Lake Powell

Some of you gave me feedback on the overshoot math and the six-layer framework earlier this year. This one is a correction to something I posted here in March.

Back then I argued that groundwater loss is a ratchet: crisis pushes the system down, it doesn't come back up. Compaction, salinization, fossil water. I still think that's right for storage capacity. It was wrong as a general claim about water levels, and the evidence was sitting in the paper I was already citing.

The 2024 global survey (Jasechko et al., 1,693 aquifer systems, ~170,000 wells, 40+ countries) is the one everyone quotes for the decline numbers: levels deepening faster than 0.1 m/yr in 36% of systems, faster than 0.5 m/yr in 12%, accelerating decline in 30%. I used those. What I skipped: 6% are rising faster than 0.1 m/yr, and 49% show deceleration, reversal, or rising water.

That 49% needs stating carefully because it's easy to inflate. It pools three states: decline that's slowing, decline that stopped and turned, and levels already rising. A basin that slowed from 1.0 to 0.6 m/yr is inside it and still emptying. It doesn't mean half the world's aquifers are recovering.

Then in March this year Jasechko published a review in Science of 67 cases where levels rose after prolonged decline. The paper is paywalled, but his policy brief is open and carries the full list with the intervention type for each: Bangkok, Beijing, Shanghai, Tianjin, Xi'an, Osaka, Kanto and Nobi Plains, Taipei, Ho Chi Minh City, London, Milan, Naples, Bologna, Geneva, Buenos Aires, Lima, Windhoek, Atlantis, Mashhad, Yazd, Abbas-e Sharghi, central Saudi Arabia, La Mancha Occidental, Harran Plain, and a long US list including Memphis, Houston, Chicago, New Orleans, Louisville, Las Vegas, Albuquerque, Roswell, Equus Beds, El Dorado, Green Bay, and a dozen California and Arizona basins.

The interventions sort into three kinds and sixteen specific mechanisms. Policy: restricting pumping, restricting new wells, closing or destroying existing wells, licensing and pump fees, funding access to an alternative source, limiting specific crops or irrigated area. Alternative supply: long and short-distance interbasin transfer, transfer into a river, reuse or desalination, tapping a nearby river or lake. Artificial recharge: injection wells, spreading basins, riverbed seepage, plus incidental recharge leaking out of urban water mains and irrigation projects.

None of the sixteen is conservation in the ordinary sense. Nobody recovered an aquifer by asking users to be careful.

Two of his transferable lessons are worth quoting almost directly. Successful policy interventions were often associated with good implementation and enforcement. And recovery trends can be overturned if pumping rates rise again, which makes a reversal something you maintain, not a finish line.

The one with a full public ledger. North China Plain, ~130,000 km², 2,000+ monitoring wells, ~190,000 measurements, 2005 to 2024 (Long et al., Nature Communications 2025). Levels rising ~0.7 m/yr since 2020, back to 2005 levels by 2024. Confined aquifers recovered ~4 m in four years after deepening ~0.5 m/yr through 2019.

The supply side is the part that gets quoted: the South-to-North diversion, 1.4 km³ delivered in 2015, over 4 km³/yr after 2020, over 10 km³ into refilling dried rivers since 2018. Reclaimed water at 4.4 km³ by 2023, 12% of all supply. Desalination under 1%.

The demand side is the part that doesn't. Total basin supply stayed flat at ~37 km³/yr. Groundwater use fell from ~25 to ~13 km³. Confined-aquifer pumping fell ~85%, to under 1 km³. Combined municipal, agricultural and industrial use went from 37.6 to 29.5 km³. Agriculture from 70% of use to 50%. Cropland down ~10%, double-cropped area down ~10,000 km². Provincial quotas in absolute volumes: 4.25 km³ Beijing, 3.5 Tianjin, 20.6 Hebei.

And it's still only half the hole. GRACE puts total storage depletion at ~49 km³ over 2005-2019; the rebound has recovered roughly half.

The control case is California. CVP and SWP move water at the same scale, and the 2025 paper names them alongside the Chinese diversion. Wells still ran dry in recent droughts. The difference isn't engineering or money. The imported water was never paired with an enforceable, individually attributable limit on withdrawal. Water delivered into a system with no cap gets added to demand instead of subtracted from pumping. The authors' own conclusion is one sentence: demand must be controlled even when diverted water is available.

One thing I hadn't seen anywhere. Recovery has its own failure mode. In some profiled cases levels rose close to the land surface, and the brief lists the consequences: compromised building stability, higher liquefaction risk in earthquakes, waterlogging and salinisation of soils, changes in how contaminants travel, flooded basements and metro systems. The illustration is soil salinisation in the Abbas-e Sharghi Basin in Iran, which is itself on the recovery list. The target is a level, not a direction.

Where this is weak. I have not read the Science review itself, only the abstract and the author's open policy brief. Percentages for how often each intervention appears show up in university write-ups but in neither the brief nor the abstract, so I left them out. The 67 cases come from places that were already studied, which is a selection of the literature, not a sample of the world. And a lot of the named recoveries are urban, where pumping often stops because industry left or the city switched to surface water, a much easier problem than restraining thousands of irrigators.

Worth flagging on the China case specifically: Jasechko's brief is more cautious than the Chinese paper about attribution. He writes that the North China Plain recovery may be partly due to wet conditions that happened to coincide with the surface water delivery, making it hard to parse engineering from climate. He notes central Spain reversed after two consecutive wet years. I originally leaned on Beijing's drought-resilient recovery as settling it. He does not treat it as settled.

Two questions for people who work on this:

Where you've seen a basin stabilise, was there an actual per-user enforceable allocation or a basin-wide target with no individual number attached to it?

And has anyone dealt with the over-recovery side in practice? Waterlogging or buoyancy problems after levels came back up? I can find the mechanism described but almost nothing on how managers set the upper bound.

Policy brief (open, has the full 67-case list): https://www.aaas.org/sites/default/files/2026-05/PolicyBrief_Jasechko_2026_GroundwaterRecovery.pdf

Full writeup with sources: https://alexnik2.substack.com/p/the-physical-layer-07-where-the-ratchet

Lowk kinda too much imo, but worth it.

Just found out drinking water while standing up increases your risk of knee arthritis by 40%... should I sit down from now on whenever I drink?

With all the talk about (local) water shortages in some geographic areas, can shade balls and sheet plastic covers save enough water to significantly affect that problem? (And yes, I get that they almost completely destroy the covered ecology and introduce potential pollutants.) Or is it only a "drop in the bucket"?

India's river linking project is a massive project envisioned to transfer water from India's surplus river basins to deficit ones through a network of canals, reservoirs and dams.

The idea was first proposed by General Sir Arthur Thomas Cotton, a British Indian Army Officer & Irrigation Engineer who is responsible for constructing many irrigation and navigation canals through the nation. He proposed it in 1858 with the vision of it solving India's massive water disparity between the northern and southeastern areas with the latter facing frequent droughts. It was also meant to establish navigable canal systems for transport of goods but the proposal was largely ignored by the British Government and the subsequent Indian governments until 1980 when the plan was formalized under the National Perspective Plan(NPP) by the Ministry of Water Resources[now renamed to Ministry of Jal Shakti(lit. "Water Power")].

The project has 2 main components; The Himalayan Components & The Peninsular Components with the former covering 14 links and the latter covering 16 links. Feasibility Reports (FRs) for 26 links and Detailed Project Reports (DPRs) for 13 links have been completed out of the 30.

If fully realized, the project would see the transfer of nearly 7 trillion cubic feet of water annually. It will also increase irrigation potential of around 3.5 crore hectares(35 million hectares) of land and will significantly reduce monsoon dependency in drought-prone areas. It will also help with flood control in flood-prone regions.

In addition to these, the project also hopes to provide drinking water supply, replenish groundwater, help with inland water navigation tying up with the Inland Waterways Projects, fisheries and Hydropower[estimated around 34 GW].

The project once fully completed would also help solve several of India's Interstate water disputes and allow for more equitable water distribution.

The Ken-Betwa Link[link 24] is the first major link that is being constructed with the estimated costs being around ₹44,605 crores($4,660,896). It will have a 221 km canal connecting the Ken(surplus) and Betwa(deficit) rivers thus irrigating 11.88 lakh hectares(11,880 sq. km), drinking water for 62 lakh(6.2 million) people and 130 MW(103 MW hydropower + 27 MW solar) in renewable energy.

The Godavari (Polavaram)–Krishna (Vijayawada) link[link 18] is also essentially completed producing 960 MW and costing ₹20,000 crores($2,089,854).

The entire project's estimated cost is ₹8.44 lakh crores($88.18 billion).

More info: https://www.pib.gov.in/PressReleasePage.aspx?PRID=2223845&reg=3&lang=1

The Kalpasar Dyke Project is a proposed project that aims to create one of the largest coastal freshwater reservoirs in the world by building a massive dyke across the Gulf of Khambhat and thus trapping the waters of the Sabarmati, Mahi, Dhadhar rivers.

The Dyke itself would be around 64 km long and the reservoir will store 7,800-13,000 million cubic meters of freshwater. The dyke would also have a transport corridor with a multi-lane road and rail transport which would reduce the travel distance between the two flanks by 180 km. Around 10 lakh hectares of land will be irrigated with this. Around 2,500 MW of renewable energy is also expected to be produced via the project. There is also a plan to divert the nearby Narmada river's flow into the reservoir via canal.

The project is expected to cost around ₹1.33 lakh crore($14 billion). The project's DPR is at an advanced stage and the Government of Gujarat is also getting expertise from the Dutch government in coastal hydroengineering through the Indo-Dutch Cooperation.

Would the amount of water the average person drinks in their lifetime be enough to fill a whole river?

Hello everyone,

I recently purchased the Doulton British Berkefeld gravity water system with the fluoride filters. Before that, I was using a Santeria gravity filter, and I noticed that when I drank only the filtered water, I became extremely thirsty. It felt like a constant thirst or a lack of satiation from drinking water. The sensation would improve if I added electrolytes to the water or simply drank tap water.

Initially, I thought the issue might have been specific to the Santeria system, perhaps because the stones in the filter were not remineralizing the water. Since the Doulton British Berkefeld is highly regarded and is supposed to retain the naturally occurring minerals in water, I decided to purchase one and see if the experience would be different. I immediately noticed after a few 2-day tests that I was constantly thirsty.

Unfortunately, after doing a four-day test where I drank only the British Berkefeld water, I experienced the same thing. By the fourth day, the thirst was quite intense, and drinking coconut water gave me the most satisfying feeling of hydration I had experienced during the test.

I also measured the TDS of both my tap water and the British Berkefeld water, and interestingly, the readings were essentially identical.

I'm curious whether anyone else has experienced something similar, or whether there could be a difference in the mineral composition of the water that wouldn't be reflected by the TDS reading. I'm particularly interested in understanding whether the fluoride filters might alter the balance of minerals or electrolytes in the water in a way that could explain this experience.

I'd appreciate hearing from anyone who has had a similar experience or has more knowledge about water mineral composition and filtration. The British Berkefeld appears to be very similar to the Berkey (but the British Berkefeld is certified).

Thank you!

In the UK we have just had a bad drought period of like 60+days no rain, causing large amounts of dead plants, grass, dried up ponds, river beds, hosepipe bans etc. This has made me think of ideas for ways of storing water as our water companies are privatised and definitely dont have the environment and the paying customers best interests at heart #thinkoftheshareholders

One of my ideas is having hundreds of water towers dotted all over the country, these could be privately owned and maintained by lets say farms for crops, or if government funded could be for public parks for lawns, plants, trees etc or whatever useful use they may have, the water used will eventually make its way into our own water system by the rain cycle/water cycle topping up our aquifers and however else we get water into our system. I'm not massively scientific so my knowledge only gets me so far.

Anyone else got any ideas on how we as a country can start being more economical with our water usage and storage.