I believe those are called aquifers aka geologic water reservoirs. There's a lot that can happen, especially in urban areas with lots of hard scaped surfaces, to encourage rain water to enter aquifers instead of run off into the water shed or sewer/storm drain system.
While not offshore, the Great Man-Made River project [1] in Libya exploits the Nubian Sandstone Aquifer [2] which may have 150,000 km3 of groundwater (7x the volume of The Great Lakes), or if you’re in the UK enough to fill Wembley Stadium 131,682,907 times.
> Wells generally tap flowing water even if it’s simply not obvious that’s what’s going on. Basically, the ground can only hold so much water and it normally absorbs excess from rain which eventually flows into streams etc.
This was news to me, thank you. Do you have a source for further reading?
I don’t know why I find water harvesting so fascinating, nifty use of aquifers.
There was a civilisation in the Sahara that had tunnels in the mountain that provided water, I imagine they ran dry.
Persia had (has?) underground tunnels that convey water to farmland.
With the increasing amount of heavy rain fall I’m not sure how much of that can be caught and sequestered.
This was made all the more apparent when there was a sudden downpour in London some years back and the river Fleet, sewer as it is now backed up into the office’s canteen.
Something like that. Aquifers are different from reservoirs -- reservoirs are our above-ground water stores, aquifers are our below ground water stores.
The problem is that while reservoirs can be refilled from the surface watershed with a good rainy season or two, aquifers take decades of water slowly percolating down through the soil to replenish. If your rate of consumption exceeds the refill rate, well, you're in a bit of an unsustainable situation and the clock starts ticking.
As the drought progressed and surface water became scarce, agriculture started drilling deeper and deeper wells to access the aquifer reserves. The aquifers got so drained that there were stories of fracking companies being hired to drill wells which had depths beyond the capabilities of most traditional well-drilling machines.
Worse, there's also positive feedback loops at play -- as an aquifer gets depleted, the ground above it can settle in a way that slows the refill rate (I've heard it described as the volume occupied by the water goes away so dirt fills in the small gaps creating more compacted/sealed off soil). If the refill rate slows down and your consumption rate stays steady or increases (development!), well, the aquifer's rate of depletion accelerates. Feedback is a bitch.
The anecdote about fracking companies being called in to drill super-deep water wells tells you all you need to know about how market forces price the sustainable consumption of our water reserves.
>Figured that tapping the drainage flow of water from a whole area combined would work better and for that need a organised drainage system all connected and yes you do get those.
If I'm not mistaken, the technical term for these broad-area drainage systems is "river"
Chicago, for example, stores water and sewage in a nearby quarry during periods of heavy rain.
Um, it's more than a quarry. Chicago is 3/4 through a sixty year project to install more than 100 miles of underground tunnels and reservoirs which will hold 66 million cubic meters of water when finished in 2029 (or thereabouts). The quarry is a temporary reservoir.
I wanted to emphasize that, if it's what I think it is. I saw a TV show about Australian property (one of those shows that follow a couple trying to buy a house). One startling thing was seeing houses there with large, multi-thousand liter water storage tanks along the side of the house. I assume these collect rainwater.
Is that what you're talking about? If so, that's quite uncommon in the USA. I've seen older houses that had a way to store rainwater collected from the roof into a cistern in the basement. But that sort of thing just is not done here in new construction.
The problem in the USA is people (generally) don't understand anything other than price. Which means there's no way a builder can include an expensive "extra" such as this. At least not in a subdivision. Of course out in the boonies where there is one house in 160 acres, wells and cisterns are used.
In Australia are these water tanks required by building codes?
In a city as sensitive to water issues as Tucson this isn't novelty at all. I participated in the student group that helped install cisterns at the UofA visitors center back in 2006 and 2007. We got most of our ideas from a local named Brad Lancaster who'd been doing it far longer.
https://en.m.wikipedia.org/wiki/Cistern
reply