Background
Type: Article

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

Journal: Environmental Modelling and Software (13648152)Year: 2018/11/01Volume: 109Issue: Pages: 329 - 341
Qi J.Zhang, XuesongMcCarty G.W.Sadeghi A.aCosh, Michael H.Daughtry, Craig S.T.Lang M.W.
BronzeDOI:10.1016/j.envsoft.2018.08.024Language: English

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. © 2018 Elsevier Ltd


Author Keywords

Land surface processesModelingRichards equationSoil water

Other Keywords

Choptank RiverUnited StatesModelsRainSoil moistureSolute transportIrrigation managementLand-surface processMoisture simulationsRichards EquationSoil and water assessment toolSoil and Water assessment toolsSoil moisture measurementSoil waterintegrated approachland surfacemodelingperformance assessmentsimulationsoil depthSoil surveys