Nebraska Sand HillsExtensive tracts of sand dunes are common throughout the central Great Plains and

Nebraska Sand HillsExtensive tracts of sand dunes are common throughout the central Great Plains and Rocky Mountains. The greatest among these is the Nebraska Sand Hills, which cover nearly 20,000 square miles (52,000km2) in north-central Nebraska and southernmost South Dakota.The Nebraska Sand Hills are the biggest expanse of sand dunes in the western hemisphere, more than three times larger than the state of Massachusetts, and one of the largest areas of native prairie in the Great Plains. The sand hills are located along the principle route of the North American central or Great Plains flyway for migrating waterfowl and shorebirds, which find food, shelter, and rest in the myriad wetlands of the region. The main end points for this migration path are central Canada and the Gulf of Mexico, but some species travel from the Arctic to Patagonia.The Nebraska Sand Hills are now largely stabilised by prairie vegetation (Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands etc), which has preserved the dune forms. The dunes resemble giant waves on the ocean and are comparable to other great sand seas in Africa, Arabia, Asia, and Australia. Individual large transverse dunes are typically several kilometers long, one kilometer wideand up to 100m tall. The dunes appear to have been active several times during the past 10,000 years, most importantly during the mid Holocene climatic optimum, some 8000 to 5000 years ago, and again from about 3000 to 1500 years ago.Thick dune sand rests on unconsolidated alluvial sand and gravel that cover poorly consolidated Ogallala strata, all of which are parts of the High Plains aquifer system. Throughout nearly all of the Nebraska Sand Hills, the saturated thickness of the aquifer is at least 100m, and exceeds 150m in the central portion. This represents the greatest volume of water storage in any portion of the High Plains aquifer.~ JMImage Credit: http://bit.ly/1UH5ICfMore Info:Nebraska Sand Hills: http://bit.ly/1Nud7khHigh Plains Aquifer: http://bit.ly/1MrtbWPOgallala strata: http://bit.ly/1PbEGPVLabedz, T.E. 1990. Birds, in bleed, A.S. and Flowerday, C. (eds), An atlas of the Sand Hills, Conservation and Survey Division, Resource Atlas No. 5a (2nd edn), pp. 161-180. Institute of Agriculture and natural Resources, University of Nebraska-Lincoln.Keech, C.F. and Bentall, R. 1938. Dunes on the plains: The Sand Hills Region of Nebraska. Conservation and Survey Division, Resource Report 4, 18 pp. Institute of Agriculture and Natural Resources University of Nebraska-Lincoln -- source link

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