Diversity assessment of macroinvertebrates in the dam progressed Subansiri river in the North –Eastern India

Abstract

Different indices such as Shannon Index H, Pielou Index J, Simpson Index D, Simpson 1-D, Marglef Index Ma, Maclintos Evenness Index McE, Maclintos Index Mc of macroinvertebrates were analysed to know the health status of the downstream of river Subansiri (from the site of construction of the 2000MW Subansiri Lower Hydroelectric Project to its confluence with the Brahmaputra) prior to the construction of the dam. In the modality of operation of the dam, to generate power, the dam authority proposed to release only 06 m3 s-1 of water for 20 hours of the day and release some 2579 m3 s-1 of water for 4 hours during the ‘peak load demand period’ in the evening / night, without considering the adverse effect on aquatic life and environment.