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Towards a computationally efficient free-surface groundwater flow boundary condition for large-scale hydrological modelling

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)225-233
Number of pages9
JournalAdvances in Water Resources
Volume123
Early online date4 Dec 2018
DOIs
DateAccepted/In press - 30 Nov 2018
DateE-pub ahead of print - 4 Dec 2018
DatePublished (current) - Jan 2019

Abstract

Shallow groundwater is a critical component of the terrestrial water cycle. It sustains baseflow in rivers, supplies root zones with soil moisture during dry periods, and directly influences the land-atmosphere exchange processes. Nonetheless, the integration of groundwater into large-scale hydrological models remains challenging. The most detailed way of representing groundwater dynamics is to incorporate three-dimensional, variably saturated flow processes in the subsurface representation of hydrological models. However, such detailed modelling is still a challenge for global hydrological applications, mainly due to its high computational demand. In this study, a free-surface boundary condition called the Groundwater Flow Boundary (GFB) is developed to represent groundwater dynamics in a more computationally-efficient manner than the full three-dimensional models do. We evaluate GFB using two synthetic test cases, namely an infiltration experiment and a tilted-v catchment, which focus on groundwater recharge and discharge processes, respectively. The simulation results from GFB are compared with a three-dimensional groundwater flow model and with an over-simplified approach using a free-drainage lower boundary condition to assess the impact of our assumptions on model results. We demonstrate that GFB is computationally more efficient compared to the three-dimensional model with limited loss in model performance when simulating infiltration and runoff dynamics.

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  • Full-text PDF (accepted author manuscript)

    Rights statement: This is the author accepted manuscript (AAM). The final published version (version of record) is available online via Elsevier at https://www.sciencedirect.com/science/article/pii/S0309170818303701 . Please refer to any applicable terms of use of the publisher.

    Accepted author manuscript, 1 MB, PDF document

    Licence: CC BY-NC-ND

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