RESUMEN

El aumento paulatino de las zonas impermeables en muchas de nuestras ciudades contribuye al aumento de los volúmenes de escorrentía superficial que, además, llegan a la red de drenaje o directamente al medio receptor sin ningún tipo de filtro proporcionado por la vegetación. En este contexto, exacerbado por los efectos de cambio climático que en muchas zonas del planeta están determinando un drástico aumento de las intensidades máximas de lluvia, los Sistemas Urbanos de Drenaje Sostenible (SUDS) constituyen una válida alternativa para hacer frente a estas problemáticas aportando, además, una larga serie de co-beneficios a nivel ambiental y social. El objetivo del presente estudio es plantear la implantación de cubiertas verdes en una nueva urbanización de la ciudad de Zaragoza y valorar sus beneficios hidráulicos, ambientales y socioeconómicos. El análisis de los beneficios hidráulicos y ambientales se ha realizado a través del software USEPA-SWMM5 que incluye un módulo específico para cubiertas verdes, permitiendo definir sus capas principales y sus efectos a nivel de parcela y de cuenca de estudio. A nivel hidrológico, las simulaciones llevadas a cabo para eventos de lluvia extremos (periodos de retorno de 2, 5 y 10 años), indican que la reducción de las puntas del hidrograma puede estar entre 31 y 38%, mientras la reducción en términos de volúmenes de escorrentía presenta un rango entre 17 y 27%. Con respecto a las simulaciones continuas de una serie anual de lluvia, la reducción de volúmenes de escorrentía variaría aproximadamente entre el 30% y el 37% dependiendo de la tipología de cubierta verde empleada. Finalmente, con relación a los parámetros de calidad de los caudales vertidos, la reducción de contaminantes sería muy significativa variando de un 92% a un 99% en función del tipo de contaminante y tipo de cubierta.

Abstract

Different hydroclimatology researchers apply eigenvectors-based techniques to compress large volumes of information while preserving the invariant structure of the original data. This research developed a methodology applying one of these techniques, Principal Component Analysis, on the elements of variability in hydroclimatic time series, and then to identify clusters with the “k-means” method. The result is a regionalized map by variable. Finally, these maps are intersected, obtaining areas with a homogeneous hydroclimatic structure, because the variables have similarity in their variance structure. In the case study, 8 variables were evaluated for Colombia (9268 time series), obtaining as a result 26 hydroclimatic regions. Obtaining hydroclimatically homogeneous regions The progressive increment of impervious areas in many of our cities contributes to the increase of surface runoff volumes that, moreover, reach the drainage network or, directly, the receiving water bodies without any type of filter provided by the vegetation. In this context, that in several sites could be exacerbated by the effects of climate change that are determining a drastic increase of maximum rainfall intensities, Sustainable Urban Drainage Systems (SUDS) suppose a valid alternative to address these kinds of problems, and providing, at the same time, a long series of other co-benefits at environmental and social level. The objective of this study is to propose the implementation of green roofs in a new urbanization of the city of Zaragoza and assess their hydraulic, environmental and socioeconomic benefits. The analysis of the hydraulic and environmental benefits has been performed through the USEPA-SWMM5 software that includes a specific module for SUDS simulations with special regard to green roofs, allowing to define and fully characterize their main layers and to simulate their effects at local or catchment scale. The hydrological simulations carried out for extreme rainfall events (return periods of 2, 5 and 10 years), indicate that the reduction of the hydrograph peaks can be between 31 y 38%, while the reduction in terms of runoff volumes is ranged from 17 up to 27 %. Concerning the simulation of a continuous annual rainfalls’ series, the reduction in runoff volumes would vary approximately between 30% and 37% depending on the type of green roof used. Finally, regarding the water quality parameters of the sewer discharged overflows, the reduction of pollutants would be very significant, varying from 92% to 99% depending on the type of pollutant and the type of roof.
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