There are 30 centimeters left before the Montejaque ghost dam becomes a very real problem

At the beginning of the 20th century, getting light to the most remote towns in the Serranía de Ronda and Grazalema was an impossible mission. Despite “being close”, they were areas that could only be accessed with a lot of effort and any infrastructure became a logistical problem. It was at that time when the Sevillian Electricity Company decided to make a clean break: build a dam on the Gudares River and produce the energy (up to 20,000 kW) right there. They commissioned the work to a Swiss company and built an 83-meter concrete structure near Montejaque, in Malaga. Then they realized that it was tremendously stupid: the limestone soil in the area turned the reservoir into a sieve and, in the more than a hundred years since its construction, it has never been in use. Until now. Although “use” isn’t exactly the word. Because, in reality, what has happened is that, given the enormous amount of water that has fallen in the area in recent weeks, the dam has filled. Of course, this filling is relative: from the first moment the water has been filtering through the cat’s cavevery close to there. But, thanks to it, it has been possible to ‘laminate’ Gudares Avenue and control the flows. The problem is that, right now and for the first time since we have data, Montejaque is about to overflow. 30 centimeters away from it, in fact. A ghost dam filled to the brim? And draining as if there were no tomorrow: at a rate of 200 cubic meters per second. The images are not only spectacularbut (also) are completely unheard of. There were no clear precedents, but the system (using siphons, as opposed to the usual spillways) has been put into operation before it overtopped the dam. And now what? In principle, monitoring and preparation. The town councils of Jimera de Líbar and Benaoján they have evacuated 150 people and monitor both the Guadiaro riverbed and the Hundidero-Gato cave system. This dam system stands between the reservoir and the closest towns, but no one is very clear about what could happen: it is expected to collapse the possible flood, but it has never happened and the UME continues to monitor the situation for what may happen. Calm. That is the message most repeated by the authorities and, from what we know so far, it is justified. However, it shows that too often we forget what is in the bush. The Montejaque concession has already declined, but it is still there, converted into a tourist attraction. From now on it will also be the constant reminder that we have to rethink all our water infrastructures. Image | Ronnie Macdonald In Xataka | Andalusia anticipates the storm and has already canceled in-person classes and activated the UME. The doubt is placed on the workers

the margin of error is only five centimeters

If everything goes well, and that is saying a lot when it comes to the work that is taking place in northern Europe, in 2033 one of the most hyperbolic and complicated excavations on the planet will have been completed: that of the longest and deepest tunnel of the world, a work kilometer under the sea whose sides advance irremediably until they find themselves at a point whose margin of error is tiny. Engineering under the fjords. He Rogfast project represents a qualitative leap in the history of European infrastructure: we are talking about an underwater tunnel of almost 27 kilometers long and 400 meters deep that will cross the bedrock under the Norwegian fjords to connect Stavanger, Haugesund, Bergen and the intermediate communities through a continuous route without ferries. Its scale is such that it will reduce travel time between Norway’s two large western cities in forty minuteswill alter the work and logistics patterns of the entire region and will become the axis of the future E39, the great coastal highway that aims to fluidly link the south and center of the country. The most in everything. Conceived to be completed in 2033 and executed by drilling direct into solid rockRogfast will not only be the longest underwater road tunnel in the world, but also the deepest, a work that takes advantage of the experience accumulated in more than forty Norwegian underwater tunnels and demonstrates the national preference for this type of infrastructure over bridges exposed to severe weather conditions. The hidden heart of the project. At 260 meters below sea level, in a cavern carved out of living rock, two underwater roundabouts They allow the main tunnel to be connected with a branch to Kvitsøy, the smallest municipality in Norway. It is a design unprecedented: an internal cruciform that not only guarantees the connection with the island, but also acts as an operational safety valve to maintain the flow of vehicles even in the event of partial closure. The tunnel’s twin pipes function as redundancy and as a refuge: Any driver trapped by an incident can evacuate through internal exits to the other gallery, monitored by location cameras capable of guiding rescue teams with precision. This approach, which avoids exclusive dependence on a single route, responds to both the extreme geology and the Norwegian priority for safetywhich requires at least fifty meters of rock between the tunnel vault and the seabed, a distance that helps stabilize the structure against water pressure. Tunnel map No margin of error. Here comes the trickiest part, because simultaneous execution from both ends requires extraordinary topographical precision: when the two TBMs meet, they must do so with a deviation no greater than, attention, five centimetersa tolerance among the strictest in the world. To achieve this, they use rotating laser scanners capable of capturing two million points per second and creating digital twins of the tunnel, allowing ccorrect any deviation in real time. Such fine control is not a technical whim: a larger deviation would involve removing large additional volumes of rock and a significant environmental and economic cost, in addition to increasing structural risks. Added to this is a challenging environment where, at more than 300 meters deep, the tunnel is already has suffered leaks of salt water, forcing the development of new grout injection techniques to seal the rock mass and guarantee the safety of the crews. Rogfast as a key piece. The tunnel is integrated into a broader program to transform the E39 on a route without ferries, with the aim of reducing the current twenty-one hour journey between Trondheim and Kristiansand by almost half. This involves building additional bridges, tunnels and links that completely redefine mobility on the West Coast, a region historically marked by its fragmented geography. Rogfast is the most complex component of this strategy, due to its depth, length and the integration of technologies longitudinal ventilation, vents to Kvitsøy, surveillance cameras, traffic radars and real-time alert systems to manage incidents. All these elements will not only improve safety, but will also allow dynamic control of vehicle flow and rapid response to breakdowns or congestion within a closed environment at great depth. Economic impact. The project is not limited to its technical feat; its economic influence is (will be) deep and lasting. By eliminating ferries, it reduces logistics costs and expands commercial possibilities for key industries such as seafood, which will be able to reach markets more quickly. Likewise, it creates new employment opportunities during its construction and facilitates access to jobs, education and public services for communities until now isolated by geography. Reducing travel time as well will attract more tourism towards the western Norwegian landscapes, especially towards Bergen and the nearby islands, promoting an already consolidated sector. Official estimates estimate that by 2053 they will circulate daily about 13,000 vehicles through the tunnel, figures that consolidate it as a structural axis of the coastal Norway of the future. The final frontier. Although there are longer tunnels, such as the Seikan in Japan or the Channel Tunnel under the English Channel, none combine the length and depth that Rogfast will reach, which will descend to 392 meters under the seawell below the 240 meters of the Seikan or the 115 of the Canal. In this way, Norway strengthens its position as a world leader in underground engineering and in the construction of rock tunnels under bodies of water. Rogfast will become, when it opens in 2033, the maximum expression of this tradition: a gigantic infrastructure that demonstrates how a country with an impossible geography has learned to move under its own fjordsguided by technological precision, safety as a principle and the ambition to unite what nature separated. Image | ImpleniaStatens Vegvesen In Xataka | The largest hotel in the world is not in Las Vegas or Dubai. It is in Malaysia and has 7,351 rooms In Xataka | 125 kilometers of water separate 140 million inhabitants. China is going to solve it with a mega railway … Read more

Venice is an inverted forest that is sinking. There is a radical plan to save it: raise it 30 centimeters

Venice is, in essence, a prodigy of Inverted engineering: It stands on millions of stuck piles On the contrary in the Lagunar mud, creating what has been described as a submerged forest down. These trunks, made with trees, have supported for centuries the burden of stone palaces and imposing bells without resorting to steel or concrete. The physical principle that supports this system is not based on the brute force of the materials, but on the friction of compressed humid soil that, together with wood and water, constitutes a resistant tripartite structure. However, that skeleton It has a serious problem. The abyss. The mythical city lives a cruel paradox: it is not only a city that floats, but one that It sinks. In the last century, the Venetian floor has descended about 25 centimeterswhile the sea level has risen about 30. In other words: it is a lethal combination that has triggered increasingly frequent and severe floods. While its decay adds some tourist magnetism (visiting it before it disappears), for Venetians it is a persistent threat that compromises your future. The city sinks two millimeters a year due to natural subsidence, while the waters increase some Five millimeters annually due to climate change. An unpublished plan. Before this existential threat, the engineer Pietro TeatiniAssociate Professor of Hydrology and Hydraulic Engineering at the University of Padua, proposes a solution as bold as controversial: physically raise the city Injecting water into aquifers deep between 600 and 1,000 meters under the lagoon. The idea is born from the observation of gas reservoirs in the Valle del Powhere when filling during the summer, the terrain rises, and goes down when they are emptied in winter. According to Teatini, through this technique, Venice It could rise 30 centimeters In a stable and homogeneous way, enough to grant a break of about five decades, in which the authorities could plan a definitive solution. Drill and drill. The project would consist of pour a dozen wells Distributed in a circle of 10 kilometers around the city, all located inside the lagoon. Water to be injected would be saline, taking advantage of the abundant local resource and without risk of contaminating fresh water aquifers. To ensure stability, it would be injected at low pressure and slowlyavoiding fractures in the underground rock. The choice of a wide circumference guarantees a uniform elevation that would not damage historical structures. Chioggiaat the southern end of the lagoon, it would be outside the radius of action. The system that was not enough. The search for solutions also exposes a failure. Currently, Venice’s main defense against high tides is The Mose system (Sperimentale Electromeccanico Module), a series of mobile gates that rise from the seabed to isolate the Adriatic Sea lagoon. Although it began to plan in the 80s and was tested for the first time in 2020, its cost has exceeded seven billion of euros and is not yet officially operational. Originally conceived to activate five times a year, since 2020 it has already been used about 100 timesreflex of the problem. Every time it is activated, interrupts maritime traffiche harms the port (the second most active in Italy) and alters the ecological balance of the lagoon by preventing the natural flow of water. Mosetherefore, it does not solve the problem, and Teatini proposes its project as a temporary complement by extending the combined functionality of both systems during those 50 yearsmargin that could be used to develop a definitive structural solution. Venice towards the end of the seventeenth century Underground technology Theatini’s plan It is not frackingnor is it based on extreme pressures. It is rather a controlled process that has been used in oil engineering to stabilize platforms. The idea is that water gradually penetrates the deep sandy substrate, expanding and pushing the ground up without causing fissures. A maximum elevation of 30 centimeters is the technical limit that can be achieved without compromise stability. The pumping rhythm would gradually reduce to avoid overloading aquifers, and the incorporation of additives that maintain the expansion achieved even if the pumping is interrupted is studied. To prove the viability, a pilot project is proposed in another part of the lagoon, less critical, with an estimated cost of Between 30 and 40 million euros. The complete implementation would be three times cheaper than the Mose. Plus: The approach is more realistic than other ideas raised in the past, such as shallow cement injections that were used limited to islands such as Poveglia in the 70s. Race against time. No doubt, some experts are skeptical. David Dobson, professor of materials at University College London, acknowledges that the idea generates “skeptical optimism”. It warns that the aquifers already collapsed (as happened in Marghera when water was extracted in the 60s) may not recover its original volume. In addition, injecting water is more difficult than gas, as it flows more slowly and requires greater pressure. However, he argues that, if a successful essay is carried out and the process control is demonstrated, the proposal It could be truthful. In any case, he points out that the root of the problem remains Global warmingand as long as it is not addressed, any solution will necessarily be temporary. Symbol and priority. Teatini has been studying the phenomenon of the Subsidy in Venice. His Thesis with doctorate He already addressed this problem, and was his former professor, Giuseppe Gambolati, who first proposed those deep injections as a solution. Today, in the face of institutional inertia, he insists that his proposal is the only technically developed that can begin to be tested immediately. In addition, with the creation in March 2025 of the New authority per the lagoona state entity that will be in charge of evaluating interventions in the lagoon and planning the future, a window of opportunity opens. Although every plan will have high costs, Teatini argues that it is a Reasonable investment and even possible with citizen financing. The big doubt. In addition, there is the … Read more

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