Assessing the Performance of a Physically-Based Soil Moisture Module Integrated Within the Soil and Water Assessment Tool

TitleAssessing the Performance of a Physically-Based Soil Moisture Module Integrated Within the Soil and Water Assessment Tool
Publication TypeJournal Article
Year of Publication2018
AuthorsQi, Junyu, Zhang Xuesong, McCarty Gregory W., Sadeghi Ali, Cosh Michael, Zeng Xubin, Gao Feng, ST Daughtry Craig, Huang Chengquan, Lang Megan W., and Arnold Jeffrey G.
JournalEnvironmental Modelling & Software
Volume109
Pages329 - 341
Date PublishedJan-11-2018
Abstract / Summary

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.

URLhttps://doi.org/10.1016/j.envsoft.2018.08.024
DOI10.1016/j.envsoft.2018.08.024
Journal: Environmental Modelling & Software
Year of Publication: 2018
Volume: 109
Pages: 329 - 341
Date Published: Jan-11-2018

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.

DOI: 10.1016/j.envsoft.2018.08.024
Citation:
Qi, J, X Zhang, GW McCarty, A Sadeghi, MC, X Zeng, F Gao, CS Daughtry, C Huang, MW Lang, and JG Arnold.  2018.  "Assessing the Performance of a Physically-Based Soil Moisture Module Integrated Within the Soil and Water Assessment Tool."  Environmental Modelling & Software 109: 329 - 341, pp. 329 - 341.  https://doi.org/10.1016/j.envsoft.2018.08.024.