The effects of the DANA are generating a serious environmental problem

Raúl García Hémonnet/Editor

The recent DANA that caused enormous human and material damage in the Valencian Community is generating a “very serious” environmental problem. This is one of the main conclusions of the conference 'Extreme floods: understanding why and how they occur to prevent and mitigate the catastrophe', held last week at the URJC.

The event was attended by ESCET professors Tatiana Izquierdo, Francisco Carreño and Javier Lillo.

As Francisco Carreño (External Geodynamics) points out, the idea was “to present an analysis of floods from a technical point of view, which is our role as a university, to offer knowledge to help better manage this type of situation.”

In this sense, one of the main conclusions is that the area experiences an accumulation of waste and highly polluting substances, such as those from broken-down vehicles (oils, fuels, coolants and brake fluids, among others). Substances that end up filtering into the soil, with the risk of being incorporated into the natural cycle of living beings and the food chain. “All the contamination will end up in the aquifers and groundwater, and at this point, it will be very difficult and almost impossible to apply decontamination techniques in such extensive areas,” explains Francisco Carreño.

This was the aspect that generated the most debate, in which students and teachers from the University participated, and after which it was concluded that phenomena of this type require a “transversal and interdisciplinary” solution. There is no unique solution and each situation requires a specific solution,” says Francisco Carreño, who adds that “the University has the Degree in Water Resources in which students are trained in aspects as related as hydrology, study of extreme climatic events, river dynamics, modelling of flood zones mapping and subjects related to environmental pollution,” in addition to the Master's Degree in Hydrology and Water Resources Management.

The aforementioned conclusions were reached after addressing in depth different aspects of extreme flooding with a focus on the DANA in the Valencian Community.

From a climatic point of view, an aspect that corresponded to Professor Tatiana Izquierdo (External Geodynamics), the climatic and meteorological situation that gave rise to these events was addressed and she focused on the formation process of the DANA itself in Valencia, which had some peculiar characteristics. As she explained, it was not an unprecedented situation, nor the most extreme phenomenon in terms of precipitation, but its location generated an accumulation of water in the form of surface runoff greater than what usually occurs and it overflowed.

Francisco Carreño analysed the floods in the area and in Spain as a whole from a historical point of view, making a review and an overview. “The Mediterranean arc is characterised by this type of extreme events associated with water, not only floods but also prolonged periods of drought. There are documents that report records of floods since 1321 and throughout history with situations very similar to those occurring now. What has happened now is an extraordinary event that usually occurs every 20-30 years, and that will continue to occur. The great challenge that we scientists face is to determine in advance when and where the next one will occur. In Spain we have the National System of Cartography of Flood Zones (SNCZI) with the cartography of flood zones throughout the territory made with mathematical models. If we consult this cartography, we will see that the affected areas are already perfectly identified as high risk for flooding. The situation of the event has been considerably aggravated by the high level of occupation and urbanisation in flood-prone areas.

Furthermore, Carreño has refused to blame everything that has happened on climate change, “we have the knowledge and the technical and legislative tools to deal with situations like this and considerably reduce the disasters caused and the loss of human lives, but courageous decisions and more committed efforts are required from multiple actors: scientists, technicians, legislators, managers, politicians and citizens. The planet has value in itself, and we must take care of it no matter what, by working to make environmental policies, regardless of whether there is climate change” and added that, “when a DANA occurs, what generates this type of event is the thermal contrast between the warm temperature of the sea and the cold air. The greater the contrast, the more extreme the event is; if the global temperature increases, we have warmer oceans and a greater risk of these extreme events occurring.”

Act before the damage is irreversible

The environmental impact analysis was carried out by Professor Javier Lillo (Internal Geodynamics), who explained that the contaminants will be concentrated mainly in the Albufera National Park and that this impact will have to be analysed and remedied before it becomes irreversible. In addition, the accumulation of sludge in the soil causes a sealing effect that alters the development and function of the soil, which is so important for crops and ultimately the natural environment. According to Lillo, a collection of sludge and rubbish is being carried out, which contains a large amount of contaminants, but one of the main problems is that the waste is very mixed, which makes its management very difficult. The normal thing would be to take it to landfills and controlled areas, “but the news we receive is that it is accumulating in the Barranco del Pollo itself and on land used for agriculture where there is no control,” says Francisco Carreño in reference to what was presented by Professor Javier Lillo.

A day that has allowed us to address the DANA and its effects from a multifaceted perspective that has included the environmental, water resource management and geological aspects.