Recurrent summer floods along the Brahmaputra river and its tributaries are a major challenge for the people and state governments of Northeast India. While riverine communities in the region rely upon a variety of adaptation strategies to live with these destructive floods, climate change is expected to further exacerbate this challenge, as melting Himalayan glaciers and changes in the South Asian monsoon lead to an increase in the frequency of severe floods. At the same time, a multitude of new dams are under construction in the Brahmaputra river basin, to meet India’s growing energy demands. Though these dams could provide flood protection for downstream communities, political and economic factors have led dam-builders to prioritize hydroelectricity generation over flood control. Furthermore, hydroelectricity generated along the Brahmaputra is “evacuated” to distant urban centers, while rural dwellers in Northeast India suffer from high levels of energy poverty. Using the Ranganadi Hydroelectric Project in Arunachal Pradesh as a case study, this paper examines how, by changing the flood regime and undermining current adaptive strategies, large dams along the Brahmaputra are testing the capacity of downstream communities to live with summer floods. This work highlights the ways in which poor and vulnerable communities in Northeast India are forced to bear the costs of both climate change impacts and decarbonization efforts.