Reservoir reserves are at their best in two and a half years

BarcelonaThe heavy rains of the last few days have pushed the reservoirs of the internal basins to levels that had not been seen for a long time. Right now they are already over 40%, with nearly 275 cubic hectometres (hm).³), the best data since August 2022. A rise that has been very sudden, considering that on Friday, before the heaviest rainfall, they were still below 32%. Therefore, in just a few hours we have gained more than a month and a half of additional reserves.

The rise in reservoirs such as Sau is particularly noteworthy, which has gone from 7% to over 22%, or especially Darnius-Boadella, which has seen its reserves rise from 17% to over 30% in just a few hours. The sharp rise in this reservoir in the Empordà region suggests that the situation could soon improve for the municipalities in Alt Empordà that are still in the drought emergency phase.

The two largest reservoirs in the internal basins also show good figures: Baells is already close to 67%, while Susqueda is at 42%, for the moment with contained growth because all the water from the Ter river is being collected by Sau. La Llosa del Cavall is at 38% and Sant Ponç at 58%, while the small reservoir at Foix is completely full. The two main reservoirs in the south of the country – the most affected by the drought – are also improving, but more discreetly: Riudecanyes is already over 25% and Siurana over 10%. Considering where we come from, these are very positive figures.

The easterly wind of the last few days and the front of general and abundant rains associated with the storm Jana The events that we experienced over the weekend have caused a significant increase in the flow of the main rivers in the country, which has left images that have not been seen for a long time. The most abundant rainfall has been concentrated especially where it was most needed, in the main headwaters of the internal basins, where in some cases 150 or 200 l/m² have been exceeded throughout the episode. Very beneficial water in torrents that will continue to arrive over the next few hours and days towards the reservoirs, thus maintaining this progressive rise. An important change in trend after a generally dry winter that had accumulated a drop in reserves of about four points since the end of autumn.

It should be noted that at the high altitudes of the Pyrenees all this precipitation has been in the form of snow, with thicknesses that in some cases exceed half a metre of new snow. Of particular note is the nearly 70 centimetres that fell at the source of the Ter River, specifically in Ulldeter, located at an altitude of 2,400 in Ripollès. Therefore, in view of the thaw, all this will be more water towards the reservoirs, which suggests that the rise in reserves will be fairly continuous throughout the spring.

A good blow to the drought

The rains that fell in these first days of March and the large amount of snow in the Pyrenees leave a panorama that was unthinkable a year ago, when the reservoirs reached the minimum of this historic drought (14.41%). Therefore, we are close to tripling that fateful figure. The rains finally began to arrive last spring, and now the weather forecasts indicate that this year's meteorological spring - which includes the months of March, April and May - will be rainy.

Therefore, the spectacular rise in reserves in the last few hours has been a good blow to the historic drought that we have been dragging on for more than three years. If the long-term forecasts are met, we are facing a great opportunity to begin to see the light at the end of the tunnel. For the moment, this week the instability will continue, with new irregular showers.

Unlike a year ago, the ground is now very wet, and this means that all the rain that falls is not quickly absorbed by the vegetation and reaches the rivers that feed the reservoirs more directly. The aquifers, which were especially dry, will also gradually fill up. It should be said that not all the country is in the same situation, since there are areas – especially in the south – that continue with fairly dry ground and with a still very marked water deficit. Therefore, we continue to need more water, and in general.

The other extreme is found in the Catalan reservoirs of the Ebro Hydrographic Confederation (CHE), which are at 70%. Very good figures that are explained by the fact that in the Pyrenees of Lleida and Huesca the rainfall has been more abundant and frequent for more than a year. For example, the large Rialb reservoir is full as it has not been for a long time, which will guarantee the irrigation campaign of the Urgell canal.