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Low water conditions below Little Long hydroelectric station.

Improving dam safety at Little Long

Ontario Power Generation is making safety improvements to water control structures at the Adam Creek spillway, and other nearby dams on the Mattagami river.

Explore below to see another way OPG is working with community partners on efficient energy projects.

Controlling water levels

The Little Long Dam Safety Project proposes to increase the discharge capacity at eight-gate Adam Creek spillway structure located on the Little Long Reservoir. The project will add four new sluice gates at the Adam Creek spillway and make other reliability improvements to the existing Little Long, Smoky Falls and Adam Creek sluice gates.

A sluice gate is a water control structure that works like a garage door, which dam operators use to control water levels and flow rates in rivers. This helps OPG regulate levels and maintain safety for Ontarians.

Improving safety, infrastructure and economies

The Little Long Dam project improvements will allow OPG to pass additional water around the stations of the Lower Mattagami river complex, to improve safety in the event of rare large flood and to comply with updated requirements established by the Province of Ontario.

For further details, explore OPG’s Project Overview, which details our efforts.

The project will help protect the assets improved in 2015 through the $2.6-billion Lower Mattagami Redevelopment Project, which added generating capacity at our Little Long, Smoky Falls, Harmon and Kipling generating stations and was an important partnership with Moose Cree First Nation.

Our generation on Lower Mattagami River

Latest update

When OPG studied the wildlife habitat, plant community, and at-risk species around Adam Creek, we found the construction of the sluiceway to have previously disturbed the habitat, but that no species were harmed.

OPG is committed to moving forward with Indigenous and local communities to assess risk, mitigate issues, and produce detailed, technical engineering plans for the area.

A detailed engineering work plan including technical specifications is also in progress.