Malaga would need another 200m euros spent on works to deal with a downpour on the scale of Valencia

It is almost impossible to safely drain away some 630mm of rain in 24 hours, which was the peak of the deluge during the 'Dana' storm in Valencia. That is the amount it rains in Malaga province in a whole year of good rainfall. Zero risk, if such a thing really exists, requires infinite investment. Still, it is always possible to minimise the impact of sudden, heavy rain and to ask ourselves what would have happened in Malaga during a similar occurrence.

SUR has already consulted several experts this week and Malaga city's mayor himself, Francisco de la Torre, has commissioned a technical simulation of such a weather event. As a starting point, what is clear is that Malaga city and its surroundings would need at least 206 million euros of work done to cope with such an excessive downpour.

This figure is the result of adding up the pending improvements and the planned work on the tables with the different governing bodies (local, regional and national). The channelling of the Campanillas river is estimated at 100 million euros, according to sources from the Junta's department of sustainability. Then there is the completion of flood protection for the Guadalhorce river that is based on an estimate of another 36 million euros. Emasa (Malaga city's public water authority) has an investment plan that includes 43.7 million euros in work related to drainage, water-collection points and storm tanks. Lastly, there are the charges to be assumed by all the developers of the new areas in the city for the water infrastructure part of their projects, which amounts to 27 million euros.

No one can say that nothing has been done in this regard in recent decades. Since the inauguration in 1983 of El Limonero reservoir, which replaced and rendered redundant the Agujero reservoir (1907) to contain the historic and devastating floods of the Guadalmedina river that was also channelled with run-off points, several big bucks investments have been made, running into the millions. After the 1989 floods the Casasola dam, which controls the levels for the Campanillas river, was designed and inaugurated in 2000. Three years later, the same was done to channel the lower water course of the Guadalhorce. Finally, two years ago, the Junta invested 8.5 million euros in work to improve the safe containment of the Guadalhorce.

However, here we are years later and the investments already made in all these projects amounting to more than 150 million euros is still not enough. Moreover, neither the Guadalhorce nor the Campanillas rivers are safe enough should it rain as heavily as it did in Valencia last week.

So how is it that the Guadalhorce is still not safe after four reservoirs have been built along its course and tributaries (Campanillas, Turón and Guadalteba), plus channelling and further work have been completed? Theoretically, the river needs to be able to drain off more than 4,000 cubic metres per second. The flood reached a flow of 2,100 in 1969 and 1,800 in the floods of 1989. Nevertheless, we must leave room for extraordinary weather events, like a Dana storm.

At this point, the biggest issue is the MA-21 bridge near the old sugar factory, hence its popular name of the 'Azucarera' bridge. Central government's Ministry of Sustainability plans to invest 36 million euros in widening the span of this bridge. Other work to date has been completed, including a clean-up of the bridge by Malaga council, demolition of other elements no longer required and an environmental impact assessment.

For the Campanillas river the situation has improved a lot after easing the load with the Casasola reservoir at Almogía, but there is a point of conflict at the confluence of the river with the Los Pilones stream, which in turn flows into the El Tomillar mini-dam, which acts as a regulating reservoir. During Storm Gloria in 2020 Casasola gained 4 hm³ and the floodgates did not have to be opened. It would have been fatal if opened.

Years later, no progress has been made on this issue. The only actions taken have been small-scale improvements supported by Malaga city council in certain streets such as Calle Adonis. However, a group of developers, in order to speed up planning approval procedures, have contracted some preliminary studies into channelling the river with the help of the architectural studio of Ángel Asenjo. In addition to the safety of residents who live nearby, thousands of homes depend on the unblocking of this area as a flood zone. In this case, the regional government has decided that it is not a work to be declared as being of regional interest, but it would be willing to collaborate in certain phases. For the time being, there is only a budget for this first phase.