general manager of the San Diego Water Authority. “We recently did a stress test, and we are good until 2045” and even beyond.
San Diego is not alone. While the public image may be that booming southwestern cities such as San Diego, Phoenix, Las Vegas, and Albuquerque are on the verge of a climate apocalypse, many experts agree that these metropolitan areas have enough of a water cushion to not only survive, but continue to grow into the surrounding desert for the foreseeable future, even during the worst drought in 1,200 years.
DB2
Somebody said that out loud and was serious? Are we expecting Armageddon in 2045; is the world ending in 2045?
Has it been that long - damn, I’m old; but thanks. Is that cake calorie free?
JimA
Given enough chocolate…