The proposed Farmersville dump site is located in the north reach of the Allegheny River Basin east of Conewango on a steep slope alongside Johnson Creek, Carpenter Brook and extensive wetlands associated with both streams. Both Johnson Creek and Carpenter Brook flow year round, charged in part by active year round springs originating on the proposed dump site. These waters discharge into Ischua Creek which flows south, approximately two miles from the site. The Ischua Creek is a major source for the Olean Creek, which travels no more than two miles from the confluence, through the City of Olean, before emptying into the Allegheny River oxbow, pushing into New York from Eldred, PA.
An independent study commissioned by the City of Olean concluded that, in the event of a release of leachate from the proposed landfill, "the travel time via surface water path from the landfill to the city would be on the order of days to weeks." (Golder Associates, Review of Hydrologic Conditions [of] Proposed Landfill -- Integrated Waste Systems, Farmersville, New York (March 19, 1992)).
The Allegheny River oxbow is already stressed by substantial TCE loading. TCE, or trichloroethylene, is an industrial degreaser widely used in decades past but since found to be a carcinogen.
All of the City of Olean's municipal wells, located alongside the Allegheny River, are currently shut down for TCE contamination. A TCE plume is located beneath the east end of the City, along the north bank of the Allegheny River.
Another substantial TCE plume has been identified by the EPA, from Little Valley to Salamanca, where it reaches the Allegheny River. As a consequence of this TCE plume the valley floor from Little Valley to Salamanca has been designated a federal Superfund site, and all residents have been advised to avoid drinking or showering with well water unless a household stripper has been installed to evaporate a portion of the TCE from their water.