Author(s): Jochen Hack

Linked Author(s): Jochen Hack

Keywords: Nature-based Solutions, urban flooding, water contamination, real wolrd lab, Costa Rica

Abstract: Nature-based Solutions (NBS) are considered promising approaches to solve a variety of socio-ecological challenges. In urban contexts, however, several limitations to their promotion and implementation exist, mostly because a high competition for space, diverging stakeholder interests and predefined grey infrastructure development pathways. This contribution presents experiences from an ongoing 5-year inter- and transdisciplinary research project related to NBS real world lab in highly urbanized watershed of the Metropolitan Area of San José, Costa Rica, with severe urban flooding and river contamination problems. The real world lab provides physical space and a socio-economic context representative for the testing of NBS. It serves for joint knowledge generation and synthesis as well as a basis for knowledge transfer and upscaling of the tested NBS. Starting with the participatory selection process of the real world lab followed by a participatory co-design approach, it was aimed for the development of context-adapted NBS prototypes and the establishment of a shared vision for transformation. The initial field work-based assessment of the potential for NBS consisted of four steps: (1) a detailed site analysis and co-design process including consultations of local community leaders, street markets, residents’ workshops, and interviews leading to an identification of suitable types of NBS, general placement locations and dimensions as well as vegetative design aspects. (2) The establishment of design criteria and placement strategies to achieve a high degree of multi-functionality. (3) The development of spatial typologies based on street network and open space characteristics allowing upscaling through replication of NBS in other areas of the watershed with similar spatial typology, i.e. implementation potential for NBS such as available space and land use patterns. And finally, (4) a spatial suitability assessment of NBS elements to reveal the specific NBS implementation potential for the real world lab. The results of this assessment allowed a detailed high-resolution hydrological modelling of the flood mitigating effect and micro climate regulating impact of NBS in this particular area. Furthermore, it enabled the identification of suitable sites and guided the implementation of four exemplary NBS prototypes to address the prevailing socio-ecological challenges of river contamination by untreated greywater discharge, urban flooding, and a general lack of green spaces. In the beginning of 2020, three prototypes for household greywater treatment of different degrees of decentralization and one prototype for stormwater storage were constructed. The performance of these prototypes is still being monitored and evaluated, however, the planning and construction process already revealed several challenges regarding the implementation of NBS in densely urbanized areas. However, the realization of NBS prototypes initiated an important learning process about implementation and maintenance challenges for a larger socio-ecological transformation (from neighborhood to the watershed level).

DOI: https://doi.org/10.3850/IAHR-39WC252171192022SS934

Year: 2022