More revelations on Venezuela’s “drought” and the Guri Dam

Just when I thought my recent post on the Venezuela drought was dead and buried a comment appeared. It was posted by Miguel Octavio, a physicist by training who lives in Miami but who visits Venezuela frequently, and it linked to a follow-up post on Miguel’s blog that contained a lot of local rainfall and stream flow data that weren’t available to me but which prove beyond any doubt that there is no drought at or around the El Guri dam. This post presents Miguel’s post in its entirety and adds two other items as footnotes:

  • A video claiming that Venezuelan authorities are undermining a rockfill dam to supply more water to the El Guri turbines, thereby threatening the dam’s integrity. (Note that Energy Matters cannot confirm the veracity of this claim).
  • A revealing Twitter exchange between Miguel and Luis Motta Dominguez, Venezuela’s Minister for Electricity and Energy, who refuses to acknowledge that there isn’t a drought despite all the evidence to the contrary.

Is Drought Really Causing The Problems With Guri Dam?

April 17, 2016

The title of this post may seem strange to some, when you look, for example, at the pictures in this Reuters report, it certainly seems like there is a drought in Guri, except that if the pictures were of the bottom of the now half -dry lake that forms the dam, it is obvious that it will look dead and drought-like in the pictures.

When I was in Caracas, someone told me that they had gone fishing in one of the tributaries of the river Caroni and the water level was quite high, something that was later confirmed by another friend who went fishing in the La Paragua river and saw the water level rise by a meter in a few days.

Despite this, the dam level keeps going down, so, what gives?

Both of my friends deduced from this, that the problem was not drought, but the managing of the Guri dam.

I stored this information in the back of my mind and did not look into this for  a couple of weeks, but all of a sudden, this blog post by Roger Andrews came out. While Andrews is not an expert in this particular field, he seems to be someone that likes charts and numbers and understanding problems. What Andrews showed, and I will come back to it, is that this has not been an anomalous year in terms of rainfall in Guri and that the problem with the water level was simply overuse of the dam to generate electricity.

It is useful before we discuss this, to show you an overall map of the area of Guri:


On the left, you can see the overall area in the Southeast of Venezuela down to Brazil and Guyana. In the blow up on the right, you can see the Caroni river and all its tributaries, which is the area that feeds the dam. What matters in the end, is what rainfall is doing there, not in Caracas or Maracaibo or even Ciudad Bolívar, far from the dam, not in the basin of the Caroní river.

What Andrews did, was to look at the data in five rain stations in Bolivar and Amazonas and see if rain was particularly light in the last few years. Here I show two of them: Tumeremo, to the right of the dam, and Santa Elena to the South and which is in the Caroni basin:

PluviometriaAs you can see, rainfall in Tumeremo was in 2015 about the same as any other year and in the case of Santa Elena, rainfall levels were at 200 mm per month level, not exactly low given the long term record.

While I could not find a long term record for the Santa Elena Station, I did find the record for Kavanayen nearby:

KavaThis graph shows the maximum rainfall at the Kavanayen Station (black), the average (blue) and the lowest level (red) from 1969 to 1998 (Funny, there is no data after Chávez was elected)

As you can see 200 mm. is way above the lowest level ever measured.

Just to make sure, Andrews blew out the data and I will show what is seen for Santa Elena:

SantaHelenaAs you can see, last year was not too different than any of the past five years, when there was no “El Niño” to blame the supposed drought on.

At this point I wished I had current data for the stations with a long term record to compare. But then, a person I follow in Tweeter (@meteovenezuela) posted the following recent rainfall map:


This is a map of the Caroni river basin above Guri, showing the accumulated rain from March 15th. to April 13th at a number of stations. What is interesting is that we have two stations that we can compared to the long term record: Kavanyen and Uriman. At Kavanayen, the rainfall was 229.1 mm for this almost one month period. This number is way above the average rainfall for April 1st. from 1969 to 1998 in the graph above, which was of the order of 150 mm per month, and we are  talking about comparing to the average! Not to the lows…

We can do the same thing for the Uriman station, close to the dam as seen above above, where the rainfall was 151.7 mm in the same almost one month period.

Below is the long term record for this station:


I have placed a red dot on the curve with the data for this year, as you can see, it is right on the historical average, far from being an anomalously low value, as the presence of a severe drought would require.

Despite this, the Guri dam level continues to go down…

And to increase the mystery, I found this plot of the water volume in the Caroni river tweeted by @800GWHMWH:


Clearly, the volume of the river is at levels which are historically high, not low.

I am no expert, I just enjoy looking at data and graphs, I have looked for as much new data to complement Andrews’ and I must say, everything that I have found confirms what he concludes. I do hope one or many of the readers of this blog can help me in getting more information and data and debunking the Government’s claim that this El Niño-induced drought has been anomalously strong, because it certainly does not look like it.

In closing, I show a plot of the peak power demand in Venezuela in the last few years:


Clearly, despite the billions that were invested in order to increase power generation, we are now back to 2007 levels, indicating that something has been going downhill in the grid and I would bet, this has to do with the overuse of Guri, to compensate the decline of the whole network.

—- End of post ——

Footnote 1: The El Guri rockfill dam

In comments to Miguel’s post Eugene Weixel posted this video (commentary in English). It purports to show how excavation at the toe of a rockfill dam threatens to undermine the dam and to place cities and towns downstream in danger of flooding. The video is, however, dated 1980. Anyone with additional information on this subject is encouraged to provide it.


Footnote 2: Twitter exchange between Miguel and the Venezuelan Minister of Electricity and Energy:

(Translation by RA, vetted by MO)

Miguel:  Here it is, an analysis by an expert who says there is no anomaly (followed by a link to the Energy Matters post)

Minister:  Of course you can demonstrate it …. everyone who follows you will know that you get precipitation data from the web.

Miguel:  Precipitation data show that rainfall hasn’t been abnormal

Minister:  Miguel, go to the internet and search for rainfall data. It’s what I’m telling you. Don’t deceive! Don’t manipulate!

Miguel:  Can you demonstrate that it’s rained less?  The problem isn’t that they have generated more electricity?

Minister:  You can check it in the Hydrological Bulletin …. It’s not necessary for me to prove it to you.

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40 Responses to More revelations on Venezuela’s “drought” and the Guri Dam

  1. Euan has suggested that it would be helpful to show some data on Venezuela’s electricity generation, and here are the I best can find (from Trading Economics and EIA)

    They only go as far as 2011, but the suggestion is that the shortfall is in hydro and not in the FF plants.

    • Willem Post says:

      Venezuela has been in an economic slump since about 2008, and the current low price of oil, gas and other commodities reduce export earnings.

      Hydro production decreased starting about 2008.

      Did it increase or decrease beyond 2011?

      When were alleged “drought conditions” first observed?

      What was rainfall, mm/y, during these later years?

  2. singletonengineer says:

    By way of background:
    My engineering training, both undergrad and postgrad, includes hydrology, ie railfall, runoff and streamflow computation. There were also substantial components For decades I supervised construction of and/or managed maintenance and condition monitoring of several large earthfill dams as part of my career in the electrical power generating industry. I never was the designer, however as owner’s representative I engaged professional design offices in relation to the above.

    The discussion regarding the rainflow, streamflows, capacity factor and related appears to me to be compelling. The Venezuelan Minister is avoiding an unfortunate truth.

    If the “hydrological report” mentioned by the Minister comes to light it should cover the rainfall and runoff issues thoroughly, but the name might be deceptive. The report might have been produced for political, rather than professional purposes, in which case it might be meaningless. It would also need a portuguese-speaking engineer’s review to determine which is the case.

    So, well done, Euan and others!

    The construction work appears to be essentially downstream of the existing embankment and right abutment, which are thus intact for the moment. Essentially, the relevant portion of embankment will not be threatened until the end of the construction period, when the coffer dam (ie embankment at the right abutment) will need to be breached in order to permit water to flow to the intakes of the Stage 2 Power Station.

    Removal of the coffer dam can only be done with the dam virtually drained and after the new section of embankment has been completed, including at least the intake valves in the Stage 2 Power Station. Once drained, the dam will not be able to generate power reliably until normal working heads (thus pressure) are restored, which might take several years.

    So, I suggest an additional theory, which is that the hidden truth might be that the water levels in the dam has been intentionally reduced over time in anticipation of the need for it to be virtually empty for a few months and then for it to be restored as weather conditions permit.

    Is it possible that the original plan included steps such as:
    1. Construct new power station, right abutment works and right embankment while leaving the existing works in place during construction in lieu of a specially constructed coffer dam.
    1A. In parallel with the above, construct additional FF electricity generating plant tocover the period when hydro generation will be reduced due to Steps 4 and 5 below, when the dam is either at very low levels or is being allowed to refill.
    2. Reduce water levels in the dam by generating electricity and/or operation of the bypass valve(s).
    3. Remove the earthen portion of the right embankment.
    4. Complete electrical and mechanical works in the Stage 2 Power Station.
    5. When water levels have risen to within the normal operating range, commission the new Stage 2 works.
    6. Decommission or place on standby the surplus FF plant.

    NB1 During steps 2 to 5, hydro generation will be reduced in capacity, availability and reliability due to the low water levels. If weather conditions are not favourable, refilling of the dam might take several years or a major flood.

    NB2 Hydro will be at the top of the dispatch merit order during the draw-down phase. Hydro will be down the dispatch order during the recovery period, in order to conserve water.

    Having been asked to explain, has the Minister fabricated a story of a drought in order to hide the real corner-cutting, high risk truth, that adequate additional FF generating capacity was not installed and that the dam has been intentionally emptied in order for the Stage 2 power station to be constructed, thus severely curtailing hydro availability, reliability and capacity for several years during construction plus future years until the dam is refilled by a few above-average rainfell years?

    I do not see this as a geotechnical problem. It is all about failure to provide replacement generation capacity to replace that which needed to be intentionally withdrawn from service for construction of the Stage 2 Power Station.

    A quick check with ICOLD might help. See, but note that the databases is password protected.

  3. singletonengineer says:

    Errata, first para:
    …There were also substantial components of geotechnical engineering. For decades…

    Let’s see if my novice attempt at HTML coding worked.

  4. singletonengineer says:

    Venezuela also exports a proportion of its electricity to Brazil. This might complicate comparisons of trends in electricity generation and consumption.

  5. Euan Mearns says:

    Singletonengineer wins the coconut!

    I went to bed believing that there was a dam failure in prospect, but quite the opposite. The 3 pics show various stages of the dam expansion.

    1 = original overflow race
    2 = original power house
    3 = phase 2 power house
    4a = phase 2 coffer dam
    5 = island

    Pic1 shows phase 2 under construction

    Pic2 (above) shows phase 2 power house complete and we now have 2 tail races instead of 1 (pic1). The coffer dam in pic 2 (4b) is clearly not the same as in pic 1.

    Pic 3 shows the ongoing phase 2 expansion (6) which maybe is now almost complete? When the politician in the vid says they need to take the rocks away to let the water get to the turbines he’s right 🙂 He’s talking about removing the coffer dam.

    Wikipedia says that Guri provides 30% of Venezuela’s electricity and its temporary closure explains the downturn in electricity production. I’m not sure they will ever have planned to build temporary plant to bridge this.

    Why the politicians find it necessary to make up stories of drought and global warming beats me.
    And a correction to the above. I went back to read Wikipedia who say this:

    Because the demand for electricity grew fast, another construction phase started in 1976, building of a 1300 m long gravity dam, another spillway channel and a second powerhouse and 10 turbines of 730 MW each were installed. The powerhouse´s inside walls were decorated by the Venezuelan kinetic artist Carlos Cruz-Díez.[citation needed] This increased the dam’s dimensions to 162 m in height and to 7426 m (according to other sources 11,409 m[3]) in length. The reservoir grew bigger and reached its water level at 272 m.[6]:12 The structure was inaugurated on November 8 1986.[citation needed]

    Since 2000, there is an ongoing refurbishment project to extend the operation of Guri Power Plant by 30 years. This project is to create 5 new runners and main components on Powerhouse II, and close to the end of 2007 is starting the rehabilitation of four units on Powerhouse I.

    So the phase 2 expansion was completed in 1986 and I can’t find any pics where the dam looks to be complete – i.e. the on-going construction work labelled 6.

    And so I’m left wondering if the original coffer dam, 4a, was never removed and now that water levels have fallen that it is in the way of the phase 2 turbines?

    So I don’t know if 4b was built as a coffer dam or as a permanent rock dam? The options now seem to be:

    1. Risk of failure so levels have been lowered
    2. Overproduction relative to available water / rainfall
    3. Level lowered for refurbishment works

    • Euan Mearns says:

      Can anyone work out where the Minister is standing? The crane in the background is on the phase 2 dam wall. My suspicion is that all this has to do with problems arising from the remnants of the coffer dam – 4a.

      • Singleton & Euan: Thanks for your detailed and helpful comments. Euan, your images in particular give me a much better appreciation of what’s been happening with the dam expansion and suggest that the 1980 video might indeed have been a bit of a red herring, as I suspected.

        But regardless of whatever progress has been achieved in expanding El Guri’s capacity, it’s not been fast enough. Water levels are now approaching the level where production will cease altogether:

        Nicols Maduro must be praying for a wet summer. A very wet one.

    • singletonengineer says:

      4b in photos 1 and 2 are probably the same embankments (called in Portuguese rock-filled dam, or “presa de encoramiento”. I have seen nothing to suggest that a separate coffer dam was constructed – it was not needed. (Thanks, Google Translate)

      My guess is that Photo 1 was taken more recently than Photo 2, which appears to have been taken very soon after construction, before the vegetation (weeds?) started to take hold.

      The “Isla”, island, is actually not an island – it is the high ground at the right embankment and is certainly not surrounded by water.

      The Minister is standing between the new right abutment and the old right abutment. He is at the downstream toe of the old abutment, which is also near enough to where the upstream toe of the new embankment is/will be.

      Discussion of having to remove the rocks from in front of the Stage 2 powerhouse possibly refers to the need to remove the rock-fill embankment, which is no longer needed. In a perfect world, the rockfill would be removed right down to below the lowest design operating water level, because otherwise a cascade would develop as the dam flowed through the notch in the old embankment (ie coffer dam) and towards the Stage 2 Powerstation. This will result in rubble being drawn into the Stage 2 turbines and destroy them.

      So, I hope that the old embankment was removed properly and not simply broached.

      The sequence of events remains unclear, however details are emerging.

      For example, the report of a portion of Stage 1 Powerhouse being withdrawn from service for overhaul: “…and close to the end of 2007 is starting the rehabilitation of four units on Powerhouse 1”.

      My tentative conclusions remain the same, and thet are:
      1. Stage 2 powerhouse has been constructed over a number of years.

      2. The construction program requires the dam water level to be lowered during removal of the coffer dam. During this period, water pressure will be low. This reduces the capacity of the Stage 1 powerhouse.

      3. Stage 1 was also partially withdrawn from service in 2007 to enable overhaul of some turbines.

      4. It is possible (probable, IMHO) that some water was dumped via the bypass valves to lower the water level and to keep it there. This might have been kept secret in order to prevent political upheaval.

      5. There is no indication that replacement power supplies were provided during the planned partial shutdown of Stage 1. There might have been insufficient funds available for this and that an alternate policy of toughing out the inevitable shortage was followed, in which case the effects seem to have been seriously underestimated.

      6. Electricity was in very short supply due to the above and the Minister was in a tough spot. Hence the need to develop an excuse based on a fictitious drought.

      7. (Conjecture…) The coffer dam was opened by breaching but this work was not completed.

      8. (Conjecture…) The threat of damage (or actual damage) to Stage 2 turbines due to intake of rubble is an ongoing problem.

      9. Have Stage 1 turbines been fully restored to service?

      10. Due to the now years-long period of low water levels in the dam more water is needed at low head in order to generate a constant level of output. This terrible cycle of wasted water makes refilling of the dam impossible without flooding rains – the phony “drought” will continue indefinitely, because whatever water is available is not working efficiently and the minister won’t face up to the harsh realities. Roughly: 1/4 as much head => 4 times as much water required.

      11. There is no real drought, but in order to refill the dam the Venezeulans will need to wish for above-average rainfall, perhaps even flooding rains.

      12. Caution. Too much rain flowing into an empty dam could scour the backwaters of the dam and transport silt to the dam wall, ultimately threatening to be drawn into the turbines. If this happens then permanent damage could ensue.

      This was all avoidable. Why weren’t alternative power supplies made available during the construction and recovery periods? Fabriced stories about a fictitious drought will eventually be seen for what they are.

      If the hydrological report ever shows up, I’m prepared to bet my new coconut (Thanks, Euan!) that it won’t explain the relationship between head of water above the turbines and the electrical output of the generators.

      My apologies for the long post. If my worst fears are the truth, then the story of this dam and its power stations could well end up as an internationally relevant case study in how not to augment an in-service hydro power station.

      • Singleton. Thanks for another informed and detailed analysis. It would explain a lot if the turbines were in fact running at only 25% efficiency. It would be nice to be able to confirm this with up-to-date generation data but there don’t seem to be any.

        However, according to recent statements from the President of the Electrical Commission of the Venezuelan College of Engineers, which I may get round to posting later, there are sixteen operating turbines in the Guri dam and eight of them will have to be shut down when the water level falls to 244m above sea level. The capacity of the eight turbines is given as 5,000 or 5,500 MW. This may help answer your question 9.

        • singletonengineer says:

          I’d love to get my hands on the following data:
          1. Top operating water level of the dam. NB spillway crest level might be significantly higher, in which case the storage capacity between TOL and Spillway is known as the Flood Storage Capacity.
          2. Intake level(s) for the turbines – presumably, different for each of two sets of 8 for the first stage, plus maybe higher again for Stage 2.
          3. Turbine types (Pelton wheel, etc) and the RL of the entry to the turbines.
          4. Records of pond water levels during the past few years – ideally, 10 or more – for Guri Dam. Statements such as “8m below normal” are close to meaningless, unless the relationship between normal, top operating level and so forth are known.

          Some bits and pieces:
          Lowest operating RL before vortexes form in the outlets is RL240.

          Same reference:
          water level 244.9 on March 29th 2016
          Levels can fall up to 15cm/day (!! That’s amazing.)

          16th March 2016: Water level 247 metres. Turbine cutout RL244 m. The difference between 240 and 244 might be an additional safety margin.

          2 machine rooms, each with 10 generating units. Total 10GW installed capacity. (Other refs differ).

          From ABB: Probably the best I have found in the limited time available:


        • Stuart Brown says:

          Roger, my thanks too for another intriguing post. (and singleton for the analysis with possibly part of an answer to your point 5)

          I wondered whether the water was ending up in the Tocoma Dam, which has been filling since November apparently. And came across this:

          “From 2009 to 2015 the revolutionary government spent very large sums of money in a thermal park having a generating potential similar to that of Guri; that is, the national electricity system capacity was increased by almost 10,000 MW. But, of that total only 40% is currently available because most plants are obsolescent and non-operational due to lack of maintenance. Such is the case with the Planta Centro thermoelectric plant, located in Morón (northern Carabobo state). This plant is the country’s largest and has an installed capacity of 2,000 MW, but it has not generated a single watt of power since last December 17, according to Lara. Additionally, those thermoelectric plants that are functional are operating below their installed capacity.”

          Far from having reserve generating capacity available they seem to be going the other way!

          • Stuart Brown says:

            Meant to add – didn’t understand this bit:
            “As explained by Gómez, the Guri level has decreased because the Lower Caroni hydroelectric plants have had to work beyond the safe operating margins ensuring their long-term performance.

            “If the safe operating flow rate is 4,500 cubic meters per second (m3/s), that means water is being turbined at a rate well beyond that level…”

            Does that mean the lower plants are having to work harder to make up the lost output from Guri? Isn’t that just self defeating?

          • singletonengineer says:

            The reference that Stuart Brown cited is excellent!

            It is authoritative. It explains the various lower operating levels of 240, 244 and 250 metres above sea level which had me wondering. It provides essential chronological background.

            Everything in it rings true, especially the conclusion that Venezuela’s electricity system as a whole needs new management.


            I’m afraid that the picture is bleak for Venezuela. All generating plant that can be run is being run, thus depleting water storages. Little maintenance is being completed. Much plant, thermal and hydro, is not available due to lack of maintenance. Current low international oil prices will starve the national government of the funds that are needed to reverse the downward trend.

          • The reference is indeed excellent – apart from one thing. The author doesn’t question that there is an El Niño-caused drought in Venezuela.

          • singletonengineer says:

            Agreed. I was really referring to the engineering content, which is the same regardless of the weather.

            Other sources state that there are variously 16, 20 or more turbines at Guri dam, for example, plus I found at least three so-called lower limits to operation of the turbines. This fellow brought it all together.

      • Euan Mearns says:

        Singleton, I’m afraid you seem to have partially lost the plot. 4a and 4b are definitely not the same. And Pic 1 shows phase 2 under construction while pic 2 shows the dam complete. The GE image above leaves no doubt about the island. One can see in 2014 that water levels were already down.

        You can see a lot on GE. There are lots of interesting pics. It is clear to me now that 4b is an extensive rock dam.

        Is it possible the reservoir is leaking? If you look at the SE end of the lake you’ll see that it spills into neighbouring catchment.

        • singletonengineer says:

          Thanks for the GE image, Euan. I accept your criticism.

          The Isla is indeed now an island…I wonder whether this was always so or whether the earth needed to construct the lower embankment on the right side of the dam was excavated from the right abutment in such a way as to produce the island… too many questions and not enough answers.

          My brain is rapidly filling with images, many out of chronological order.

          Upthread, someone asked whether hydro plant that is running on low water pressure uses more water. The answer is that at low pressure, the flow rate through a single turbine cannot exceed the normal maximum flows but will do less work and thus generate less electricity at peak flow rate.

          Thus, to generate a given amount of electricity a greater number of units must be in service and thus use more water. The amount of additional water is in rough proportion to the decrease in water level/pressure where it enters the turbine.

          Regarding leaking of the reservoir, I certainly hope not. All reservoirs have slight seepage. The seepage flows are of the order of litres per minute, or less. Seepage sufficient to affect the water levels in the dam would very quickly cause catastrophic failure.

  6. oldfossil says:

    When I’m the Don of all Dons I want that Minister as my spin doctor. “Admit nothing, deny everything.” Thanks for a great analysis that answers the question in my mind, although you can be sure it won’t put the matter to bed.

    I speak as that oddity, the libertarian socialist, i.e. an advocate of the poor who believes in free markets, when I say that Venezuela is the model of how socialism ruins an economy. Chavez accomplished Venezuela’s transition to basket-case banana republic in a record 14 years. Toilet paper has become known as White Gold there because of its scarcity. I’d like to know what part price-fixing has played in the Guri Saga. I’d suspect that giveaway prices encouraged consumers to use electricity like it was free.

    • Lars says:

      Old Fossil, the first post about this stated that the retail electricity price in Venezuela is 0,02 US$/KwH. It sounds like very little, but maybe not when comparing it to Venezuelan wages. I have an internet friend from Venezuela, she was once applying for a job as cashier in a super market. Her salary would be around 60-70 US$/month. Now you can do the math yourself.

      The problem is no pricing flexibility in true socialist style. Electricity is subsidised for the poor. For the rich Venezuelan elite it is nothing, they have less reason to reduce demand, whereas for the poor the low price keeps them going, until the Guri dam can give no more of course.

      • michael branagan says:

        Price of electricity, based on by travels in Venezuela, are irrelevant for the poor. As a Venezuelan brother-in-law told me long ago, the poor get their electricity by “tossing a hook”.

    • moctavio says:

      I rented an apartment in Caracas until last November. My landlord never charged me for electricity during the three year rental. By the end of the rental, the bill was 6 US$ cents per month US$ 0.06 per month. Chávez froze electric rates in 2001 or 2002.

      BTW at the old gasoline price, my tank cost me US$ 0.04, all of 4 cents to fill up. After the recent 6000% increase its is like 25 cents US.

      • Hi Miguel:

        I read that you are now going to get scheduled 4-hour blackouts until El Guri fills up, which apparently will need help from God:

        CARACAS, Venezuela—President Nicolás Maduro’s government said on Thursday that it would cut electrical power by four hours a day for 40 days across much of Venezuela to save energy, even though the country is already reeling from frequent blackouts.

        The rationing will begin Monday in 10 of Venezuela’s 23 states, said Electricity Minister Luis Motta Dominguez. The move would cover many of the country’s largest cities, including the capital.

        Mr. Motta said the cuts were necessary to reduce electricity consumption in homes, as the government awaits rain needed to power the turbines at El Guri, a massive hydroelectric dam in eastern Venezuela that provides 65% of the country’s power supply. “With God’s help, the rains will come,” said Mr. Motta, who called the sacrifice patriotic and asked Venezuelans to show solidarity.

  7. This image from an article in the Nueva Prensa de Guayana – dated today – shows water levels in Lago Guri 8 meters below normal, which dovetails with the graphic I posted earlier:

    The accompanying story begins (my translation): “The Guri reservoir is 8 meters below its ideal level owing to the severe drought that has affected the country and that obliges all of us to save energy, as the Minister (of electricity and energy) Luis Motta Domínguez pointed out ….”

  8. sod says:

    any informations about temperature?

    Water levels are influenced by rain and by temperature.

      • Greg Kaan says:

        Water expands with temperature but the coefficient is only 0.000214 per Kelvin/degree Celcius (limited between 0 and 100 degrees Celcius, of course). So even if the water temperature varied from just above freezing to just under boiling, the volume would only change by 2.14%.

        Roger’s graph shows no such temperature variation, of course.

        • sod says:

          Evaporation depends on temperature.

          “drought” in a climate sense is a combination of “drought” (lack of rain) and temperature (evaporating parts of that rain, be it from the reservoir or from the terrain feeding it.

          • singletonengineer says:

            Evaporation from a free surface depends primarily on wind speed, air and water temperatures, I agree.

            I do not agree that thermal expansion of water is significant – the dam is over a hundred metres deep, so the average thermal range will be only a few degrees.

            Other factors affecting evaporation rates include relative humidity of the air at the water’s surface, water turbidity and salinity and the season of the year (insolation).

            The primary factors remain air temperature at the water’s surface and wind speed.

            Offset, of course, are primarily precipitation onto the surface of the pond plus inflows from the catchment.

            The dam is in a country where 6000mm of rain annually is typical – say 16mm/day average, not counting runoff from the catchment.

            Evaporation will be in the order of 5mm per day. (Personal experience)

            Reported water level reductions are of the order of 16cm per day. This figure was obtained from newspaper and similar results of a Google search and thus is order-of-magnitude only.

            Thus, evaporation is very approximately 3mm out of 16cm, say 3% and can be safely ignored in a first order discussion. The “hydrological report” which the Minister referred to might consider these factors in closer detail, if in fact it exists.

          • sod says:

            I did not actually consider expansion of water. I was only talking about water missing.

            And water can be missing because of a lack of rain (which the data does not show in this case) or higher temperatures (which is also not confirmed by data here).

            I really like this article, even though i have some doubts about the results it presents:


            Basically it seems to say: an open water (hydro lake) will evaporate slightly less than the typical landscape in a northern country, about the same in a tropical region and more in arid regions. (text below figure 3).

  9. Pingback: More revelations on Venezuela’s “drought” and the Guri Dam – Climate Collections

  10. singletonengineer says:

    Temperature has no significant effect on water level in the pondage of a dam or of the efficiency of turbines.

  11. Information from Winston Cabas, President of the Electrical Commission of the Venezuelan College of Engineers, on the performance of thermoeletric plants in and around Caracas:

    Tacoa plant, capacity 1,540MW, generating 850MW
    Picure plant, capacity 131MW, generating 35MW (3 of 4 units are inoperative)
    José Maria España plant, capacity 440MW, generating 240MW
    Guarenas 1 plant, capacity 156MW, generating 75MW
    El Sitio plant, capacity 720MW, generating 500MW
    Total in and around capital: 3,864MW installed, 2,070MW operative

    In Venezuela as a whole: 17,500MW installed, 9,000MW available but 3,000MW “intermittent” because of lack of maintenance

    And from the same source:

    “The problem isn’t the El Niño phenomenon but the thermoelectric plants that are operating below their installed capacity. The plants that should be supplying electricity when an El Niño or a hot summer occurs are not generating.”

  12. Joe Public says:


    BBC today reports “Venezuela introduces two-day week to deal with energy crisis”

    Doesn’t mention climate change!

  13. Glenn R. says:

    Interesting Roger…..

  14. Here’s an example of how so-called climate experts are still reporting the non-existent Venezuelan drought, this one from Accuweather, dated today:

    Rainfall across the country has been about 20-25 percent of normal for the most populated areas since 2013, AccuWeather Senior Meteorologist Rob Miller said. In more isolated regions it can be as low as 15-25 percent, he added. El Niño appears to be the main influence with regards to the lack of rainfall, Miller said. Typically, when El Nino occurs, stronger wind shear across Venezuela can disrupt the daily thunderstorm formation across the country, leading to lighter rainfall amounts,” Miller said.

    It would be difficult to cram more factual distortions into a short paragraph.

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