(Roanoke, Va.) — Pipeline opponents have vowed to fight a plan that allows construction to begin on the controversial Mountain Valley Pipeline.

The Department of Environmental Quality on Monday approved what it described as “detailed site plans” and “engineering designs that will protect water quality in all areas of Virginia, during and after construction of the pipeline project.”

Approval of a plan to stem the dirty water that will flow from building the natural gas pipeline through Southwest Virginia is another step forward for developers.

To this point, work on the 300-mile pipeline has been limited to cutting trees along its path. By clearing this regulatory hurdle, actual construction will be allowed start.

Opponents fear the environmental effects of digging along the mountainous terrain and say the runoff from trenching will contaminate streams, private wells and public water supplies.

Peter Anderson, Appalachian Voices Virginia program manager, said opponents “will monitor every move the pipeline company makes, because now they have little faith in government officials.”