A simple modelling framework for shallow subsurface water storage and flow

Lucile Verrot, Josie Geris (Corresponding Author), Lei Gao, Xinhua Peng, Joseph Oyesiku-Blakemore, Jo. U. Smith, Mark E. Hodson, Ganlin Zhang, Paul D. Hallett

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Abstract

Water storage and flow in shallow subsurface drives runoff generation, vegetation water use and nutrient cycling. Modelling these processes under non-steady state conditions is challenging, particularly in regions like the subtropics that experience extreme wet and dry periods. At the catchment-scale, physically-based equations (e.g., Richards equation) are impractical due to their complexity, while conceptual models typically rely on steady state assumptions not found in daily hydrological dynamics. We addressed this by developing a simple modelling framework for shallow subsurface water dynamics based on physical relationships and a proxy parameter for the fluxes induced by non-unit hydraulic gradients. We demonstrate its applicability for six generic soil textures and for an Acrisol in subtropical China. Results showed that our new approach represents top soil daily fluxes and storage better than, and as fast as, standard conceptual approaches. Moreover, it was less complex and up to two orders of magnitude faster than simulating Richards equation, making it easy to include in existing hydrological models.
Original languageEnglish
Article number1725
Number of pages20
JournalWater
Volume11
Issue number8
Early online date19 Aug 2019
DOIs
Publication statusPublished - Aug 2019

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Keywords

  • hydrological modelling
  • soil water content
  • soil water fluxes
  • vadose zone
  • non-unit hydraulic gradient
  • transient state

Cite this

Verrot, L., Geris, J., Gao, L., Peng, X., Oyesiku-Blakemore, J., Smith, J. U., Hodson, M. E., Zhang, G., & Hallett, P. D. (2019). A simple modelling framework for shallow subsurface water storage and flow. Water , 11(8), [1725]. https://doi.org/10.3390/w11081725