Transforming to hydrological modelling approach for long-term water resources assessment under climate change scenario - a case study of the Godavari Basin, India

This communication discusses quantifying basin-scale water wealth by transformation from the presently adapted basin terminal gauge site run-off aggregation to distributed hydrological modelling approach. In this study, an attempt was made to propose modifications to simple monthly water balance model using time-series land-use grids derived from the temporal remote sensing satellite data to compute run-off at basin scale. This approach will help in studying runoff and water resources availability with limited meteorological parameters. The study was aimed at computing mean annual water resources in the Godavari Basin, India during the last 18 years (1990-91 to 2007-08) using the proposed approach and to compute availability of water resources during extreme wet and dry rainfall conditions in the basin. The land-use grids were integrated with soil textural, digital elevation and command area grids to compute hydrological response unit grids. Groundwater, reservoir flux, domestic and livestock water consumption and industrial water consumptive use were computed using the spatial data and integrated in the model environment to compute run-off. The model was calibrated and validated using observed discharge data at various prominent gauge stations in the basin. Long-term water resources availability in the basin was computed using the developed methodology.