City of 1000 tanks

OOZE architects & urbanists with local team

Project implementation: India
Project development: India, Netherlands

City of 1,000 Tanks, Chennai – Holistic urban strategy to combat floods, droughts and pollution through blue-green strategies.

Chennai is at risk of running out of water in the next decade, given its projected population increase and groundwater depletion. The City of 1,000 Tanks project, part of the Water as Leverage for Resilient Cities Asia program, identifies the interrelationships between the underlying causes of flooding, water scarcity, and pollution in Chennai and offers a holistic solution to these three problems. It is developing a citywide Water Balance Model by harvesting rainwater, treating wastewater and runoff pollution with decentralized Nature-Based Solutions (NBS), and recharging both to the groundwater aquifer. This will prevent climate-change-induced droughts by increasing groundwater reserves and prevent saline intrusion from sea-level rise.

It will simultaneously mitigate risks associated with high-frequency flooding and sewage pollution. This project aims to address supply-side challenges by creating water retention and supply capacities of 200-250 MLD (Million Liters per Day) in the first two phases (compared to a current urban demand of 1,580 MLD).

The 1,000-Tank City Water Balance Pilot at Little Flower Convent School for the Blind and Deaf is a transformative demonstration project that envisions a water-abundant Chennai. Using NBS, the project repaired damaged infrastructure, harvested rainwater, and treated wastewater on-site to recharge the aquifer, thus ensuring local water security and climate resilience for Little Flower Convent, a school with 500 students with visual and hearing impairments.

This replicable and scalable demonstration project investigates the processes and steps needed to achieve the required change and aims to engage government departments, resident groups, businesses, and institutions; thus enabling implementation at district, municipal, and urban levels.

The project is funded by the Government of the Netherlands and co-financed by the Goethe Institut and the Wipro Grants Program. City of 1,000 Tanks is Chennai's first collaborative water alliance, led by OOZE architects & urbanists with Madras Terrace, IIT Madras, Care Earth Trust, Eco Village International, Atma Water, IRCDUC, Uravugal Social Welfare Trust, Paperman Foundation, Rain Center, TU-Delft, HKV, and others.

OOZE architects & urbanists was founded in 2003 by Eva Pfannes and Sylvain Hartenberg in Rotterdam. They are passionate professionals who love working in complex, rapidly evolving environments with public and cultural sector clients, focusing on the benefits to society and the natural environment. OOZE specializes in strategic and holistic systems thinking at the urban and neighborhood scale, as well as in the development of bankable concepts that mitigate and adapt to the impacts of climate change.

www.ooze.eu.com
www.cityof1000tanks.org

We thank everyone who participated and visited the 14th São Paulo International Architecture Biennial, from September 18 to October 19, 2025

NOTE OF CONDOLENCE

With deep sorrow, the Brazilian Institute of Architects – São Paulo Department (IABsp) mourns the passing of architect and landscape architect Kongjian Yu, a global leader in ecological urbanism, and the members of his team who accompanied him, tragically killed during the filming of a documentary. The institute is honored to have had him as a participant in the 14th São Paulo International Architecture Biennial, where his transformative vision strengthened the dialogue between global challenges and local realities. IABsp emphasizes that Yu's contribution, which transcends borders, will remain an inspiration for generations and expresses its condolences to China, to the families of all the deceased, to his friends, and to all those impacted by his genius and dedication. Read the full note here.