Vitoria-Gasteiz has advanced in climate adaptation through the planning of Nature-Based Solutions

16/01/2025

During the second phase of the LIFE IP Urban Klima 2050 project, TECNALIA has carried out an analysis of climate threats to identify areas of the city where new actions can be developed and has also evaluated the effectiveness of specific solutions.

In response to the threats of climate change, Vitoria-Gasteiz continues to develop innovative climate change adaptation measures within the framework of the LIFE IP Urban Klima 2050 project and within action C.4.1 Nature-based solutions and their co-benefits. This action, on which advances have been made during the second phase of the project, which were approved by CINEA (European Climate, Infrastructure and Environment Executive Agency) in September 2024, includes the participation of TECNALIA, the Centre for Environmental Studies (CEA) and Vitoria-Gasteiz City Council.

Study Methodology and Approach

The analysis focuses on the city of Vitoria-Gasteiz and divides the work into four key phases:

  1. NBS cataloguing: Identification and registration of nature-based solutions (NBS) that have already been implemented or those that are in the pipeline. 
  2. Climate threat modelling: Use of advanced tools to map the main climate threats on a meso (city) scale.
  3. Design and implementation of interventions: Development of new NBS based on the modelling results.
  4. Effectiveness monitoring: Continuous evaluation of interventions to ensure their effectiveness and optimisation.

Climate threat modelling

Following the development of the NBS Catalogue of the city of Vitoria-Gasteiz by the CEA during the first phase of the project, a document compiling 79 interventions carried out in the capital of Alava, TECNALIA has advanced with the mapping of climate threats on a meso-scale in the second phase of Urban Klima 2050.  As a result, cartographic maps have been obtained regarding the analysis of the city's urban climate and heat stress, as well as the risk of flooding through surface run-off (pluvial flooding), which serve as a basis for the identification of urban areas where new interventions with NBS can be developed. To do so, the technology centre has used the 'Basque Country's High Resolution Regional Climate Change Scenarios' study carried out by Ihobe in 2019, which portrays future climatic conditions in the Basque Country in detail.

Main results

Heat stress and air quality

Simulations show that the urban morphology of Vitoria-Gasteiz significantly affects both heat stress and the dispersion of pollutants such as NOx. The neighbourhoods around the Old Town have higher temperatures in the afternoon and evening due to the lack of vegetation and continuous exposure to the sun. The implementation of NBS in these areas could mitigate urban heat, although it is crucial to accompany these measures with emission reduction strategies so as to avoid an increase in the concentration of pollutants.

Pluvial flooding

The industrial areas of Júndiz and Gamarra, as well as the Lakua-Arriaga neighbourhood, have been identified as critical points with a high risk of pluvial flooding. These areas have experienced rapid water accumulation during heavy rainfall, affecting the operability of key infrastructures. NBS, such as improved natural drainage systems, will be instrumental in reducing this vulnerability and providing additional benefits, such as improved soil and air quality.

Conclusions

The study reveals a trend towards an increase in extreme rainfall and heat waves for the period 2071-2100 under the RCP 8.5 scenario, a pessimistic scenario characterised by high levels of greenhouse gas (GHG) emissions. These extreme climate conditions could lead to flooding and high levels of heat stress, having a significant impact on the quality of life in the region and on infrastructures.

The study concludes that nature-based solutions not only improve resilience to climate change, but also bring about numerous environmental, social and economic benefits. The methodology developed is transferable to other cities facing similar climate challenges, provided that quality data and adequate resources are available for accurate modelling.

Design and implementation of interventions

Based on the results obtained in the analysis of climate threats and as a prior step to the actual implementation of the solutions, TECNALIA has identified the areas of the city in which the development of new NBS interventions is a priority. In collaboration with the CEA, it went on to carry out a prioritisation exercise based on criteria of technical and economic feasibility and timeliness of intervention within the implementation period of the LIFE Urban Klima 2050 project, resulting in the selection of two sites to carry out micro-scale modelling exercises to assess the effectiveness of diverse NBS in terms of thermal comfort and surface run-off, under climate change scenarios. These sites are the Cantón de Carnicerías in the Medieval Quarter and the playground in Luis Elejalde /Rogelia de Alvaro public school. While in the first case the solution to be adopted has not yet been decided, in the second, the proposed solution (planting of 20 new trees, increasing the green area by 585 m2 and installing a wooden deck) shows a 9% increase in the area with thermal comfort levels compatible with children's play; and a 6% increase in the volume of water retained in the ground, which contributes to less run-off.

Next steps

Immersed in the final phase of the LIFE IP Urban Klima 2050 project, the work to be carried out within the framework of this action will focus on the definition, design and implementation of greening solutions in the previously modelled Medieval Quarter. Later, the impact of this transformation on thermal comfort, biodiversity and the perception of space will also be assessed.