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Atlantic Richfield has completed the river cleanup phase of its Wellsville project.

In 2010, AR completed the second phase of its Wellsville project, constructing a sheet pile wall along the Genesee River to prevent impacted groundwater from reaching it and excavating the swale and portions of the river to remove historic impacts from the operation of the Sinclair Wellsville Refinery.

Project Manager Eric Larson said, "This was the second phase of our project. In the first phase of the project, we built a groundwater capture trench that prevents potentially contaminated groundwater from reaching the River. Then, we constructed and brought on-line the wetland treatment system that will remove any residual contaminants from groundwater at the site and clean the water to strict state and federal standards. In this phase, we moved to the River itself where we excavated portions of the riverbed to remove potential contamination left there from the operation of the old Sinclair refinery."

Larson explained that the project was timed so as to not affect the Annual Trout Derby.

Once the sheet pile wall in the riverbank was completed, crews began the River excavation. The work was done in segments along the length of the former Sinclair refinery site. The starting point was a little upstream from the pedestrian bridge in the park and continued to the first drop structure (low-head dam).

For each segment, workers sealed off a portion of the River by constructing steel sheet pile cells. The area within the cell was de-watered and excavated to a depth of four feet in the southern footprint, and six inches in the northern footprint. After that, a low permability barrier (aquablock) was laid down to prevent any potential deeper contamination from seeping into the River in the future. Then the riverbed was restored with a natural material. Excavated material was placed into the on-site landfill. Workers then moved the cell upriver and began the process again until they reached the endpoint.