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Skagit River Salmon Model

The Watershed:

The Skagit River Watershed, located in the Pacific Northwest Coastal Ecoregion (Naiman & Bilby 1998, Abell et al. 2000), drains the North Cascades mountain range of Washington, USA and British Columbia, Canada. The watershed encompasses 8,270 km2 (Beechie et al. 1994) and is the largest watershed in the Puget Sound Basin, providing over 30 percent of all freshwater flowing into the sound. The mainstem of the Skagit River is 260 km long with its headwaters located in British Columbia, Canada. Elevations within the watershed range from sea level to the peak of Mt. Baker, which is approximately 3,275 m, with many other peaks in the basin reaching over 2,500 m. Average annual rainfall ranges between 900 mm in lowland areas to more than 4,500 mm at high elevations. Mean annual discharge of the Skagit River at Mt. Vernon (only a few minor tributaries enter the Skagit downstream from Mt. Vernon) is 470 m3s-1.

Geologically, the landscape is young influenced by recent and current glaciation, volcanism, uplifting, folding and faulting. The watershed contains 394 glaciers, 387 lakes, 35 major tributaries, 5 large hydroelectric dams (regulating discharge), and 32 towns.

The Skagit River is unique in the Puget Sound Region by still being home to all 8 Salmonid species. Salmon are keystone species in Pacific Northwest Ecosystems.

Overview Map of Skagit Watershed | Aquatic Eco-region Map

Watershed Definition: An area of land that drains water, sediment and dissolved materials to a common receiving body or outlet. The term is not restricted to surface water runoff and includes interactions with subsurface water. Watershed vary from the largest river basins to just acres or less in size.

Objective of the Model

The salmon model presented here is a conceptual model (no empirical data) created to promote the understanding of the complex human and ecological interactions taking place within the Skagit River Watershed.