The Canarias has many ravines and run-off channels which, during periods of heavy rain, can pose a serious risk of flooding. A course titled ‘Adeje and the risk of flooding: adaptation, management and sustainability’ is exploring the issue from both a theoretical and practical perspective, including a field trip that will give students the chance to see the potential dangers in situ.
The course is led by Jaime Salvador Díaz Pacheco, a professor from the Geography and History Department at the University of La Laguna. He stressed the importance of not only having emergency response plans in place through Civil Protection and other agencies, but also improving earlier stages of planning — including land use, infrastructure, and, most importantly, informing the public about what the emergency plans involve.
Events such as the 2002 flash flood in Santa Cruz de Tenerife and Tropical Storm Delta were turning points in how emergencies are handled. After these, the systems for planning and response were improved. “Having a good plan for response and recovery is vital, but the preparation stage — which is one part of those plans — is still a weak spot,” said the expert.
“That means informing the public, technical personnel, journalists, everyone, that natural hazards are a key part of ensuring sustainability in any territory. We’re still falling short when it comes to implementing the plans. That’s always a section in the documents, but it’s rarely put into practice.” He added that there are signs this message is starting to get through — for example, in September, Tenerife will host a volcanic eruption drill which will involve evacuating a residential area.
Nerea Martín Raya, a researcher from the same department and another of the course instructors, looked specifically at flood risk. She said it’s vital to improve infrastructure such as drainage, channels and anything that helps to prevent water from building up. But she also stressed the importance of non-structural measures: “We need proper coordination between different administrations, and people need to know about where they live. You’re not going to demolish every residential area that’s already built, but at the very least residents should be aware they live in a flood-prone area for instance — and know basic things like staying out of the ground floor or not going outside if there’s a heavy rain alert.”
In addition to informing the public, it’s essential that administrations work in coordination, so that each one knows its role when the time comes. This was a lesson learned during the recent floods in Valencia, where there was confusion about responsibilities — even though the region has PATRICOVA, a plan that maps all flood zones in the region and is considered a national example of good practice. It integrates all flood areas into one document — “so you don’t have 80 different plans for 80 different flood zones,” the speaker explained. “It’s the first autonomous community where all the risk assessments have been brought together into one single map,” added Díaz Pacheco. “Here, we have several — the PEINCA (Special Civil Protection and Emergency Response Plan for Flood Risk), and the Flood Risk Management Plan — and both use different maps.”
Understanding geography is essential for responding to emergencies, which is why the course has focused on the concept of a ‘cuenca’ or drainage basin — an area where all water flows to the same point. “A ravine is part of a drainage basin, and people often don’t realise that even if it’s not raining where they are, the ravine can still fill with water coming from a much larger area. The water gets funnelled into this space and in some places it can overflow,” the course director explained.
In the Canaries, the flood risk doesn’t come only from the ravines — it also stems from surface runoff and flash floods, which can happen when water flows over both urban and rural land to reach the ravine. “Problems aren’t only caused along the usual channels — which we tend to see flood when it rains — but also when there’s rainfall across the whole basin. In basins that are heavily urbanised, the issue often isn’t in the riverbed but in parts of the urban area that haven’t been properly drained or where the flood risk wasn’t taken into account,” added Nerea Martín.
The course includes a hands-on component, where students had to identify ravines that had been built over as urban development spread. “We’ve got maps from the 1960s, before the south of Tenerife was urbanised, and we’re seeing which water channels were covered over by development. These are the areas where we now see localised flooding and waterlogging.” Students are also being taught how to research historical heavy rainfall events using newspaper archives, to find out which places have flooded in the past.
