Geologic Map geodatabase of the valley corridor of the 59-mile reach of the Missouri National Recreational River, South Dakota, Nebraska, and Iowa:  Gavins Point Dam to North Sioux City
This geologic map area of 5,430 km2 spans a reach of the lower Missouri River valley and adjoining uplands for about 100 kilometers east of Gavins Point Dam, the easternmost mainstem dam on the Missouri River.  Understanding the surficial geologic history of the valley is relevant to natural resource management of the …