Drainage Density and Controlling Factors in Cascade Range, Oregon, USA

This paper demonstrates a feasibility of automated drainage density mapping on regional scales and in high resolution, using remotely sensed elevation data. Such maps offer affordable means of surveying large regions for variability in spatially extended features, which themselves are difficult to sense remotely, but are expressed by the drainage density. We show that the proposed mapping method can be achieved by a combined utilization of two novel techniques: the curvature-based stream delineation algorithm, and the at-point assignment of drainage density values. In order to showcase our concept we have generated a map of drainage density for the study area in the Oregon Cascade Range. The map shows a sharp contrast in landscape dissection. A number of factors, potentially responsible for that contrast, were considered, and the variation of the underlying geology was judged to be a major factor responsible for an observed drainage density pattern. Although the unique geological setting of the study area was know to us a priori, we envision applying our mapping method to locations where remotely sensed elevation is the only available data, and the generated map is used to extract new geologic or environmental information.