Whose Water?

Tamil Nadu’s traditional eri (tank) system sustained agrarian livelihoods for centuries, functioning as a vernacular hydrological network that harvested rain, recharged groundwater, and equitably distributed irrigation. Rooted in collective governance, eris balanced ecology with social life, supporting agriculture, festivals, and micro-habitats. Today, urbanization, industrial growth, and centralized control have disrupted this commons-based infrastructure. The case of Chembarambakkam eri illustrates this rupture: once vital for paddy irrigation, it is now over-extracted to supply Chennai’s drinking water, intensifying urban floods and eroding rural livelihoods. Land-use analyses from 1965–2015 reveal shrinking command areas, ecosystem fragmentation, and exclusion of traditional users. This project reframes eris as socio-hydrological infrastructure, proposing decentralized governance, revived tank ecologies, and integration into urban planning. Strategies include restoring catchments, creating landscape buffers, and introducing Special Eri Zones (SEZ) that safeguard tanks as ecological-commons. By treating water as a shared resource, the proposal advances equity, resilience, and ecological continuity across rural-urban thresholds.