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Draining California

nationalgeographic.com

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Re: Draining California

#51

Post by bjelkeman-again »

markvdb wrote: post #41
x86_64Ubuntu wrote: post #40

Earlier quoted context omitted.

What does evaporation have to do with anything? When people are talking about the drought and competition of water, they are talking about the net water available, not what is lost through natural processes.

Man has created big surfaces of water in hot dry areas. A significant portion evaporates before it can be used...

Also, things like road surfaces and parking lots stop rain from percolating down in the soil and it becomes runoff instead and drains to the ocean quickly.

Re: Draining California

#52

Post by lisper »

seanflyon wrote: post #23
Someone wrote: post #19

Earlier quoted context omitted.

"Changes to individual use will only have a small impact on our water use" Every single farmer can argue the same way ("I only use a tiny fraction of what the state as a whole uses, so it won't help" or "almond farming only uses 10% (I'm making up this number), so it won't help if we, almond farmers, economize on water use") Everybody can find a group they are in that will have a small impact.

The point is that the vast majority of the water is used by a small minority of the people.

But that small minority uses that water to produce food, which is used by everyone.

Re: Draining California

#53

Post by hughdbrown »

ghshephard wrote: post #47
hughdbrown wrote: post #36

Earlier quoted context omitted.

Barrels, gallons, acre-inches, acre-feet. This is why I find the metric system so much preferable: only liters and cubic meters (1000 liters).

If you have an acre of farmland, an acre-foot of water is the most relevant way of measuring required water.

Maybe American farmers should trade in their acres of farmland for hectares. There could be a government program to exchange one for the other.

But really -- read the comments and check out the number of times these units are mentioned and converted:

- "200 million acre-feet of precipitation to California in average years"

- "No doubt when water hits $100/barrel..."

- "1 Barrel = 42 Gallons. It costs $0.75/cubic meter (264 Gallons)"

- "There are 326,000 gallons in an acre-foot. So, Most Farms can't pay much more than 2000/326000, = $0.006/Gallon."

- "$0.75/cubic meter = .75 / 264 = $0.002/Gallon."

- "In 2011, the average californian used about 326 gallons/day of water"

If you are going to have a conversation about how urban residents compete with farmers for water, it helps to have a common unit. People don't drink water in acre-feet and farmers don't consume gallons or cubic feet or whatever of water. But if the conversation were in liters or cubic meters, at least you'd have a fighting chance of talking the same units.

Take this from the comments: "For example, Crystal Springs, a 70k cubic meter reservoir in San Mateo, is entirely for urban use. There is no agriculture competition for it. Every gallon we conserve there, is another gallon conserved for city use."

First, it is not 70 000 cubic meters. It's 70 000 000 cubic meters or 70 000 000 000 liters. [1]

What would that look like? Well, we have 7e7 cubic meters to divide up into three dimensions. It would be a lake like 700 meters across by 10 meters deep by 10 000 meters long (10 km).

Those Californians who consume 326 gallons (1200 liters) per day? One of them could use that reservoir in about 60 000 000 days. Or if you had a million of them, they'd take two months.

Four acre-inches would be like [2] one hectare by 10 cm deep -- 10 000 square meters by 0.1 meters, so 1000 cubic meters or 1 000 000 liters. So you can irrigate 70 000 hectares with that much water at that depth per area of land.

I am saying the math is way simpler and you can pretty much do it in your head. And you can visualize it. So: common unit across multiple uses, easily scaled up, easily visualized.

[1] https://en.wikipedia.org/wiki/Crystal_Springs_Reservoir

[2] Not because an acre is the same size as a hectare but because you'd have proportionately fewer hectares than acres.

Re: Draining California

#54

Post by tanzam75 »

refurb wrote: post #43
hughdbrown wrote: post #36

Earlier quoted context omitted.

Barrels, gallons, acre-inches, acre-feet. This is why I find the metric system so much preferable: only liters and cubic meters (1000 liters).

Really? I find acre-inches pretty intuitive. Maybe convert to hectare-centimeters?

That's non-metric thinking. In the metric system, you could simply use the cubic meter.

A hectare is 10000 square meters. A centimeter is 0.01 meters. Thus, if 1 centimeter of rain falls on a 1 hectare field, then that's simply 100 cubic meters of water.

The nice thing about this is that you can easily compare quantities from different contexts. A cubic meter is a cubic meter, whether the water came from a pipe or from the sky.

But what does it mean to have an acre-foot of piped water? Nobody specifies pipe cross-sections in acres. Or a barrel of rain falling on a 1-acre field. How many inches is that equivalent to?

It's not just water. Look at HVAC. In the US, natural gas is billed in therms, and electricity is billed in kilowatt-hours. In metric countries, both electricity and natural gas are specified in kilowatt-hours.

And why not? Energy is energy. If you have a heat pump with gas backup, then you could use gas and electricity interchangeably to heat your house. If you've got a residential cogen system, like they have in Japan, then you could buy either gas or electricity to run your television.

Re: Draining California

#55

Post by ghshephard »

hughdbrown wrote: post #53
ghshephard wrote: post #47

Earlier quoted context omitted.

If you have an acre of farmland, an acre-foot of water is the most relevant way of measuring required water.

Maybe American farmers should trade in their acres of farmland for hectares. There could be a government program to exchange one for the other. But really -- read the comments and check out the number of times these units are mentioned and converted: - "200 million acre-feet of precipitation to California in average years" - "No doubt when water hits $100/barrel..." - "1 Barrel = 42 Gallons. It costs $0.75/cubic mete…

No argument from me on any of that, totally makes sense. And thanks for the correction of 70,000 m^3 -> 70,000 * 1000 m^3 for Crystal Spring Reservoir.

(I'll admit to having to have Soulver up just to have this conversation - Metric system would make it way, way easier.)

Re: Draining California

#56

Post by palderson »

Big problems, create big opportunities. Some of the developments that may occur to address this issue over the next 10+ years:

- Development of a robust water entitlement exchange - Decoupling a water right from the land to create a more tradable asset - Regulation change to allow for water leases - A shift away from growing 'thirsty' crops in drought-prone regions - Decentralization of water treatment plants to reduce distribution costs - Increased use of grey and recycled water in the home - Pricing changes based on its use within high water use industries - Increased use of GM crops designed to require less water - State-sponsored overseas farming specifically for US import of thirsty crops - Less water exporting occurring. I.e. selling thirsty crops to China

And I'm sure, much, much more.

Re: Draining California

#57

Post by jonknee »

blahedo wrote: post #37
bryanlarsen wrote: post #32

We live in Ottawa, Canada. Last year we had a very dry summer, so the city sent out notices asking people to please water their lawns regularly. The Ottawa River is a major river, Ottawa is the only major user of its water, and doesn't really make a dent in the flow, especially since we put our wastewater back into the Ottawa (after treatment, mostly). They had no concern about water security, but they did have a con…

The Great Lakes region is a whole other thing. In fifty or a hundred years, it's cities like Milwaukee, Chicago, Cleveland, Ottawa, and even Detroit that will be booming---because they will still have bountiful access to clean freshwater.

Unless we keep pumping in fertilizer and the water becomes a toxic soup...

http://www.nbcnews.com/science/environment/toxic-algae-bloom...

Re: Draining California

#58

Post by lnanek2 »

snomad wrote: post #34

Many people will often say agricultural uses 80% of the water. This is not the whole picture. "Nature provides about 200 million acre-feet of precipitation to California in average years. Of this total, 65% is lost through evaporation and transpiration by trees and other plants. The remaining 35% stays in the state’s system as runoff. More than 30% of this runoff flows out to the Pacific Ocean or other salt sinks. Th…

I know in Berkeley the reservoirs are all covered over. So if anything, moving water down to here probably prevents loss. If you read the article, a lot of water is kept near the source as well, like Hell Hole reservoir, and only let out prematurely if the reservoir is near full. So I'm not sure what you are complaining about. Are you claiming the water should be used in the north instead of the south? Northern Cali is already wine country, e.g. Napa, so it is already in use. There isn't any way to move the southern agriculture businesses there.

Re: Draining California

#59

Post by DanBC »

x86_64Ubuntu wrote: post #40
snomad wrote: post #34

Many people will often say agricultural uses 80% of the water. This is not the whole picture. "Nature provides about 200 million acre-feet of precipitation to California in average years. Of this total, 65% is lost through evaporation and transpiration by trees and other plants. The remaining 35% stays in the state’s system as runoff. More than 30% of this runoff flows out to the Pacific Ocean or other salt sinks. Th…

What does evaporation have to do with anything? When people are talking about the drought and competition of water, they are talking about the net water available, not what is lost through natural processes.

Farmers have to hange their moethods to reduce the amount of evaporation.

Thus they'll plant extra plants to provide shade for the ground and reduce evaporation.

http://www.bbc.co.uk/programmes/b04fz6kt

http://www.bbc.co.uk/programmes/galleries/p025p8yy

Re: Draining California

#60

Post by azinman2 »

jmathai wrote: post #3
alsetmusic wrote: post #2

Link goes to site homepage, not an article. Can anyone provide a link to the intended story? edit: or maybe it's my browser, but I didn't check

I'm on an iPad and using Safari or Chrome renders the page fairly unusable. Scrolling doesn't work and it does appear to go to more of a home page than one specific to an article about California.

On my iPhone I couldn't see anythjng really. That is one not mobile friendly side
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