«In winter, we go up one step, in summer, we go down two», in the storage of surface and underground water, in the Algarve. The phrase is by Nuno Loureiro, professor and researcher at the University of Algarve, and is confirmed by current figures, which say that March 2023 was a hot and dry month, with higher temperatures and less rain than average, but also by the of recent years, which indicate that this is increasingly the norm.
Even before the latest meteorological data for the past month were released, the Municipal Assembly of Lagos promoted a seminar dedicated to climate change, where specialists analyzed the consequences that are already there and anticipated others that will still happen, in Lagos and in the Algarve.
At the local level, currently, the most obvious consequence of climate change, in the Algarve region, but also, specifically, in Lagos, is the tendency to decrease the available water.
Nuno Loureiro analyzed the data since 1966 and realized that the trend points to «a significant decrease in precipitation», while «we have more and more problems with storage underground and on the surface».
In his intervention, in the special session of the AM in Lagos, the researcher focused a lot on the volumes stored in the Odeleite and Odelouca reservoirs, since, «in reality, they are what determine whether we have water or not» in the Algarve, given its high capacity.
«In Odelouca, the situation is absolutely dramatic. It is the worst year ever for the Odelouca dam [since its entry into operation in 2010]. Odeleite had a big increase with the rains this winter, which put it close to the average of the last five years», he summarized.
In Odelouca, the dam with the most capacity in the Algarve, there was, at the end of March, a stored volume of 38,6%, (39,1 at the end of February). Odeleite, the second largest reservoir in the Algarve, was at 56,7% of its total capacity (58,6% in February)
«We are 7% below the stored volumes we had a year ago, even with the December rains, which were a fortuitous phenomenon. In winter, we go up one step, in summer, we go down two”, concluded Nuno Loureiro.
As for the Bravura Dam, located in the municipality of Lagos and which is in the most critical situation in the whole country, it currently has 13,6% of its total storage capacity, well below the average, which is 76% , in March.
This reservoir, which «needs two years of average rainfall to fill up», is being affected by «a negative precipitation anomaly that has been more intense in that location in recent years», revealed Pedro Coelho, director of the Portuguese Environment Agency. /ARH do Algarve.
However, this is a general trend. «In 2010, annual water availability in the Algarve was around 300 cubic hectometers (hm3). At the moment, we are in the order of 150 hm3», said Nuno Loureiro.
And, without rain, there are no great alternatives for finding water – desalination and reuse of wastewater help, but do not solve the problem -, since “the Algarve is a hydrological island. We live in a system that, in hydrological terms, is isolated from the rest of the country».
In other words, as far as water resources are concerned, «we cannot knock on the door of Alentejo, or Lisbon – only if it is to ask for checks», joked the researcher and professor at UAlg.
As you can see, this is not a one-off situation. After all, the most recent Climate Bulletin of the Instituto Português do Mar e da Atmosfera (IPMA) shows that part of the Algarve and almost half of Baixo Alentejo were, at the end of March, in a situation of severe drought, returning to a scenario that has been recurrent .
“Over the last few decades, there has been a predominance of very hot temperature anomalies, with higher average temperatures and record heat, as well as below normal precipitation. There is a new climate and we have to learn to live with it», warned Ricardo Pais, from IPMA, another guest at the Lagos Municipal Assembly session.
Pedro Coelho pointed out that «six of the ten driest years in Portugal, since records exist, were after the year 2000. In the Algarve, in the last 10 years, precipitation has always been below average. Only in 2017 was it average. Since 2000, there have only been three years above average».
The seminar “Climate Changes and its influence in Lagos” also featured, as speakers, Francisco Ferreira, president of ZERO – Sustainable Terrestrial System Association, Luís Azevedo Rodrigues, executive director of the Centro de Ciência Viva de Lagos, and Vera Rosado, senior technician of the Environmental Management Technical Unit of Lagos City Council.
Francisco Ferreira warned that «we need to start doing math and making decisions quickly, to see how we can mitigate the effects».
Luís Azevedo Rodrigues, on the other hand, drew attention to the importance of good communication of science, to change the mentality of the population, in general, but particularly of decision-makers.