Most watersheds in the North Cascades NP drain into the Skagit River basin on the west slope of the North Cascades Range and the Stehekin River on the east slope. They are unaltered by past human-induced disturbance and can serve as reference sites and templates for restoration efforts in the Pacific Northwest. The condition of a watershed is the reflection of the distribution and types of seral classes of vegetation, land-use history, effects of previous natural and cultural disturbances, and the distribution and abundance of species. Major natural disturbances affecting the mountainous regions in the Pacific Northwest are episodic floods, volcanic eruptions, earthquakes, geomorphic changes in stream channels and landforms, fire, wind, insect and disease outbreaks, and glacial activity. Important landform disturbances include landslides and earthflows in glacial deposits on steep slopes.
Watersheds have distinct physical boundaries and define the ranges of plants and animals.
They integrate climatic, geologic, hydrologic, and biotic components in the alteration of habitat as vast quantities of water and sediment move from source areas in high mountains to low-elevation valley floors. Watershed analysis methods provide a framework for understanding ecological processes at various scales. These watersheds were selected based on patterns of climate, geology, hydrology, biology, accessibility, and linkages to management concerns. Big Beaver Creek flows easterly into Ross Lake reservoir, so there is a strong linkage to the Seattle City Light hydroelectric project. The valley floor is covered with lush riparian and wetland vegetation that is part of a Research Natural Area.