Environmental flow of the river Sone at Indrapuri barrage was estimated using 36 years of discharge data and the Global Environmental Flow Calculator Software. To maintain the river in moderate condition and to keep basic ecosystem functions intact, at least 18.9% of mean annual runoff (MAR) has been estimated, while the annual discharge of the river was merely 5.16% of MAR. The river presently holds 89 fish species, but 20 species reported in an earlier study were not observed, while 14 new species were encountered.

Read this special report in Down To Earth on how government bent all rules to ensure that Mahan forest in Madhya Pradesh goes to Essar and Hindalco for mining coal.

The Patna High Court has directed the Centre to set up a tribunal for the settlement of the Sone river water dispute between Bihar and Uttar Pradesh, especially, on the question of water sharing fr