Analyzing streamflow changes: irrigation-enhanced interaction between aquifer and streamflow in the Republican River basin

Abstract

Abstract. Groundwater-fed irrigation has altered surface and groundwater interactions in the Republic River basin (RRB) in the midwestern United States, where agriculture heavily depends on irrigation. The decreasing flow trend recorded at the RRB gauging station since the 1950s reflects the synthetical effect of dynamic interactions between surface water and groundwater systems, which has been enhanced by groundwater pumping and irrigation return flow. This study uses a systematic modeling approach to analyze the conjunctive effects of pumping and return flow on streamflow. A watershed management model, the Soil and Water Assessment Tool (SWAT), is modified and established for the Frenchman Creek basin (FCB), a subbasin of RRB, to examine the causes of streamflow changes. The baseflow component in SWAT is linked to aquifer storage so that the model can simulate the combined effects of groundwater pumping and irrigation return flow on natural streamflow. Results show that irrigation has not only depleted streamflow but also changed the flow pattern and seasonal variability. The changes can be decomposed into decrease in the slow component (baseflow) and increase in the fast components (surface and subsurface flow). Since the fast components are subject to higher variability than the slow component, the annual streamflow variability is amplified. Agricultural water use in this region also has changed the groundwater storage seasonal regime from the pattern of "summer recharge and winter discharge" in the past to "summer discharge and winter recharge" at present. This challenges the existing groundwater modeling, which usually assumes fixed recharge pattern and rates.

Moving sociohydrology forward: a synthesis across studies

“…For example, several studies considered the effects of land use change altering the hydrologic regime, through increased irrigation in the Heihe River in China (Zhang et al, 2014), alterations to the water cycle through tile drainage (Yaeger and Sivapalan, 2013), irrigation from groundwater in the midwestern US (Zeng and Cai, 2014), and deforestation in eastern Mexico (Muñoz-Villers and McDonnell, 2013). The oneway nature of influence in these studies possibly results from a timescale separation between the rapid timescales of human intervention in the water cycle and the longer timescales on which these interventions alter agricultural productivity.…”

“…Existing models used in the special issue, such as the Soil and Water Assessment Tool (SWAT) (Zeng and Cai, 2014;Zhang et al, 2014), land surface hydrologic models (Kummu et al, 2014), or policy models (van Soesbergen and Mulligan, 2014), can be used to provide detailed descriptions of hydrological response to exogenous human drivers. These modeling approaches, while informative, do not clearly depart from the current hydrological paradigm.…”

Proximate and underlying drivers of socio-hydrologic change in the upper Arkavathy watershed, India

“…In large part, hydrologic non-stationarity on short to medium timescales de-30 rives from direct anthropogenic influences on the water cycle, which may be much more significant than the more widely studied impacts of climate change (Kumar et al, 2006;Vorosmarty, 2000;Taylor et al, 2013;Schewe et al, 2014). Anthropogenic drivers of non-stationarity include changes in land use (Fox et al, 2015), direct manipulation of surface water resources (Grafton et al, 2013) and groundwater abstraction (Zeng and Cai, 2014). changes can be expected in underlying social drivers, for example those associated with changes in economics, technology and governance.…”

Spatial Extent of Future Changes in the Hydrologic Cycle Components in Ganga Basin using Ranked CORDEX RCMs

“…The belief, that the climate change would have an evident impact on different hydrologic components, is established by the long-term assessment of catchment's water balance (Abbaspour et al, 2009;Serrat-Capdevila et al, 2007). Hence, watershed models are essential for studying hydrologic processes and their response to different climate changes (Eckhardt and Ulbrich, 25 2003;Li et al, 2009;Zeng and Cai, 2014;Zhang et al, 2012). Several physically based hydrological models have been recognized and adopted to simulate hydrological processes in a river catchment.…”