Chennai’s Flood and Drought Challenges: Insights from IIT-M Professor on Sustainable Solutions – The Times of India

Report on Urban Water Management and Flood Resilience in Chennai

Introduction: Aligning with Sustainable Development Goals

Chennai faces the recurring and paradoxical challenges of severe flooding and acute water scarcity. This report, based on insights from Professor Balaji Narasimhan of IIT-M, examines the city’s water management crisis through the lens of the United Nations Sustainable Development Goals (SDGs). The analysis underscores the urgent need for integrated, sustainable solutions to build urban resilience, directly addressing SDG 6 (Clean Water and Sanitation), SDG 11 (Sustainable Cities and Communities), and SDG 13 (Climate Action).

Current Flood Risk and Technological Interventions

Forecast and Compounding Factors

The flood risk for the current season is elevated due to a confluence of factors:

• An India Meteorological Department (IMD) forecast predicting an above-normal north-east monsoon.
• Pre-existing conditions of saturated soil and full water bodies from an above-normal south-west monsoon.

Real-Time Flood Forecasting and Spatial Decision Support System (RTFF & SDSS)

In a significant step towards achieving SDG 9 (Industry, Innovation, and Infrastructure) and SDG 11.5 (reducing the impact of disasters), the state government, with World Bank funding, has implemented the RTFF & SDSS. This project, technically supervised by IIT-M, represents a state-of-the-art initiative for a major Indian metropolis. Its key features include:

1. Deployment of hundreds of real-time sensors across Chennai’s river basins.
2. Establishment of multiple flood modelling control rooms.
3. Capacity to provide early flood warnings to state agencies and stakeholders.
4. Aiding in the design of long-term flood mitigation measures.

Despite its advanced capabilities, the system’s accuracy is hampered by localized issues not captured by models, such as clogged storm water drains and localized storms missed by rain gauges.

Systemic Challenges in Urban Water Governance

Fragmented Institutional Framework

A primary obstacle to achieving integrated water management, a core tenet of SDG 6, is the fragmented governance structure in Chennai. Responsibilities are divided:

• CMWSSB: Manages water supply and sewerage.
• GCC: Manages stormwater drainage and solid waste.

This division leads to operational conflicts, infrastructure inefficiencies, and pollution of water bodies, undermining the city’s progress towards SDG 11.

International Best Practices

Models from other cities offer pathways to integrated management:

• Singapore: Its Public Utilities Board serves as a single umbrella agency for water supply, drainage, and sewage, ensuring a holistic approach.
• Seoul, South Korea: In response to rapid urbanization and increased impervious surfaces, Seoul has massively adopted Low-Impact Development (LID) and blue-green infrastructure to manage urban runoff and enhance the ecosystem, providing a clear model for achieving SDG 11.3 (inclusive and sustainable urbanization).

Strategic Recommendations for a Resilient Chennai

Policy and Planning for Sustainability

Long-term resilience requires strategic policy interventions aligned with SDG 11 and SDG 13. The foundational steps are:

1. Develop a comprehensive Drainage Master Plan for the city.
2. Conduct a thorough Flood Hazard–Risk–Vulnerability and Capacity Assessment (HRVCA).
3. Implement a long-term project roadmap based on the assessment to reduce risk and create space for waterways and aquifers.

Adoption of Low-Impact Development (LID) and Blue-Green Infrastructure

Moving beyond conventional grey infrastructure (storm water drains) is critical. A focus on blue-green infrastructure and LID measures can simultaneously address flood and drought challenges, contributing to SDG 6 and SDG 11. IIT-M is currently researching the feasibility of implementing such measures:

• Rain gardens and vegetative swales
• Green roofs
• Permeable pavements
• Infiltration trenches

Multi-Stakeholder Engagement

Achieving urban resilience is a collective responsibility, reflecting the spirit of SDG 17 (Partnerships for the Goals). Households and developers must play an active role by:

• Ensuring functional rainwater harvesting structures are in place.
• Maximizing open, porous space on plots to facilitate water infiltration.
• Adhering to building rules that limit maximum plot coverage to reduce surface runoff.

Conclusion: Embracing a Future of Adaptation and Concerted Effort

It is acknowledged that completely avoiding floods is not feasible, especially as climate change increases rainfall intensity, a direct challenge to SDG 13. Current drainage designs are being updated for higher rainfall capacities, but a paradigm shift is required. The path forward for Chennai involves orienting urban planning to its natural topography and hydrological systems. Achieving a flood- and drought-proof city is a long-term endeavor that will require a decade of concerted effort, hard decisions, and collaboration between the government, academic institutions, and the public to fully realize the vision of a sustainable and resilient urban community as outlined in the SDGs.

Analysis of Sustainable Development Goals in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

1. SDG 6: Clean Water and Sanitation
   • The article extensively discusses the management of water resources in Chennai, including issues of water supply, sewerage, stormwater drainage, water quality, and the need for integrated management. It mentions recycling treated wastewater, lake rejuvenation, and preventing pollution of water bodies, all of which are central to SDG 6.
2. SDG 9: Industry, Innovation and Infrastructure
   • The development of resilient and sustainable infrastructure is a key theme. This includes designing sustainable drainage systems (SuDS), blue-green infrastructure, and improving traditional grey infrastructure like stormwater drains (SWDs). The article also highlights innovation through the development of a state-of-the-art ‘real-time flood forecasting and spatial decision support system’ (RTFF & SDSS).
3. SDG 11: Sustainable Cities and Communities
   • This is the most prominent SDG in the article. The entire discussion revolves around making Chennai a more resilient and sustainable city by mitigating the impacts of floods and droughts. It covers sustainable urban planning, disaster risk reduction, integrated policies, and the implementation of low-impact development (LID) and blue-green infrastructure to manage urban runoff and improve water security.
4. SDG 13: Climate Action
   • The article directly links the increased flood risk to climate change, noting that “With climate change, rainfall intensity in Chennai can reach 90 mm/h.” The focus on building flood resilience, developing early warning systems, and adapting urban infrastructure to handle more intense rainfall directly addresses the need to strengthen adaptive capacity to climate-related hazards.
5. SDG 17: Partnerships for the Goals
   • The article highlights multi-stakeholder collaboration. It describes the partnership between the state government, academic institutions like IIT-M and Anna University, and international bodies like the World Bank to fund and implement the flood forecasting system. This collaboration is essential for achieving the other goals.

2. What specific targets under those SDGs can be identified based on the article’s content?

1. Under SDG 6:
   • Target 6.3: Improve water quality by reducing pollution. This is addressed by the call for integrated management to “improve water quality by preventing the mixing of sewage with stormwater and the dumping of solid waste into water bodies.”
   • Target 6.5: Implement integrated water resources management. The article strongly advocates for this by suggesting that bringing water supply, storm drainage, and sewage disposal “under a single umbrella agency” would lead to more responsive and integrated management.
   • Target 6.6: Protect and restore water-related ecosystems. This is mentioned through the work on “lake rejuvenation” and giving “room for our waterways and water bodies.”
2. Under SDG 9:
   • Target 9.1: Develop quality, reliable, sustainable and resilient infrastructure. This is central to the discussion on designing “sustainable drainage systems (SuDS),” implementing “blue-green infrastructure,” and increasing the design capacity of stormwater drains to make the city’s infrastructure resilient to floods.
3. Under SDG 11:
   • Target 11.5: Significantly reduce the number of people affected by water-related disasters. The development of the “real-time flood forecasting and spatial decision support system” is a direct measure to provide early warnings and strengthen disaster management capacity, thereby reducing the impact of floods on the population.
   • Target 11.b: Increase the number of cities implementing integrated policies and plans towards climate change adaptation and disaster risk reduction. The article calls for a “drainage master plan, along with a flood ‘hazard–risk–vulnerability and capacity assessment’ (HRVCA)” and “sustainable urban planning that integrates concepts such as ‘water-sensitive urban design’.”
4. Under SDG 13:
   • Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters. The entire article focuses on this target by discussing measures to mitigate floods, improve drainage, and adapt to higher rainfall intensities caused by climate change to “improve our resilience against floods and drought.”
5. Under SDG 17:
   • Target 17.17: Encourage and promote effective public, public-private and civil society partnerships. The article provides a clear example of this through the project funded by the World Bank, where “IIT-M assisted Tamil Nadu urban infrastructure financial services limited (TNUIFSL)” in implementing the flood forecasting system, showcasing a partnership between government, academia, and an international financial institution.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

1. Existence of a National Disaster Risk Reduction Strategy:
   • The development and implementation of a “drainage master plan” and a “flood ‘hazard–risk–vulnerability and capacity assessment’ (HRVCA)” for Chennai serves as a direct indicator of progress in disaster risk reduction planning.
2. Early Warning System Implementation:
   • The deployment of the “real-time flood forecasting and spatial decision support system – Chennai’ (RTFF & SDSS)” is a tangible indicator. Progress can be measured by its operational status, accuracy, and the number of people reached by its warnings.
3. Monitoring Infrastructure:
   • The number of deployed sensors and rain gauges is a quantitative indicator. The article mentions “hundreds of sensors have been deployed” and “1,000 automatic rain gauges across the state.”
4. Infrastructure Design Capacity:
   • The design rainfall capacity of stormwater drains is a specific engineering indicator. The article tracks its evolution: “Before 2015, this design quantity was about 32mm/h; subsequently, it was about 68mm/h. The recent designs aim for a design rainfall of about 79mm/h.”
5. Urban Land Use and Permeability:
   • The percentage of impervious surface area is an implied indicator. The article cites Seoul’s increase from 7.8% to 47.7% as a negative outcome. Conversely, measuring the increase in permeable surfaces through “permeable pavements” and “open, porous space” would be a positive indicator for Chennai.
6. Adoption of Sustainable Urban Drainage Solutions:
   • The number and area of Low-Impact Development (LID) and blue-green infrastructure projects implemented, such as “rain gardens, roof gardens/green roofs, permeable pavements, vegetative swales and infiltration trenches,” can be used as an indicator.

4. Summary of SDGs, Targets, and Indicators

Source: timesofindia.indiatimes.com