Milltown Dam Removal

Regular on-site civil surveying across an international border ensured demolition and riverbed reconstruction matched the design.

The 3 MW Milltown hydroelectric dam was built in 1881 to power a cotton mill on the lower St. Croix River at Salmon Falls, on the border between Canada and the United States. NB Power acquired it in 1958, and by 2023 it had reached end of life. The utility decommissioned the site for removal of the dam and restoration of free-flowing conditions, which various stakeholder groups had requested.

Our role

Pennecon Limited’s Heavy Civil division, awarded the contract to remove and dismantle all equipment, buildings and infrastructure on both sides of the border, required regular surveying to ensure the demolition and reconstruction of the former riverbed and the naturally occurring waterfall followed the design drawings.

What we surveyed

From March 2023 to summer 2024 we were routinely on site for bathymetric surveys, cofferdam installation and monitoring surveys, a fish passage survey, demolition as-builts, cofferdam removal surveys, slope stabilization surveys and volume surveys.