Chennai is a city that is often in the news for water related issues. While periodic cyclones cause flooding and water-logging in winter, these events are followed in summer by water shortages and droughts. Many reports put Chennai along with Bengaluru among major cities likely to run out of water in the near future, a situation known as “Day Zero”.

Similar to Bengaluru, Chennai does not sit close to any major water sources that can be tapped into endlessly. Both cities increasingly rely on faraway sources of water to quench the thirst of their rapidly increasing millions, and where that falls short they have bored deep to bring water from 100s of feet below at unsustainable rates.

The most recent report from the Central Ground Water Board finds that both Bengaluru and Chennai are extracting more groundwater than they are replenishing each year and the already low ground water levels are expected to plummet even further over the years.

Chennai Water Design Jam

It is in this context, that the “Chennai – Water” design jam was held, where participants came together with the goal of using data to design a water secure Chennai. The event was held at Bhumi – Alwarpet in partnership with CAG Chennai, WELL Labs, Poovulagin Nanbargal and Arappor Iyakkam.

Unlike in datajams, where the focus is on analysing data to look for trends and make recommendations, a design jam asks participants to use data to design a better system of governance. In this case, a system that can ensure not only water security for the city and its surroundings, but also equitable supply of water to all residents irrespective of socio-economic status.

There were twenty participants from diverse backgrounds – GIS, Civil engineering, water studies, sustainability and activists with experience on the ground, and they were were split into four teams.

Problem Statements

The problem statements chosen by the teams were:

1. Understanding the temporal nature of a lake’s catchment area in Chennai and the factors affecting it, with a case study of Puzhal lake.
2. Designing a ward-level water security index and ranking for Chennai.
3. Mapping the demand-supply gap in Chennai and what it could like in 2030 based on projected trends of important water sources.
4. Chennai Groundwater – A critical review. How can groundwater be used sustainably in Chennai?

Outputs

Team Puzhal

Anuviya, Charan, Meghaa, Venugopal and Vishwanthan of Team Puzhal looked at how the Puzhal lake and its catchment areas have varied over the years and what are the factors affecting it. They used satellite imagery, census data and built-up area changes over the years to make their case.

The team noted that Puzhal Lake (aka Red Hills lake) has had an average annual storage of 1684 mcft over the past 18 years, which is around 50% of its full storage. However, the annual demand in Chennai is for 15,040 mcft assuming 135 litres per person and 2011’s census numbers.

They noted the high urbanisation around the lake and how it could affect catchment flows. They recommended deeper studies that could help demarcate the boundaries of the lake and delineate the canals, streams and minor lakes that are part of the catchment which can help in protecting them.

Team Coovum

Niranjana, Pranith, Ravi Teja, Saravana Ganesh and Renu of Team Coovum tried to develop a water security index and ranking at the ward-level. Such an index can shed light on areas that are suffering from water scarcity and help authorities focus on improving those areas.

They developed the index by combining the following metrics: Groundwater availability, external water supply, demand stress, water quality and recharge potential.

They noted that western and southern zones like Anna Nagar, Sozhinganallur and Valsaravakkam had high water security. Northern zones (Z4, Z5 and Z6) had lower water security, highlighting the existing socio-economic boundaries in Chennai.

Team Kosasthaliyar

Durai, Lokesh, Nigazh, Sarojini and Tamil of Team Kosasthaliyar tried to map the demand and supply of water in Chennai in 2025, and tried to estimate what the situation would be like in 2025.

They noted that the supply from the major lakes has been coming down in Chennai and is expected to show a downwards trend, also given the increasing population. Desalination, while being touted as a silver bullet, is not likely to help much, while it comes with its own set of collaterals.

While the demand in 2023 was 2110 Million Litres per Day (MLD), it is likely to go up to 2321 MLD by 2030 and the unmet demand is also likely to double from the 230 MLD in 2023 to 462 MLD in 2030 if we don’t plan for the increase in demand.

Team Adyar

Chandrasekhar, Rithika, Rohan, Subashree and Varsha of team Adyar looked at the current rate of groundwater usage and tried to come up with a system where ground water usage is more sustainable.

They noted that as per the latest ground water report, 13 of the 16 Taluks in Chennai are in over-exploited state (using more than 100% of what gets recharged). They noted that a better regulatory mechanism, large scale rainwater harvesting systems, sponge parks are among the host of solutions available to improve the groundwater status in Chennai that can lead to more sustainable extraction.

Conclusions

The teams looked at various aspects of the water supply in Chennai, and across the teams they noted how the main water supply from lakes is being threatened by increase in built-up area around the lakes and in their catchments. They noted that lake levels over the years has been showing a decreasing trend.

Groundwater extraction has been well beyond what is recharged which means that Chennai is now using its fossil water which might run out at any point. With all these challenges, there is also the socioeconomic angle, where the marginalised parts of the city are much less water secure than their counterparts in the well-off parts of the city like Adyar or Anna Nagar.

Manikandan M, of CAG noted that “water scarcity is one of the major challenges across many places in the country. The Chennai design jam event enables the participants from diverse technical backgrounds to identify water related data, analyze and come up with recommendations.”

According to Radhika Sundaresan, Senior Researcher at WELL Labs “these datajams have opened up datasets around topics such as urban heat, flooding, lakes etc to a wider audience. It provides a platform to use and interpret these datasets and create a narrative that can open up wider discussions around these topics by different stakeholders- academicians, policy makers to students from diverse disciplines”

Jenny Mariadhas of Poovulagin Nanbargal felt that “the event came out with many challenging and important questions. The teams with diverse members joined hands ideating the issue including data collection, planning, research, mapping, coding and came up with interesting approaches and solutions the city can do.”

Haris Sulthan of Arappor Iyakkam called out the challenges of public data. “Data is a valuable resource and the most critical asset for initiating any project. However authentic data is not readily made available to the public by the government creating significant disadvantages particularly in areas like Chennai water security.”

For the participants, it was a one of a kind experience. Renu S note that “it was a great learning experience working as a team especially with GIS experts and coming up with possible ideas.”