Water security

[Nick]

Access to sufficient clean water for personal health and business production is becoming an increasing problem in many areas of the world. It is used for leverage in existing conflicts, and scarcity of fresh water supplies may in future become a source of conflict itself. As the climate changes, droughts in some areas are increasing, while others may see melting of large quantities of snow and ice.

[Nick]

Californian farmers, estimated to grow around 80% of the world's almonds, have been accused of siphoning off groundwater at the expense of the state's future water reserves.
As rivers and lakes have dried up, with more than 80% of the state in the grip of "extreme" or "exceptional" drought, the state's farmers have resorted to pumping groundwater – underground reserves – to nourish almond trees, vineyards and orchards. David Zetland, economics professor at Leiden University College in the Netherlands, says farmers are pumping water at a rate four to five times greater than can be replenished: "The people of the state of California are more or less destroying themselves in order to give cheap almonds to the world."

Full press article:
http://www.theguardian.com/business/...california-dry

[ewmayer]

Re. California crops, the really silly thing is that if growers simply made modest efforts (e.g. liberally use bark mulch and allow leaf litter to accumulate) to help retain water in the soild, they could easily cut their water needs in half or more. Go by a typical almond (or other) orchard in the central valley - in my case that happens every few years when I drive from the SF bay area to Yosemite - and what do you see? Endless rows of trees standing in bare dirt. I expect there is probably some reason for that related to ease-of-harvesting, but it surely pales compared to extremely rapid depletion of already-scarce groundwater that is being done to support the madness now. As far as household use, if the drought goes on a few more years I expect extensive rainbarrel collection systems fed from roof gutters and household-scale pumping and purification systems are going to become very common.

Interestingly, there are states (e.g. Colorado) which have legal enjoinments against such household-scale water collection, based on the idea of rainwater - even that falling on the roof of the house you mistakenly thought you owned - being a "public good". They'd rather see it run down the storm drains, apparently. (Or maybe this is just another form of municipal rent extraction, via "you need a permit for that".)

[xilman]

Originally Posted by ewmayer

As far as household use, if the drought goes on a few more years I expect extensive rainbarrel collection systems fed from roof gutters and household-scale pumping and purification systems are going to become very common.

We've moderately large scale rainbarrel collection systems around our house, though entirely for watering the gardens so purification is not needed.

The UK is generally thought of as a rainy country but, believe it or not, around here in Cambridge is officially classified as semi-arid because we receive under 50cm of rainfall per annum ---- though not by much. Notoiously soggy cities like Marrakesh and Jerusalem receive more rainfall per annum than Cambridge.

[pinhodecarlos]

I think it is amazing not having a water meter on my house in Irthlingborough, UK. I pay a monthly value, I can waste/spend all water I want.

[xilman]

Originally Posted by pinhodecarlos

I think it is amazing not having a water meter on my house in Irthlingborough, UK. I pay a monthly value, I can waste/spend all water I want.

You are in a rapidly decreasing minority. Politicians of all kinds have been talking about making meters compulsory but there are never-ending arguments about who is to pay for them and how people who can not, or will not, pay their bills should be treated. I believe, but may be wrong, that newly built houses must have meters fitted from the start.

I've had a water meter for many years now. It's partly because I have to pay for every litre used that I collect rain water for the garden. It seems senseless pouring relatively expensive and highly treated water on to plants when free rainwater is perfectly good for them. The capital cost of the containers and the hose fitting was paid off within 2-5 years. The collection system holds about a tonne (a cubic metre) of water, which is almost always enough to keep the garden green during the dry spells.

[ewmayer]

Originally Posted by xilman

It seems senseless pouring relatively expensive and highly treated water on to plants when free rainwater is perfectly good for them.

Heck, even untreated toilet water - of the #1 variety, that is - is perfectly fine, and contains natural fertilizers. I've long wished toilets with a built-in diverter to become a common household fixture. (A simple screen on the toilet-built-in splitter could prevent accidental discharge of solid waste.) Now, especially if you're a gent, you can always take matters into your own hands, as it were, in terms of feeding your excreted nitrates into the garden, but ya gotta be aware of neighbors' eyes, and these days, drones.

In rural areas I've known folks who periodically mulch their gardens with "sufficiently fermented" septic tank waste - sounds nasty, but properly done makes very good environmental sense.

[chalsall]

Originally Posted by ewmayer

In rural areas I've known folks who periodically mulch their gardens with "sufficiently fermented" septic tank waste - sounds nasty, but properly done makes very good environmental sense.

Heck, only a few weeks ago I had to open the values of the tanks so they didn't overflow back up the intake pipes.

No joke.

[Xyzzy]

Heck, even untreated toilet water - of the #1 variety, that is - is perfectly fine, and contains natural fertilizers.

Many outdoor camps are switching to waterless urinals. (The ones we used did smell some.)

http://science.howstuffworks.com/env...ss-toilet4.htm

In a previous life when we "lived in a desert" we partially buried 4" diameter PVC pipe into the sand at a 45° angle to serve as urinals.

[Xyzzy]

Vaguely related: http://en.wikipedia.org/wiki/Drug_pollution

[ewmayer]

Mark Rodenkirch (a.k.a. rogue) posted this NPR link to the Science News thread:

Cheap Drinking Water From The Sun, Aided By A Pop Of Pencil Shavings | Goats and Soda | NPR

Sounds overoptimistic, though - What we really need is a cheap membrane-based version of industrial desalination technology - a membrane which allows fresh water to seep through without requiring large pressurization, and which doesn't clog (or at least does not clog very quickly) with use.

Note that if one is starting with fresh (but non-potable) water, one can sterilize it effectively using plastic bottles and sunlight:

http://www.wikihow.com/Sterilize-Water-With-Sunlight

By way of earthquake preparedness, I'm gonna save up ~50 gallons worth of clear plastic family-sized juice jugs, fill 'em up with tap water and then simply leave them in a sunny nook of the patio for emergency use - the sunlight will keep them sterilized indefinitely.

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