There are already almost 50 towns in the Foral Community of Navarra that have specific plans that will allow them to face future episodes of flooding and overflowing of river channels due to torrential rains.
The terrible floods last Tuesday, October 29 in the Valencian Community, with historic rainfall of 179 liters per square meter in one hour, recorded at the Turís meteorological station, force us to question how prepared Navarre is for this type of extreme events, which are increased in frequency and severity with climate change.
Navarra’s historical records do not reach the levels recorded in Levante last week, but Yes, very important rains have been recorded and, sooner or later, similar or greater rainfall will occur again.
For example, just a month ago, on September 21, a abundant and sudden storm hit the Ultzama valley about 150 liters per square meter, with a record of 64 liters per square meter in one hour. The State Meteorological Agency AEMET considers that when 60 liters of rain per square meter are exceeded in less than an hour – in Ultzama it was more than double and in Valencia, triple – we are facing episodes of torrential rain, the most intense level. of precipitation.
The residents of the towns of Auza and Eltzaburu (Ultzama City Council) were barely able to do anything; The river water overflowed and reached a meter high entering their houses. They did not remember such an extreme rain episode in this valley in the last 45 years.
The meteorological stations of the Foral Community have only recorded a total of ten episodes of torrential rain above this value since 1970. And the vast majority (7 out of 10) have occurred in this last decade, from 2011 to today. And even more intensely in the last five years: in February and September of this year.
The storms of December 9, 2021 (more than 200 l/m2 in two days) that caused flooding in the Pamplona Region, with the highest flow ever recorded for the Arga River; or two other episodes in 2019, in July and December, which caused flooding in the Tafalla area and the course of the Cidacos river, with the tragic result of two dead people.
The evolution of the data collected by the AEMET During these last 50 years in Navarra there is evidence that climate change is altering the water cycle and the repetition of extreme rain episodes with greater frequency in the Navarrese territory. Precisely, river flooding is one of the main natural risks that affect the Foral Community.
One of the most important challenges that must be faced in adapting to climate change. According to UN data, since 2000, flood-related disasters have increased by 134% across the planet compared to the previous two decades. The Government of Navarra, aware of this problem, has been working for years in different areas to protect the territory and the people who inhabit it.
The Department of Rural Development and Environment, through its new Climate Change Office, has launched this year a program of aid and subsidies of 5 million euros, intended for local entities, individuals or private entities, to undertake adaptation and flood risk prevention actions in all localities of the Foral Community, as well as the intervention in 18 bridges of provincial ownership.
Planned investments: preventive and adaptive
In addition to this innovative call, the General Directorate of the Environment previously supported the preparation of local flood risk management plans in 48 Navarrese municipalities and, through the European climate change adaptation project LIFE NAdaptahas also developed a digital early warning system to anticipate floods and the installation of 28 measuring stations in different parts of the territory to evaluate the flow of rivers in real time.
The Minister of Rural Development and Environment, José Mari Aierdi, has highlighted on numerous occasions that “the Government of Navarra has proposed to address extreme weather events not only with patches or aid to alleviate the damage once the floods have already occurred, but with preventive, adaptive and planned investments to anticipate floods, reduce their risks and do so with a perspective of environmental integration.”
It is true that, sometimes, reality exceeds all forecasts, as in the case of the July 2019 floods in Tafalla: the storm that was suddenly generated in the Sierra de Izco tripled its intensity with respect to all the forecasts and indicators that existed. More than 158.9 liters per square meter were collected in less than an hour at the Guetádar meteorological station and 95.7 l/m2 in Tafalla.
But, in general, the effects and consequences of floods can be prevented through responsible management of the river spaceearly warning systems and action, prevention and resilience plans for local populations.
In Navarre, 50 municipalities are required to have their own flood prevention planan action protocol created exclusively for the characteristics of each municipality (depending on its geography, planning or urban planning). Currently, there are already 48 city councils that have developed and approved this plan.
Many of these plans are mandatory in those localities that both the Ebro and Cantabrian Hydrographic Confederations have identified as Potential Significant Flood Risk Areasdepending on historical floods and possible effects on urban areas.
The main objective of the plan is to provide citizens with a adequate level of protection and reduce material and personal damage that could occur. Once the plans are agreed upon by the technical staff and the local authorities, they are sent to the Civil Protection Service of the Government of Navarra for review and approval.
Flood prevention and warning
The fact that these 48 municipalities have their own specific emergency plan It is a great advance in terms of prevention. A decade ago, only four or five municipalities in Navarra had these plans.
This impulse has been possible due to the update of the Special Emergency Plan of the Foral Community of Navarra that was carried out in 2018 – which regulates actions at the level of the entire community – and the push that allowed the climate change adaptation project LIFE-IP NAdapta-CC led by the General Directorate of the Environment.
“Municipal officials are becoming very actively involved in the drafting, maintenance and updating of their municipal plans; events of unusual severity such as those that occurred in Tafalla and Olite in 2019, and situations of serious illness such as those that occurred in San Adrián and Burlada in 2021, have generated a notable concern in the local authorities of Navarra”explains Luis Sanz, technical director of the public company GAN-NIK.
At the local level, after the drafting these municipal emergency plans22 town councils in the Foral Community have also approved the implementation of a digital warning tool that provides them with information in real time and specific to their locality.
One of these tools is URA, developed for the Tafalla City Council, with special attention to defining the threshold values of recorded rainfall and flow circulating through the rivers in its area. In this specific case it has up to four rain gauges in the headwater area and middle section of the Cidacos Riverwhich record data that is updated every 10 minutes.
“It is a computer tool that makes it easier for city councils to manage a flood event, indicating the steps to follow according to the level of emergency in which it is found, also sending alert messages to neighbors so that they know the state of the emergency. and allows them to improve their self-protection,” details Ana Castiella, technician in the Water Area of GAN-NIK.
Anti-flood technology
More recently, and also through the LIFE NAdapta project, an innovative digital platform has been developed for the Government of Navarra that provides a overview of possible flood episodes through a cartographic viewer, compiling information recorded in real time from more than 170 rainfall stations and circulating flow data from 70 gauging stations installed in rivers.
These data come not only from the measurement networks of the Government of Navarra, but also from the AEMET, the Ebro Hydrographic Confederation or the neighboring councils of Gipuzkoa and Álava. These and other complex functionalities provide the Government of Navarra with greater notice time.
According to data from the Intergovernmental Panel on Climate Change (IPCC), the main international body in charge of evaluating knowledge about the climate emergency, this type of flood early warning systems and other water-related hazards provide a return more than ten times greater than the investment made and can significantly reduce the risk of disasters: a 24-hour warning of the arrival of a storm can reduce the resulting damage by 30%.
“In a few years, the civil protection has evolved from a reactive vision of management from emergencies towards a more integrative and proactive concept; We have gone from mobilizing resources to respond to emergencies to completing the cycle with information actions for the population, improving knowledge of risks, alert communications and involving municipalities in the civil protection tasks that are their responsibility. competence”, details Pablo Cabañas, technician of the Civil Protection and Emergency Service of the Government of Navarra.
“Currently, measures that are not so much construction-related, but rather those more linked to the field of management, are gaining relevance; those that assume floods as a sudden, inevitable and recurring phenomenon,” explains Arantxa Ursúa, technician at the Climate Change Office of the Government of Navarra.
“New ways of acting involve recovery for the river space of a series of terrains, meanders and alluvial plains that are currently degraded or occupied by other uses or the elimination of and other types of similar obstacles,” he adds.
Regarding the prioritization of the areas in which action is taken, the middle section of the Ebro River presents frequent floods that flood large areas of land due to the low slope of the valley. In this way, after the serious floods that occurred in 2015, the then Ministry of Agriculture and Environment, the Ebro Hydrographic Confederation and the communities of La Rioja, Aragón and Navarra agreed to launch the Ebro Resilience Strategy, a plan that aims to improve response capacity of the population in the face of these episodes.
“The objective is to ensure that economic activities and population centers coexist with an Ebro River in a good state of conservation, without the inevitable floods causing significant damage,” says Arantxa Ursúa.
There is no better way to solve this problem than by preventing it. The Floods may come, but if the alarm systems work and the population knows that it is exactly what they have to do, precious lives will be saved and material damage and environmental disasters will surely also be avoided.