It utterly debunked all the nonsense you have posted in this thread.
Exactly: Nobody is discussing seasonal precipitation. This thread is not about seasonal precipitation. It is about water fluxes over geological timescales
No, it is often impossible to remediate, as Stranger On A Train has already noted.
Even in those instances where it can be remediated, it occurs over geological timescales. A point that you don’t seem to understand
Over those timescales, it is necessary to maintain withdraw at below recharge capacity. This is not something that is affected by seasonal precipitation.
Thought the reference to ANWAR would make it obvious that it was tongue in cheek. :smack:
As for staying strictly within the bounds of the OP?
I’d say rationing and credit trading are about it. In a world with a booming population expecting water consumption to stabilize through any means that are not intrusive is a pipe dream.
Guys, the problem is not that people are taking long showers and flushing twice instead of once. Home water usage is a tiny fraction of water usage. By far the biggest use is for agriculture. Desalinization plants might supply expensive drinking water for a city, but they aren’t going to supply agricultural water.
Water rights are a classic example of a commons, and the canonical solution of granting private property rights to the commons doesn’t work that well for water, because water doesn’t stay put. It drains onto land, it drains off land, it evaporates, it precipitates.
While aquifers (stretching across multiple states) may be a commons, in fact water rights are a large and heavily litigated traditon in the US west. IIRC the Colorado’s flow is legally subdivided to various users before it its the sea (or doesn’t). WHere’s the incentive in reducing what you can draw, only to allow someone else to get a larger quota?
Um, this post hasn’t been addressed yet, and maybe I’m missing something here, but:
I kinda thought “the whole point of applying water to agricultural land” is to water the roots of the plants being grown. Why would a farmer want the water to evaporate, rather than being absorbed by his crops?
This remaining “heavily contaminated” water of which you speak is different from what municipal water-treatment centers have been re-purifying for decades .. how?
Yes and no. The ideal would be to water just enough to make sure the roots have enough water to do their job. OTOH, if that water did not go anywhere, the ground would become waterlogged. Worse yet, overwatering that does not evaporate soaks into the soil deep down, leaches salts etc. up to the surface (or if it is porous soil,leaches your soil nutrients down into the local aquifer.) Run-off, taking your soil and fertilizer with it, is also not good.
In heavily irrigated areas, surface salt has become a big problem. I recall reading once that it has destroyed much of the fertility of the original fertile crescent over the millennia.
However, it’s cheaper to set irrigation going and just leave it than to micromanage it as long as it does not cause significant run-off Unless leaching is a problem, the excess will usually go away on its own - evaporation. Basically you are spreading water thinly across the land - what else would it do?
Make water expensive and farmers will use it wisely. I recall a discussion of prices and resource use many years ago; it mentioned that Egyptian government subsidies for food meant that bread for the public in Egypt was cheaper than animal feed. Guess what the farmers did? (Part of the cause for recent unrest was trying to reduce those subsidies in the face of rising food prices)
It’s already done in many places - Las Vegas for example, IIRC.
Usually it’s not purified to the same standards as drinking water, and distributed in a separate system as “brown water” to be used for watering lawns, etc. In other places it’s pumped underground and allowed to seep into an aquifer, or pumped into the same river or lake that the water purification plant gets its water from. Very rarely is it pumped straight back into the water supply because most people don’t like the thought of it. (One Australian town tried to do it, but the people voted against it; they ended up building a pipeline from another reservoir, which cost much more than a recycling system would have.)
Some places may be doing that, but not all. Water is a local issue, not a global crisis. There are many areas of the world where there is sufficient rainfall to supply a river that can support vast stretches of irrigated farmland downstream. (Though there are also places where there is insufficient water for household use because too much water is used for irrigation. This is one of the problems in India, as I understand, where most cities only get less than an hour of water a day.)
While driving from LA to San Francisco on Highway 5 I couldn’t help but notice that the California Aqueduct is transporting millions of tons of fresh water from the north to the south in an open canal. Really? They couldn’t do it in pipes that would greatly reduce evaporation? :smack:
Reservoirs and lakes are open as well. If I remember correctly, more water evaporates from Lake Mead than is used by the entire city of Las Vegas. It’s still not worth the cost of covering it up.
Also, over 10% of purified water in the US is lost to leakage. In some European cities it’s as high as 25%.
Compared to these, I suspect evaporation from the aqueduct is pretty small.
There’s evaporation, and there’s transpiration. Evaporation would be the water sprayed/sprinkled/dripped/flooded into the fields, that then evaporates into the air without ever really making it into the soil
Transpiration is the water that a plant takes up through its roots and then releases into the air.
You want a small amount of evaporation (hence drip irrigation systems), but whatever transpiration a healthy plant would produce.
More importantly, only 10% of the water use is actually non-industrial or agricultural. Obviously the biggest gains are likely to be had in those sectors vs. the home/commercial ones. It sounds like everyone in the country could have HE washers, and it would make less of a dent than 2% of farmers going to drip irrigation or something similar.
Drip irrigation is terrific- we had stage 3 water rationing a while back in my part of N. Texas, and my city let me water my garden with a drip system despite not letting people wash cars, water lawns, etc… This is because I used between 5 and 10 gallons a day total doing it. (sounds like a lot, but think about how much a sprinkler system would put out for an hour!)
Is Israel so successful with desalination because its relatively flat in comparison to the US in terms of being able to pump desalinated water over long distances to supply its urban centers?