Numerical modeling groundwater recharge and its implication in water cycles of two interdunal valleys in the Sand Hills of Nebraska |
| |
| Institution: | 1. Nuclear Fuel Cycle Backend Research Center, Civil Engineering Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Chiba 270-1194, Japan;2. Horonobe Underground Research Center, Japan Atomic Energy Agency, 432-2 Hokushin, Horonobe, Hokkaido 098-3224, Japan;1. Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile;2. Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Casilla 1280, Antofagasta, Chile;3. Department of Geo-Engineering, Technical University of Catalonia/Barcelona Tech (UPC), Barcelona, Spain;4. Geological Institute of Spain (IGME), Zaragoza, Spain;5. Centro de Investigación y Desarrollo en Recursos Hídricos (CIDERH), Vivar 493, Iquique, Chile;1. Institute of Environmental Assessment and Water Research (IDAEA), CSIC, c/Jordi Girona 18-26, 08034 Barcelona, Spain;2. Associated Unit Hydrogeology Group UPC CSIC, Barcelona, Spain;3. Univ Politecnica de Catalunya, Dept Civil & Environ Eng, Jordi Girona 1-3, ES-08034 Barcelona, Spain;4. Barcelona Cicle de l''Aigua SA (BCASA), C/de l''Acer 16, 08038 Barcelona, Spain |
| |
| Abstract: | The topography and geomorphology of the sand dunes and interdunal valleys in the Nebraska Sand Hills play important roles in regional water cycle by influencing groundwater recharge and evapotranspiration (ET). In this study, groundwater recharge, associated with precipitation and ET as well as soil hydraulics, and its spatial variations owing to the topography of dunes and valleys are examined. A method is developed to describe the recharge as a function of the storage capacity of dunes of various heights. After the method is tested using observations from a network of wells in the Sand Hills, it is used in the MODFLOW model to simulate and describe recharge effects on groundwater table depth at two different dune-valley sites. Analysis of modeled groundwater budget shows that the groundwater table depth in the interdunal valleys is critically influenced by vertical groundwater flows from surrounding dunes. At the site of higher dunes there are steadier and larger vertical groundwater flows in the dunes from their previous storage of precipitation. These vertical flows change to be horizontal converging groundwater flows and create upwelling in the interdunal valleys, where larger ET loss at the surface further enhances groundwater upwelling. Such interdunal valley is the major concentration area of the surface water and groundwater flow in the Sand Hills. At the site of shallow dunes and a broad interdunal valley the supply of groundwater from the dunes is trivial and inadequate to support upwelling of groundwater in the valley. The groundwater flows downward in the valley, and the valley surface is dry. Weak ET loss at the surface has a smaller effect on the groundwater storage than the precipitation recharge, making such area a source for groundwater. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
