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I'm curious if you have more information about that.

by e40 11y ago

akanster 11y ago
This 60 mins segment touched on it: http://www.cbsnews.com/news/depleting-the-water/ http://www.cbsnews.com/news/depleting-the-water/
- twsted 11y ago
  Just seen, thanks. Well done and... much less optimistic.
dccoolgai 11y ago
Not really more information about that, per se, but if you have ever seen Ken Burns' documentary on the Great Dustbowl it is interleaved with a lot of really fascinating things about how groundwater/water effects the overall affluence and economy of America as a whole - enough to cause Great Depressions and so forth. At the end, if memory serves, they discuss the Oglala aquifer and how it is at currently dangerous levels that could potentially cause another Dustbowl/Great-Depression like chain of events.
bradleyjg 11y ago
This is a good article on subsidence (caused by collapsing aquifers) and saltwater intrusion: http://www.desertsun.com/story/news/environment/2013/12/21/calls-grow-for-more-oversight-of-californias-groundwater/4161653/ http://www.desertsun.com/story/news/environment/2013/12/21/c... And here's an article with the timeline for the law's implementation: http://news.nationalgeographic.com/news/2014/09/140917-california-groundwater-law-drought-central-valley-environment-science/ http://news.nationalgeographic.com/news/2014/09/140917-calif...
ehvatum 11y ago
Subsidence is a huge issue associated associated with aquifer depletion. http://geochange.er.usgs.gov/sw/changes/anthropogenic/subside/ http://geochange.er.usgs.gov/sw/changes/anthropogenic/subsid... http://geochange.er.usgs.gov/sw/changes/anthropogenic/subside/ http://geochange.er.usgs.gov/sw/changes/anthropogenic/subsid... That fact alone tells you a lot. Some formations are more resilient; these tend to experience less subsidence. In systematic terms, sticky bag vs rigid tank.
ChuckMcM 11y ago
As a number of folks have commented when water is removed too quickly from the aquifer it subsides and can't be refilled by percolation. In a sad, and very close to home, way Sunnyvale has been drawing more heavily on wells in the area to back fill water allocations and that appears to have created some subsidence near my home. But from a technical point of view, one wonders if it would be possible to build replacement aquifers underground. I'm imagining something related to a tunnel boring machine but leaves behind a structure capable of holding water and supporting the ground above itself when "empty" sort of a loose lattice network of structures.
- bradleyjg 11y ago
  It might be possible, but I don't think it would be practical. It's easy to forget how big the numbers are when dealing with water. For example, all three Chunnel tunnels add up to less than 4500 acre-feet in volume.
- mapmap 11y ago
  I remember reading about Sun Valley in LA County that built cisterns to regulate flooding and then use that water for irrigation during dry periods.
- whyenot 11y ago
  The relationship between subsidence and groundwater pumping was actually discovered in the Santa Clara Valley in the 1940s. As a result, percolation ponds were built in the 1960s to recharge local aquifers and ground water pumping by the Santa Clara Water District (which serves Sunnyvale) was reduced to sustainable levels. Subsidence basically stopped in 1969. If it has returned, that would be a sad development.
bduerst 11y ago
Overdrafting and dropping water tables can cause the following: - Land subsiding (sinking) which permanently lowers the capacity of the aquifer - Chemical and pH composition changes, which can limit the usefulness of water drafted in the future - Irreversible damage to native aquatic ecosystems, where the water table reaches the surface, which would have normally survived the drought.

I'm curious if you have more information about that.

by e40 11y ago

I'm curious if you have more information about that.

This 60 mins segment touched on it: http://www.cbsnews.com/news/depleting-the-water/ http://www.cbsnews.com/news/depleting-the-water/

twsted 11y ago
Just seen, thanks. Well done and... much less optimistic.

dccoolgai 11y ago

Not really more information about that, per se, but if you have ever seen Ken Burns' documentary on the Great Dustbowl it is interleaved with a lot of really fascinating things about how groundwater/water effects the overall affluence and economy of America as a whole - enough to cause Great Depressions and so forth. At the end, if memory serves, they discuss the Oglala aquifer and how it is at currently dangerous levels that could potentially cause another Dustbowl/Great-Depression like chain of events.

bradleyjg 11y ago

This is a good article on subsidence (caused by collapsing aquifers) and saltwater intrusion: http://www.desertsun.com/story/news/environment/2013/12/21/calls-grow-for-more-oversight-of-californias-groundwater/4161653/ http://www.desertsun.com/story/news/environment/2013/12/21/c... And here's an article with the timeline for the law's implementation: http://news.nationalgeographic.com/news/2014/09/140917-california-groundwater-law-drought-central-valley-environment-science/ http://news.nationalgeographic.com/news/2014/09/140917-calif...

ehvatum 11y ago

Subsidence is a huge issue associated associated with aquifer depletion. http://geochange.er.usgs.gov/sw/changes/anthropogenic/subside/ http://geochange.er.usgs.gov/sw/changes/anthropogenic/subsid... http://geochange.er.usgs.gov/sw/changes/anthropogenic/subside/ http://geochange.er.usgs.gov/sw/changes/anthropogenic/subsid... That fact alone tells you a lot. Some formations are more resilient; these tend to experience less subsidence. In systematic terms, sticky bag vs rigid tank.

ChuckMcM 11y ago

As a number of folks have commented when water is removed too quickly from the aquifer it subsides and can't be refilled by percolation. In a sad, and very close to home, way Sunnyvale has been drawing more heavily on wells in the area to back fill water allocations and that appears to have created some subsidence near my home. But from a technical point of view, one wonders if it would be possible to build replacement aquifers underground. I'm imagining something related to a tunnel boring machine but leaves behind a structure capable of holding water and supporting the ground above itself when "empty" sort of a loose lattice network of structures.

bradleyjg 11y ago
It might be possible, but I don't think it would be practical. It's easy to forget how big the numbers are when dealing with water. For example, all three Chunnel tunnels add up to less than 4500 acre-feet in volume.
mapmap 11y ago
I remember reading about Sun Valley in LA County that built cisterns to regulate flooding and then use that water for irrigation during dry periods.
whyenot 11y ago
The relationship between subsidence and groundwater pumping was actually discovered in the Santa Clara Valley in the 1940s. As a result, percolation ponds were built in the 1960s to recharge local aquifers and ground water pumping by the Santa Clara Water District (which serves Sunnyvale) was reduced to sustainable levels. Subsidence basically stopped in 1969. If it has returned, that would be a sad development.

bduerst 11y ago

Overdrafting and dropping water tables can cause the following: - Land subsiding (sinking) which permanently lowers the capacity of the aquifer - Chemical and pH composition changes, which can limit the usefulness of water drafted in the future - Irreversible damage to native aquatic ecosystems, where the water table reaches the surface, which would have normally survived the drought.