Enhancing Blue-Green Infrastructures for Flood and Water Stress Management: A Case Study of Chennai

The urban water system has been severely affected across the globe in the recent decades due to rampant urbanisation, industrialisation and climate change. Many cities in India have witnessed a rise in the frequency of urban flooding as well as water scarcity. Chennai, the fourth largest metropolitan city lying on the southeast coast of India and the capital of the state of Tamil Nadu, is severely facing both flooding and water scarcity. In 2015, the city suffered the most disastrous flood in a century. More than 400 human casualties were reported; about USD 80,000 million loss were estimated and about 2 million people were very badly affected. While four years later in June 2019, the city was surprisingly hit by ‘Day Zero’ and all of its major reservoirs ran dry. With the rapid urbanisation, the blue and green spaces of the city have been drastically decreased. This paper focuses on the roots of flooding and water scarcity issues of the city. The paper further explores ‘Blue-Green Infrastructure’ (BGI) approach to integrate flood management along with water crisis management as an innovative, sustainable and nature-based solution. The paper also explores the emerging concept of BGI and analyses the existing plans and research projects in some major global cities and further, the possibility of their implementation in India. It is observed that adaptation of BGI measures (wetlands, lakes, ponds, rivers, swales, rain gardens, parks, green roofs etc.) minimises the flood risks as well as water stress including other urban ecosystem services (UES) to derive multiple benefits regarding ecological, socio-economic and overall urban well-being.