The major project efforts and events include:

  • Land-Based Remediation Activities - a comprehensive program on the Arconic (formerly Alcoa) West plant site to eliminate and minimize the discharge of contaminants to the Grasse River.
  • 1995 Non-Time-Critical Removal Action - a pilot project in which PCB-containing sediments were removed from a small area of the Grasse River.
  • 2001 Capping Pilot Study - a trial of various capping techniques.
  • 2005 Remedial Options Pilot Study - a combination trial of capping and sediment removal techniques.
  • 2006 Activated Carbon Pilot Study - to evaluate the effectiveness of applying and mixing activated carbon in sediments of the lower Grasse River.
  • Ice Management Evaluation - a study to determine the best way to manage ice in the river to prevent bottom scour of contaminated sediments due to an ice jam.
  • 2013 to 2016 - In river studies (pre-design investigations) to define remediation boundaries, look for Threatened and Endangered species that could be impacted by the project, understand geotechnical conditions, and support the development of a habitat reconstruction plan.
  • 2015-2019 - Design efforts conducted including development and submittal of the river Preliminary Design, Intermediate Design, and Final Design
  • 2017-2018 - Constructed land-based facilities and conduct other support activities in preparation for the future in-river remediation work. These activities included expanding the Secure Landfill on the Arconic Massena West property to safely store dredged material, as well as construction of a staging area near the Route 131 bridge to unload sediment from the river and load capping materials onto the river during in-water remediation work. Completed other support activities including remediating select upland areas and the Unnamed Tributary, and performing preliminary capping work in the river to verify construction sequencing.
  • 2019-2021 - Major in-river remedial construction activities (dredging, capping, and habitat reconstruction) began in 2019 and finished in 2021.
  • 2022 - Initiate long-term monitoring and maintenance program.
  • 2023 - Continue long-term monitoring and maintenance program and initiate habitat reconstruction monitoring.
  • 2024 - Continue long-term monitoring and maintenance program and habitat reconstruction monitoring. Finalize planning for cap repairs needed as a result of March 2022 ice jam event.


Regulatory Process Milestones

Land-Based Efforts

River-Based Efforts

Pilot Studies

Pre-Design & Construction