Ross Lake

Ross Lake is a reservoir created by damming the Skagit River at Ross Dam to generate hydroelectric power for Seattle City Light. Its water level and volume are managed by scheduled releases from the dam. When full, typically in late spring, the lake stretches about 2 km into British Columbia, Canada. Before the area was flooded, the forested area was cleared to prepare the site.

The Skagit River supplies roughly 30% of the freshwater flowing into the Puget Sound and remains mostly free-flowing, aside from three dams that power Seattle. It supports strong populations of salmon, bald eagles, and snow geese. Though the International Joint Commission (IJC) currently has no active orders on the Skagit, it facilitated a 1984 agreement for a “paper dam.” This deal allowed Seattle to access hydropower from British Columbia at a cost comparable to expanding Ross Dam—which would have flooded 2,000 hectares of land in BC.

Ross Lake is a 24-mile-long reservoir formed as the rising Ross Dam flooded the logged Upper Skagit River valley. Today, it’s a hub for camping, boating, and hiking, with 19 water-access campsites and trailheads reachable by shore. The lake typically reaches full pool in late spring to support recreation, while Seattle City Light also manages water levels for flood control and to sustain downstream fish migration. With climate change causing earlier snowmelt and reduced runoff, refilling the reservoir fully has become increasingly challenging in recent years.

The fluctuating zone between full pool and drawdown levels is known as the riparian area. To reduce erosion here, Seattle City Light funds innovative restoration projects—often facilitated and funded by SEEC and implemented by the North Cascades National Park Service. The entire U.S. portion of Ross Lake lies within the Ross Lake National Recreation Area, a unit of the North Cascades National Park Service Complex that surrounds the reservoir.