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Comment by hamburgerwah | Hacker News Reader

Arizona has a policy of maintaining 100+ years of water (and all new construction must demonstrate that). The phoenix metro area has the most responsible and thoughtful water management policies of any major american city and is a net contributor to ground water. What arizona gets from the colorado river is icing and a literal drop in it's well managed supplies.

Arizona was preparing for this possible outcome in the early 1980's. It's a total non event for the state.

Save your outrage for the cities on our coasts whose antiquated and poorly managed treatment systems dump millions of gallons of untreated sewage into our rivers and oceans.

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Many of the rapidly growing Phoenix suburbs are projected to find themselves in trouble with regards to water resources in the future. These suburbs have met their 100+ years of water requirement using the Central Arizona Groundwater Replenishment District (CAGRD), an entity created in the 1990s tasked with replacing pumped groundwater by finding renewable water supplies and injecting that water back into the aquifer.

However, the current drought and temperature projections going forward show that it will be increasingly difficult for CAGRD to find water to inject back into the aquifer to meet its obligations. In the end these suburbs will either need to pay super high rates for water to inject into aquifers or will need to slow growth.

https://www.hcn.org/issues/53.6/south-water-rapid-growth-in-...

Thanks for this -- it's critical to recognize that the supply for the groundwater replenishment upon which much of the "100+ year" assured water contingency rests is provided in part by the Colorado River.

Thanks for this comment, and largely good points here, but you're certainly mistaken on the most pertinent point you made here, namely the role of Colorado River water in Arizona's water plan.

Arizona gets 35% of its water from the Colorado River [0]. "A literal drop?" I wouldn't agree.

However, since reductions affect various water-using constituencies differently, Tier 1 reductions don't have an effect on municipalities' water availability (but future tiers do) [2].

Again, largely important points you've raised here, but it's also important not to understate the value of the Colorado River / Central Arizona Project in municipalities' water availability and water contingency planning, as you have.

[0]: http://www.arizonawaterfacts.com/water-your-facts [1]: https://www.nytimes.com/2021/08/16/climate/colorado-river-wa... [2]: https://www.amwua.org/blog/tier-1-shortage-what-does-it-mean...

The majority of colorado water river is simply banked. So in terms of consumption in the scheme of statewide water usage I stand by "drop". Prior to the water bank Arizona consumed about 15% of it's entitled colorado river water and forwent the remainder. Planning accounts for the possibility of 0 acre feet of colorado river water by 2025. Arizona is legally entitled to its share of the colorado river and takes it and stores it rather than forgo it.

My comment was in response to the salacious title that Arizona's water supply has been "slashed" which is not a factually accurate headline.

https://e360.yale.edu/features/how-phoenix-is-preparing-for-...

https://tucson.com/news/local/arizona-water-bank-started-as-...

I haven't been to Phoenix in twenty years, but it's hard for me—as someone who is not a civil engineer—to grasp how this is the case. I remember walking around there in the summer and being shocked to see a higher concentration of lush green lawns there than in Ohio where I lived at the time. Homeowners had spigots poking out of the corner of their yard, which they'd turn on to literally flood their yard. Flying into the airport you could see the profusion of green lawns, private backyard swimming pools, and expansive golf courses. Is there a good resource where I can see how that opulent water use squares with having a 100+ year native supply and is actually a net water contributor?

I always wondered how Phoenix homeowners get away with watering their lawns just by flooding them.

Water prices so cheap that they do not reflect externalities, such as water supply per capita being lower in the future.

I attended high school in Phoenix in the late 1960s. There was a widespread irrigation infrastructure that consisted of gated ditches running throughout residential areas. This was way before drip irrigation or other water conservation measures were a thing.

These ditches were supplied with water on a scheduled basis. One watered one's lawn by shutting off your downstream neighbor's ditch gate and opening yours on schedule. After your hour or two of flooding, your upstream neighbor would do the same, leaving your deeply flooded yard to absorb the water. This was a 2 or 3 times/week thing.

It was horribly inefficient in terms of evaporation losses. About the only positive aspect I recall is socializing with our neighbors in the after-midnight hours that we usually drew for our turn at the floodgates.

While this is true, we're not 100% out of the woods. My brother is an architect in the region and mentioned to me that our exurbs and suburbs are notorious for fudging their water sustainability numbers vs actual use.

Is there a tort? It seems reasonable for these regions to compensate by funding reclamation projects.

Since 1980 total water use has declined in the state by about 25% while population has tripled (300% growth). New construction is required to use grey water where suitable and it's waster water makes it back as treated or depending on geography is used by Palo Verde nuclear station. This is a non issue.

> while population has tripled (300% growth).

Tripling would be 200% growth, quadrupling would be 300% growth. Therefore I wasn't sure which one you meant, and I checked: according to [1] there was roughly a tripling from 1.5M to 4.5M between 1980 and 2020.

[1] https://www.macrotrends.net/cities/23099/phoenix/population

You can drain a river to dust, harming everyone down stream and still be a net contributor to ground water by, say, dumping it on desert sand to grow crops.

Arizona is not in any form a net contributor to water resources as that is physically impossible unless they are fusing hydrogen and oxygen from space.

If there's no precipitation, every drop of water we have came from someone else's bucket.

>Arizona is not in any form a net contributor to water resources as that is physically impossible unless they are fusing hydrogen and oxygen from space.

Arizona is not a closed system, so why would it be impossible for water to be flowing out of the state?

[Or water vapor]

The Colorado River Delta is an ecological disaster. Because it is in Mexico, it is not part of the analysis done in places like Phoenix.

The Gila River in Arizona is about run dry before it reaches the Apache Nation at San Carlos. Mostly for cotton in the desert. Cotton in the desert is only possible because of water rights.

Since you seem to be knowledgeable, care to comment on this:

https://www.azcentral.com/story/news/local/arizona-environme...

It very much sounds like it directly contradicts your confident tone.

"We planned well and have water security for at least one or two generations to come" would get approximately 0 clicks as a headline. News makes money on fear even when they have to make up things to be afraid of.

One or two generations isn't 100 years though.

What does it mean to maintain 100+ years of water? As in reserves to last them 100+ years or something else?

This should answer most questions:

http://www.arizonawaterfacts.com/water-your-facts

No, the plan doesn't expect every single water supply to go empty, and then have 100 years of water in storage tanks. But it does expect that there may be a very large drop in water coming in for years at a time.

Actually, it sort of does put water away in storage tanks.

Groundwater replenishment is a huge part of how urban development projects "get away" with assuring 100+year supplies. In a way, this replenishment is sort of equivalent to putting water in a storage tank. Especially when the water comes from somewhere else, like the Colorado River.

But not 100 years worth.

Cities and suburbs are only one component of water use. A large amount of water is used by agriculture, and they have different restrictions, if any. So it's not a disaster for the metro areas, but really impacts rural areas and farmers.

if i've driven through arizona, it's been 25+ years. is there a lot of rural agriculture?

More than ever, and more water intensive than it used to be. For example: https://www.azcentral.com/in-depth/news/local/arizona-enviro...

Arizona was built on the 5 C's: Cattle, Cotton, Citrus, Copper and Climate.

> Save your outrage for the cities on our coasts whose antiquated and poorly managed treatment systems dump millions of gallons of untreated sewage into our rivers and oceans.

I was with you until that last comment.

Most West Coast cities have adequate water supplies and management. The drought affects small towns the most. If they are caught off guard its because these are unprecedented weather events. It is reasonable for Arizona to conserve water from the get go. Not so for the west coast, which could rely on precipitation/snow melt for the past several decades.

Also the root cause isn't poor water management by cities, its that the farming industry consumes most of the water.

The Monterey Peninsula area has terrible water management. Sewage spills into the ocean have been a frequent problem. Despite the housing shortage, property owners can't get building permits due to a lack of water.

https://www.montereyherald.com/health/20180224/addressing-th...

Every major city in southern california dumps raw sewage into rivers and oceans with regularity. There is too much of it to even keep track of. Here is massive one from not even 30 days ago: https://www.latimes.com/california/story/2021-07-12/la-me-po...

There is no municipal grey water systems or mandates. No reasonable person would say anything about southern california's water policy or water history is "responsibly managed". I don't know enough about northern california's situation first hand to offer comment but I would be shocked if it's any better. Oroville remind you of anything?

It is completely true that agriculture consumes many times more water than residential use. California is a complete disaster there too. 25% of irrigable water is diverted to the ocean for the delta smelt, and another 25-40% is controlled by the resnick family's holdings and the sham of the kern county water bank.

I believe if you don't divert water... you get salt water encroachment, which will poison fresh water aquifers.

Substantially less could be diverted to address that issue. There was much argument over the amount in the delta smelt litigation but probably as little as 1% would suffice for that purpose.

IRWD pioneered the purple pipe system and GWRS is the largest indirect potable reuse system in the world, but because the only means of unpermitted greywater use in California is from laundry machines, "No reasonable person would say anything about Southern California's water policy or water history is "responsibly managed"."?

What municipalities mandate greywater systems?

In the story you link the system discharged sewage into the ocean because it was overwhelmed with a unexpectedly large amount of debris that prevented 6% of the daily flow from being processed. In this case, it seems like the alternative was having the sewage overflow onto the land, which is a bit less desirable.

There is no major city in California with ‘adequate supplies and management’ - they’re all irresponsible and failing. None have a decent gray water program, almost no new water storage has been built in 40 years, and they dump untreated sewage on a semi-regular basis (accidental of course).

I would be interested in seeing US cities rolling out and enforcing gray water systems.

Are they used at scale... anywhere in US?

Arizona. 2/3 or more of residential areas have and use grey water. It is a requirement for new construction in most if not all of the counties. Almost all of the water use you frequently see arizona criticized for, fountains, golf courses, etc, are all using grey water.

I don't get the intense focus on grey water in these threads. Grandparent poster mixes up grey water and tertiary recycled water down thread, so maybe confusion over that or selective use of terms so Arizona comes out on top? Who knows?

Sure, Arizona seems to be leading in grey water, but treated effluent are exponentially higher flows and that absolutely is being used and applied in Southern California. GWRS is currently operating at 100 MGD of indirect potable reuse and in the midst of an expansion to 130 MGD and San Diego is currently building their indirect potable system to 83 MGD. All in addition to the 100s of MGD tertiary recycled water distributed via purple pipes and other means throughout the region. This is not to say the current status is sufficient(I'd love to see an exponential expansion on managed aquifer recharge), but seeing a number of recent threads opining as if no "responsible" water management is being done in the region, which is frankly, absurd.

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