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Comment by fargle | Hacker News Reader

I've heard the rule of thumb is that an acre of carrots uses as much water as an acre of tract homes.

I just did a little math and it's about right: an average crop irrigation might be 2-acre-feet water per-acre (imagine water 2ft high covering the field) which is 651800 gallons. It's almost double that for alfalfa. Most crops are in between and it varies depending on how many harvests per season are done.

Now, at 7 homes per acre at average of 12,000 gallons a month is 7 x 12 x 12000 = 1008000. About 50% of that goes to landscaping/pools/etc., btw. and with better management could be significantly reduced if people, as a whole, gave a hoot.

So ballpark, it's pretty accurate. The difference isn't that ag is so wasteful. It's whether you have 10 taxpayers and a whole bunch of carrots per 640 acres or two thousand taxpayers.

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> I've heard the rule of thumb is that an acre of carrots uses as much water as an acre of tract homes.

Two things are wrong with this comparison:

1 - Houses use potable water. Crops use a mix of irrigation water and rainfall. When you grow crops in arid climates like Utah, you lose the benefit of rainfall and have to pull everything from irrigation. Ideally you'd grow those crops in environments that provide more of their water needs from the sky rather than divert rivers to cover it all.

2 - Carrots aren't being grown in Utah, it's alfalfa and hay. Alfalfa is one of the more water-intensive crops to grow.

3 - The news articles say that Utah is growing a lot of this alfalfa for export. They're basically exporting their water to other locations, at the expense of residents.

It doesn't make sense for an arid state with a shrinking lake to allow people to use 2/3 of their water to export a water-intensive crop like alfalfa.

That doesn't explain why suburban lawns are needed in an arid climate. At least alfalfa is a product. When you water a lawn with potable water you are flat out wasting it. When you water a crop you are using it.

Now, over-farming or farming the wrong crops isn't right either, but if you cancelled all the ag, every different crop and replaced it with houses, guess what - still a drought.

That's why I used carrots in my comment. In the area where we experienced this, they over-built and also somewhat over-farmed. Ran out of ground water. Create water board which decided that the carrot farmers who had been there 100 years were 2nd in line for the water under their own land, which they both had legal title to and state constitutional rights to, and took it from them. They ran them out of town because it became uneconomical. Then the developers (who also ran the water board) bought the now-cheaper land and put houses there. Guess what, 20 years later - still not enough ground water. Still a bunch of suburban nimbys watering their lawns, just a lot more of them now. Guess why we import carrots from mexico now.

Growing carrots in an arid area is wasteful, because you could grow them at a place where water is more abundant. Then, carrots can be transported and they don't need almost any water anymore.

Doing the same with taxpayers would be problematic.

highly problematic also for the agencies collecting the taxes.

it's odd that you focus on "growing carrots" is wasteful when if you got rid of lawns and golf courses in the desert you'd immediately save enough water to fix the problem in this article. at least when you grow carrots you have a product. a suburban lawn produces nothing whatsoever.

suburbia is, in it's current form, far more wasteful of water and also produces far less carrots. but far more tax revenue.

All home water usage in Utah amounts to about 2% of the total use state wide. Literally you could get rid of every residence including lawns, and you'd still have 98% of the water use from farms, industrial, and commercial enterprises. Alfalfa farming I believe is at least 80% of the total water use and there's zero need to keep farming water-intensive crops which alfalfa is, we wouldn't even need to stop all farming activities just this one crop.

> if you got rid of lawns and golf courses in the desert you'd immediately save enough water to fix the problem in this article

That's simply not true. 75%-80% of the water use in the southwest is used for agriculture [1]. Even if "lawns and golf courses" are the remaining 20-25%, it is a minority of the water use. Furthermore, food doesn't have to be grown there. Bananas come from South America, oranges come from Florida, why does alfalfa (the food for livestock) need to be grown there? The answer is it does not but the current water is so cheap that people don't care salting the earth to line their personal pockets.

[1] - https://geochange.er.usgs.gov/sw/impacts/society/water_deman...

apples and oranges - per acre suburbia if anything uses more water.

if it's good enough to shift the high water use crop farming elsewhere, then why isn't it good enough to shift the golf courses and lawns, to say Iowa then too?

it's the same answer for houses, the climate is good and the land/houses/water/etc. is cheaper. you choose the characterize the farmers as "don't care salting the earth to line their personal pockets" while excepting the developers putting big cities in the middle of a desert for the same reason and for the same result.

> if it's good enough to shift the high water use crop farming elsewhere, then why isn't it good enough to shift the golf courses and lawns, to say Iowa then too?

That's very easy to answer. Because the number of humans impacted is minimized. An average farm size is ~400 acres. This is around 0.6 square miles. SLC's density is 1,800 per square mile so 400 acres is ~1k people. What do you think is easier? Displacing 1k people in a city center or 1 farmer? No one is saying the solution is perfect but between nobody being able to enjoy SLC due to inaction, 1 farmer, or 1k people, the obvious solution is for the 1k people to band together, buy the farm, and shut it down.

As per your last comment, no one here is saying that other people choosing to live in the desert are nobler than farmers. No one is "blaming" the farmers for making use of cheap water and fertile land. It all makes economic sense. The reality is that there is a finite resource and we should be working together to maximize societal benefit otherwise the tragedy of the commons will ensure none of us can. At this point in time, the most good least harm principle makes the calculus straightforward that agriculture is where the ROI is at.

oh, I don't blame the 1000 people. I blame the asshat developers who tricked them into buying into a fake utopian suburbia there.

you don't need to displace anybody. you need to stop blaming the farmers and/or taking their water and start ENFORCING reasonable water restrictions on the existing developments. About 50% of the water being used by municipalities is potable drinking water being sprayed on lawns and golf courses. You get rid of that before a telling a farmer to get lost because it's "easier".

You’re being deliberately obtuse and are repeating propaganda that’s irrelevant for total water usage.

Per acre suburbia consumes more, but as it stands farming is the vast majority of water consumption overall. It doesn’t matter how efficiently they use it. If farmers don’t make major cuts the lake will be gone.

Getting rid of lawns and golf courses will barely slow down the decline, let alone change the direction. You’re talking about optimizing 20% of the water users and suggesting the 70% is fine, which is insane.

Put another way, if all urban usage stopped immediately, the lake would still dry up because of the farmers irrigating away with reckless abandon.

As the article points out, this happened once already when SLC was much smaller and it was just lucky enough to be rescued by a thousand year rain event.

Farmers can pound sand, regardless of their water rights. Constitutional water rights for a shared resource are a travesty. They should pay for it like the rest of us so market dynamics can properly identify what is important and the lake can be protected.

Your math isn't really accurate though, is it? you say 7 homes uses 1,008,000 gallons and then you eliminate 50% of that usage because it's for 'pools and landscaping' - but homes have pools and landscaping, so you can't just ignore that usage.

Using your numbers, it sounds like the rule of thumb should be that an acre of carrots uses 1/2 as much water as an acre of tract homes, no?

i didn't make that rule of thumb up. but yeah, it's within margin of error. change the crop or number of harvests or have less lawns and it could go either way.

the point is that, the water use for developed land is roughly the same either way.

the secondary point is that growing something is productive and 50% of the water used by today's suburban lifestyle is just wasted. there's such a thing as "desert landscaping" vs. lawns.

i point this out from time to time because where ever i first heard it (in the southwest US where these water fights and drought has been brewing for more than 50 years), it made and impression on me.

it's also subtly snarky because we all hope and suppose that good government will save us from the perennial water crisis. but of course government is a machine that feeds and grows on tax revenue. and since fixing the urban and suburban sprawl doesn't align well with the government's feeding habits, here we are.

Like some of the power usage discussions here, these numbers surprised me!

Here in northern CA, our water bill for a single-family home on about a 1/3 acre lot might peak around 110 gallons/day in summer so under 3.5k gallons/month, while in other seasons it might be 10-20% less.

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