The use of water to produce hydro electricity has been in existence on the Mississippi River since the early 1900’s. There are three hydro generation facilities on the system that were built near the turn of the century, those being the High Falls Generating Station, the Mississippi River Power Generating Station in Almonte and the Galetta Generating Station at the outlet of the river. There are two additional hydro generating stations on the system, the Appleton Generating Station in the village of Appleton and the Enerdu Generating Station in Almonte, that were built more recently. There was an additional generation station at Carleton Place, however, this site was retired in 1958 and the current dam was built in 1973.
HIGH FALLS GENERATING STATION
Originally built in 1920 by the former Ontario Hydro Corporation, this dam is located on the Mississippi River below the hamlet of Snow Road and upstream of Dalhousie Lake.
The dam is currently owned by Ontario Power Generation and operation of the stoplog section of the dam is contracted to MVC. Often being associated with water level problems on Dalhousie Lake due to its size and location, this dam has a capacity of only 14.3 cms through the generating facility itself. As a “run-of-the-river” facility, any flows that exceed that value must be passed through the stoplog sections of the dam. There are 4 stoplog bays, which hold a total of 56 stoplogs, 20 in the 1st bay, 12 in each of the other 3 bays. Stoplogs are replaced or removed at a rate which mimics the inflow with the objective to maintain water levels in the Snow Road village between 187.00 m and 187.63 m as much as possible. This station is a 2.3 MW (megawatt) facility.
APPLETON GENERATION STATION
This site was the original site of the Appleton Woollen Mill and was rebuilt as a generating station in 1995 by Merol Power Corporation. The generating station was subsequently sold to the current owner, Canadian Hydro Developers in 1998.
This dam has a capacity of 35 cms through the generating station. The dam also has a bypass control section of four stoplog bays, one mechanical gate and an overflow weir. This is a “run-of-the-river” facility, therefore, any flows in excess of 35 cms must be passed through the control section of the dam. This is a 1.3 MW facility.
ENERDU GENERATION STATION
This site was originally part of the Wylie Flour Mill site located within the community of Almonte. The generating station was incorporated into the dam in 1997. It is also a “run-of-the-river” structure with a plant capacity of 15 cms.
Although Enerdu does not have stoplog control sections, the site does use flashboards across the river to raise levels by approximately 45 cm (18 inches). These flashboards are designed to fail under high flow conditions to reduce input on water levels within the community. Any flows in excess of 15 cms pass over the flashboards and natural weir across the river. This site is a 0.35 MW facility.
MISSISSIPPI RIVER POWER GENERATION STATION
Formally known as the Almonte Public Utilities Commission Generating Station, this structure was originally built in the early 1900’s. It is currently owned by the Mississippi River Power Corporation.
This dam is located immediately downstream of the Enerdu Generating Station and is also a “run-of-the-river” structure. This dam has a capacity of 34 cms through the generation station with flows in excess passing over the natural waterfalls or down the chancery channel bypassing this structure. This is a 2.4 MW facility.
GALETTA POWER GENERATING STATION
This dam was built in 1907 by the Galetta Power and Milling Company and sold to Ontario Hydro in 1929. Ontario Hydro retired the facility in 1981 and sold the structure to private interests in 1983.
They undertook some modifications to the structure making it operational in 1984. After a couple of different owners, the dam was sold to the present owner, Canadian Hydro Developers, in 1998.
This site is also a “run-of-the-river” structure with a plant capacity of 30 cms. Flows exceeding this volume are passed through the three stoplog bays or over the concrete weir. This site is a 1.6 MW facility.