St. Mary

The St. Mary hydroelectric facility is located at the base of the St. Mary Dam near Magrath in southern Alberta.

Constructed on Alberta Environment’s irrigation system, the facility consists of an intake in the diversion tunnel valve room, a 1.5-metre diameter steel pipe penstock, powerhouse and 25-kilovolt power line. It uses water flowing from the low level riparian outlet located within the original diversion tunnel that flows into the St. Mary River. Water is withdrawn from the bottom of the reservoir and discharged into the diversion tunnel through a flow-regulating valve. The hydro facility takes all, or a portion, of this flow through the penstock installed inside the tunnel.

TransAlta owns and operates the St. Mary facility.

Environmental highlights

Protection of the environment is an important part of our hydro power business, as is responsible water use. We continually work with environmental and community groups to ensure habitats are protected, and that all users’ needs are heard.

The St. Mary hydroelectric facility has a UL ECOLOGO® Certification for Renewable Energy.