Modelling the performance and sustainability of urban vegetation as Nature-based Solutions in current and future climate
File(s)
Author(s)
Zhang, Ziyan
Type
Thesis
Abstract
Urbanization has become a concern due to a need in development for an increasing population. Climate change due to elevated global carbon emissions is predicted to increase the severity of extreme weather events, and will amplify urban-related risks such as surface flooding and urban heat island effects. Vegetation as the key component of urban Nature-based Solutions has been identified as an effective tool to provide a resilient and sustainable urban environment. However, its performance and sustainability in different countries and under climate change has not been fully understood yet.
The main aim of this PhD study is to examine and understand the performance of urban vegetation in flood control, heat mitigation and carbon sequestration across multiple major cities. To do so, I implemented the state-of-the-art ecohydrological model T&C for an urban set-up, and used and further developed urban ecohydrological model UT&C for multiple cities at a global scale.
First, I focused on London, UK, and tested the performance of urban parks and grassed swales in urban flood control with different urban drainage designs. I found a clear improvement in performance of urban parks and grassed swales in urban flood control when urban green spaces are integrated with urban drainage systems. Then, I identified the key drivers to urban heat island intensities and investigated the role of vegetation and its irrigation in heat mitigation across multiple Northern Hemispheric cities. Lastly, I designed a plausible urban street-level greening scenario supported by local rainwater harvesting (RWH) systems. I examined the long-term performance and co-benefits of urban greening and RWH under the extreme climate change scenario RCP8.5. The outcome of this thesis can provide a vital guidance on urban planning for different cities in order to reduce surface flooding, mitigate urban heat and offset urban carbon emission especially under climate change.
The main aim of this PhD study is to examine and understand the performance of urban vegetation in flood control, heat mitigation and carbon sequestration across multiple major cities. To do so, I implemented the state-of-the-art ecohydrological model T&C for an urban set-up, and used and further developed urban ecohydrological model UT&C for multiple cities at a global scale.
First, I focused on London, UK, and tested the performance of urban parks and grassed swales in urban flood control with different urban drainage designs. I found a clear improvement in performance of urban parks and grassed swales in urban flood control when urban green spaces are integrated with urban drainage systems. Then, I identified the key drivers to urban heat island intensities and investigated the role of vegetation and its irrigation in heat mitigation across multiple Northern Hemispheric cities. Lastly, I designed a plausible urban street-level greening scenario supported by local rainwater harvesting (RWH) systems. I examined the long-term performance and co-benefits of urban greening and RWH under the extreme climate change scenario RCP8.5. The outcome of this thesis can provide a vital guidance on urban planning for different cities in order to reduce surface flooding, mitigate urban heat and offset urban carbon emission especially under climate change.
Version
Open Access
Date Issued
2022-10
Date Awarded
2023-03
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Paschalis, Athanasios
Mijic, Ana
Publisher Department
Civil and Environmental Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)