Great Deception in Iowa

Somehow, an oxbow along the Des Moines River in Iowa has garnered the name “Deception Hollow”. It is located a few miles southeast of Lehigh, IA and now hosts a public boat launch. The stretch of the Des Moines through this area is part of Iowa’s [Des Moines River Water Trail](https://www.iowadnr.gov/Portals/idnr/uploads/riverprograms/watertrails/wt_dsmwebster.pdf), which has benefited from the recent [removal of dams ](https://www.snyder-associates.com/projects/des-moines-river-dam-removal/) in the Fort Dodge area. The HRTM was generate in Global Mapper GIS using Iowa DNR Lidar provided through the USGS 3D elevation program. 1 meter dataset IA_NorthCentral_2020_D20. The protocol used to map elevations to colors utilizes a 200-step human perceptive [color table](https://carolina-bay-survey.s3.amazonaws.com/mapfiles/kml/Elevation-ColorScaleC6.png) that cycles every 10 meters relative to sea level. This provides an intrinsic relative elevation relationship across the image, and also [adds](url) continuous sets of contour lines. If the viewer selects the Open Topography base map, the 10-meter contour lines map well to the “dark Blue” in the color table, and supply the actual elevation values.