Duke Energy says the move is an attempt to use "fear and the courts to upend public policy."
Anderson Mayor Thomas Broderick wants more information about the project's funding before offering support.
Waters of the U.S. dictates which waterways are subject to federal clean water regulations.
President-elect Donald Trump says he wants to do away with unnecessary regulations, including the EPA's Waters of the U.S. rule.
Panelists at the conference looked at roles clean energy and mass transit could play in reducing the impacts of climate change in Indiana.
With the United States Supreme Court granting a stay on the Clean Power Plan, groups on both sides of the aisle are planning for a long battle ahead.
The Hoosier Environmental Council has long been concerned about the effect of the roughly 8,000 outdoor wood boilers across the state.
The nationwide halt comes after Indiana and 17 other states filed a legal challenge against the new rule.
Statewide environmental organizations have spoken out against the plans, but DNR officials say they're conservation-minded and are open to feedback.
A report from the Hoosier Environmental Council identifies spills and contamination caused by coal ash ponds in the state.