Friday, March 29

Castrovido, the cursed reservoir of Burgos that accumulates 20 years of delay and whose filling is unfeasible due to a leak


It arose as a project to regulate the flooding of the Arlanza River in its upper part, about 19 kilometers from where it starts, in Fuente Sanza. The Castrovido reservoir, located on one side of the CL-117 between Palacios de la Sierra and Castrillo de la Reina, in Burgos, was called to stop the floods that affected beyond Salas de los Infantes and serve as a reserve for uses agricultural. 20 years after the start of the project –although the first machines started working in 2004– there is no clear date for it to be 100% available. And the newly found problem, despite the years of the project, is that when filling it, it has been discovered that it loses water through an undetected sink and that it affects its capacity.

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As explained by the Duero Hydrographic Confederation (CHD), the detection of the leak occurred during the filling of the dam, which began last year: “During the loading phase, within the inspection work carried out during the first In the filling phase, without prior knowledge of it, the existence of a sink was detected, located upstream of the dam and in an area not yet covered by the waters”.

This problem is added to the fact that the 2021-2022 hydrological year, which ends on the last day of September, is being extremely dry. Initially, the filling was scheduled to take place over two years, starting in June 2021. With the low water in the Duero basin, the water reserve is at 30% of its capacity, 14.3 points less than a year ago. year. All of this, as the CHD points out, means that the Castrovido dam does not receive the necessary contributions and does not go at the expected rate. Another new delay.

This unexpected sinkhole –and undetected in two decades of project– has paralyzed the second loading phase of the dam, which is considered the main reservoir, with the largest storage capacity. The first stage was reached in December 2021 and represents only 11% of the total water capacity that it is capable of holding, with a volume close to four cubic hectometres. Since the middle of the year that it was detected, Castrovido has been waiting for a new patch to address the problems that arise during its construction.

This type of water leak in the reservoirs can be common, according to sources consulted by this newspaper, and is due to the fact that sometimes the studies do not take into account the weight exerted by the water itself, which is why these fissures can appear. They have also explained that, depending on the composition of the soil, this liquid tends to seek a natural escape, hence the existence of these cavities. What is not understood is that it has been detected now and not at an earlier stage.

The procedure for detecting this type of sink, as detailed by the Ministry of Ecological Transition, has been carried out during the inspection of the areas of the reservoir vessel that will remain submerged “in order to verify adequate behavior of the whole”. Prior to the next stage of filling, and as a result of that revision of the reservoir vessel carried out in greater depth, the existence of a sink was detected in the bed of the Vaquerizas stream (tributary of the Arlanza river on its right bank, which carries water intermittently ), in an area that will be flooded by the Castrovido reservoir once it is filled.

The large area that the Castrovido reservoir occupies and the small size of this sink mean that its detection did not occur in the early stages and is now, with the detailed inspection of the areas of the reservoir that will remain submerged in each stage of partial filling, when its existence has been discovered and it is going to be sealed.

Currently, as the CHD has defended, there is a project drafted that is in the processing phase. This intervention has not yet materialized on the ground and what is being done is work to clear the vegetation of the reservoir vessel. The plants have grown, as expected, after being eliminated during the construction phase and now they are preparing to clean this area to improve the possible conditions for the filling. The Ministry has defended that “the data and technical documents prepared in this regard are currently being evaluated”, with the aim of defining “the most appropriate treatment for sealing said sink, whose design will take shape through the drafting of the corresponding definitive execution project, which will give rise to the contracting, immediately, of the required actions”.

A history full of controversy

The Castrovido reservoir has already been a conflict since before the first stones were laid. The affected towns, with Palacios de la Sierra at the head, were always opposed even before the first plans were approved. In 1996 the people were up in arms against the project and this was demonstrated in the Vuelta a Burgos, also to Miguel Induráin, through banners opposing the work. Organized on the platform ‘Salvemos el Arlanza’ and with the mayor of Palacios at the time, Félix Llorente, they protested in Burgos and even planted themselves in the Ministry of the Environment at the time to make their demands known, which were barely taken into account.



For the ex-regidor, in statements collected by the newspaper El País in 1997, the reservoir was going to suppose an economic and environmental affectation to the entire region since, at least in the initial project, the tail of the reservoir was going to flood 100 hectares of the fertile plain of the municipality, dedicated to cattle ranching and the exploitation of its forests, from where 100,000 cubic meters of wood were extracted per year. If the dam is executed, Llorente affirmed, the dry climate that prevailed in the valley will be modified.

Various environmental organizations, such as Ecologists in Action, were also opposed and scientific articles were published that exposed the project. in post New Water Culture, in the report: Castrovido dam conflict: the defense of one of the last living rivers in Burgosits authors pointed out: “The headwaters of the Arlanza is the only fluvial section of a certain value that remains in the province of Burgos, and one of the few in inland Spain that still conserves a good part of its primitive natural value”.

In its conclusions, this report states that the reason for its construction is that the work is understood in terms of political logic. “The legitimate aspirations that were born in the lower basin of the Arlanza at the beginning of the century have been until today an important asset that all political parties have played to win votes in those populations.” Another reason, as they denounce, “would be the pressure from the construction and hydroelectric lobbies for the large profits they would obtain with the execution of the dam.” The text concludes by reflecting on the agony of the rural world “as a result of traditional policies that in general have never concerned themselves with the people” and point out that with the investment of 40,000 million pesetas -240.4 million euros at the exchange rate- that was going to be done, in the Arlanza region “an enormous number of initiatives” could have been carried out to generate in it “the illusion of development, services, quality of life or, simply, a sweet agony”.

Between the end of the 20th century and the beginning of the 21st, the Castrovido dam has finally taken shape despite the protests. The project to create a reservoir in the upper section of the Arlanza was not new and dated from the beginning of the last century, during the dictatorship of Primo de Rivera. So the object of the construction was the same as that given by the CHD: to put an end to the overflows of the Arlanza, something that according to the entity itself has already begun to be noticed, although the dam is not 100% operational. The germ of the dam put the small municipality of Retuerta, downstream from the current location, as a location, but its approach was lengthened over time given the opposition of the residents of the area and the change in water policies. Unanimously, without taking into account the locals of the Sierra de la Demanda, or ecologists, or experts, the place indicated was the place known as ‘Los Vados’; where before all kinds of cattle grazed, now the water was going to flood the area.



The project was very slow from the beginning and took time to materialize. First, beyond the initial location changes, between the 80s and 90s it began to be conceived and it was not until the year 2000 when the Ministry of the Environment approved it. It takes another four more years to lay the first stone and it is estimated that the works will continue until 2007. Three years of construction that have lasted until the end of 2020, when it was considered finished and the tasks began to start preparing the fill.

That idea of ​​a Castrovido dam, kneaded by so many hands for so long, was on its way to becoming real. With numerous modifications, the initial plan had little or nothing to do with the current one due to the constant changes: at first it had a budget of 75 million to be later expanded to 100 million. Perhaps one of the most significant modifications occurred in 2010, when the Government authorized the modification of the execution contract to change to redefine the foundation of the dam in order to increase safety. This action meant an increase of more than 95 million euros in the cost of construction. The constant increase in the budget, up to more than 250 million, gives a sample of all the alterations suffered.

The main purpose of the construction of this dam is to regulate the Arlanza River, a tributary of the Pisuerga, by generating a reservoir with a storage capacity of 44 cubic hectometres and an area of ​​214 hectares, equivalent to 212 medium-sized soccer fields. In addition, although it does not produce energy, it is classified by the CHD as dams with the possibility of being used for hydroelectric purposes, a possibility that was in eliminated projects.

Four employees killed and two seriously injured

During the construction of the dam, in 2011, a tragic event occurred. Three men and a woman died after being crushed by a concrete chute that passed over them. In addition, two other people were seriously injured. In 2019, the Criminal Court 3 of Burgos acquitted the two defendants for the work accident, the magistrate understood that the passage of the concrete tank over the workers was the only way to build a dam. The ruling estimated that the accident was caused by the breakdown of the structure. The company responsible for the construction paralyzed the works after the accident until in 2013 its resumption was authorized and it had to pay. For its part, the Labor Inspectorate fined the winning company 163,956 euros on the understanding that it incurred a very serious infraction due to deficient prevention measures.

After returning to work, several dates were set for the completion of the work. In March 2012 there were “at least two years or even three years” left, according to the president of the Duero Hydrographic Confederation at the time, José Valín. At the end of 2018, for the president of the CHD, Cristina Danés, the work was 98% complete and all that remained was to be finished. The previous head of the institution set the beginning of the filling at the end of the year and the beginning of 2019. The process could not begin until June 2021 to conclude in December 2021. It remains to be seen how long it will take to finally see a reservoir at full capacity that, as many elderly people in the Pinares region commented sarcastically and sadly, “my eyes do not They will see it finished.”



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