Acid mine drainage (AMD) is a significant pollution problem that degrades water quality conditions in the Lackawanna River watershed. AMD is mine water that flows from the flooded underground coal mines into the River, its tributaries, or, in some cases, a wetland. Since the last anthracite coal mines closed in the Lackawanna Valley, the underground mine pool and mines have been filling up with ground and surface water creating a huge underground lake known as the Northern Anthracite Mine Pool. The size of this mine pool rivals one of New York's Finger Lakes. As the water level of the pool rises, it fills the underground mining tunnels and begins to flow from openings onto the surface. These openings, or outfalls, formerly served as entries to the underground mine works or were pipes and culverts built to convey the rising water from the flooded mines. As water percolates through the abandoned mine voids, it picks up metallic compounds and minerals from the coal and the rocks between layers of coal. Iron, aluminum, manganese, and sulfur compounds are dissolved in the mine water and carried to the surface. The dissolution process also creates sulfuric acid, giving the mine water its acidic quality and name. While underground, the mine water is naturally low in dissolved oxygen levels, however, when it reaches the surface, the dissolved metal compounds bind to the oxygen molecules that are mixed in at the surface. This reaction causes the metal compounds to drop out of their dissolved form and settle as particulate compounds onto the River's bottom. This creates a yellow-orange coating of metal oxides on the rocks in and along the riverbank. The coloring reflects the large concentration of iron compounds that are dissolved in the mine water underground and then "deposited" in the River. This yellow-orange coating is called "yellow-boy" by miners. For more information on the anthracite coal mining history in our watershed and its impacts on the River, see Chapter I of the Lackawanna River Guide Book.

  An additional source of AMD into our River and its tributaries is runoff from the Abandoned Mine Lands (AML) that dot our watershed. AMLs include property that was used for processing coal after it was transported to the surface (collieries) and areas where waste rock dug from the mines was dumped, creating the "culm" piles we have today. Since most of the AML sites in our watershed are directly along the River or one of its tributaries, they act as a non-point source of AMD pollution to our water resources.

 The above map shows the outfall areas with the Lackawanna River watershed. The link to each outfall provides a description of that outfall, the latest water quality data collected by LRCA staff from that outfall, pictures of the outfall, and surrounding area, and maps that show the locations of each outfall.