Evapotranspiration in the Nebraska Sand Hills

The Nebraska Sand Hills cover over 50,000 square kilometers and are the largest stabilized sand dune field in the world. While this fragile ecosystem exists in a semi-arid climate (450 to 500 mm annual rainfall), there exists within it, several different sub-systems, representing a wide range of moisture regimes. These can range from wetlands and small, shallow lakes to dry dunal uplands. Soils in this ecosystem are mostly eolian sands and support a thin vegetation cover that is responsible for holding the dunes in place. Despite this seeming fragility, the region is home to a thriving free-range cattle industry and it's associated haying and grazing. To help in understanding this complex ecosystem, we have instituted a program of evapotranspiration measurements in areas that are instrumented with logging wells. In this poster, we will report on our results to date from two seemingly different valley ecosystems.