Quantifying the streamflow response to groundwater abstractions for irrigation or drinking water at catchment scale using SWAT and SWAT\u2013MODFLOW

Wei Liu,Jacob Skødt Jensen,Hans Thodsen,Hans Estrup Andersen,Erik Jeppesen,Dennis Trolle,Seonggyu Park,Anders Nielsen,Eugenio Molina-Navarro,Ryan T Bailey,Jacob Birk Jensen

doi:10.1186/s12302-020-00395-6

Abstract

BackgroundGroundwater abstraction can cause a decline in the water table, and thereby affects surface streamflow connected to the aquifer, which may impair the sustainability of both the water resource itself and the ecosystem that it supports. To quantify the streamflow response to groundwater abstractions for either irrigation or drinking water at catchment scale and compared the performance of the widely used semi-distributed hydrological model SWAT and an recently integrated surface–subsurface model SWAT–MODFLOW, we applied both SWAT and SWAT–MODFLOW to a groundwater-dominated catchment in Denmark and tested a range of groundwater abstraction scenarios.ResultsTo accommodate the study area characteristics, the SWAT–MODFLOW model complex was further developed to enable the Drain package and an auto-irrigation routine to be used. A PEST (parameter estimation by sequential testing)-based approach which enables simultaneous calibration of SWAT and MODFLOW parameters was developed to calibrate SWAT–MODFLOW. Both models demonstrated generally good statistical performance for the temporal pattern of streamflow, with better R2 and NSE (Nash–Sutcliffe efficiency) for SWAT–MODFLOW but slightly better PBIAS (percent bias) for SWAT. Both models indicated that drinking water abstractions caused some degree of streamflow depletion, while abstractions for returned irrigation led to a slight total flow increase, but may influence the hydrology outside the catchment. However, the streamflow decrease caused by drinking water abstractions simulated by SWAT was unrealistically low, and the streamflow increase caused by irrigation abstractions was exaggerated compared with SWAT–MODFLOW.ConclusionWe conclude that the SWAT–MODFLOW model produces much more realistic signals relative to the SWAT model when quantifying the streamflow response to groundwater abstractions for irrigation or drinking water; hence, it has great potential to be a useful tool in the management of water resources in groundwater-dominated catchments. With further development of SWAT–MODFLOW and the PEST-based approach developed for its calibration, this study would broaden the SWAT–MODFLOW application and benefit catchment managers.

Highlights

Groundwater abstraction can cause a decline in the water table, and thereby affects surface stream‐ flow connected to the aquifer, which may impair the sustainability of both the water resource itself and the ecosys‐ tem that it supports
Since the Soil and Water Assessment Tool (SWAT)–Modular finite-difference flow model (MODFLOW) complex used in this study was newly developed and allowed use of the Drain package and auto-irrigation, a new graphical user interface based on the new SWAT–MODFLOW complex could ensure that a study such as that presented here is repeated with less effort and technical challenges. Generally both models simulated well the temporal patterns of streamflow at the two hydrological stations during the calibration and validation periods, with better R2 and Nash–Sutcliffe efficiency (NSE) for SWAT–MODFLOW but slightly better percent bias (PBIAS) for SWAT during validation period. Both models indicated that drinking water abstractions caused streamflow depletion and that irrigation abstractions caused a slight total flow increase
Abstraction scenarios simulated by SWAT and SWAT–MODFLOW showed different signals in streamflow change

Summary

Introduction

Groundwater abstraction can cause a decline in the water table, and thereby affects surface stream‐ flow connected to the aquifer, which may impair the sustainability of both the water resource itself and the ecosys‐ tem that it supports. The specific field techniques (e.g., flow analysis, permeameter tests, thermal regime tests and tracer tests) used to estimate patterns of groundwater/surface water interaction are typically performed at small spatial scales and over a short time period [6,7,8,9,10]. In this regard, surface–subsurface hydrological models can overcome the above limitations to some extent because of their ability to simulate longterm groundwater–surface water interactions through a holistic approach and enable scenario analysis (e.g., climate change, groundwater abstraction and land use planning, etc.)

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Discussion

Conclusion