An environmental group was threatening to sue Dominion Virginia Power over the mere presence of its outmoded coal ash ponds near Quantico Creek’s intersection with the Potomac River when the power plant announced plans last month to do away with them — by draining them into the nearest waterway.

Dominion’s draft permit that lays out the change of course at its Possum Point Power Station was the subject of an impassioned public hearing this week. It drew more than 50 local residents, public officials and representatives from regional environmental groups concerned about the proposal’s impact on local water quality. Many of them pleaded with the Virginia Department of the Environment for more time to consider the proposed changes, the comment period for which will end on Dec. 14.

State elected officials and the Prince William County Board of Supervisors were among those who submitted letters formally requesting an extension of the comment period, but DEQ spokesman Bill Hayden said today those requests have been denied.

The DEQ advertised the public hearing and 45-day comment period in the required outlets, but some residents said notice in the D.C.-based Washington Times was not sufficient for those who live near the affected Quantico Creek.

“We are aware of no reason that this permit must be rushed through the process,” said Greg Buppert, senior attorney at the Southern Environmental Law Center, which has threatened suit over this and other coal ash ponds he says have contributed pollution to local waterways for decades.

The DEQ received 175 written comments before the public hearing, where 30 people provided additional verbal comments on the proposal. Of those, only comments delivered by the company and its contractor favored moving forward with the draft permit as written. The DEQ will submit a summary of comments and its recommendations to the State Water Control Board for a decision at its mid-January meeting.

Residents near Quantico Creek said they felt blindsided by the company’s proposal to “dewater” its longstanding coal ash ponds into an unnamed tributary of the creek. But several factors are contributing to the company’s decision to suddenly do something about the ponds that some groups allege have been leaking pollutants for years.

In the wake of environmentally devastating coal ash spills in Tennessee and North Carolina, the EPA released a ruling in April that requires plants to shut down their coal ash ponds in the coming years.

Coal ash contains toxins such as arsenic, lead and mercury that can be harmful to human and environmental health. A byproduct of burning coal for power, the ash is one of the most ubiquitous types of industrial waste, with more than 100 million tons of it produced in the United States in 2012, according to the EPA.

As the country turns away from coal to other power sources, states are left to deal with the massive piles — or ponds — of the coal ash that has been mounting for decades.

Dominion responded to the EPA’s ruling by announcing plans to close all its ash ponds within three years, said Cathy Taylor, the company’s Director of Electric Environmental Services. Since 2003, the company has converted eight coal power stations to natural gas, leaving behind ash ponds at Possum Point, Chesapeake Energy Center on the Elizabeth River and its Chesterfield and Bremo power stations on the James River.

In a move toward closing them, Dominion requested changes to its permits at both Possum Point and Bremo that entail discharging the ponds’ waters into local waterways.

“This is a pretty new issue,” said DEQ’s Hayden. Dewatering ponds by discharging their contents into the water “hasn’t come up before, because they haven’t closed a coal ash pond before. Now, they’re closing two.”