Soils of Thunder Creek Watershed, North Cascades National Park

Wilderness areas and national parks provide us with natural landscapes in which to study soil formation as well as other environmental phenomena. This map shows the distribution of soils as they form under the forces of nature in Thunder Creek Watershed. Since access within the watershed is limited to a few trails, the map is the result of a GIS model called the Remote Area Soil Proxy model. It is based on the soil-forming processes of the watershed. Maps of vegetation, a digital elevation model, and a landform map were used to predict soil distribution.

These serve as proxies for the soil-forming factors of climate, organisms, and relief. The other factors, parent material and time, are uniform over the watershed. Three orders of soils were found in the watershed: Spodosols, Andisols, and Inceptisols. Spodosols form on stable landscape positions where cool and moist conditions promote growth of coniferous forest. Andisols form on stable landscape positions where rapid weathering of volcanic glass occurs but leaching does not occur. Inceptisols form on landforms that are not stable but are subject to colluvial and alluvial disturbance.