The data resource contains daily time-series of simulated streamflow, ground water levels and estimated demands, from humans, livestock, irrigation and industry, across the Cauvery Basin, India. The data were generated using the Global Water Availability Assessment (GWAVA) Model 5. A baseline of 1986-2005 is presented along with two future time slices (2041-2060 and 2061-2080) for these variables. The data were produced to help predict how rapid economic development and population growth in the region would impact on future water security. The data resource was produced by the data authors. The research was funded by NERC research grant NE/N016491/1 Upscaling Catchment Processes for Sustainable Water Management in Peninsular India