Latest El Hierro reservoir images

Rainer Strassburger is back on El Hierro and has downloaded more Gorona del Viento reservoir images on his Cloud site, which is now accessible via the El Hierro portal . Here we take a quick pictorial look at what has changed since he took his last photographs in April. The main changes are a) two flexible pipelines are now delivering water to the Upper Reservoir from the island pipeline network and b) three long graduated poles presumably intended to measure water levels have been installed in the Upper Reservoir, suggesting that GdV may finally be planning to fill it. Otherwise GdV has continued to work with the ~100,000 cu m of water that the reservoirs contained in April.

Figures 1 and 2 compare reservoir level changes between April 13 and December 3 2016. I’ve not made any quantitative measurements but I would judge that the Upper Reservoir has lost maybe 40,000 cu m of water while the Lower Reservoir has gained about 50,000 cu m. In short, there have been no large additions or subtractions of desalinated water since April:

Figure 1: Decrease in water level, Upper Reservoir, April 13 – December 3, 2016 (as of December 3 the UR was effectively empty). There is still no evidence of any water having come down the spillway. As noted in the water goes round and round post it’s believed that water pumped uphill from the Lower Reservoir is diverted downhill again at the pump station below the Upper Reservoir and never makes it to the Upper Reservoir.

Figure 2: Increase in water level, Lower Reservoir, April 13 – December 3, 2016. Water from the Upper Reservoir appears to be coming down the spillway in both images.

Figure 3 now shows the flexible pipeline that was installed at the Upper Reservoir a few years ago with the apparent intention of extracting water and delivering it to the Island capital of Valverde a short distance up the road (blue arrow). I also assumed at the time that the flexible part of the pipeline between the road and the reservoir was a temporary measure and would shortly become permanent.

Figure 3: Pipeline laid from Upper Reservoir to Valverde before project startup. The pipeline is buried under the concrete ditch and heads off north (arrow).

Which goes to show how wrong you can be. The flexible pipeline has been left in place and is now delivering water to the Upper Reservoir, not extracting water from it.

Figure 4: Flexible pipeline balanced on poles and delivering water to the Upper Reservoir (the water can be seen emerging just above the lower row of concrete blocks).

According to Rainer’s images of the flow meter at the location shown in Figure 3 the pipeline delivered 36,414 cubic meters of water to the Upper Reservoir in 17.1 days between December 3 and December 20, representing a rate of 2,134 cubic meters/day. This substantially exceeds the 1,200 cubic meters/day of the Tamaduste desalination plant to the north, the closest to GdV.

Figure 4 also shows another interesting feature – a supported white metal pipe leading from a metal box on the top row of concrete blocks down to the Upper Reservoir outflow, or close to it. Figure 5, which shows an expanded view of the pipe, suggests that it’s a conduit for electric cables and not a water pipe. Exactly what it does is unclear.

Figure 5: Close-up of white metal pipe shown in Figure 4

There’s also activity on the other side of the Upper Reservoir. Figure 6 shows (dimly) a new flexible pipeline that originates somewhere along the road above the Upper Reservoir and brings more water into the reservoir, presumably also from the island pipeline network. It’s impossible to say how much water but it seems reasonable to assume that the capacity of the pipeline would be similar to that of the flexible pipeline shown in Figure 4, i.e. 2,000-2,500 cubic m/day.

Figure 6: Flexible pipeline delivering water on the other side of the Upper Reservoir

Finally comes the most intriguing innovation of all. GdV has installed three long graduated metal poles (Figure 7 dimly shows the graduations) that as far as I can see can have no purpose other than to measure water levels in the Upper Reservoir up to its full capacity. The three pipes cover the vertical intervals between the base of the Upper Reservoir and the “marker levels” defined by the concrete block terraces (Figure 8) and are close to the flexible pipeline and the metal pipe shown in Figures 4 and 5. But why bother to install them unless you plan to fill the reservoir?

Figure 7: Graduated metal pipes showing graduations at one-meter (?) intervals

Figure 8: Graduated metal poles showning relation to concrete block terraces

Discussion:

According to Rainer’s images we now have maybe 4,000-5,000 cubic m/day flowing into the Upper Reservoir plus three metal poles that are apparently designed to measure Upper Reservoir water levels up to full capacity, suggesting that GdV may finally be taking steps to fill the 385,000 cubic meter Upper Reservoir. This raises the following questions:

Is there enough water to do this? According to 2008 data reported on 27 December 2016 (!) El Hierro produced 4.1 million cubic meters of fresh water in 2008 and used only 2.4 million cubic meters, leaving a “reserve of 40%”. Where this 1.7 million cubic meter reserve went isn’t stated, but it’s substantially in excess of the ~350,000 cubic meters that would be needed to fill the Upper Reservoir. So we might tentatively assume that the water is available.

What does GdV get out of it? Since project startup GdV has used an operating system under which water pumped uphill from the Lower Reservoir acts as a dynamic resistor to shed surplus wind power while matching generation to demand and maintaining grid stability, and to handle high-wind periods the 150,000 cubic meter Lower Reservoir must be kept full. (It’s not necessary to leave space in the Upper Reservoir if the water is diverted back down again at the pump house.) But if the Lower Reservoir is full no hydroelectricity can be generated regardless of how much water is in the Upper Reservoir. Maybe the idea is finally to use the Upper Reservoir for fresh water storage, which was its original purpose, and to use surplus wind power to pump water up to the upper reservoir to replace fresh water extraction. But unless GdV finally relents and supplies full details of its future plans I’m just guessing.

And of course it’s always possible that GdV is taking whatever water it can get while it’s there to be had and that the graduated poles have some other purpose.

Will the Upper Reservoir withstand being filled? This comment from an island resident (in Spanish, English translation below) on the “water goes round and round” post suggests that it may not. Certainly some suspicious-looking wrinkles are visible in the Upper Reservoir liner when the sun is in the right direction:

Figure 9: Wrinkles in liner, Upper Reservoir, December 2016

Finally, Figure 10 summarizes the locations of pipelines and other features around the Upper Reservoir for reference purposes:

Figure 10: Layout of pipelines and other features around the Upper Reservoir

A GdV performance update through the end of December 2016 will be published in the New Year.

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53 Responses to Latest El Hierro reservoir images

  1. Phil Jones says:

    The white pipe is surely to do with automatic measuring equipment – depth and temperature.

    • The cable in the pipe seems to be quite thick, and you wouldn’t need a thick cable to measure depth, temperature etc. I suspect it has some regulation function, but I’ve no idea what.

      • donoughshanahan says:

        I agree with Phll, looks like a cable for some sort of instrumentation. Thinking about it, I suspect it is a low-low level switch, a probe would surely be vertically mounted in the centre of the reservoir on a platform, vertically..

        The thickness of the cable is for insulation, not only for water but for the signal as well. It costs little to over thicken your cable on one cable.

        • All of the necessary switchgear would presumably already have been installed in the pump house below the UR. I’ve no idea why they should want more unless it has something to do with regulating outflow from and inflow to the UR from the island water network. I agree with Euan – this project looks more like Rube Goldberg every day.

          • donoughshanahan says:

            Roger

            It looks a pretty standard instrumentation kit to me for level measurement or the like. See them all the time mounted like this on tanks though for a pond of this size, I would have expected a vertical arrangement somewhere.

  2. jim brough says:

    What is the predicted benefit ?

    • Willem Post says:

      Jim,

      The ACTUAL benefit is a giant hole into which Europe entities are pouring money, to prove a point that may not be provable, without spending tons of more money.

      Get the government out of energy.

  3. Euan Mearns says:

    From Figure 8 it looks like the length of the poles is scaled to span the vertical height between the concrete ledges. It seems that detailed knowledge of water depth in upper reservoir has become important.

    Of course, if you wanted to fill the upper reservoir, all you have to do is to pump water into from the lower reservoir. It was supposed to be a water distribution point for the island. Now it appears to be used as a water collection point. You couldn’t make this nonsense up. The construction of that upper reservoir and everything around it looks tacky as hell.

    I’d also judge that volume of water in the system has increased. The level in lower reservoir has gone up quite a bit. When the lower reservoir is full, the system is full. There is no point in pouring water into the upper reservoir when the lower reservoir is full – there is nowhere for the water in the upper reservoir to go.

    • Roger Andrews says:

      Euan: The UR has a capacity of 385,000 cu m, so each increment between the three layers of white concrete blocks represents about 130,000 cu m. The LR has a capacity of 150,000 cu m, so each increment represents only about 50,000 cu m. Eyeballing the changes in Figures 1&2 using these numbers gives me an increase of about 1*50,000 = 50,000 cu m in the LR and a decrease of maybe 0.3*130,000 = 40,000 cu m in the UR. These numbers are the same within limits of eyeball estimation error.

  4. robertok06 says:

    How about evaporation rates of water from the different reservoirs?… must be huge at that latitude and that amount of wind…

    • Roger Andrews says:

      Roberto: Hubert Flocard estimated evaporation at about 500cu m/day in an earlier analysis. The actual amount would have been less than this because the reservoirs have been close to empty and therefore have had a small surface area. Even so we might expect that ~100,000 cu m would have evaporated over April-December. This was presumably made up by occasional trickles of input water from the Island water supply.

      • robertok06 says:

        Thanks Roger… timely and precise, as usual. 🙂

      • jacobress says:

        So they are desalinating water (at considerable cost) to feed the evaporation…
        Any idea what the total consume of water in El Hierro is?

        • singletonengineer says:

          My guess is that desalination is not avoidable. The three purposes of the completed system are domestic water supply, irrigation and electricity. Possibly a fourth, drought resistance – for which putting desalinated water into an otherwise empty reservoir seems like a good idea.

          Ideally,of course, the energy comes from wind not diesel but another comment demonstrates that the annual diesel:wind ratio is of the order of 2:1.

  5. jacobress says:

    A very interesting data would be the amount of diesel fuel used by the power plant – and a comparison of the amount used in 2015 vs. 2016.
    This data might be available in the financial statements of the power company of GdV itself.

    • Between project startup in late June 2015 and the end of November 2016 El Hierro consumed 66,320 MWh of electricity, 40,920 of which came from the Llanos Blancos diesel plant and 25,399 from GdV. The savings on diesel are therefore 25,399MWh.
      According to https://www.hydropower.org/blog/case-study-el-hierro-%E2%80%93-renewable-energy-for-remote-island-systems

      Prior to the implementation of a renewable energy system, the island relied upon imported diesel to produce 45 GWh/year via nine diesel units (13.36 MW total) located in the Llanos Blancos power station with a peak production of 7 MW. The annual diesel consumption was 40,000 barrels

      This gives a ratio of 45/40 = 1.125 barrels/MWh. Diesel savings over 17 months of operation are therefore 25,399 * 1.125 = 20,574 barrels, or an average of about 14,500 bbl/year. I don’t know what the delivered cost of a barrel of diesel to El Hierro would have been.

  6. Flocard says:

    If GdV begins to use the island’s irrigation system to get water into the upper reservoir, this means it not only injects water but also energy which may not be only wind energy: the energy used by the pumps of the irrigation system.

    If at the same time that water gets into the upper reservoir, a fraction of the electricity recorded by REE is generated by the diesel plant, this means that potentially GdV may be partly running on diesel.

    This goes against the moral contract of GdV (renewable only) and also against the real contract signed with the spanish government. which explicitly states that it should not happen.

    Even, if GdV is able to show that it later returns to the irrigation system the same amount of water it got from it via injection into the upper reservoir, to be honest (?) GdV will also have to show that it returns it in a way that balances the energetic contribution of the diesel.

    Anyhow this business of injecting water into the reservoir makes the task of understanding the energetic balance from the outside much more complicated.

    Hubert

    • Good point Hubert! Although right now the amount of power involved would be small. Something to keep an eye on nonetheless.

      • donoughshanahan says:

        There maybe some issue if the irrigated water is treated and then requires retreatment.

        Equivalent Pumping power for say 200 m3/h at 100 m head will be less than 100kW.

  7. Rainer says:

    Roger,
    thank you to sort up the raw information.
    Special figure 10 shows the surroundings of the upper storage.

  8. Mike Tomlinson says:

    Hello Roger, regarding the material used to line GdV and Barlovento, these links may be of interest. They refer to the liner used at Barlovento.

    http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.714.1394&rep=rep1&type=pdf

    http://www.renolit.com/fileadmin/renolit/waterproofing_civil_engineering/images/BARLOVEN.pdf

    The second one appears to be from a civil engineering firm which had some involvement in the construction of Barlovento.

    ATB
    Mike

    • singletonengineer says:

      Mike and Roger, it is not essential for liners to be entirely flat. Pretty, yes. Necessary, no.

      I have seen satisfactory liners with wrinkles and creases – just as long as there are no splits or tears.

      One job was a complete failure after kangaroos got in – their rear toes can slice HDPE liners like razors.

  9. singletonengineer says:

    ICOLD, the International Commission on Large Dams, was formed in 1918 and has about 90 country members. ICOLD shares information on dams, currently about 55,000 throughout the world.

    The online ICOLD register of dams is behind a paywall, but assuming that Spain is a signatory, then any dam over 15 metres high or with other safety issues, though less than 15 metres high, will be on the list.

    If my assumption about Spain being a member is correct, then it is reasonable to assume that the design, construction and operation of the Canary Islands’ dams are to international standards.

    With respect for others’ concerns, I suggest that our discussion does not need to examine dam safety.

    • it is reasonable to assume that the design, construction and operation of the Canary Islands’ dams are to international standards.

      GdV has no dams. The reservoirs occupy two pre-existing volcanic craters and water levels are well below the crater rims in all places except on the south side of the lower reservoir. How would international standards apply here?

      With respect for others’ concerns, I suggest that our discussion does not need to examine dam safety. Here on Energy Matters we are at liberty to discuss what we like provided it’s not wildly off topic and provided we keep it civil. And as far as GdV is concerned there are enough questions regarding the stability of the rock underlying the reservoirs to make it a valid topic for discussion. I just wish we had more information on it.

      • singletonengineer says:

        Hi, Roger.

        My intention is not to start an argument. Those who would like to understand Spain’s dam safety management processes will find a link at the bottom of this post.

        The simple answer to your question is that adapting existing geological features to make a water reservoir is included in the definition of a dam. ICOLD principles apply, included among which is the principle of having experienced and qualified designers and independently reviewed designs and witnessed construction, as well as periodical review of maintenance and inspection records. The “stability of the rock” should be beyond question if ICOLD processes have been followed.

        My suggestion re discussion of dam safety is based on this and the fact that there is no indication that the dam is distressed.

        It was not an attempt to say that discussion is off limits, only that it is likely to be fruitless.

        Personal explanation: I have as Site Engineer, Project Manager or Asset Manager supervised construction and maintenance of at least five large dams, including liaison with national and ICOLD representatives regarding design, construction, operation, maintenance and safety monitoring.

        The following link demonstrates that Spain is a member of ICOLD and uses identical processes to those with which I am familiar. https://www.unece.org/fileadmin/DAM/env/water/damsafety/2013_11Nov._19-20_Almaty_regional_meeting/11_20_03_Fleitz_Dam_safety_management_in_Spain_Almaty.pdf

        • singletonengineer says:

          I have read the second of two documents linked above by Mike Tomlinson. The first appears to have disappeared.

          The description of the liner is pure gold – I had not realised that the liner is almost 25 years old. The details provided indicate that much care was taken in both selection and installation of the liner. I’m somewhat surprised that the liner is as thin as it is, but then again, I’m not an expert in PVCp liners. My experience is primarily with HDPE materials. The construction details appear to be sound and the inspection regime adequate.

          The current condition of the liner, in its 25th year in service, can be assessed by records of flow records obtained at the seepage measurement weirs which are commonly installed at the discharge points of the under-membrane drains which were mentioned in the document. If these measurements are not being taken, then they certainly should be.

          Simply: if the seepage flows increase or decrease then something has changed and this should be investigated and reviewed by external experts periodically. I imagine that it would be normal practice for these flows to be monitored and recorded at least once each week.

          There may also be piezometers beneath the liner… but guessing about their presence is futile.

  10. Euan Mearns says:

    Regarding the upper reservoir, Figures 3, 4 and 5 suggest really tacky construction to me. It seems a pretty straightforward engineering challenge to build two reservoirs and to pump and flow water between them. There has to be a reason they are not doing this. And their has to be a reason that GdV are so reluctant to answer questions, and there has to be a reason that they are now piping water into the upper reservoir.

    As a working hypothesis I think failure of the reservoir floor and failure of the membrane is as good as any. Perhaps they are piping water in to keep some water in the floor of the reservoir to give the impression of normality?

    The islanders had better hope that the water does not find its way down to a magma chamber

    • Corresponds with an abrupt decrease of wind generation from around 7MW to zero while the wind at the airport was blowing at “near gale force”.

      • John F. Hultquist says:

        Large wind turbines near me do this:
        The rotor spins clockwise at 16.5 revolutions per
        minute; the turbines generate electricity at wind
        speeds as low as 9 mph, reach peak generation
        at 31 mph, and shut down at constant wind
        speeds of 56 mph

        The last is 8 m/s.
        A “near gale force” would require a shutdown, but one would have to know the sort of installed equipment to learn when and how that is done.

        • singletonengineer says:

          Precisely that response appears to have been involved in the blackout of the whole of South Australia a couple of months back, probably combined with a failure to “ride through” disturbances, whether propagated from the grid to the wind turbines or vice-versa.

          The resulting investigation has a distance to run, but AEMO is due to release its third (and final?) technical report in another couple of months.

    • With the wind coming from the SSE – the opposite of the prevailing northerly direction.

  11. Rainer says:

    2016-12-30 16:20 till 16:30 Eólica 8.5 MW the max ever??

  12. Mike Tomlinson says:

    singletonengineer: “I have read the second of two documents linked above by Mike Tomlinson. The first appears to have disappeared”

    I have a local copy, but for obvious reasons can’t republish it due to copyright. Presumably the authors have been made aware of the link on this blog and have removed it. It is headed “5th European Geosynthetics Congress. Valencia 2012” with a website link of http://www.eurogeo5.org/ and entitled “Long-term performance of the Laguna de Barlovento reservoir water-proofing using a PVC-P geomembrane”.

    It essentially concludes that there is some cracking in areas prone to flexure, but overall the liner (referred to as a geomembrane) is in good condition 19 years after installation, which is referred to in one part as “good” and in another as “excellent”.

    • Barlovento reservoir liner failure, April 2011:

      (The 2012 report) essentially concludes that there is some cracking in areas prone to flexure, but overall the liner (referred to as a geomembrane) is in good condition 19 years after installation, which is referred to in one part as “good” and in another as “excellent”.

      Are we talking about the same Barlovento reservoir?

      • singletonengineer says:

        Thanks for the continuing discussion about Barlovento. There appears to be a chicken-and-egg issue here. Did the liner system (ie drainage blanket, concrete skin and PVCp membrane) fail because the earth beneath it failed, or did the membrane fail, resulting in weakening and washing out of the supporting volcanic clays.

        Ultimately, the result is pretty much the same, but refer back to my comment regarding seepage measurement. If the liner failed first (eg through puncture or a split or a failed weld) then the seepage rates would have increased. This would have been noticeable at the outlets of the seepage drains.

        If, on the other hand, some subsidence-type failure resulted in the failure of the membrane then there is a chance that seepage flows from that location would have reduced due to having been lost underground. That reduction in seepage flow would have been able to be identified and,possibly, the dam emptied and inspected before too much harm was done.

        On the available evidence, we simply do not know, but it appears probable that those involved do know the failure mode in some detail.

        But Barlovento isn’t el Hierro. Here’s hoping that history doesn’t repeat itself.

        By the way, IMHO lining systems incorporating very thin plastic membranes have short life spans. 20 years without a failure of some kind or another would be an excellent result, even for systems which are drained and inspected regularly – say, not more than every 5th year. On a remote island and with no alternative reservoir available, this is probably not practical, so failure is ultimately inevitable. If so, then maintenance is always major and unplanned. Condition monitoring might take place along the lines that I suggested above, but actual repairs at an early stage might be deferred until hundreds of thousands of cubic metres of water has flushed through the failed section.

        Indeed, this suggests further reasons for keeping the upper dam part full. One: the value of water at risk is lower. Two: The pressure on the liner system is minimised. Three: If seepage measurement has indicated that there are problems, then it is advisable to hold the dam at a low, constant level while investigations are proceeding.

        Maybe there was cause for concern from Day 1 which resulted in the decision not to fill the upper reservoir.

        • singletonengineer says:

          Before I go, and in recognition that 2017 is a bright new year…

          Is anybody running a book on the odds of failure of the Upper Reservoir during 2017, if it is, as appears to be in train, filled during the year?

          And re the nature of the real backbone of the El Hierro power supply…

          What must the island do to stabilise the wind turbines when the liner and hence the dam and hydro system are out of service?

          Diesels, of course – just like every other day! The dams, the hydro and the wind turbines are optional extras to the essential diesels. Nice to have, but not much use by themselves.

        • Singleton: Here are a few more references on Barlovento construction and failure – mostly in Spanish but Google Translate should work if all else fails.

          https://www.google.com.mx/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwiw9uKSn6LRAhUp_4MKHdVsBNYQFggbMAA&url=http%3A%2F%2Fvzb.baw.de%2Fpublikationen%2Ftc213%2F0%2F7_290_ICSE-6_Dam%2520failure_12-08-29_R290_FRY.pdf&usg=AFQjCNHOlw6ZNDunQRkg3DfPhxgO_1L6QQ&sig2=GJaB4OsWScARNI9GonQ6ZQ

          http://www.eldiario.es/lapalmaahora/municipios/Laguna-Barlovento-mermada-capacidad-embalse_0_206830224.html

          https://www.google.com.mx/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0ahUKEwjr3d2VoaLRAhWC7IMKHZ76AYcQFgg5MAQ&url=http%3A%2F%2Finformesdelaconstruccion.revistas.csic.es%2Findex.php%2Finformesdelaconstruccion%2Farticle%2Fdownload%2F2774%2F3083&usg=AFQjCNGwDSAL9_0DbFHL_Vd4GpcowPYguA&sig2=ktLRa8cwowHbAt-1_rs6BQ

          The second reference states that the failure was caused by a small break in the liner which no one noticed but which suddenly ruptured and caused a “spectacular” flood in the valley below the reservoir. The hole through which this water escaped must have been large indeed, which doesn’t say much for the competence of the rock underlying the liner.

          And the rock below the GdV reservoirs is in all probability just as weak as the rock below Barlovento. The Barlovento and GdV reservoirs are geologically the same – recent volcanic collapse features – and are therefore likely to contain the same material. GdV reservoir capacities were in fact cut back (UR from 500,000 to 385,000m3 and LR from 250,000 to 150,000m3) during the design & construction phase, which was in progress at the time of the Barlovento failure, because of unexpectedly weak rock conditions.

          • singletonengineer says:

            Google Translate is far from perfect, but I think that I now have the picture of Barlovento.

            Barlovento
            This is not a small dam. A portion of the east side is man-made embankment 12 metres high.

            The initial proposal was to line the reservoir with 450mm of earthen material, then to apply an asphalt (bitumen) coating.

            Evidently, the PVCp membrane is an afterthought. I’m not sure of the details, but if it is akin to the GdV description, there are permeable concrete and gravel layers beneath the plastic membrane. These lead to drains and hence I stand by my comment that it should have been normal practice for the seepage flows to be monitored and any increase or decrease in flow rates investigated. Perhaps this was not done – I am not confident, based on the information in front of me, but there is a hint in the text and in one comment above that a small rip was discovered and that this subsequently became a torrent – this was presumably first detected via changes in seepage flows.

            I wouldn’t immediately conclude that the floor of the former volcano collapsed/subsided, because of the presence of 450mm blanket of fill material, which would have washed out readily once seepage velocities of the order of one foot per second were established. From that moment on, the failure would progress rapidly and there would be no practical way to stop it.

            It appears to me that the probable failure sequence was:
            1. Small defect in the membrane.
            2. Increased seepage flows not identified early enough for the reservoir to be emptied…or decision taken not to do so.
            3. Washout of the drainage material beneath the membrane and eventual collapse of the permeable concrete skin which underlies the membrane.
            4. Very rapid increase in the damaged section of liner and of the erosion path beneath the dam.

            Managers of the GdV project were correct to reduce the water level within the reservoir, but if even a tiny defect develops in the PNCp membrane, it will be only a matter of time before it suffers a similar fate.

            In my country, a commission of enquiry, possibly under the oversight of a Coroner, would gather in the construction drawings, the operation records and the dam safety inspection reports for the life of the dam(s) and, with the assistance of expert witnesses, draw a conclusion. Whether this happened in the Canary Islands, I cannot tell.

            While not entirely discounting deeper failure within the former caldera, I still believe that it is probable that a small liner failure that went unnoticed and/or unrepaired led to a washout of granular and clay materials of construction of the Barlovento Reservoir.

            Further, and especially if the GdV UR is filled,it is possible that a similar failure will occur.

            I repeat my earlier recommendation, which is that the condition of the membrane must be monitored frequently throughout the life of the reservoir.

            I add that any change in seepage rate must be investigated thoroughly and immediately.

            Further, that any unexplained change in seepage flow rates should result in the immediate emptying of the reservoir via the outlet works, in order to reduce the risk of uncontrolled damaging flow via washouts.

            Finally, that a detailed inspection of the whole of the surface of the membrane should be completed before any increase in water level is authorised. This is particularly essential if there has been no recent such inspection.

            Thank goodness that for the new diesels… it seems probable that they will be essential.

            From the Powerpoint set I referred to a couple of days back:

            Comprehensive Dam Safety Management
            Programs
             Detailed review of safety conditions of existing dams
             Review and improvement of operation and maintenance procedures
             Ongoing dam surveillance activities

            Spain has 1200 dams under the safety oversight of SPANCOLD (Spanish Commission On Large Dams)
            The same principles apply to each of them, including on islands.

          • A new theory suggests itself to me. El Hierro’s water users were originally very keen to use the UR as fresh water storage but are now afraid that a Barlovento-type failure could lead to the loss of a large fraction of the island’s supply of fresh water. Guessing again, but this could explain why the UR has never been filled to more than about a third of its capacity.

          • Phil Jones says:

            Instead of guessing, why doesn’t someone ask the Spanish authorities..? European Council Directive 2003/4/CE on public access to environmental information

            http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2003:041:0026:0032:EN:PDF

            provides, subject to some exemptions, for the disclosure of stuff like this. Every Member State is bound by such Directives. In the UK it’s been implemented via the Environmental Information Regulations 2004.

            http://www.legislation.gov.uk/uksi/2004/3391/pdfs/uksi_20043391_en.pdf

            Guidance on this subject in the UK is provided at

            https://ico.org.uk/for-organisations/guidance-index/freedom-of-information-and-environmental-information-regulations/

            There’s undoubtedly a Spanish website giving guidance on their implementation of the Directive.

  13. Rainer says:

    @Phil Jones,
    El Cabildo de Hierro and GDV do not respect teh ley de tranparencia at all

    http://www.diarioelhierro.es/t26496/ab02.asp?idweb=26496&idrg=161247

    Google translator
    “The Commissioner of Transparency resolves in favor of Podemos and asks the Cabildo of El Hierro to give information about Gorona”
    “To this end, the Commissioner has requested the Cabildo Insular to send the documentation requested by the Director within 15 business days.”

    Till now i did not find this new information……….

    • Phil Jones says:

      That suggests that someone has appealed against a refusal to disclose certain information and that the Commissioner has ruled that the information requested (whatever it was) must be disclosed – to the person who requested it (whoever that was), not necessarily published for all to see.

      So that appears to confirm that the body involved in operating the facility is indeed subject to the Directive on on public access to environmental information. In that case I’d suggest a fresh request for all the information you want to see, rather than look for the information previously requested.

    • Phil Jones says:

      PS. The report to which you provided a link shows that the disputed information request related to commercial matters (minutes of board meetings, award of contracts, etc).

      They might be more willing to disclose technical (non-commercial) information about the project itself and that’s what you’re interested in, if I understand correctly.

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