Potential climate change effects on groundwater recharge in the High Plains Aquifer, USA

Abstract

[1] Considering that past climate changes have significantly impacted groundwater resources, quantitative predictions of climate change effects on groundwater recharge may be valuable for effective management of future water resources. This study used 16 global climate models (GCMs) and three global warming scenarios to investigate changes in groundwater recharge rates for a 2050 climate relative to a 1990 climate in the U.S. High Plains region. Groundwater recharge was modeled using the Soil-Vegetation-AtmosphereTransfer model WAVES for a variety of soil and vegetation types representative of the High Plains. The median projection under a 2050 climate includes increased recharge in the Northern High Plains (þ8%), a slight decrease in the Central High Plains (À3%), and a larger decrease in the Southern High Plains (À10%), amplifying the current spatial trend in recharge from north to south. There is considerable uncertainty in both the magnitude and direction of these changes in recharge projections. Predicted changes in recharge between dry and wet future climate scenarios encompass both an increase and decrease in recharge rates, with the magnitude of this range greater than 50% of current recharge. On a proportional basis, sensitivity of recharge to changes in rainfall indicates that areas with high current recharge rates are least sensitive to change in rainfall and vice versa. Sensitivity analyses indicate an amplification of change in recharge compared to change in rainfall, and this amplification is in the range of 1-6 with an average of 2.5-3.5 depending upon the global warming scenario.

Vadose zone lag time and potential 21st century climate change effects on spatially distributed groundwater recharge in the semi-arid Nebraska Sand Hills

“…Because of the large discrepancy between these two GR p datasets, we opted to use a modified "Delta" method implemented by the U.S. Bureau of Reclamation (USBR, 2010), and follow the approach similar to Crosbie et al (2013) in presenting future climate change results as changes in GR p . With this method, adjustments are made to the modern period (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)) GR p,MODIS rates based on relative changes projected by the CMIP3/VIC scenarios as recharge scaling factors (RSFs).…”

“…Thus, interest in this topic has increased greatly over recent years (e.g., Crosbie et al, 2013;Ferguson and Maxwell, 2012;Green et al, 2011;Gurdak et al, 2007).…”

“…Among the various hydrologic cycle components, GR is the leading variable determining groundwater resources availability and sustainability in semi-arid and arid environments (Crosbie et al, 2013;Szilagyi et al, 2011b). Of practical importance to groundwater modeling and water resource management are the effects of projected changes in potential groundwater recharge (GR p ) rates (deep drainage beneath the root zone) on multi-decadal to century time scales, because regions with deep water tables and/or experiencing low GR p rates with fine-textured soils can have vadose zone lag times that exceed a century (McMahon et al, 2006;Scanlon et al, 2010).…”

“…In this way, we address the desired high resolution, large scale (>10 5 km 2 ) simulation of soil moisture movement without resorting to parallel supercomputing, commonly involved in variably-saturated 3D numerical modeling of basin hydrology. We utilize published, spatially distributed, high accuracy and high resolution (1.1-km) estimates of GR rates based on long-term (10 yr) MODerate resolution Imaging Spectroradiometer (MODIS) satellite measurements, rather than upscaling results of point-scale vadose zone modeling as done in previous studies (e.g., Allen et al, 2010;Crosbie et al, 2010;Crosbie et al, 2013).…”

Uncertainties and Challenges in Distribution of Groundwater Recharge in Climate Change Scenario

“…Russell S. Crosbie (2013) concluded that vegetation is not necessarily a strong determinant of the sensitivity of recharge to climate change as sensitivity differs based on the amount of historical baseline recharge and not necessarily vegetation type. Sensitivity of recharge to changes in rainfall is least for high baseline recharge and greatest for low baseline recharge.…”