Topographic Relief Map of Iowa
by James D. Giglierano and Jean C. Prior
This soaring view of Iowa’s terrain shows the unevenness, or relief, of the land surface. Particularly noticeable are the large number of rivers within the state and the directions in which they flow. Using river alignments, can you follow the Missouri-Mississippi drainage divide along its length in Iowa?
The amount of topographic relief and the patterns of stream dissection are related to underlying geologic materials. In northeastern Iowa, sedimentary bedrock at the land surface sharpens and steepens the landforms. In far western Iowa, adjacent to the level Missouri River valley, rise the intricate blufflands of the silt-dominated Loess Hills. Fresh glacial drift deposited just 14,000 to 12,000 years ago across north-central Iowa yields level terrain, only a few well-developed rivers, and a landscape scored with curved ridges of glacial moraines. In contrast, drainage networks are well established across the much older glacial deposits of southern Iowa (over 500,000 years old), and extensive erosional sculpture is evident.
This computer-generated map is based on a grid of land surface elevations artificially illuminated from the northwest. The intriguing view reveals a variety of physical shapes and features, as well as broader landscape patterns. These clearly demonstrate remarkable differences in Iowa’s terrain from one part of the state to another.