STUDY ON SUSTAINABLE DRAINAGE SYSTEM (SUDS) IMPLEMENTATION, WATER ROUTING, AND PURIFICATION FOR THE MUNICIPALITY OF LEGAZPI, AND DEVELOPMENT OF CONCRETE ACTION

Thematic sectors:

Water resources

Urban planning

Political sectors EU:

Water resource management, urban

Geographic characterisation - Biogeographic region:

Atlantic

Project duration:

2018 - 2019

Adaptation initiative typology:

Green or based on ecosystem services

Type of climate impact:

Floods

Storms

Description of the case study

Within the framework of the project, a study on sustainable drainage system implementation, water routing, and purification was carried out for the municipality of Legazpi.
In addition, two concrete actions were carried out:
» A SUDS was designed for a school yard in Latxartegi that also included other natural elements. The SUDS installed is able to recover rainwater and return it to the aquifer below the municipality.
» The one developed for Laubide consists of the construction of a green roof. In addition to obtaining a new covered space, the hope is to slightly mitigate the effect of climate change thanks to the plants on the top part of the roof. Also, an underground rainwater collection tank was built, used to water plants in dry periods using the same water collected from the roof. Together with the deposit, a SUDS system was implemented to avoid overloading the public rainwater drainage network.

Challenges :

Study on implementing urban SUDS and implementing two concrete projects.

Objectives :

The sustainable drainage systems are installed to restore the natural rainwater cycle conditions that existed before urban development work, achieving a routing and purification process.
The main aim of this study is to analyse the possibilities available in Legazpi to implement Sustainable Urban Drainage Systems (SUDS) and implement two concrete projects.

Solutions :

1. PHASE: ASSESSMENT
In this first phase of the study, a detailed study of the municipality area was carried out (permeability, types of soils, potentially contaminated surface areas, etc.).
2. PHASE: PRIORITISATION
Prioritised valuation and zoning was carried out on the areas of the municipality that could be improved by implementing infiltration, routing, and purification processes.
3. PHASE: STANDARD INTERVENTION TECHNICAL PROPOSAL
In this third phase of the study, actions were developed that could be applied to future remodelling in the municipality.
4. PHASE: ENVIRONMENTAL POLICY IMPLEMENTATION PROPOSAL
Developing actions for sharing, education, and communication. Lastly, the potential of local taxation promoting environmental improvements was analysed.
5. PHASE: EXECUTING A CONCRETE ACTION
A concrete action was carried out in Latxartegi and a project was designed for the construction of a green roof in Laubide.

Importance and relevance of the adaptation :

Case study developed and implemented as a climate change adaptation measure.

Key words :

Sustainable drainage systems

adaptation

resilience.

Region and / or city:

Basque Country

Countries involved:

Spain

Geographical governance level :

Regional

Organisations involved :

The agents involved directly have been: » The Municipal Council of Legazpi (promoter of the study)
» The Krblan SL and Endara ingenieros SL companies (consultants that carried out the study)
» Gipuzkoako Urak for the assessment of the current systems.
» The Agenda 21 Forum, with which the city council’s priorities were compared.

Additional Information

Stakeholder participation :

Two sessions at the Agenda 21 Forum were dedicated to debating and reaching an agreement with neighbourhood residents:
» 25 September
» 15 November

Success and limiting factors :

Barriers:
» The need for increased knowledge on new techniques.
» A lack of awareness about the results that can actually be achieved.
Success factors:
» Expert advice
» Public participation

Cost-benefit analysis :

Study: €21,595 (VAT included)
As a result of implementing the study’s first actions, the following costs were also incurred:
» Labour in Latxartegi: This cost is not itemised. It is part of the overall children’s park renovation work.
» Construction work on the green roof for the Laubide children’s park:
€159,419.70 (VAT included).

Legal aspects :

Town strategy: the project falls within the municipality of Legazpi’s Klima 2030 strategy. In addition, it is adapted to the development of the municipal ordinance to fight against climate change.
Gipuzkoa Strategy: the project falls within the Gipuzkoa 2050 Strategy to Fight Climate Change.
Basque Autonomous Community strategies:
» The 2020 BAC environmental framework programme.
» The Basque Country Klima 2050 Strategy
» The Basque Declaration
European strategies: the project is aligned with the European Climate Change Adaptation Strategy.

Implementation period :

2018 - 2019 (1 year - completed)