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Analyzing the dynamic hydrologic conditions of the Sandhills is critical for water and range management and sustainability of the sandhills ecosystem as well as for dune stability. There are complex models available to quantify both surface and subsurface hydrological processes. However, we present in this study an application of a relatively simple model to arrive at best estimates of the water balance components. Using the Thornthwaite-Mather model, water balance components were estimated for four automated weather data network weather monitoring stations. Estimated averages of the water balance components suggested that mean annual precipitation of these four sites was only about 420 mm but water loss through plant evapotranspiration (ET) was 861 mm, with potential ET of about 1,214 mm. Our investigation shows that there was surplus of water between December and March and a deficit occurs at the start of the growing season in May and extends through senescence in September–October. This study also suggests that the High Plains aquifer possibly met the plant water requirement during this deficit period as well as during the soil water extraction period, from May through September. [ABSTRACT FROM AUTHOR]

Soil moisture, evapotranspiration, and other major water balance components were investigated for six Nebraska Sandhills locations during a 6 year period (1998–2004) using a hydrological model. Annual precipitation in the study period ranged from 330 to 580 mm. Soil moisture was measured continuously at 10, 25, 50, and 100 cm depth at each site. Model estimates of surface (0–30 cm), subsurface (30–91 cm), and root zone (0–122 cm) soil moisture were generally well correlated with observed soil moisture. The correlations were poorest for the surface layer, where soil moisture values fluctuated sharply, and best for the root zone as a whole. Modeled annual estimates of evapotranspiration and drainage beneath the rooting zone showed large differences between sites and between years. Despite the Sandhills’ relatively homogeneous vegetation and soils, the high spatiotemporal variability of major water balance components suggest an active interaction among various hydrological processes in response to precipitation in this semiarid region. [ABSTRACT FROM AUTHOR]

The article presents a closure to the study "Estimation of the Water Balance Using Observed Soil Water in the Nebraska Sandhills" from authors V. Sridhar and K. G. Hubbard themselves. The authors contend that it is not possible to simplify the water balance behavior of the Sandhills. They note that the overall evapotransportation of Sandhills does not even exceeds the precipitation. They determine the soil moisture storage of Sandhills by computing the soil moisture and actual evaporation.