Assessing the performance of a physically-based soil moisture module integrated within the Soil and Water Assessment Tool

Junyu Qi, Xuesong Zhang, Gregory W. McCarty, Ali M. Sadeghi, Michael H. Cosh, Xubin Zeng, Feng Gao, Craig S.T. Daughtry, Chengquan Huang, Megan W. Lang, Jeffrey G. Arnold

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

A Richards-equation-based soil moisture module was developed and integrated within the Soil and Water Assessment Tool (SWAT). Four years of daily soil moisture measurements from 10 monitoring stations at three depths (i.e., 5, 10, and 50 cm) in the Choptank River watershed, Maryland, were used to test the module performance. Results show that, as compared with the original SWAT soil moisture module, the Richards-equation-based soil moisture module improved R2 from 0.12 to 0.45 and reduced soil moisture simulation bias (mean[simulation] – mean[measurement]) from −0.10 to −0.02 (m3 m−3), averaged across the 10 stations at soil surface layer (i.e., 5 cm depth). Noticeable improvements were also observed for deeper soil layers, and for both dry and wet periods. Notably, the soil moisture coupling strength between different soil layers was substantially improved with the new module. The enhanced SWAT model is expected to better inform soil water and irrigation management.

Original languageEnglish (US)
Pages (from-to)329-341
Number of pages13
JournalEnvironmental Modelling and Software
Volume109
DOIs
StatePublished - Nov 2018

Keywords

  • Land surface processes
  • Modeling
  • Richards equation
  • Soil water

ASJC Scopus subject areas

  • Software
  • Environmental Engineering
  • Ecological Modeling

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    Qi, J., Zhang, X., McCarty, G. W., Sadeghi, A. M., Cosh, M. H., Zeng, X., Gao, F., Daughtry, C. S. T., Huang, C., Lang, M. W., & Arnold, J. G. (2018). Assessing the performance of a physically-based soil moisture module integrated within the Soil and Water Assessment Tool. Environmental Modelling and Software, 109, 329-341. https://doi.org/10.1016/j.envsoft.2018.08.024