According to the Saugeen Valley Conservation Authority (SVCA) “The SVCA owns and operates 3 dams. There are at least 50 other privately owned dams in the watershed. Settlers built dams in the 1850s during the settlement times of our watershed. They constructed dams to create power to saw logs and to grind up grains for flour. Today most dams serve no purpose. A small number of dams have been retrofitted to supply hydro power for personal use or for the hydro grid.
Dams and the Ecosystem
Many of the dams built decades ago need ongoing repairs to stay in good working order. Dams create a barrier in a stream or creek. They are not good for the general health of the river, its ecosystem, and the watershed. Among other things, removal of dams serves to remove a barrier or blockage along a creek or river. Removal also cools down water temperature, making it better for fish. It improves the oxygen levels in the water for aquatic life, it balances out the movement of sediment and nutrients to downstream areas of the stream and it reduces erosion downstream. In general it improves ecosystem health in the stream corridor and its watershed and aquatic habitat.”
Denny’s Dam
During the 1940s and 1950s, there was a devastating invasion of the sea lamprey into the Great Lakes. Denny’s Dam was constructed in 1870 but was rebuilt in 1970 to block the sea lamprey and halt the spawning process. A single sea lamprey can destroy 18 kilograms of fish in its parasitic phase and it’s estimated that without the dam 30,000 lamprey would out-migrate into the Saugeen River and Lake Huron (that works out to 540 metric tonnes of fish lost). While the lamprey population has been under control for many decades, a breach in the dam would be catastrophic. Accordingly, Denny’s Dam was rehabilitated in 2017 – 2018 in order to extend its life so that it may continue to control the sea lamprey population.
Before and after pictures of the Truax Dam in Walkerton – 2019
Removal of Dams
A number of dams on tributaries of the Saugeen were removed. Below are before and after pictures of the Lockerby Dam on the North Saugeen River, which was removed in 2015 (about a 4 minute drive East of Paisley).
Below is a very interesting video (under 10 minutes) on the logistics of removing a dam and its impact on native fish after removal. A must watch.