Inverse Modeling of Soil Hydraulic Properties in a Two‐Layer System and Comparisons with Measured Soil Conditions

Abstract

Core Ideas Soil hydraulic properties were inverse modeled to in situ soil water content. The most appropriate soil property depths were identified. Best‐fit soil parameter depths compared well with characterized soil stratigraphy. Site‐specific monitoring and subsurface boundary conditions improved performance. Modeling of spatial and vertical variability in soil hydraulic properties is a pervasive dilemma in computational hydrology. In an effort to provide guidance in inverse modeling of soil hydraulic properties, this study (i) calibrated soil hydraulic properties, for different soil layer depths, to measured soil moisture, (ii) identified the best‐suited soil thickness through validation, and (iii) post‐validated the resulting best‐fit soil properties and layer depth to the observed soil stratigraphic conditions. Soil property depths were varied to identify the most important stratigraphic features in soil water modeling. Statistical and graphic goodness‐of‐fit measures indicated that calibration and validation simulations performed better at shallow depths and generally worsened with depth. A comparison of differences in modeled soil layering at two field sites reflected differences in the observed soil stratigraphic conditions. Comparison with in situ soil stratigraphy indicated the importance of soil horizon changes and human‐induced alterations to the near‐surface soils. These results indicate that soil moisture dynamics can be effectively modeled using basic soil input data and inverse methods. However, to improve model performance, a site‐specific field monitoring campaign is needed to properly account for the effects of soil stratigraphy and boundary conditions.

Quantifying Subsurface Lateral Flow along Sloping Horizon Boundaries in Soil Profiles of a Hummocky Ground Moraine

“…As the C horizon also differs in hydraulic properties, the soil profile storage capacity is affected as well, decreasing with solum thickness due to reduced soil water retention capacities. As found by Thomas et al (2017), variations in the thickness of the subsurface horizons could largely influence soil moisture dynamics and the water balance and also present challenges in property estimations and vadose zone modeling.…”

“…Pennock et al, 2014). Thomas et al (2017) argued that soil stratigraphy (i.e., thickness of the subsurface horizons) could influence soil moisture dynamics.…”

Available water capacity from a multidisciplinary and multiscale viewpoint. A review

“…The soil can be represented as (i) a single layer (Jhorar et al 2002), with the estimated soil hydraulic properties thus assumed to represent those of multiple soil horizons, or (ii) multiple layers, which increases the number of parameters to be estimated (e.g., each layer's thickness and water contents at FC and PWP) (Seki et al 2015). Some authors showed that, regardless of model complexity, using multiple layers provides better performance than a single homogenous layer, except for soils with low heterogeneity (Schneider et al 2013;Thomas et al 2017).…”

Análisis de la dinámica del agua en la zona no saturada en un suelo sujeto a prácticas de conservación: implicaciones en la gestión de acuíferos y adaptación al cambio climático

“…Esta interacción está determinada, en parte, por las condiciones del clima, el agua en la superficie y las características del medio granular superficial. El análisis y predicción del comportamiento de dicha interacción, está controlado principalmente por propiedades del suelo como la textura, estratigrafía, propiedades hidráulicas, contenidos de humedad y materia orgánica, incluidos diferentes aspectos de migración de solutos (Kung, 1990;Rudolph et al, 1996;Yazaki et al, 2006;McMahon et al, 2006;Segal et al, 2008;Thomas et al, 2017). Recientemente, el estudio del comportamiento del ciclo del agua en la zona no saturada se orienta a la predicción de los efectos del cambio climático y sus impactos en el agua subterránea, producción de alimentos y permanencia de ecosistemas (Maxwell y Kollet, 2008;Bell et al, 2010;Heinlein et al, 2017).…”