The die is cast for the Tajo-Segura Transfer. If there are no setbacks, today the proposal of the Ministry on the ecological flows of the Tagus will be known –not only Aranjuez, but also Toledo and Talavera de la Reina– and the impact it will have on the aqueduct. These days a scenario has been considered based on a slight rise in this flow, from 6 cubic meters per second in force, to 7, with a reviewable character, but there is nothing certain until Minister Teresa Ribera and the Director General of Water , Teodoro Estrela, today offer the details of the Tagus plan, after the political and territorial tensions that underlie this conflict. The Government of Ximo Puig has been in the front line to counteract the position of the Executive of Castilla-La Mancha.
Never before has the Transfer faced a challenge of this caliber that will determine its future in the short and medium term, while the changes that are proposed come from the central government itself.
The starting situation is the 8.52 cubic meters per second in Aranjuez raised last year by the Tagus Hydrographic Confederation, which would lead to a reduction of 80 hectometres of transferable reserves. This would represent a reduction of 40% of the average received by irrigated land in the Levante, which is about 205 hectometres per year. If applied to total transfers (310 and supplies to the population are included), this cut would be 25%. This does not include the generating flow, an additional reserve that would have to be left in the reservoirs at the head of the Tagus to attend emergency episodes for the fauna and flora of the river.
The Segura basin still does not have enough desalination capacity to face a drastic cut in the aqueduct
Notice of more mobilizations
The Ministry has pointed out in recent months that this reference figure of 8.52 cubic meters per second is halfway between the current 6 and the more than 10 that have been raised by other groups and institutions in Castilla-La Mancha.
On the contrary, the president of the Diversion Irrigation Union, Lucas Jiménez, maintains that it is not necessary to increase this flow because the quality of the water in the section between the headwaters of the Tagus and Aranjuez is in good condition, as certified by the company itself. Confederacy. Consider next line that the flow could be even less than 6 without affecting the quality of the river. The Círculo por el Agua del Levante will resume its protests if today it warns of an unacceptable situation for the Transfer.
The Torrevieja plant needs at least two years to reach 120 hectometres, and it would not be enough either.
The reality, as has been verified in the Confederation’s gauges, is that the average of the circulating flow in Aranjuez, Toledo and Talavera is higher than the minimum levels established by law. The Confederation of the Tagus and the Ministry must apply the rulings of the Supreme Court and expressly set an ecological flow, not necessarily an increase.
For the accounts to be settled, the Ministry must take into consideration the desalinated water production capacity in the Segura basin, the price and the energy bill. This, in order to cover with desalination the possible cut in the Transfer. On this basis, the truth is that there is still not enough desalination capacity to face a drastic cut in the aqueduct.
The president of the Segura Hydrographic Confederation, Mario Urrea, stressed in this regard that to cover the current hydrological planning with guarantees, there is no desalinated water to complement or replace it. He pointed out the figure of a flow of 7 cubic meters per second in Aranjuez as the red line that should not be crossed in order not to put “at risk an important part of the Murcian irrigation production, associated with the volumes of the headwaters of the Tagus.” Urrea clarifies that its powers are limited to the Segura demarcation.
How much can be desalinated?
The CHS Report on the 2021-2027 planning cycle indicates that there are currently 13 seawater desalination plants of different sizes, with a maximum production capacity of 339 hectometres per year for supplies and irrigation (the total demands of the basin are 1,834 hectometres). The effective production of the year 2017 was 228, of which 156 were for irrigation. It is increasing because 40 more hectometres of Torrevieja will be added. Lucas Jiménez warns that desalinated flows are already discounted, since they are assigned or about to be. In this sense, it highlights that the cut that may occur in the Transfer is not covered with extra desalination.
How much can desalination grow? The Águilas and Valdelentisco plants may increase their production, although the main project is the expansion of the Torrevieja desalination plant, the largest in Europe, from 80 to 120 hectometres. This will take at least two years. The expansion project is being drawn up, to tender the works at the beginning of next year. The execution period will be one and a half years. Knowing how complex it is to start a desalination plant, the time to reach 120 hectometres can be longer.
CHS says more water should be shipped if aquifers close
The Segura basin faces another important challenge for the year 2027, the deadline to meet the environmental objectives of the EU Framework Directive on good water status, which directly affects overexploited aquifers, which would have to be closed, although there could be exemptions. In the worst case scenario, the CHS points out that to counteract the decrease in underground flows «the resources from the Tajo-Segura Transfer should exceed 380 hectometres every year, with an individual annual minimum of 100 hm3 / year for supply and 280 hm3 / year for irrigation (now there are 205) ». In other words, far from cutting the Transfer by 80 hectometres, it should be increased by 75.