Lake Mead Low Water Levels, Part 2: Colorado River Inflow Variations and Trend

From Dr. Roy Spencer’s Global Warming Blog

by Roy W. Spencer, Ph. D.

Key Points

  • Contrary to claims that drought is causing Lake Mead water levels to fall, the Colorado River natural flows into Lake Mead show no long-term trend since 1930.
  • Decadal time scale variations in river flow do occur, though, related to the Pacific Decadal Oscillation (PDO).
  • Since about 2000, use of Lake Mead water has exceeded river inflow, causing water levels to drop. The negative phase of the PDO since that time has exacerbated the problem.

Natural Water Flows into Lake Mead: No Long-Term Trend

Record low water levels in Lake Mead are widely blamed on drought, although what “drought” means is seldom specified. The public perception is that lower precipitation amounts have reduced water supply to Lake Mead (which comes from the Colorado River), usually attributed to human-caused climate change, and that this is why water levels are falling.

But data from the U.S. Bureau of Reclamation (USBR) show that there has been no long-term trend in natural Colorado River flow into Lake Mead:

Fig. 1. Yearly “natural” water flows into Lake Mead, corrected for local human-induced changes in water flow upstream. Details of those corrections are described here. Data source here.

The flows in Fig. 1 have been slightly adjusted for local human-caused changes to the flows upstream, and provide our best answer to the question of whether long-term global climate change is responsible for a decrease of river water flow into Lake Mead.

The answer is “no”.

Does Climate Change Theory Even Predict Reduced Precipitation? No

The next question is, does climate change even predict future reductions of precipitation over the Colorado River watershed? The following plot shows an average of 183 climate model simulations of average yearly precipitation in an area approximating the Colorado River watershed. The models suggest a slight increase in total precipitation with warming.

Fig. 2. CMIP6 model average yearly precipitation 1930-2050 over an area approximating the upper Colorado River watershed. Data source here.

Most of the water entering Lake Mead is from snowmelt in the mountains; little of the water falling on lower elevations tends to be used by local vegetation with little runoff reaching the Colorado River. Fig. 3 shows there has been no long-term trend in the snowpack measurements in the upper Colorado River watershed.

Fig. 3. April snowpack measurements in the upper Colorado River watershed, 1938-2022.

So, not only has there been no observed long-term reduction in water flow into Lake Mead, or reduction in the watershed snowpack, climate change theory doesn’t even support such a change up to the current time (or even to 2050).

So, Why are Lake Mead Water Levels Falling?

What has changed since Hoover Dam was constructed in the 1930s is the amount of water being removed from Lake Mead. Since about 2000, that water use has exceeded the water input into the lake. This is the most recent available demonstration of that fact, published in 2012:

Fig. 4. The Colorado River basin water supply exceeded demand up until the year 2000 or so, and since then Lake Mead water levels have fallen due to overuse.

As long as water use exceeds supply, Lake Mead water levels will continue to fall. (This is somewhat dependent upon the regulated releases from Lake Powell, upstream. There is a “Fill Mead First” initiative that would draw down Lake Powell in an attempt to raise Lake Mead, based upon calculations that net natural water losses from combined evaporation and bank seepage from Mead and Powell would be reduced.)

The Role of the Pacific Decadal Oscillation (PDO) in the Current Problem

While the major problem with Lake Mead is overuse, there are multi-decadal fluctuations in Colorado River flows which have made matters worse since approximately 2000. If we take the river flow data in Fig. 1 and compute the accumulated departures from the long-term average flow (because this is how a reservoir like Lake Mead responds), we find that there have been periods of lesser and greater flows.

Fig. 5. As in Fig. 1, except time-accumulated departures-from-average Colorado River flows into Lake Mead.

Before the 1980s, there was somewhat reduced river flow into Lake Mead, but it made little difference because water use (Fig. 4) was still low.

Then from the 1982-83 super El Nino year to approximately 2000 there were above average flows, so Lake Mead could handle the increasing water usage. In fact, the lake reached near full-pool status.

But as usage peaked around 2000, river input to the lake was reduced once again. This put Lake Mead into an unsustainable state where more water was being extracted than the Colorado River could replenish it.

It has been long known (e.g. here) that precipitation in this region is affected by El Nino (more precip) and La Nina (less precip). Also, the Pacific Decadal Oscillation (PDO), which is basically a low-frequency manifestation of El Nino and La Nina activity is related to precipitation in this area.

I computed the cumulative average departures from the long-term mean of both the PDO index and the MEI (Multivariate ENSO Index). The PDO is somewhat higher correlated (r=0.52) with the cumulative river flow data in Fig. 5. As Fig. 6 shows, positive PDO periods are generally associated with higher stream flows, and negative PDO with lower stream flows. Most notably, the period since 2000 has seen more negative PDO activity, which is worsening the problem with Lake Mead not getting enough water. Of course, this will eventually reverse when the PDO flips back into its positive phase.

Fig. 6. Cumulative departures of the Pacific Decadal Oscillation index from its long term mean, which is r=0.52 correlated to cumulative streamflow into Lake Mead from the Colorado River (Fig. 5.)


The popular narrative that drought due to climate change is causing Lake Mead to have less water available to it is incorrect. Since 1930, there has been no long-term change in the Colorado River flow upstream of what is now Lake Mead.

The latest climate models do not even predict a reduction in precipitation in the upper Colorado River watershed.

Multi-decadal changes in river flow do occur, though, and are related to the Pacific Decadal Oscillation, a natural fluctuation in weather patterns over the northeast Pacific. Recent record-low water levels in Lake Mead are primarily due to record high water demand from the lake, since approximately 2000. The problem is being made somewhat worse by the negative phase of the PDO, also since approximately 2000.

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August 27, 2022 2:13 pm

Excess population.

Tom in Florida
Reply to  Chaswarnertoo
August 27, 2022 7:50 pm

More likely excess irrigation in Arizona and California.

Bryan A
Reply to  Tom in Florida
August 27, 2022 11:51 pm

Food doesn’t grow very well without irrigation.

Reply to  Bryan A
August 28, 2022 1:50 am

Or you could grow food where food will grow, and live where food is available. Not in cities in the desert.

Ben Vorlich
Reply to  Roger
August 28, 2022 6:22 am

That’s very 17th century

James Schrumpf
Reply to  Ben Vorlich
August 28, 2022 7:02 am

Very Sam Kinnison: “MOVE TO WHERE THE FOOD IS!!!”

Tom in Florida
Reply to  James Schrumpf
August 28, 2022 10:17 am

“It’s a desert. Nothing grows there. That’s why they call it a desert.”

Bryan A
Reply to  Roger
August 28, 2022 8:31 am

Stop growing food for fuel and less waster will be needed for growing food

Reply to  Tom in Florida
August 28, 2022 5:13 am

The irrigated farm fields in the southwest US long predated the massive increase in population of the last 50 years. In western water law, priority of water rights is all based on seniority – first come, first served. Plus much of the food produced in those irrigated fields feeds all of America, not just southwestern residents.

Food production is not the cause of increasing water consumption in the southwest – it is entirely due to increased population, and the cowardice of politicians who refuse to mandate water conservation measures.

Tom in Florida
Reply to  Duane
August 28, 2022 10:15 am

However, there is many times as much agriculture being irrigated in the desert SW these days. It was naive to think that continuing the growth of such agriculture and the increased population that goes with it would be sustainable. But those decisions happened many moons ago and those people got what they wanted at that time and the future be damned. Now the chickens have come home to roost.

Rich Morton
Reply to  Tom in Florida
August 29, 2022 10:56 pm

I lived in Yuma AZ for over 10 years. Yuma is part of the Imperial Valley – this is where 90% of the vegetables that ALL of America eats in the winter come from.
Before you go off blaming local DSW farmers of being greedy and thoughtless in regard to growing things in a desert, you might want to educate yourself on the subject a little more thoroughly first. You might have learned that the Imperial Valley is an excellent place to grow crops – AND that it can plant crop cycle after crop cycle continuously all year round to feed not only the residents of the DSW – but the vast majority of the rest of the country as well.
Anyone who has the brazen audacity to eat a salad anywhere in America between the months of October and April is just as guilty is draining lake Mead as anyone else.🤔

Reply to  Chaswarnertoo
August 28, 2022 3:28 am

Two bullets from a very dated (1985-2010) USGS survey of water use on the Colorado river:

Water used to generate hydroelectric power represents the majority of total water use, but is an instream use. Irrigation of crops is the largest offstream use of water in the CRB, averaging 85% of total offstream use over the 35-year timespan.

Population in the CRB increased from 4.6 million people in 1985, to over 9.4 million people in 2010, and most of the people were in the lower CRB with about 90% in 2010.


August 27, 2022 2:20 pm

I’ve recently added a new dimension to my ongoing sun-climate work wrt sunspots numbers and hydrology, which is applicable to the Lake Mead situation, with a tie-in to the PDO too.

This mostly addresses the long-term supply side of the Colorado River, not the demand side.

The difference between droughts/deluges long-term is sunspot activity (SN), using the same technique as I used to determine the decadal sun-ocean warming threshold of 95 SN.

The zero-crossings of the cumulative departure from average (CDA) of the streamflow at Lee’s Ferry Arizona were used as endpoints to calculate the average sunspot activity between them. Three periods were averaged for Lee’s Ferry data to a SN of 99.
The Lake Mead inflow and outflows were similarly analyzed for SN ave of 97.7 and 106.5, respectively, and for the Lake Mead mean sea level elevation (MSLE) for a SN ave of 104.8.
The Lake Mead MSLE CDA function peaked after the solar modern maximum ended in 2004 after climbing the entire period since 1935.

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The last panel of the 5 image plots summarizes precipitation and drought indices that were all similarly analyzed. The PDO has a CDA zero-crossing average of SN = 99 too.

These results indicate world drought and precipitation hinge upon the sunspot number range of 100 +/-6 SN.

Since the sunspot average after 2004 is 42 SN, much lower than the prior few decades, drought has increased, especially in the US. The drought has recently begun to ease after above-average monsoonal deluges occurred this summer after solar activity increased to above 100 SN late last year into this year, confirming the results of this new analysis method.

We can therefore expect the Lake Mead situation and elsewhere to improve more as this drought period recedes during/after higher precipitation from the top of this solar cycle, particularly from expected upcoming El Nino activity.

Reply to  Bob Weber
August 27, 2022 4:07 pm

The middle chart in the panel below is the OST in the Nino34 region. It has a distinct cycle of about 11 years. The cycle is not due to Earth’s orbital changes. Jupiter has no observable direct impact on Earth’s orbit.

The period is very close to the period of sunspot activity. It has a weak, yet statistically significant, correlation to sunspot activity. The highest correlation is a 31 month lag between solar activity and temperature.

The current down trend in the Nino34 temperature should reverse this year following the start of the current solar cycle in 2020.

The ENSO cycle is independent of the 11 year trend other than the Nino34 temperature reaches a higher level if El Nino occurs at the peak of the trend as it did in 2015/16.

Last edited 1 month ago by RickWill
Reply to  RickWill
August 27, 2022 4:51 pm

Good points Rick. The downward Nino34 trend is because your plotted period starts during high solar cycles 21 & 22 and ends with lower solar cycles 23 & 24.

The 25N to 35N region uptrend is then due to OHC transport from the equatorial region. It would be interesting to see when the 55S-65S started to downtrend or when it was above/below the cumulative departure from average. It looks like after 2004, after the solar modern maximum ended.

OT – You might like to see my results that verifies our individual insights on Javier’s blogpost a week ago or so that the NH SST significantly influences the NH Sea Ice Extent and then both affect the 80N temperature, rather than 80N T being only a function of atmospheric inflows as he said:

John Bell
August 27, 2022 2:24 pm

Interesting video of 1983 overflow at Hoover dam: Hoover Dam Spillway Overflow 1983 – YouTube

Gary Pearse
August 27, 2022 2:25 pm

Yeah, Roy, but we’re going to go ahead with the planned global depopulation of 50%, shut in fossil fuels, ban fertilizers, meat animals, windows etc, because of the Precautionary Principle. Ya never no, he?

Rud Istvan
August 27, 2022 2:45 pm

Both Spencer posts on Lake Mead are excellent, especially this one. The climate change narrative is mostly (not completely—PDO) false. When you grow semiarid Phoenix, Las Vegas, San Diego, and LA by many millions of people, all using lots of water, the inevitable eventually happens. Eventually is now.

The obvious solution is CCGT or nuc powered desalination along the California Coast, something that California has already firmly rejected. What will happen instead is that agriculture in Arizona and California will be curtailed sharply. Not many old farmers to outvote all the new city folks.

Having owned a largish (350 head total, about 150 milking at any given time) SW Wisconsin dairy farm for almost 4 decades, an example for WUWT enlightenment. The largest milk producer in the US is California, not Wisconsin. The reason is pure government distortion. The milk price support by law varies proportionate to distance from its base in Madison, Wisconsin. Southern California is the furthest away in CONUS, so has the highest milk support price. My farm is zero higher than the Wisconsin base price support—only 50 miles west of Madison. Which means California grows over 5 million acres of very thirsty alfalfa to support the country’s largest dairy herd, even tho it makes no farming sense.

Reply to  Rud Istvan
August 27, 2022 3:12 pm

Alfalfa make sense in a climate like Arizona even though it takes a lot of water. Unlike Wisconsin, if you time things right, you can get 12 cuttings a year from a field. This greatly reduces the amount of water needed for a cutting. It produces local dairy and it reduces or eliminates the need for Nitrogen. Often after a field has been in Alfalfa for a year or two, the farmer will cycle a crop of Corn for silage or Cotton for a money crop. After that, the field is put back into Alfalfa.

Rud Istvan
Reply to  Dena
August 27, 2022 3:40 pm

My dairy farm is all contours because hilly. We do a 3/2 crop rotation per contour. 3 years alfalfa. First year overseed and harvest oats while alfalfa roots. Then two years alfalfa harvest, typically three cuttings per year. Then till and put into either corn or soybeans for two years. We no till the second row crop year. Till again before the 3 year alfalfa rotation.

Reply to  Rud Istvan
August 27, 2022 5:37 pm

Our fields are pancake flat. They didn’t start out that way but they use flood irrigation and far too much dirt washes off the field if there is any slope. The water that runs off is captured and pumped back out to irrigate another field.
When you watch a farmer prepare the field, it may take several days because they keep going back and forth until the field is perfectly flat.

Gilbert K. Arnold
Reply to  Rud Istvan
August 27, 2022 5:03 pm

@Rud Istvan……let us not forget the differences in water use laws… the western US vs eastern US… which is a whole ‘nother can of worms

Rick C
Reply to  Rud Istvan
August 27, 2022 5:04 pm

Not that it matters much, but the milk price support rule is based on distance from Eau Claire, WI. It is a travesty foisted on the mid-west by the politically powerful in California, New York and Florida. If it was rescinded, California’s dairy industry would collapse over night and they’d save massive amounts of water.

Rud Istvan
Reply to  Rick C
August 27, 2022 5:27 pm

My bad. My farm is 80 miles from Eau Claire.

Reply to  Rud Istvan
August 28, 2022 9:24 am

Rud ==> Santa Barbara. CA has a de- sal plant. My alma mater is UCSB …where I learned journalism by practical experience in radio journalism covering civil unrest. The plant produces 3 million gallons of drinking water per day. But that is only 1/3 of the city’s needs.

August 27, 2022 3:12 pm

Believe or not – someone proposed a pipeline to carry water from the Mississippi and/or Missouri Rivers to Lake Mead…..sounds like a China project. The 3 Gorges Dam in China was threatened with overflow a few years ago due to a typhoon causing heavy rains….it is now at a record low.

Last edited 1 month ago by Anti-griff
Rud Istvan
Reply to  Anti-griff
August 27, 2022 3:43 pm

That someone was not an engineer. The energy required to lift water over (or thru) the continental divide up a few thousand meters is insane. Making rivers flow uphill is very difficult.

Robert W Turner
Reply to  Rud Istvan
August 27, 2022 4:32 pm

If it were done it would need to be from Canada. And even then it would be from probably a minimum of 600m up to 2100m.

Rick C
Reply to  Rud Istvan
August 27, 2022 4:54 pm

Lee Dreyfus, a former Wisconsin governor said about transferring great lakes basin water West: “[we] would be glad to sell anybody any amount they want as long as it comes mixed in cans with malt, beer, hops and barley.”

Nicholas McGinley
Reply to  Rick C
August 28, 2022 9:24 am

Nick McGinley said, “Hey Lee, ***** **** ***’* **shut ***** *** *******, ** yap, ***** ** ***** **, ***** * ** *** ** * *****’*, who cares if it does.”

Editor’s note:
This comment has been partially redacted for reasons that are nunya.

Last edited 1 month ago by Nicholas McGinley
Reply to  Rud Istvan
August 27, 2022 6:53 pm

The Chinese have dreams of moving water from the wet east to the dry west…involves lined canals…tunnels and pipes. If I remember, the US scheme was going to use a southerly route….and was aimed really at Arizona….no need to actually reach Lake Mead since it would just be a turnaround back to Phoenix.

Nicholas McGinley
Reply to  Rud Istvan
August 28, 2022 9:12 am

Not necessarily.
If it is a pipeline and not a canal, the only things that matter are the elevations of the endpoints.
Siphon effect and gravity will move the water over any height if it ends up lower than it started.
California currently moves water over some steep and high terrain.

In any case, I proposed a far more ambitious project years ago, and mentioned it a few years back on this site…several times IIRC.

We should have a series of projects on the scale of the Interstate Highway System.

One for water, one for nat gas.

Nat gas ought to have the equivalent of the Rural Electrification Act passed, mandating pipelines to everyone, everywhere.

Water needs to have a modified grid system set up, to move water from regions of excess to regions of deficit.
There is always about the same amount of rain over an area the size of the US.
Invariably, when there is below average rainfall in one region, a region nearby is getting that precip missing from where the drought is.
The reason is obvious…TSI is nearly constant, and except for variations in cloudiness, evaporation from the oceans is overall very likely a constant as well.
If you doubt this, look it up.
In nearly, and perhaps every, every instance of major widespread drought, an adjacent or nearly adjacent region is getting flooded with excessive rain.

Of course, one has to keep in mind that for places that are deserts, lack of rain in some years, and successive years of lower than average precip, are not exactly droughts, in the sense of them being unusual and unexpected changes in precipitation patterns
It is normal and average for the western US to have very dry years and very wet years, and occasionally long strings of such in a row.

Also, let us not forget that in some recent very wet years, the state of Insanity otherwise known as California deliberately flushed massive amounts of their excess rainfall into the ocean for such reasons as to “save” what amounted to a small bucketful of a certain little tiny minnow.

And let us not over look that most of the people now living in the by-now highly populous desert Southwest, are recent transplants, who have moved to a desert and planted grass and leafy trees in vast profusion, installed swimming pools by the tens of millions, and then go into a tizzy when they suddenly discover that places that are deserts do not have all the water that tens of millions of carefree jackasses might care to waste.
Then they do things like insists that people who have lived in these places for generations, farming and ranching and such, setting up extensive infrastructure for impounding, pumping, and/or moving the water they need, now need to find something else to do besides farm and/or ranch, because oopsie daisy those things can use a lot of water compared to how much a cup of tea and a shower use.

I am, speaking personally for myself, not entirely sure what the right balance is between such sorts of competing interests, but I am sure that a lot of people are shortsighted, unreasonable, and reactionary jackasses, to whom no one ought to pay a whole lot of attention to.
We have a free country and system, supposedly and often apparently and in fact.
People self select all sorts of things that might be better if this was not the case.

Is it a good idea for many tens of millions of people move to very dry places that have not had so many people in the past? And then to plant the stuff that grows where they came from just because who the hell knows why?

Is it a good idea for anyone who wants to move anywhere they want to and decide they are gonna farm or ranch and raise or grow whatever the heck they feel like doing? It is bound to lead to at least some problems, but what are the alternatives? Central planning and command economies have not always worked out so well when and where they have been employed.

(For that matter, should anyone who wants to be able to get become something like a teacher or a police officer? There are people who want to have those jobs for reasons that ought to instead make them ineligible, but whose job is it to screen them out and stop them? AFAICT, no one at all has that job. The worst sorts of people can wind up in jobs where they can do immense harm, and/or do an important job very poorly, and somehow, we have made it impossible, in many cases, to remove them, even when it becomes obvious they need to go.)

Anyway, getting back to the original subject at hand…
Wind flow patterns explain nearly all the variations in temperature and precip over time and between various areas.

In any case, some time spent perusing the highly detailed and regularly updated drought monitor maps is instructive. There are ones for short term and long term surpluses and deficits, soil moisture, rainfall, stream flows, ground water…
For example:
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Seriously…do it, look over a bunch of months from years past.
There have been times that not one county in the US had an ongoing drought whatsoever, just in the past five or so years.
I know this because about 20 years, I got into the habit of checking the weekly maps every week.

We regularly have huge amounts of excess rain in one place or another, and also places where wide areas are lacking in usual amounts of precip.
The main point is most of the time, excessive rainfall goes completely to waste.
There are no large scale projects to store it or transport it between river basins.
But there could be.

The Romans moved water over immense distances using muscle power for construction and gravity to move the water.
Good engineering and careful planning are all that is required, and then the will to do it.
There is plenty of water. Distribution over time and over areal extent is the only problem.

What it comes down to is, “How seriously are we going to take the needs of a large and growing population that increasingly wants to reside where it is hot and sunny, and not necessarily where it is plentifully rainy all year around?”

If it is built to last, the cost to install such a system would fade to insignificance.

On a sidenote (OK, everything I write is sidenotes…yeah yeah…)
Be on the look out for sites that have endless climate change-caused droughts, right next to stories about huge floods in recent months.

The only weather story I never see is any report of normal weather, anywhere…EVER!
And yet, almost every place has normal weather nearly all the time, and always has and always will.
And it will never ever ever get reported. Not a single whisper.

Last edited 1 month ago by Nicholas McGinley
Nicholas McGinley
Reply to  Nicholas McGinley
August 28, 2022 9:16 am

BTW, it turns out I am not the only or even the first to propose a huge network of water transfer pipelines.
I found this while I was looking something up for the comment just above:
The Abandoned Plan That Could Have Saved America From Drought (

We should always be doing things that are ambitious and daring and that seek to solve huge problems.

Nicholas McGinley
Reply to  Nicholas McGinley
August 28, 2022 9:20 am

Looks like we are gonna have to annex Canada.
No biggie…I do not think anyone is really living up there.
They have the same population as Poughkeepsie.

Reply to  Rud Istvan
August 28, 2022 9:35 am

An economist at the University of Kansas thought it would be a good idea to take water from the Missouri River and pump it uphill to western Kansas to replenish the Ogalallah Aquifer so that farmers could continue to pump out of that for irrigation. that or just use the muddy Mo for irrigation straight up.

Reply to  Anti-griff
August 27, 2022 4:59 pm

Kennedy (the most famous dead one) was tentatively on board with a North America interconnection system for water (NAWAPA). It wasn’t just the Mississippi … it included flooding part of Rockies trough.

It was argued it could have been a net producer of energy.

(Although flooding a couple Canadian cities, for the overall social good, would have had to be accepted.)

Nicholas McGinley
Reply to  DonM
August 28, 2022 9:36 am

Yeah, so what is Canada gonna do about it?
I mean really.
Their armed forces amount to…what, about 17 or 18 guys on horseback wearing jodhpurs and with silly hats on? True, they keep them boots shiny as all get out, but still…

Clyde Spencer
Reply to  Nicholas McGinley
August 28, 2022 8:38 pm

They can always borrow some guns from civilians — no, wait …

Reply to  Anti-griff
August 28, 2022 2:44 am

Not too long back, it was William Shatner was hawking something like that for California. A pipeline from the Columbia, if I remember right.

Mark Whitney
Reply to  Anti-griff
August 28, 2022 5:52 am

When the Great Salt Lake rose threateningly in 1983 Utah Governor Norm Bangerter championed the building of a pump system to send water into the west desert. It was a local example of just such a China project. The pumps were never actually needed and have remained dormant ever since.
As for the reservoirs of the west, geologist and explorer John Wesley Powell was adamantly opposed to such projects. He would be quite disturbed that one of them was named after him!

Last edited 1 month ago by Mark Whitney
Tom in Florida
August 27, 2022 3:30 pm

Let us not forget that Lake Mead is a man made lake made for use by humans.

John C. Gardner
August 27, 2022 3:45 pm

I seem to recall a great deal of publicity 15-20 years ago about deliberate release of Lak Meade water to improve the habitat downstream from the dam (or maybe I have the wrong lake). If it was Mead I wonder how long they did that and if they ever stopped.

Robert W Turner
Reply to  John C. Gardner
August 27, 2022 4:33 pm

By law they release downstream for water rights. It still goes underground before making it to the sea.

Rud Istvan
Reply to  John C. Gardner
August 27, 2022 5:33 pm

It is lake Powell upstream of the Grand Canyon, not lake Mead downstream of same.

Reply to  John C. Gardner
August 27, 2022 7:02 pm

They bump the flow up for a week or two in order to replenish the sand bars. They don’t use much water and the wildlife greatly improves. To my knowledge they are still doing but not to the extent that it happened naturally before the dam was built.

Nicholas McGinley
Reply to  Dena
August 28, 2022 9:42 am

Before the dam(s) was(/were) built, there were, with regularity, obscenely terrible floods and equally horrendous droughts.

Robert W Turner
August 27, 2022 4:11 pm

Time to build a pipeline from Canada.

Reply to  Robert W Turner
August 27, 2022 5:04 pm


Last edited 1 month ago by DonM
Len Werner
Reply to  Robert W Turner
August 28, 2022 7:45 am

Those if us in Canada have seen what happens when you get into such an agreement with the US–the demand becomes insatiable. If people will blame climate change for there not being enough water in Lake Mead (and Powell) now, they will blame Canada for not supplying enough when they run short in the future. Canada kept bulk water out of the North American Free Trade Agreement just because of such foresight.

Even those commodities that are in the Agreement have a clause that Canada cannot restrict any supply below what it has ever been, regardless if there’s enough for Canada or not. What Canada has to supply to the US can only go up, never down.

Nicholas McGinley
Reply to  Len Werner
August 28, 2022 9:45 am

Oh, boo frickin’ hoo!
Keep up that whinin’, and we might just have to close Florida to everyone up there but Jordan Peterson.

Len Werner
Reply to  Nicholas McGinley
August 28, 2022 1:06 pm

Ha, enjoyed that; especially most pleased about the Florida acceptance of JP, we’d also be happy to reciprocate and invite your JP (Sears). But remember that China is going to soon say the same boo frickin’ hoo to the US. We’ll be listening for the pinching shoe.

Reply to  Len Werner
August 29, 2022 7:55 am

We could trade you for a little Yukon River water.

Craig Howard
Reply to  Len Werner
August 29, 2022 5:01 pm

Of course, you’re right. Shipping in water from Canada is another, pardon the pun pipedream.

August 27, 2022 5:00 pm

The only large mistake is to refer to refer to (human caused) climate change as a theory. In terms of science, it is a hypothesis. A hypothesis with the bulk of evidence contradicting the claims.

Reply to  Ted
August 27, 2022 11:45 pm

The only large mistake is to refer to refer to (human caused) climate change as a theory.

Man-made climate change is more of a conjecture than a hypothesis. Only in the deluded minds of some climate seancetists, churnalists, and extreme left miscreants politicians could it be called a theory.

A conjecture is an idea, a hypothesis is a conjecture that can be tested by experiment or observation.

There is not one experiment or observation of the real world showing CO2 is the cause of the current warming recorded by dodgy weather stations and manipulated data – lots of models masquerading as data, but no empirical evidence.

Mike Lowe
Reply to  Redge
August 28, 2022 3:17 am

“Churnalists” – thanks, I like that!

Johne Morton
August 27, 2022 5:38 pm

This article is amazing. It also demonstrates a larger problem that we have in the academic argument about “climate change”. Lake Meade is just one data point in an argument about a supposed unnatural trend regarding the precipitation element of climate over a certain region of a specific Northern Hemisphere continent (SW USA). It takes many articles like these just to crack one shell of what are now innumerable arguments for the “fossil fuel capitalism is killing the planet” garbage…and stories like this one never see the light of day in our current lamestream media.

Johne Morton
Reply to  Johne Morton
August 27, 2022 6:23 pm

Sorry, Lake Mead. I lived near Ft. Meade, Maryland, so it’s just habit…

August 27, 2022 5:49 pm

IMO, overuse here is mis-management of water resources. Mead was near full in December. Had the point of release from Hoover Dam been water conservation for agriculture and to support “natural” habitats downstream, the thing to do would have been to release based on bugeting for what was stored. Instead the Bureau of reclamation has expended the annual 4 billion kWh of hydraulic energy in the period January-June, leaving almost none for the remaining few months until the watershed begins to recharge (hopefully) in October.

The increased electrical demand from California and Southern Nevada has driven the management and engineering decision to run out the “battery.” Had either area reliable electrical generation capacity, Mead would still be at least half full.

Agriculture hasn’t really suffered, since released capacity has exceeded the need. Dry weather is necessary for harvest, and wet weather for early planting has been provided naturally through a normal. La Niňa rainy “monsoon” season, beginning in July and just now beginning to end. If agricultural water is needed when Colorado supply isn’t up to minimum, Arizona farmers have been pumping it from wells for decades — longer than Hoover has been around.

Hoover’s (and the Bureau of Reclaimation or Wreck Claim Action) purpose should be primarily water conservation and flood control. Instead woke green cultists, mainly Californian, are using political and financial influence to cause mismanagement of the resources charged to them.

The only drought is in responsible journalism and government ethics.

Reply to  dk_
August 27, 2022 6:57 pm

I am not sure if power generation is the problem as I haven’t heard that story before. I do know that the last peak was in 2020 and at that point it was still over 100 feet low. The last time the dam was full was 2000 and strangely enough, they were worried about the dam topping. I remember the images well on the news.

Last edited 1 month ago by Dena
Reply to  Dena
August 27, 2022 7:46 pm

Lake Mead for the last year

NOAA Rainfall last December:comment image

The first shows most of last year, and includes a late “bump” for this year’s annual monsoon. In the beginning at late August shows the “Megadrought” lake level 24 ft greater than this year.

The second link shows a map, one of a series from NOAA for December precipitation levels. It is a little above average, but preceded by a pretty rich October rainfall for the region, which mostly was responsible for filling the lake. Low November rainfall was low, as were Jan-March, but had it been conserved, the lake level should have been adequate for agriculture, natural habitat, and to satisfy treaty obligations.

Not the same watershed but, incidentally, Bonneville speed week canceled out this year due to flooding (called by NWS regional representative “once in a thousand year event” which happens to my memory every 20 years or so) The same or similar precip patterns occurred all across the Southwest.

Not bad for a drought?

As for this year’s monsoon, there seems to have been lots of flash flood water rescues going on this year. This one typical:

In my limited experience, this July-August monsoon has been just about average. Last year’s was missing, but two years ago was heavier than in 2022. The other rainy season, Dec-Feb, has been irregular over the past 20 years. Low for the last couple, but not missing entirely.

Incidentally, what we really need for a good summer rainy season is a lot of Pacific hurricanes. These seem to me to bring the Southern Rockies a lot of rain. The Atlantic has had only a few this year, but the Pacific has rocked a dozen or so, only striking land a bit in Central America. But if we’re really in for increased severe hurricanes, Mead will probably be fine.

And of course you haven’t heard this before. That’s why you’re reading here, isn’t it?

Reply to  Dena
August 27, 2022 9:25 pm

I am doubling on my prior comment. Beg Pardon.

Megadrought debunked 18 Feb ’22 WUWT:

Hoover, then Boulder dam, built at the height of a megadrought, took 8 years to fill lake Mead, but began producing power as soon as soon as they could flip the switch. Power production is water release, but if you’re supposed to conserve water, you don’t leave the tap on at a rate greater than the input. Dr. Spencer’s data and interpretation show that snow and rainfall have been normal. Where did it all go?

   Metropolitan Water District of Southern California – 28.5% of total electrical output
   Nevada – 23.4%
   Arizona – 19%
   Los Angeles, CA – 15.4%
   Southern California Edison Co. – 5.5%
   Boulder City, NV – 1.8%
   Glendale, CA – 1.6%
   Pasadena, CA – 1.4%
   Anaheim, CA – 1.1%
   Riverside, CA – 0.9%
   Vernon, CA – 0.6%
   Burbank, CA – 0.6%
   Azusa, CA – 0.1%
   Colton, CA – 0.09%

Last edited 1 month ago by dk_
Nicholas McGinley
Reply to  dk_
August 28, 2022 9:51 am

Mead was near full in December.”

Why are you making stuff up?
A lot of what you wrote here is malarkey.
Just sayin’.
Have at it.

Nicholas McGinley
Reply to  dk_
August 28, 2022 10:56 am

“Instead the Bureau of reclamation has expended the annual 4 billion kWh of hydraulic energy in the period January-June”

That is the amount of power produced annually at Glen Canyon Dam power station, not Lake Mead/Hoover Dam.

Hover Dam’s annual power output dwarves that of the flow from Glen Canyon.
Not sure why…they are both roughly 700 and some feet high.

Glen Canyon Dam is like a worn out speedbump compared to Hoover. And not one of those big ass speedbumps in front of gubmint buildings and such, but the dinky kind they make by just shoveling some asphalt onto the road in a line-type shape…

Again, just so you do not think I am only here to bust on peeps who say stuff what’s not the case…
Glen Canyon Dam annual power: 4 GWh’s (actually it is 4.717, so five if you round up to one sig fig like you done did do…done…did…) per annual year/annum. And that’s annually (BTW, do NOT misspell annually by leaving out an “n” and the u. Just sayin’.) Oh crap, I am gonna hafta edit that out later.

Hoover Dam annual power generation per annum, yearly: 3.3 TWh!
Yup, that is a T as in tera. Many hundreds of times more than Glen Canyon dam.
Just sayin.
I am not from there, but I am pretty sure it is Hoover than sends power to CA, since, you know, it is nearly on the border of that state and all, and Glen Canyon is way over on the other side, closer to New Mexico than to California.
Just sayin…

And also BTW…some jackass politicians in CA or LA do not determine what the Federal Gubmint does to manage the huge responsibility of managing all that water for all those people and all that power.
That ain’t how it works.
And also also BTW…mostly, the reservoirs on the Colorado river, specifically Powell and Mead, get most of their recharge when spring rains melt the snowpack in the Rocky Mountains. There are other major tributaries from elsewhere, like the Green River/ Utah/Wyoming. But it is that snowpack…
Them thar mountains are very efficient at wringing the moisture out of the air flowing past/over them, mostly from October to April or May. Mostly.

And it is not always how much rain falls or how much snow has accumulated, but instead how and when and how fast it falls (for rain) and melts(for snow) is often the key factor.
Slow melting and/or gentle rain over many days…it soaks into the ground a lot more than fast melting/torrential rain that falls in a short time…like the monsoons rains they have been getting out there for the past couple a months. Those downpours on hard dry desert ground surfaces typically mostly run off.
There is an amazing video of Grand Canyon white water rafters coming up a torrent of muddy rocks and water shooting out of a side canyon…like hundreds of feet up the cliff it was coming.
Lemme find it…

Here…you gotsta watch this:

And look at the rock falls in the foreground and also way up the cliff walls.
This places are dangerous!
Turns out the entire Grand Canyon is still under construction.

Last edited 1 month ago by Nicholas McGinley
Reply to  Nicholas McGinley
August 28, 2022 4:04 pm

From Bureau of Reclaimaition web site

Hoover Dam

Frequently Asked Questions and Answers

Hydropower at Hoover Dam

Hoover Dam generates, on average, about 4 billion kilowatt-hours of hydroelectric power each year for use in Nevada, Arizona, and California – enough to serve 1.3 million people.

“Billion kilowatt-hours” is BuRec’s units, not standard or mine. Reckon that works out to 4*10^12, so yes, Terrawatt hours, but I was quoting their average for my own hyperbolic purposes.

From USGS, repeat from above:

rado river:Water used to generate hydroelectric power represents the majority of total water use, but is an instream use. Irrigation of crops is the largest offstream use of water in the CRB, averaging 85% of total offstream use over the 35-year timespan.

CRB is Colorado River Basin, including both Hoover and a couple others.

Map showing Mead 2021 water levels attached, since following links seems difficult for you — not full, agreed, but full enough if it wasn’t over subscribed. Link anyway:

Even greenies think the Colorado is oversubscribed since the project was completed..

“News” article
(refers to)
New Journal article from 2021,forward%20toward%20the%20finish%20line.

…but they also claim (for 20 years) that there is an endless megadrought caused by climate change, despite little proven evidence and, the debunking on WUWT (see the Jim Steele piece that just posted, for example) and other reputable sites.

California is the biggest user of power; links and quotes in comment immediately above yours AND at the same BuReclamation page as the 4BkWh power production quote above . Power is sold to consortiums through at least four federal agencies, native tribal authorities, NGOs, interest groups, and monopoly service providers: politicians and contractors, all.

Can’t help it if you can’t read, nor figure out the energy or carbon costs of building and maintaining pipelines, nor understand the need for constant upgrade and maintenance any civil engineering project.

Reply to  Nicholas McGinley
August 28, 2022 11:04 pm

you are also wrong about Glen Canyon production average
Glen Canyon generates “around five billion kilowatt-hours of hydroelectric power annually”

and wrong about Hoover production. Usng Hoover released outflow as a proxy for power for production:
In terms of outflow from Hoover, and despite the lake Mead surface altitude and looming water shortfall, production has remained remarkably steady over the past two years. THe graphs are dynamic and interactive, must be captuerd as screen shots to insert here. If the user will zoom in on the web link (or download the data) and a view for the last month shows daily and weekly variability can be seen (reflecting demand). Both screenshots attached in this subsequent comments gif.

and wrong about Glen Canyon production
Lees Ferry, below Glen Canyon dam, shows a similar average production rate, except that it stops producing for weekends.

This indicates that BuRec needs both dams for weekday production, but only Hoover’s electrical production for 7 day electrical production. Montly and 2-year gifs also attached in subsequent posts.

Both dams peak outflow at midday on production days, then drop off overnight. Production is responding to daily electrical need and not to water conservation requirements.

USGS and BuRec claim that 85% of water output is for agriculture, and that most use is for hydroelectric production. BuRec shows that California uses the most electrical power inline with water release. Both dams show a steady outflow regardless of lake fill levels over the last two years. Both lake levels were 45% above “dead pool” (same links, I’ll let you find do your own research) until this year. Both lakes are now re-building after the last month to 45 days of normal “monsoon” rain in the Colorado watershed.

In addition to USGS and BuRec, regional federally generated electical power is sold by the US Department of Energy through the Desert Southwest Region of the Western Area Power Administration Also involved are the International Boundary and Water Commission, and the U.S. Army Corps of Engineers. Their 2021 annual report for the entire Western Area shows electrical generation at 80% of average.

Colorado Hoover outflow 8-2022.GIF
Reply to  Nicholas McGinley
August 28, 2022 11:08 pm

Two year Hoover outflow. Link in prior comment.

Colorado Hoover outflow 9-2020 8-2022.GIF
Reply to  Nicholas McGinley
August 28, 2022 11:10 pm

One month Lee’s Ferry/Glen Canyon outflow, Link in prior comment

Glen Canyon Lees Ferry outflow 8-2022.GIF
Reply to  Nicholas McGinley
August 28, 2022 11:10 pm

Two year Lee’s Ferry/Glen Canyon outflow. Link in prior comment.

Glen Canyon Lees Ferry outflow 9-2020 8-2022.GIF
Reply to  Nicholas McGinley
August 28, 2022 11:41 pm


Colorado Hoover outflow 8-2022.GIF
Last edited 1 month ago by dk_
Jeff Alberts
August 27, 2022 6:06 pm

“Climate Change Theory”?? What? What exactly is that theory?

Mr Ed
August 27, 2022 6:30 pm

I read the “Cadillac Desert” back in the 80’s . I remember discussing
it with a MT water commissioner at the time who dismissed the narrative
as enviro propaganda now it’s climate change….

There was serious money made stripping the water rights from farms/ranches in CO
and selling them downstream in years past.
I recall hearing/reading about a proposed canal from the Columbia
River to CA through the Willamette. A project like would be money better spent than the stuff that is going on in CA today IMO.

Mike Maguire
August 27, 2022 8:08 pm

Wonderful points, Dr. Spencer!

The temperature configuration in the Pacific right now continues to show the strong -PDO along with the La Nina that just won’t die which is once again showing a reemergence of subsurface cold water.

Screenshot 2022-08-27 at 21-39-33 PowerPoint Presentation - enso_evolution-status-fcsts-web.pdf.png
Mike Maguire
Reply to  Mike Maguire
August 27, 2022 8:43 pm

Maybe no coincidence, that the models keep killing this La Nina too early but the -PDO regime won’t let it die!

Screenshot 2022-08-27 at 21-21-05 Pacific Decadal Oscillation (PDO) National Centers for Environmental Information (NCEI).png
August 27, 2022 9:21 pm

Why bother with CMIP6 models?
1) They’re not predictions.
2) They are not climate science.

Most of the water entering Lake Mead is from snowmelt in the mountains; little of the water falling on lower elevations tends to be used by local vegetation with little runoff reaching the Colorado River.”

little of the water falling on lower elevations tends to be used by local vegetation with little runoff reaching the Colorado River“;
Little water is used by local plants… But the lower elevations have little runoff?

How does that work, exactly?
1) I expect that the lower elevations have greater acreage, receiving a larger total volume of water.
2) Areas receiving snow have easily measurable water conversion rations.
3) Hard dry ground does cause water to run off instead of soak into the ground.
4) Now about that runoff from the lower elevations? Or reasons why people should not park or set up camp in ravines, gullies, gulches, canyons, some roads out West? It’s because of greater runoff and flash floods down stream.

In Nevada, I’ve watched gullies fill with rushing water with the Colorado River just a couple miles away.

The biggest real difference is that snowpack melts over months, whereas runoff happens within hours of the precipitation event.

Roy W Spencer
Reply to  ATheoK
August 28, 2022 3:29 am

ATheoK: That sentence of mine was poorly phrased. What I meant was that little of the precipitation falling on lower elevations of the upper river watershed ends up in rivers, it is instead used by vegetation. Mountain snowpack is where most of the river water originates.

Reply to  Roy W Spencer
August 28, 2022 6:50 am

I thought so. When I read it and saw the obvious mistake I went back and read the first “little” as “most”, then it made sense.

August 28, 2022 5:07 am

The warmunist response to blaming fluctuations in Colorado River flows on PDO is simply to blame PDO on human caused climate change.

Of course that’s nonsense, but none of warmunism makes any scientific sense. Warmunism is just True Believerism du jour. Eventually to be supplanted with some other “we’re all gonna die next week if we don’t change our ways” True Believerism of the future.

Mark Whitney
Reply to  Duane
August 28, 2022 6:05 am

Indeed the perfect pseudo-theory. Anything can happen and nothing that happens can prove it wrong. Just plug in any old ad hoc modification and it’s “See, we told you so!”

James Schrumpf
August 28, 2022 7:27 am

There’s no such thing as “Climate Change Theory.” A scientific theory has to explain the causes of a large body of observations and facts, which it does not do. We gotta stop conceding that ground; it’s an hypothesis only, and its proponents can’t even give examples of things that would falsify that hypothesis.

Drought? Yes! Floods? Yes! Heat waves? Yes! Cold snaps? Yes!

There’s nothing it can’t do, and so it’s useless.

Mike Sexton
August 28, 2022 7:30 am

I’ve always said we need to pull the straw from LA out of there
They should be made to pay for desalination plants

Burk Gossom
August 28, 2022 10:59 am

Why more outflow, more people. We are at less than replacement birth rate in US so all growth is immigration, legal and illegal. So the root cause of the outflow is immigration and acknowledging this should be part of the discussion.

Michael Fox
August 28, 2022 4:57 pm

Mr. Spencer,

You say, “little of the water falling on lower elevations tends to be used by local vegetation with little runoff reaching the Colorado River.” Might you actually have wanted to say, “the little water falling on lower elevations …”? Makes more sense to me.


Mike Fox

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