Site-specific studies addressing various aspects of the Grasse River have been conducted throughout the course of the remediation project. These studies have yielded significant data used to determine the best way to remediate the river. Construction to support remediation started in 2017. Major projects 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.
  • 2016 - Submittal of the Intermediate Design (60% design) for Agency Review
  • 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 and construction of a staging area near the Route 131 bridge that will be used 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.
  • 2019-2020+ - Complete the Final Design. In-river remedial construction activities began in 2019 and and are anticipated to take 3-4 years to complete with work starting in April and continuing through November each year (weather pending).


Regulatory Process Milestones

Land-Based Efforts

River-Based Efforts

Pilot Studies

Pre-Design & Construction