Urban Fabrics to Eco-Friendly Blue–Green for Urban Wetland Development

In an urbanized world, the sustainability of cities will depend on their form and urban structure. In this sense, fabrics that are compact, dense, green, and suitable for non-motorized transport methods are more environmentally efficient. For the purpose of contributing new tools to the design, urban planning, and sustainability of nature in residential areas, this study characterizes the urban fabrics of six urban wetlands in the Latin American city of Concepción (Chile), which is known for its blue–green spaces. In a wetland city, we model urban patterns through spatial relationship using a statistical regression model (OLS—ordinary least squares) with the urban variables of density, distance, population, housing, highways, green areas, and building permits. Concepción shows predominantly low- to medium-density fabrics, and it is not integrated with the urban wetlands. In fact, it was observed that the residential areas do not take advantage of the blue–green spaces and that the urban fabrics do not favor proximity, with a transportation network that promotes the use of cars, leading to the wetlands being inaccessible and fragmented. However, as they are still surrounded by open spaces with abundant vegetation, there are highly feasible opportunities for the future development of blue–green infrastructure.

A New Imagination for Waste and Water in India’s Peri-Urban Interface

Cities are often seen as incubators for enterprise and innovation. However, in this urbanisation era, we seem to suffer from a lack of imagination on how to handle the many environmental problems associated with expanding cities. This is especially true in the case of the peri-urban interface (PUI), a geographical and conceptual landscape with which the city core often has a contentious relationship. In this chapter we look at the complex linkages between water and waste in the PUIs of two metropolitan cities: Bengaluru and Kolkata. We look at two water systems: Kannuru lake in Bengaluru and Kolkata’s wetlands. Kannuru is a freshwater lake that supported traditional livelihoods and subsistence use by local communities, while Kolkata’s peri-urban wetlands not only served as the city’s natural sewage treatment plant but also enabled agriculture and aquaculture. Urbanization has adversely impacted both these water systems. Kannuru lake is threatened by a landfill on its periphery, while sewage-based farming and fisheries in Kolkata’s wetlands have been impacted by changes in land use and composition of sewage. We unravel the complexity in the waste-water relationship, where waste is seen as a pollutant in one and as a nutrient in the other. We attempt to understand how we can re-envision waste and water linkages in the PUIs of expanding cities if India needs to move towards a sustainable future.

Integrating Artificial Urban Wetlands Into Communities: A Pathway to Carbon Zero?

In their natural state, wetland ecosystems provide an optimum natural environment for the sequestration and long-term storage of carbon dioxide (CO2) from the atmosphere. The loss of wetlands under advancing urbanization not only diminishes this capacity for storage, but increases methane and greenhouse gases as the land is disturbed. Nevertheless, there is growing scientific interest in using artificial or constructed wetlands as a way to mitigate the impact of global climate change, with most attention on their use for water management. Using a potential integrated urban wetland site in Glasgow as a case study, this paper critically examines how artificial urban wetlands can contribute to urban net zero targets in terms of their ability for carbon sequestration, and as part of sustainability initiatives more broadly. We find there are several barriers to implementing artificial urban wetlands for carbon drawdown alone, in particular regarding land ownership constraints, uncertainties in capture efficacy and capture quantitation, and eligibility for market-based crediting schemes. These issues make it currently challenging for the carbon reduction contribution of urban wetlands to be quantified and, say, certified to generate revenue to communities through market-based carbon crediting. However, if integrated within wider community-based sustainability initiatives, artificial urban wetlands can support multiple dimensions of sustainability, creating or supporting value far beyond water management and carbon sequestration objectives. Potential co-benefits range from areas such as health and wellbeing, biodiversity, education, food security, behavioural changes, and social care. Our findings show that for these co-benefits to be identified, maximised and realised, a place-based approach to urban wetland development must be adopted, engaging stakeholders from the project outset to define and facilitate collaboration towards shared outcomes for society, community, and environment. These findings will be relevant to any urban infrastructure development seeking to meet sustainability goals beyond carbon capture.

Urban Wetlands: A Review on Ecological and Cultural Values

Wetlands are a critical part of natural environments that offer a wide range of ecosystem services. In urban areas, wetlands contribute to the livability of cities through improving the water quality, carbon sequestration, providing habitats for wildlife species, reducing the effects of urban heat islands, and creating recreation opportunities. However, maintaining wetlands in urban areas faces many challenges, such as the reduction of hydrological functions, changed water regimes due to barriers, contamination by wastewater, habitat loss due to land-use change, and loss of biodiversity due to the entry of alien species. In this article, we review the theoretical background of wetlands in urban areas through the existing studies in the literature. We provide knowledge on urban wetlands and highlight the benefits of these wetlands in urban areas. These benefits include sustainability, biodiversity, urban heat islands, social perception, and recreation values. We also summarize the objectives, methodologies, and findings of the reviewed articles in five tables. In addition, we summarize the critical research gaps addressed in the reviewed articles. Our review study addresses the research gaps by performing a rigorous analysis to identify significant open research challenges, showing the path toward future research in the field. We further discuss and highlight the role of policymakers and stakeholders in preserving wetlands and finally present our conclusions.