About the Talk
India’s ‘water crisis’ took over the social media recently. The talk is the first of a set of TREAD Talks addressing India’s ‘water crisis.’ These talks seek to engage with the idea of ‘water crisis’ critically towards informing a robust discourse, and contributing to the rethinking the policy instruments and governance strategies.
The Reassessment of Water Availability in India using Space Inputs by CWC and ISRO (2019) is the most comprehensive and reliable estimates of water availability in India so far. There were earlier efforts by CWC in the past. The last assessment was in 1993, when the total water resources was assessed as 1869 BCM. This assessment had certain limitations, such as: not all basins were studied during the same period, groundwater abstractions were estimated and interpolated based upon of data of just two years, the utilisation from minor irrigation projects were seldom available, the utilisation from major and medium projects were not always available (mostly estimations), the return flow from irrigation was assumed as 10% of the diversion, etc
The 2019 assessment is an attempt to eliminate the above limitations relying on space inputs. Instead of assessing the utilisation and return flows, the evapotranspiration has been estimated using modified Thornthwaite Mather equation at sub-basin level. The water balance has been carried out at pixel level (56m x 56m) and then aggregated to sub-basin levels after due calibration and validation with observed discharge and rainfall. In addition to Land Use Land Cover (LULC) maps from NRSC, other data sets from CGWB, the assessment uses data sets from various agencies to arrive at an availability of 1999 BCM. The results indicate that there is a huge spatial variability across river basins. Most of the River basins are water-scarce or water-stressed by Falkenmark Water Stress / Scarcity Indices. The talk discusses this variation to discuss measures for augmenting this potential and meet future demands.
About the speaker
Rishi Srivastava is a Director at the Central Water Commission, New Delhi. He is currently with the Remote Sensing Directorate of CWC. In about three decades of work, he spent most of his time with the directorates of Reservoir Operations and Basin Planning. He was associated with the development of rule curves of Tehri, Bansagar, Idukki, Kakki, and Idamalayar reservoirs. He also conducted the Comprehensive System Studies of DVC system involving integrated operation of 5 reservoirs and a barrage. He was involved with Reassessment of Water Resources using space inputs right from the stage of developing the methodology for the study till its completion. He was also associated with the IWRM studies of Baitarani river basin in the Eastern region of the country.
Mr Srivastava has done his B.E. (Civil) from the Jodhpur Engineering College and completed M.S. in Water Resources Management from IHE, Delft, Netherlands.