Collins, B. and Skeikh, A.J., 2002. Methods used to map the historical riverine landscape and habitats of the Skagit River. University of Washington, Seattle, WA. pp. 47.

This report presents methods used to develop Geographic Information System (GIS) coverages of the riverine environment of the Skagit and Sauk river valleys around the time of early Euro-American settlement, or about 1870-1890. Principal materials include maps and field notes from the General Land Office (GLO) cadastral survey and US Coast & Geodetic Survey (USC&GS) charts of near-shore areas. We cross-referenced this with information post-dating the earliest settlement by a few decades, including the first US Geological Survey (USGS) topographic maps and the earliest aerial photography, and with modern sources that include published soils and geological mapping, recent topographic mapping, and a high-resolution digital elevation model (DEM). We integrated these materials into a GIS to map the channels, wetlands, forest characteristics, and ponds. Because uncertainty is inherent in working with historical materials, in the GIS coverages we document sources, the logic with which they were used, and relative certainty for each mapped feature, to make assumptions and certainty transparent. We also use GLO bearing tree data to describe riverine forests, and present results of field trials to assess biases in their use. Taken together, these landscape-scale coverages describe the historical environment and habitats, and how landforms, hydrographic features, and land cover vary along and across the Skagit valley, and can be applied to managing and restoring the riverine environment and habitats.