Numerical Analysis of Water Movement
in Agricultural Fields
with Heterogeneous Unsaturated Soils
Ephrem Yetbarek and Richa Ojha
Abstract The natural variability exhibited by soil hydraulic properties poses severe
challenges to model water movement through porous formations in agricultural fields.
In this study, a 3D numerical approach coupled with the turning bands method to
generate realizations of soil formation properties with different heterogeneity levels
to solve the governing partial differential equation in variably saturated soils was
used to simulate field scale water flow to investigate the impact of soil heterogeneity
and root water uptake on subsurface flow dynamics in cropped fields. Soil moisture, suction head and hydraulic conductivity were observed to be significantly
affected by heterogeneity of the media and root water uptake. Soil heterogeneity
was found to increase soil water content while root water uptake was decreasing it.
The effect of root water uptake on soil moisture distribution was more pronounced
under homogenous soils than in heterogeneous soils. Soil suction head decreases
with increasing soil heterogeneity whether root water uptake was considered or not.
Hydraulic conductivity increases with increasing soil heterogeneity when root water
uptake was ignored, and it depends on the heterogeneity level when root water uptake
was accounted.
Keywords Soil heterogeneity · Cropped fields · Numerical simulation · Richards
equation
1 Introduction
The natural variability exhibited by soil hydraulic properties poses severe challenges
to modeling of water movement through the porous formation in cropped fields [1–
3]. The relationship between soil physical and hydraulic properties at different scales
has been investigated [4], and one- or two-order degree of spatial variability in soil
hydraulic conductivity has been observed [2, 5–8].
E. Yetbarek (B) · R. Ojha
Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
e-mail: ephrem@iitk.ac.in
© Springer Nature Singapore Pte Ltd. 2021
C. Bhuiyan et al. (eds.), Water Security and Sustainability,
Lecture Notes in Civil Engineering 115,
https://doi.org/10.1007/978-981-15-9805-0_1
3
in Agricultural Fields
with Heterogeneous Unsaturated Soils
Ephrem Yetbarek and Richa Ojha
Abstract The natural variability exhibited by soil hydraulic properties poses severe
challenges to model water movement through porous formations in agricultural fields.
In this study, a 3D numerical approach coupled with the turning bands method to
generate realizations of soil formation properties with different heterogeneity levels
to solve the governing partial differential equation in variably saturated soils was
used to simulate field scale water flow to investigate the impact of soil heterogeneity
and root water uptake on subsurface flow dynamics in cropped fields. Soil moisture, suction head and hydraulic conductivity were observed to be significantly
affected by heterogeneity of the media and root water uptake. Soil heterogeneity
was found to increase soil water content while root water uptake was decreasing it.
The effect of root water uptake on soil moisture distribution was more pronounced
under homogenous soils than in heterogeneous soils. Soil suction head decreases
with increasing soil heterogeneity whether root water uptake was considered or not.
Hydraulic conductivity increases with increasing soil heterogeneity when root water
uptake was ignored, and it depends on the heterogeneity level when root water uptake
was accounted.
Keywords Soil heterogeneity · Cropped fields · Numerical simulation · Richards
equation
1 Introduction
The natural variability exhibited by soil hydraulic properties poses severe challenges
to modeling of water movement through the porous formation in cropped fields [1–
3]. The relationship between soil physical and hydraulic properties at different scales
has been investigated [4], and one- or two-order degree of spatial variability in soil
hydraulic conductivity has been observed [2, 5–8].
E. Yetbarek (B) · R. Ojha
Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
e-mail: ephrem@iitk.ac.in
© Springer Nature Singapore Pte Ltd. 2021
C. Bhuiyan et al. (eds.), Water Security and Sustainability,
Lecture Notes in Civil Engineering 115,
https://doi.org/10.1007/978-981-15-9805-0_1
3