headwaters

The image is straight out of a movie: a team of divers diving into the cold waters of the Arija reservoir to dredge more than three meters of silt accumulated in front of its floodgates. It’s not a whim, It’s the only way to remove them.: that is, the consequence of having hundreds of infrastructures that have not been thoroughly maintained for decades. But, above all, the most striking symptom of a very deep problem: the sediments are killing, at the same time, the reservoirs and the rivers. Reservoirs due to loss of capacity (Mequinenza has lost since its opening more capacity than the sum of the last three reservoirs put into operation), rivers because deltas need sediment to stay alive. The Ebro, without going any further, needs 1.2 million tons per year. And the authorities know it. In fact, since 2003, the Ebro Hydrographic Confederation has been carrying out controlled floods in the lower section of the river to mobilize sediments towards Tortosa. The problem is that each controlled flood moves about 10,000 tons; that is, two orders of magnitude below what is necessary. It’s like emptying a swimming pool with a coffee spoon. So in the last few months, something has changed. Since November 2024, the CHE began a series of measures to try to fix it. Things like extending the discharge by two days, starting it from much higher up (El Grado in Huesca and Camarasa in Lleida) and draining Ribarroja more than usual to mobilize all the possible sediments. Will it solve the problem? It’s not clear, but it doesn’t seem like it. We have to take into account that, only in the Ebro basin, there are many reservoirs and that is an inevitable brake. Calculations say that of the five million tons that were brought to the Mediterranean before the reservoirs, only between 100,000 and 200,000 now arrive. It would take around 100 floods to reach the appropriate figures. And no, we don’t have enough water for that. So? That is the big problem, seeing what we do. We must not forget that the Ebro delta supports 20,000 hectares of rice fieldstens of thousands of inhabitants and is a biosphere reserve. The loss of wetlands and their salinization have a direct impact on agriculture, fishing and tourism. Come on: the interests are crossed and they confront people hundreds of kilometers away. We are entering a new era of hydrological wars in which we are all against each other. Image | Sinto MQZ In Xataka | The Ebro is filling with brown prawns, an invasive species that we are going to find more and more on our plates.