Experimenting Transition to Sustainable Urban Drainage Systems—Identifying Constraints and Unintended Processes in a Tropical Highly Urbanized Watershed

Abstract

Green Infrastructure promotes the use of natural functions and processes as potential solutions to reduce negative effects derived from anthropocentric interventions such as urbanization. In cities of Latin America, for example, the need for more nature-based infrastructure is evident due to its degree of urbanization and degradation of ecosystems, as well as the alteration of the local water cycle. In this study, an experimental approach for the implementation of a prototype is presented. The prototype consists of a gray-hybrid element for first flush bio-treatment and runoff detention, adapted to the existing stormwater sewer. The experiment took place in a highly urbanized watershed located in the Metropolitan Area of Costa Rica. The characteristics of the existing infrastructure in the study area at different scales were mapped and compared using the Urban Water System Transition Framework. Subsequently, preferences related to spatial locations and technologies were identified from different local decision-makers. Those insights were adopted to identify a potential area for the implementation of the prototype. The experiment consisted of the adaptation of the local sewer to act as a temporal reservoir to reduce the effects derived from rapid generation of stormwater runoff. Unexpected events, not considered initially in the design, are reported in this study as a means to identify the necessary adaptations of the methodology. Our study shows from an experimental learning-experience that the relation between different actors advocating for such technologies influences the implementation and operation of non-conventional technologies. Furthermore, the willingness of residents to modify their urban environments was found to be associated to their own perceptions about security and vandalism occurring in green spaces. The implementation of the prototype showed that both the hydraulic performance is relevant for considering it as a success, as well as the dynamics of the adapted element with the existing urban conditions. In consequence, those aspects should be carefully considered as the design factors of engineering elements when they are related to complex socio-ecological urban systems.

Innovative Approaches to Urban Drainage System : A Review

“…In addition, cross-sectoral and cross-regional coordination is also required to achieve effective integration between drainage systems and urban infrastructure. The involvement of various parties, including city governments, environmental agencies, property developers, and local communities, is needed to align interests and resources in the development of integrated infrastructure projects (Chapa et al, 2020). Regulatory and policy aspects are also important factors in supporting the integration of drainage systems with urban infrastructure.…”

A Systematic Assessment for the Co-Design of Green Infrastructure Prototypes - A Case Study in Urban Costa Rica

“…Moreover, ensuring local participation during the planning, design, implementation and operational stages was a key principle encapsulated in the co-design idea. The prototype considered in this study resulted in retrofitting a sewer collector into a detention tank [37]. The outflow reduction in the collector was compensated by a hydraulic bypass.…”

Sistemas urbanos de drenaje sostenible (SUDS) en América Latina : ¿una solución basada en la naturaleza con criterio social?

“…Tabla 2 Escalas de trabajo de los casos de estudios analizados Finalmente, la mayoría de los estudios enfocan su pertinencia en relación con la importancia de este tipo de soluciones para el beneficio de las personas o la sociedad -especialmente en su bienestar y calidad de vida-así como la prevención del riesgo. Sin embargo, se 0bservó que solo dos estudios evidencian estudios de caso con participación ciudadana para el diseño, implementación y monitoreo de sistemas urbanos de drenaje Sostenible SUDS (Chapa et al, 2020;Miguez et al, 2019).…”

“…En ese sentido, los actores clave de los distintos niveles espaciales y socio-institucionales explicaron los conflictos más relevantes relacionados con la gestión del agua urbana, y propusieron lugares específicos para la implementación de un prototipo de SUDS. Los autores establecen que la participación e implicación de los residentes constituye la principal limitación para avanzar en la transformación hídrica, especialmente cuando la organización social es escasa, y la dependencia exclusiva de las autoridades locales pone en riesgo el éxito de este tipo de implementaciones, sugiriendo que existan redes de actores que compartan perspectivas similares (Chapa et al, 2020)…”

“…En América latina y el Caribe el paradigma de los SUDS ha empezado a desarrollarse fuertemente en la última década, como un enfoque que busca reducir impactos de la urbanización en la hidrología local mediante la integración de funciones y procesos observados en la naturaleza (Ariza et al, 2019;Chapa et al, 2020;Poleto & Tassi, 2012). Sin embargo, poco se sabe de manera integral sobre los aspectos sociales a tener en cuenta para la transición hídrica en las ciudades de Latinoamérica.…”