Blue-Green Infrastructure: Key to Sustainable Urbanization

When one thinks of an urban city, what is the first thing that comes to mind? Isn't it the well paved roads and the gleaming high towers - i.e. the very definition of grey infrastructure. For a long time, the idea of urban dwellings has been synonymous with the above image.

Although, cities and metropolitan areas are at the core of economic activities, contributing to around 60% of the world GDP, they are also the major contributors to climate change, accounting for 70% of the GHGs emissions and 60% of resource use. Given the growing consensus among experts about the complex relation between climate change and economic growth, there has been a growing realisation in international communities to actively work towards achieving sustainable development targets.

Listed 11th amongst the 17 Sustainable Development Goals established by the United Nations General Assembly in 2015 as Sustainable Cities and Communities, the main aim of this goal is “to make cities inclusive, safe, resilient and sustainable”. Goal 11 promotes inclusive and sustainable urbanisation. It encompasses investments in public transports, improving urban planning and resource management as well as implementing policies for climate adaptation and improving resilience to disasters. Particularly, target 11.6 and 11.7 aims at reducing the adverse per capita environmental impact of the cities and providing universal access to safe, inclusive and accessible, green and public spaces respectively.

The growing pace of economic growth along with commercialisation and industrialisation in India have been the driving force behind rapid urbanisation, as individuals migrate from rural to urban areas in search of better employment opportunities and to attain improved standards of living. It is estimated that by 2050, about 68% of the world population is expected to reside in urban dwellings. This means that 2 in every 3 Indians are expected to live in cities by then. Currently, most Indian cities are plagued with problems of pollution, congestion and un-equitable access to resources. Rapid urbanisation has exerted excessive pressure on fresh water supplies, sewage capacities, living environment as well as public health.

In light of these facts, there is a pressing need to change our stance around urban planning beyond the traditional grey infrastructure. Sustainable infrastructure has been identified as a crucial solution to tackle the aforementioned problems. A core component of it being

Blue-Green Infrastructure.

Although there is no universally accepted definition of Blue-Green Infrastructure there is a growing consensus among experts that it is an emerging solution for sustainable urban planning and efficient utilisation of urban space. While green infrastructure often refers to projects that include elements such as parks, green roofs, vertical and horizontal gardens, it is imperative to recognise its dependence on “blue” processes. Blue infrastructure on the other hand refers to features of urban planning which are designed to benefit both the quality and quantity of resilient provision of water supply. Therefore, the term blue-green infrastructure is an amalgamation of the above two types of infrastructure.

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Source: Integrating green and blue spaces into our cities: Making it happen, Imperial College London

Blue-green infrastructure promotes sustainable as well as resource efficient living. Taking a simple example, effective and efficient water treatment plans allow for multipurpose use of wastewater in industries and agriculture, therefore reducing excessive water wastage and depletion. The benefits of blue-green infrastructure are immense and yield cross-sectorial results across the following 3 sectors: economic, social and environmental.This type of infrastructure plays a vital role in protecting the environment, it is specially considered as a potent source of climate mitigation actions. Initiatives in this segment help to reduce pollution, lower urban temperature, and regulate local ecosystems. These in turn have an important economic impact, for example, terrace gardens promote lower temperature of building surfaces which reduces the cooling demands, in turn decreasing the demand for energy and power. Other financial and economic benefits include reduced use of important raw material and resources, pollution prevention and reduced carbon emission.

Therefore, urban planning that takes into account themes and designs from blue-green infrastructure planning provides for a feasible and effective solution for the various challenges faced by urban regions such as excessive contribution to climate change, extremely stressed water supply induced by rapid urbanisation and impervious land cover as well as the dwindling green cover in urban India.

Furthermore, SDG 11 is deeply interlinked with various other SDGs. A careful analysis of the targets of 11th SDGs highlights its role in improving not only the living conditions of urban dwellers but also its role in improving health and well being (SDG 3), provision of clean water and sanitation (SDG 6) as well as mitigation of climate change (SDG 13) making its adoption all the more vital.
 
Perhaps one of the major advantages of Blue-Green infrastructure is its applicability in the smallest of infrastructure projects such as individual buildings to large cities. Example: As depicted below, one can introduce vertical and terrace gardens in apartment complexes which apart from playing a role in reducing cooling demands of the building, also increases the water retention and recycling capabilities. Similar initiatives enacted on a larger scale across cities can then majorly improve the water level in cities while capturing airborne pollutants.

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Source: Strengthening Blue-Green Infrastructure in Our Cities

Although the concept of Blue-Green Infrastructure is relatively new, it is important that as India embarks on the journey of COVID-19 recovery with infrastructure development at its forefront, adequate policies and plans are put in place to reach the sustainable development goals by putting emphasis on Blue-Green Infrastructure. Especially with India expected to house 6 mega-cities with population above 10 million by 2030, it is important to recognise that economic and social stability of cities is hinged on the environment with efficient urban planning needed for a sustainable future.

This has been authored by Nehal Kaul and Devika Chawla.