Floods and floods generate a atavistic fear of the destructive potential of water. More, if possible, “we have to understand that the large avenues of water are part of the nature and health of our territories, so you have to make room for rivers so that they overflow without causing damage,” explains Iñaki Alday (Zaragoza, 59 years), professor and architecture dean of the University of Tulane of New Orleans, one of the places of the world to the avant -garde against the vanguard. to be razed and with thousands of dead after the hurricane Katrina In 2005. His office has projected flood parks – who avoid the harmful effects for the population – in several Spanish cities. It serves El País by video call.
Ask. What can be done to avoid flooding?
Answer. We need a paradigm shift and face the issue of floods in a coherent way as a country. We should have a national flood plan with the criteria and solutions to apply, and that guides hydrographic confederations, autonomies, municipalities … learning from other countries.
P. For example?
R. In Holland, where they have centuries with floods and – large land won to the sea through dikes – applied the project [espacio para el agua]. In the nineties they had two very violent floods that made them rethink the strategy. Until then they protected with walls, dikes and pumping, but they saw that this was a race without end and that it was increasing the risk more and more. ‘As we are increasingly raising the level of the dikes, we have so much water that if there is a break the catastrophe will be huge,’ they thought. What they did was separate the protections and made the rivers more.
P. Could it be done in Spain?
R. After the floods of Valencia, and those in spring, we are realizing that the entire country is at risk. Climate change means increasingly violent climatic events and desertification of much of the territory. We have the water where we do not want it, floods houses, streets, factories … instead of having it in the river channels, soaking the terrain, recharging the subsoil water. And what we are doing is to send it quickly to the sea to avoid flooding, along with the mud, which is fertile soil. This does not work.
P. What would the paradigm change consist of?
R. Prepare a national water program that defines new criteria and make rooms for rivers so that they overflow without causing damage, and causing the benefits that the overflows of the rivers generate, which is to deposit the mud is fertile in those overflow sites and recharge the water table. We have to delay water in the sites where it does not hurt us. The water has to circulate slower, even not circular, because we retain it on the slopes, in the forests and that does not reach the cities.
P. As?
R. The Water Park we made in Zaragoza (2008) is an example of generating space for the river at the entrance of the city to paddle the force of the flood. We have to make room for the river in alternative paths: the Pamplona Aranzadi Park (2013), which we also design, generates a road to the river so that when it goes cap, instead of overflowing, it finds an alternative channel, water the park, leave the fertile mud, recharge the aquifer and do not flood the houses. The 2004 Rotterdam Biennial was called The flood [La inundación] And it showed hundreds of projects worldwide, but then only the Zuera river park was built, which we designed with a flood place and a flood park. We have been pioneers to understand that the rivers must be made. Rivers and people are compatible, floods can occur perfectly in our urban parks, but they must be designed so that they do not spoil the park, but improve it.
P. Will there be more projects?
R. In Barcelona we are working on the Besòs and Llobregat rivers, and also in some places in Levante. We are trying to eliminate buried laughs. In the Mediterranean area there are many dry rivers that only carry water when it rains. For years we have considered that we can take advantage of them better if we understand them. With climate change we see that these tubes are not enough to carry the water, and also move it with a huge speed and pressure that breaks everything around. You have to take them out and recover the much broader channels, which make the water circulate more slowly and infiltrate, recharge the water table and generate ecologies. This [desentubar las rieras] It is starting to do, but not at the scale and the speed it touches.
P. Should we channel the rivers?
R. No. We have to let the rivers do their job: bring water at a reasonable speed to the sea, while the ground is recharging. When we see water in a river, there is much more water circulating below. When we concrete the channel, the river that goes below is weakened and the one that goes up is stressed. These channeled rivers do not allow us to recover ecological health or that of groundwater. And when the capacity of the channel is exceeded, we do not know where to send the water, which overflows with a lot of energy and without control, and we flooded catastrophically. This is the main problem with the hard systems of channeling water.
P. How is it done to have flood plains with the urban pressure in Spain?
R. It happens throughout the world: Holland has a population density twice as much as the Spanish and huge productive lands, but they have done so. We have to look for the land to make healthy rivers compatible with crops, agricultural and livestock farms and public living spaces. What hurts the field in floods? The drags of stones, washing machines, cars … we can design ways to filter those solids and let the water between the mud that fertilizes. There is eliminating the idea that a flood is a catastrophe: it is a natural effect of river systems.
P. Will there be more?
R. In Spain we are working at the Riera de Sant Just, in Barcelona, and we have been making proposals for Burgos, Valencia, and other cities. In the world they have built many flood parks in China, and there is an important one in Thailand: Bangkok, a very dense city, has generated a giant park in the center that manages urban floods like a sponge.
P. Are metropolitan parks an opportunity to make flood plains?
R. Yes. Every time they project metropolitan forests we have to do so thinking about how we are going to handle the main resource, which is rainwater, rivers or channels. Madrid is projecting a metropolitan forest to generate a green belt and we have projected the southern section – lot 4 – the most complicated. and make a true ecological transformation of the metropolis.
P. How are you going to do?
R. One of the main zones is the recovery of the Gavia stream, which usually goes dry, and the whole landscape is of the environment, where Mercamadrid and huge landfills are. It has been a backyard and we have to turn it into a front door of the city and be a magnificent metropolitan park at the level of the country house. Instead of being a series of abused fields, to which we have spoiled the water and natural ecology system. Another area is the Manzanares river itself, for which we have planned its environmental and social restoration, including its overflows and the integration of storm water spilliers as new springs that feed the riverbed.
P. What should be the role of storm tanks, those underground deposits that retain rainwater?
R. They are one of the ways to minimize flood risks. And it is fine to do them, but they have a limited capacity and cost a lot of money. It is more important that we have good flood plains. These spaces of the future Madrid park can be flooded. And what will happen? That for a few days people will not be able to step on them, but when they have dried they will be public space again. Nature -based solutions allow us to understand how nature and rivers work, the role of trees and river vegetation, which not only clean water, but are also ecological.
P. How can new floods be avoided in Valencia?
R. We have to look that is flooded without harming. We know that more rain will fall, stronger, more violently. It will happen again, we don’t know when. The issue is that it is not a catastrophe. In New Orleans; Recently and the biggest problem was that we ran out of the Internet. The difference is that the city prepared. In Spain there will continue to be storms, but we have to prepare and make room where it suits us.
P. Would you have to tear down houses built on flooded land?
R. This is an extremely complex issue. We all want to minimize the risks, but the place where we live is part of our identity. We have two challenges: minimize climate change and adapt, that is, create flood spaces, ensure that we take advantage of water directly or storing it in the subsoil, and even adapting our buildings and houses so that the floods do not harm them. The bullring of Zuera is flooded and drained without deterioration. The Arbole Theater in the Water Park closes flooders and works like an anchored ship when the Ebro overflows. The Pamplona Agriculture Interpretation Center lets the water underneath and, if the level rises even more exceptional, it would only need cleaning without materials, electrical systems or ducts.
