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Improved simulation of river water and groundwater exchange in an alluvial plain using the SWAT model

Sun, Xiaoling and Bernard-Jannin, Léonard and Garneau, Cyril and Volk, Martin and Arnold, Jeffrey G and Srinivasan, Raghavan and Sauvage, Sabine and Sanchez-Pérez, José-Miguel Improved simulation of river water and groundwater exchange in an alluvial plain using the SWAT model. (2016) Hydrological Processes, 30 (2). 187-202. ISSN 0885-6087

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Official URL: http://dx.doi.org/10.1002/hyp.10575

Abstract

Hydrological interaction between surface and subsurface water systems has a significant impact on water quality, ecosystems and biogeochemistry cycling of both systems. Distributed models have been developed to simulate this function, but they require detailed spatial inputs and extensive computation time. The soil and water assessment tool (SWAT) model is a semi-distributed model that has been successfully applied around the world. However, it has not been able to simulate the two-way exchanges between surface water and groundwater. In this study, the SWAT-landscape unit (LU) model – based on a catena method that routes flow across three LUs (the divide, the hillslope and the valley) – was modified and applied in the floodplain of the Garonne River. The modified model was called SWAT-LUD. Darcy's equation was applied to simulate groundwater flow. The algorithm for surface water-level simulation during flooding periods was modified, and the influence of flooding on groundwater levels was added to the model. Chloride was chosen as a conservative tracer to test simulated water exchanges. The simulated water exchange quantity from SWAT-LUD was compared with the output of a two-dimensional distributed model, surface–subsurface water exchange model. The results showed that simulated groundwater levels in the LU adjoining the river matched the observed data very well. Additionally, SWAT-LUD model was able to reflect the actual water exchange between the river and the aquifer. It showed that river water discharge has a significant influence on the surface–groundwater exchanges. The main water flow direction in the river/groundwater interface was from groundwater to river; water that flowed in this direction accounted for 65% of the total exchanged water volume. The water mixing occurs mainly during high hydraulic periods. Flooded water was important for the surface–subsurface water exchange process; it accounted for 69% of total water that flowed from the river to the aquifer. The new module also provides the option of simulating pollution transfer occurring at the river/groundwater interface at the catchment scale.

Item Type:Article
Additional Information:Thanks to John Wiley & Sons editor. The original PDF of the article can be found at Hydrological Processes website : http://onlinelibrary.wiley.com/doi/10.1002/hyp.10575/full
HAL Id:hal-01323983
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Agricultural Research Service - ARS (USA)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Other partners > Texas A&M University (USA)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Other partners > Helmholtz-Zentrum für Umweltforschung - UFZ (GERMANY)
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Deposited By: Leonard BERNARD-JANIN
Deposited On:30 May 2016 12:42

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