Spatial and Temporal Geomorphic Comparison of the Cedar and Wapsipinicon Rivers in Eastern Iowa

Separated by a relatively short distance, the Cedar and Wapsipinicon Rivers of eastern Iowa exhibit differences in their varying geomorphic components. Contemporary aerial images, along with historic maps, photographs and other digital topographic and geomorphic data, allowed both qualitative and quantitative comparisons of the two fluvial systems. The Cedar River, influenced more by past periods of glaciation, displays greater channel width, discharge, and incision, but narrower floodplain valleys, fewer side channels and chutes, and less channel migration than the Wapsipinicon River; which tends to sit higher on the surface. Additionally, several other aspects, such as shoreline features, bedrock type and elevation, and Quaternary alluvial deposit characteristics provide further evidence of greater glacial influences on the Cedar, but less on the Wapsipinicon. Analysis of this spatial data supports not only the historical geologic interpretations, but also reveals anthropogenic influences, and subsequent impacts, on the natural river systems.