Climate change implications for irrigation and groundwater in the Republican River Basin, USA

Gengxin Ou,Daniel R Uden,Craig R Allen,Derrel Martin,Francisco Munoz-Arriola,Nancy Shank

doi:10.1007/s10584-018-2278-z

Gengxin Ou, Daniel R Uden + Show 4 more

Open Access

https://doi.org/10.1007/s10584-018-2278-z

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Abstract

This study investigates the influence of climate change on groundwater availability, and thereby, irrigation across political boundaries within the US High Plains aquifer. A regression model is developed to predict changes in irrigation according to predicted changes in precipitation and temperature from a downscaled dataset of 32 general circulation models (GCMs). Precipitation recharge changes are calculated with precipitation-recharge curves developed for prognostic representations of precipitation across the Nebraska-Colorado-Kansas area and within the Republican River Basin focal landscape. Irrigation-recharge changes are scaled with changes in irrigation. The groundwater responses to climate forcings are then simulated under new pumping and recharge rates using a MODFLOW groundwater flow model. Results show that groundwater pumping and recharge both will increase and that the effects of groundwater pumping will overshadow those from natural fluctuations. Groundwater levels will decline more in areas with irrigation-driven decreasing trends in the baseline. The methodologies and predictions of this study can inform long-term water planning and the design of management strategies that help avoid and resolve water-related conflicts, enabling irrigation sustainability.

Highlights

Throughout the world, irrigation is the largest use of fresh water resources, and management of such infrastructure is central to the pursuit of more sustainable and integrated water, agricultural, and energy resources (Scanlon et al 2017)
The importance of using multiple general circulation models (GCM) projections has been promoted as a way to account for uncertainty in projections (Allen et al 2010; Crosbie et al 2011)
The purpose of this study is to quantitatively evaluate climate change impacts on irrigation demands and regional water resources in the Republican River basin, an agricultural basin overlying the High Plains aquifer in the American Great Plains, where water management for irrigation across political boundaries has important implications for sustainability and the economy

Summary

Introduction

Throughout the world, irrigation is the largest use of fresh water resources, and management of such infrastructure is central to the pursuit of more sustainable and integrated water, agricultural, and energy resources (Scanlon et al 2017). Irrigated agriculture can be highly vulnerable to climate change, especially in arid and semi-arid areas with intensive irrigation demands. Most studies on the effects of climate change on groundwater focus on groundwater recharge because it is directly influenced by climate (Crosbie et al 2011; Holman 2006; Jyrkama and Sykes 2007; Niraula et al 2017). Some climate change studies estimate groundwater storage or groundwater budgets under projected climate scenarios (Allen et al 2004; Goderniaux et al 2011; Jackson et al 2011). Comprehensive groundwater dynamics under climate change, provided in these studies, are more critical for water management as the system can shift to another balanced status. The overall effects of climate change on irrigation and groundwater recharge have not yet been well addressed

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