AMD from the Gravity Slope outfall discharges into the River from the west bank approximately 0.25 river miles upstream from the Constitution Ave. bridge (Decker's Bridge) in the municipality of Jessup. The AMD flows from a concrete bunker that is aligned downstream with the River and flows through a wetland created by a beaver dam before entering the River in a series of small channels. The bunker was formerly a slope entry portal used for access to the coal mines, but now serves as an outfall for a continuous flow of AMD. It is apparent from the iron oxide coloration in the wetland that it acts as a filter keeping most of the metal contaminants from entering the River and allowing the mine water to recharge with oxygen. The results of water and macroinvertebrate sampling in the River, at sites within close proximity of the AMD's input, indicates that this is the case. Any impacts on the River appear to be localized within the first few meters downstream of its input in a pool where additional iron oxide deposition is visible. Water chemistry and the macroinvertebrate community appear to have recovered within 100 m downstream of this pool. AMD from this outfall also appears to have no significant impact on the trout fisheries in this area as this reach of the River is in the middle reach of the Trophy Trout Project section of the River.