Irrigation tanks are an ancient method of water management in South India that rely on the capture and storage of monsoon rain. The use of tanks has declined dramatically in modern times, though recent pressures of water scarcity have resulted in a resurgence of tank irrigation. This paper uses GIS and remote sensing techniques to investigate the spatial patterns of tank decline and rejuvenation in the Kaveri River Catchment, building a greater understanding of the lasting effect of historic irrigation policies on the contemporary geographies of tank irrigation in South India.