Supported by the Jharkhand Mukti Morcha (JMM), the demonstrations demanded stoppage of work on the project as they feared it would submerge agricultural land in 184 villages of six blocks in the two districts.
Later, a delegation led by JMM's working president and former chief minister Hemant Soren met Governor Droupadi Murmu and submitted a memorandum seeking her intervention.
They also referred to a sub-committee of the Tribal Advisory Committee recommending scrapping of the project for alleged violation of rules in executing the work.
The issue was also raised in the state assembly today.