Addressing the Water–Energy–Food Nexus through Enhanced Green Roof Performance

Jeremy Wright,Devon Santillo,Jeremy Lytle,Kristiina Valter Mai,Luzalen Marcos

doi:10.3390/su13041972

Abstract

Urban densification and climate change are creating a multitude of issues for cities around the globe. Contributing factors include increased impervious surfaces that result in poor stormwater management, rising urban temperatures, poor air quality, and a lack of available green space. In the context of volatile weather, there are growing concerns regarding the effects of increased intense rainfalls and how they affect highly populated areas. Green roofs are becoming a stormwater management tool, occupying a growing area of urban roof space in many developed cities. In addition to the water-centric approach to the implementation of green roofs, these systems offer a multitude of benefits across the urban water–energy–food nexus. This paper provides insight to green roof systems available that can be utilized as tools to mitigate the effects of climate change in urbanized areas. A new array of green roof testing modules is presented along with research methods employed to address current issues related to food, energy and water performance optimization. Rainwater runoff after three rain events was observed to be reduced commensurate with the presence of a blue roof retention membrane in the testbed, the growing media depth and type, as well as the productive nature of the plants in the testbed. Preliminary observations indicate that more productive green roof systems may have increasingly positive benefits across the water–energy–food nexus in dense urban areas that are vulnerable to climate disruption.

Highlights

Accommodating growing populations within urbanized areas is a difficult task due to the fact that most cities have already developed the available land
Green roofs have been used as stormwater management tools in Europe for decades, with widespread implementation originating in Germany in the late 1960s [1]
A properly constructed green roofs (GR) system serves two primary functions related to stormwater management; a GR can reduce the amount of stormwater runoff through its water retention capacity, as well as delay the peak flow of runoff, alleviating the pressures on stormwater infrastructures

Summary

Introduction

Accommodating growing populations within urbanized areas is a difficult task due to the fact that most cities have already developed the available land. This creates an inherent pressure to optimize the amount of livable/usable space within a building, while still minimizing impact on the surrounding environment. GRs are considered to have multiple benefits, one of the main drivers of the implementation of green roofs is to combat stormwater. Green roofs have been used as stormwater management tools in Europe for decades, with widespread implementation originating in Germany in the late 1960s [1]. A properly constructed GR system serves two primary functions related to stormwater management; a GR can reduce the amount of stormwater runoff through its water retention capacity, as well as delay the peak flow of runoff, alleviating the pressures on stormwater infrastructures

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Conclusion