Making Chennai climate-resilient: The Water as Leverage initiative

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With nearly 70% of water being contaminated, India is placed at 120th amongst 122 countries. The water quality index according to Niti Aayogs composite water resources management report (2019), which highlights the extreme water stress situation that a majority of the population currently faces.

The flooding event in 2015 and drought this year has brought international attention to Chennai. Known as the ‘City of 1000 tanks’, Chennai now stands out as having the lowest per capita availability of water among the major metropolitan areas in India. The current situation is that trains of water are brought in, Chennai’s water infrastructure has run dry. It is very difficult to see a city where water is an integral part of the culture (temple tanks exhibit the importance of water bodies), turn into a city where tapped water supply has become a dream.

In Henk Ovink’s words ‘the connecting and interdependent strength of water provides us with an opportunity that cannot be ignored: water can be used as leverage for impactful and catalytic change’.

Water as leverage aims to be the catalyst for change so that the approach is widely adopted by cities all over the world, generating multiple, bankable projects to make cities resilient as climate extremes come to fore.

 

Water being distributed via tankers (Source: Karnan, IRCS)

 

 

 

 

 

 

 

Water Systems in Chennai

Chennai’s topography is flat with gentle slopes the highest elevation being 6 meters. Three rivers cut across the city: the Cooum River in the middle, the Adyar River in the south and the Kosasthalaiyar River that flows through the northern industrial fringes of the city. The Buckingham canal with a length of 700 km cuts across these three rivers. Chennai’s rivers are small and mostly stagnant, carrying too little fresh water to serve as water supply for the city. The water in the city moves from the gentle slopes upstream, to the rivers and canals and then to the large wetland areas parallel to the coast. The short span of the rivers with limited water, leads to siltation before reaching the coast. It is only during the monsoons when the system is flooded that the rivers connect with the sea.

Growing pains

Chennai houses some of the largest wetland systems in South India, and till the 1980’s, 80% of the city was covered by wetlands. Now that number has reduced to 15%. Historically, the wetlands were important in providing Chennai with water during drought periods, but this function has been lost to urban expansion. The wetlands in the city are surrounded by areas where economic development is rampant and the pressure to build on them is enormous. Recent development such as the boom in the IT industry and construction of the MGR highway, all cut across the wetlands altering the water systems of Chennai. The Pallikarnai marsh, situated in the heart of Chennai has shrunk extensively (90%) owing to ever-expanding real estate, industrial development and dumping of waste. Development initiatives like the newly constructed Ennore harbour has further aggravated wetland loss. The degradation of wetlands was a significant factor for the extensive damage during the floods in 2015 with economic losses amounting to over $ 2.2 billion.

Urban expansion has defined the city, leading it to great economic heights but the infrastructure has come at a cost, altering the drainage systems, loss of wetlands and overexploitation of ground water. As bore holes dig deeper looking for water, geological layers are punctured limiting groundwater recharge. The rivers natural functions are lost and they currently serve as open sewers with heavy pollution. Flood protection measures such as embankments have further isolated the rivers in the city from its surroundings.

Source Rise Chennai

Solutions

The two multi-disciplinary design teams, City of 1,000 tanks and Rise Chennai are constituted of local and international experts with backgrounds ranging from architecture, sociology, economics, hydrology, engineering, ecology and disaster risk reduction. Over the 9-month process, the two selected design teams worked on developing solutions for Chennai’s water and climate change related problems. The stakeholder process was facilitated through local workshops and the design concepts were signed off by the Water as Leverage Advisory Board during two regional workshops in Singapore. For Chennai, they came up with some very interesting and promising solutions, which are currently being developed further to acquire funding from agencies such as AIIB (Asian Infrastructure Investment Bank) and FMO (the Netherlands entrepreneurial development bank), amongst others.

The City of 1,000 Tanks design team intends to develop a closed loop water system across the city (Chitra Nagar, Mylapore, Koyembedu and Mambalam) by collecting rainwater, treating wastewater and runoff pollution with decentralized Nature-Based Solutions (such as constructed wetlands), and recharging both to the underground aquifer. The closed loop water system will aim to prevent droughts support ground water recharge, reduce pollution and mitigate flood risk. With over 50% of the city currently using groundwater to match its need, the groundwater recharge component of the design is quite critical. The design approach is complemented by a governance model where the intent is to create a governance structure to maintain the prototypes.

Closed water loop system: Source City of 1000 tanks

The Rise Chennai team uses a watershed approach, to build scalable models prototyped on two locations, these proposals address the city’s challenges in dealing with water, and use improvements to the water system for wellbeing and offer coastal protection. The prototype for Mambalam canal will be increasing the floor space index and creating permeable surfaces to allow infiltration. The designs aim to improve the resilience of Chennai’s water network by opening up and redesigning the canal profile, its bridges and surrounding urban developments; mitigating flood risk, improving water quality, groundwater recharge, waste management and reducing water use.

The current situation of Mambalam and an artist’s rendering of Mambalam. Credits: Rise Chennai and Cynthia Van Elk

On the Muttukadu coast, the design team aims at reconnecting fishery-based livelihoods with economic opportunities that are tied to the revitalization of green and blue infrastructures. It adopts water harvesting measures in order to close the water cycle locally. Further, to address coastal erosion and future sea level rise, nature-based sand nourishments will protect the coast near the basin’s mouth. The project will also look at developing alternate transport networks such as water taxis on the Buckingham canal.

Muttukadu Coast reimagination: Source Rise Chennai

Challenges

In recent times, desalination plants have received greater recognition, whereas the natural water systems, need immediate attention. Though efforts like the Coom river restoration and Pallikarnai Marsh Management plan have been initiated, but, they lack innovation in terms of integrated approaches. To move ahead the city master plan should look at economic development with greater emphasis on wetland conservation along with a network of blue and green infrastructure. The programme misses out on opportunities for landscape scale ecosystem restoration. Design proposals have limited emphasis on influencing policy specifically on integrating nature-based solutions. Natural wetlands of the city are not incorporated within the design solutions.

Partners for Resilience as knowledge partner

Partners for Resilience with Wetlands International South Asia leading the programme in India, has helped the design teams understand the community’s needs and aspirations and build in their suggestions to reflect local realities. Contributions to the process have ranged from bringing in relevant stakeholders, providing nature-based imperatives for the designs, policies, programmes and legal framework, conducting Vulnerability Capacity Assessment of community members related to water services that has been factored by the two design teams into their final proposals. Potential areas for further assistance include capacity development of communities and government officers on nature-based solutions, climate risk assessments and behavioural change as well as formulating working relationships with local authorities and contributing to knowledge development.

Wetlands International South Asia sees the Water as Leverage (WaL) initiative as an opportunity to influence the decision-making and development of water infrastructure projects in Chennai. This opportunity should lead to:

  1. Wetland conservation in the state
  2. Develop sound projects that incorporate Building with Nature, Nature-Based Solutions and Blue-Green infrastructure
  3. A multi-stakeholder process that ensures support from vulnerable communities and from provincial and district government to bring in the landscape/watershed perspective
  4. As knowledge providers support the State’s best-informed decisions on water management

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