Spain boasts of being the country with the most prey in Europe. «About 2,400, of which 1,300 are large dams, that is, they have more than 15 meters or more than a cubic hectometer of reservoir. Of them, 375 are state-owned. The rest, about 900, are concessions: 200 or so are from individuals and municipalities, that is, small concessionaires, and another 600 are in the hands of hydroelectric companies,” details Jesús Contreras, engineer of Roads, Canals and Ports, consultant for Hydraulic Works and member of the Board of Directors of the Association of Civil Engineers, Canals and Ports and Civil Engineering (AICCPIC).
The organization met this week with the Deputy Secretary of Economy of the Popular Party, Alberto Nadal, and other entities such as the Spanish Society of Dams and Reservoirs (SEPREM), etc., to analyze the state in which they are and the possible actions and investments necessary to guarantee their safety. And it is that The average life of these infrastructures exceeds 55 years. What the engineers denounce is the lack of maintenance and safety of many of the dams, if not the lack of information. Contreras alludes to a Miteco report from 2023 and to some of the data already admitted by the Ministry in the document: “The red lines of action to improve the safety of dams 2023-2033”, which concludes that 60% of state dams need to undertake safety-related actions in the near future.
«In the case of state ownership, the majority of Their dams are type A (about 292), which are those that have a risk of causing serious damage to the population. If you look at what the General Directorate itself states in its terms, it says that 60% have security deficiencies. Then he divides it into groups: 140 dams have hydrological safety problems. It means that its spillways are not capable of removing water in flood situations: 14 in normal flood situations, which occur every 20 years, and about 60 or so in extreme flood cases. They have a serious risk, because the biggest cause of dam collapse is hydrological safety. Then there are about 160 with structural safety problems; 24 large state-owned dams that do not comply with the safety coefficients with which they were designed in normal situations; another 70 in the accidental ones and another 70 in the extraordinary ones,” says the technician, who insists: “Does this mean that they are going to fall tomorrow? No. But if you have designed a structure with safety coefficients that you no longer have and you continue without acting, there will come a time when you will have a serious problem.
Third problem
Finally, it mentions the reservoirs with hydraulic safety problems. «It refers to the operation of the equipment to control the floods, floodgates and, above all, the bottom drains. The reports they manage internally are that there are about 40 dams that have them inoperative…and another 60 that do not dare to open because they do not know if they will be able to close them again.
For the association, these are more than enough reasons to be concerned and they affirm that security and maintenance today are insufficient. «There are between 30 and 40 dams that have safety problems in all three dimensions. If an event like the one a couple of years ago comes to you, there is a risk. And if it is type A, we are talking about enormous damage to the population.
In addition, the technician alerts, lack of personnel and emergency plans. «If we are playing at not maintaining them, the risk increases every year, which is what we denounce. Engineers have up to 16 dams to monitor and 75% of state-owned dams still do not have an emergency plan. If you look at the budget, what they are spending on dam maintenance, and you take the report for the year 2023, you see that 150 million of a budget of 500 have been spent on environmental projects, riverbank recovery, etc., and 16 on maintaining the dams. This is not possible, especially in areas like Levante.
What about the dealerships? The outlook for public dams is not rosy, but it is also not encouraging that what is happening in the concessionaires is not known for certain, says Contreras: “Those in the hands of hydroelectric plants are well preserved because it is in their own production interest. The rest (we are talking about about 200) are from town councils, etc. I’m not saying they are the most dangerous, but there is more uncertainty because these small owners may not have the resources to maintain them. But the important thing is that we have no information. That’s why we want there to be an independent body, which is very easy to create, and to get to work reviewing all the dams and the priority actions that need to be done,” he comments.
Juan Pedro Martín Vide, from the Department of Civil and Environmental Engineering of the Polytechnic University of Catalonia, speaks of the “existence of abandoned dams even today” and that there is concern given that “when there are two figures at play, it is easier to pass responsibility from one party to the other. That “one for another, the house without sweeping” happens and not for the public good.
Technical gap
The researcher also refers, as professional entities and NGOs have done these weeks, to the technical gaps and possible sedimentation problems that mean we have even less capacity to store water when it rains. «Then there is the issue of sedimentation. There has been negligence in the maintenance of bottom drains and now that negligence brings concerns. This is not something that has occurred in the 21st century with climate change and torrential rains, but rather it is a lack of attention from the moment of construction. On the other hand, climate change makes it necessary recalculate the drainage capacity. A large part of the dams have been built in the second half of the 20th century and were made with the information existing at that time. Therefore, it is normal that there is a concern – and there is – about reviewing the maximum flows that can be evacuated in times of torrential rains and extreme events,” says Martín Vide. We must not forget that in Spain, floods already cost 800 million euros per year on average in damages.
How much would it cost to address the problems? A recent report by the Typsa group for the Association of Infrastructure Construction Companies and Concessionaires (Seopán) says that Spain needs to mobilize 103,824 million euros in the period 2026-2035. To the adaptation and modernization of the existing dam park 4,644 million euros would be allocated and 19,180 to adaptation to climate change and to reducing the effects of flooding.
But the first thing, experts insist, is to know the state of the dams. For this, there are systems, says Martín Vide, that allow us to know if a dam is working well. «Mainly auscultation, which is having the prey monitored, its movements, because although we see a wall that does not move, in reality it moves, little by little, with the temperature, when the sun shines on it… Study all its movements and, if there are anomalous movements, then sound the alarm to lower the level of the reservoir and discover what is happening. That is auscultation: the movements that prey have. The second is the water that filters through the dams, because all dams retain water, but they also filter. Water passes through any material. That volume of water must be normal; “If it is anomalous in quantity or particle drag – that is, if clay is dragged – then the alarm must also be raised.”
The Association of Engineers also draws attention to this point since “according to the General Directorate itself, 65% of dams have obsolete monitoring. Logically. If the dam is from 1970 and you have equipped it with systems from that time, it is understood that the technology has evolved,” says Contreras.
More water stored
►The National Federation of Irrigation Communities (Fenacore) asks the Government for 100 million euros per year in investment for hydraulic infrastructure, following complaints from different Irrigation Communities about the waste of water due to recent heavy rains, which have filled the reservoirs by 10% in one week, the largest increase since 1988. Irrigators highlight that the reservoirs are releasing water, among other reasons, due to their lack of capacity, which is why it is necessary to build more dams with greater capacity. Fenacore has been demanding the construction of 27 reservoirs, which, in addition, in some cases have already been included in planning cycles prior to the current one.