The St. Croix River (Skutik River) begins its journey to the ocean some 180 kilometres to the north of its mouth. It acts as the international boundary between Canada and the United States along its eastern branch. At Grand Falls, the eastern and west branches join to form the mainstream that continues until it meets the ocean near St. Stephen, New Brunswick, and Calais, Maine.
The St. Croix watershed runs through the heart of the traditional territory of the Passamaquoddy people. In early colonial times, the St. Croix was renowned for its incredible abundance sea-run fish. Sea-run fish live in salt water but spawn in fresh water. Many of these species ascend the St. Croix each year to find their preferred spawning habitats, some travelling into the far reaches of the upper watershed. These include alewife, blueback herring, American shad, Atlantic salmon, American eel, rainbow smelt, tomcod, sea lamprey, and Atlantic / short nose sturgeon.
The St. Croix is also renowned for its bountiful forests blanketing the river valley. With timber harvests in early colonial period, also came the need to drive logs downriver to the sawmills located near the ocean. Many dams, some for the purposes of water control and some for other industries, were constructed along the St. Croix and its many tributaries. At the site of the Passamaquoddy fishing village located just above the head of tide, at what is known as Salmon Falls, several dams were built between 1803 and 1881 both on, above, and below Salmon Falls. The Milltown Dam was built directly on Salmon Falls in 1881 and once powered the world’s largest cotton mill. Located directly adjacent to the dam, this cotton mill operated until 1957 and was torn down in 1972. Today, a monument overlooking the river and Salmon Falls, commemorates the Cotton Mill and many of its workers. After the cotton mill was removed, New Brunswick Power (NB Power), took over ownership of the Milltown Dam to generate electricity for the towns of St. Stephen and Calais.
In the 1800s and 1900s, the St. Croix River provided power and industry for many river valley residents, but the construction of dams, industry pollution, and lack of fish passage led to severe declines in many of its sea-run fish, including the extirpation of Atlantic salmon. Due to its many glacial lakes, ponds, and abundant surface water, the St. Croix watershed is thought to have the potential to host the largest population of spawning alewife and blueback herring (collectively referred to as river herring) in North America.
In July 2023, NB Power began efforts to remove the Milltown Dam (at that time the oldest operating hydroelectric dam in North America) and restore Salmon Falls to its natural state. The Milltown is the first dam located along an international boundary to be removed. Removing the dam will restore approximately 16 kilometres of the river, and alongside the installation of improved fish passages at the watershed’s remaining dams, will lead to significant increases in the number of native sea-run fish migrating to their traditional upstream freshwater habitat.
At the time of this writing (January 2024), all human-made structures on the Canadian side of the river have been removed. The next steps are to begin decommissioning the remaining spillway structures located on the American side with the goal of having a natural multi-species fish passage in place by April 2024.
For more information
https://www.nbpower.com/en/about-us/projects/milltown-decommissioning/