Estimating Soil Hydraulic and Solute Transport Parameters in Subsurface Drainage Systems Using an Inverse Modelling Approach

2017 ◽  
Vol 67 ◽  
pp. 82-90 ◽  
Author(s):  
Amir Sedaghatdoost ◽  
Hamed Ebrahimian ◽  
Abdolmajid Liaghat
Keyword(s):  
Solute Transport ◽  
Subsurface Drainage ◽  
Inverse Modelling ◽  
Transport Parameters ◽  
Drainage Systems ◽  
Soil Hydraulic ◽  
Modelling Approach

scholarly journals Measurement of Field Soil Hydraulic and Solute Transport Parameters

1998 ◽  
Vol 62 (5) ◽  
pp. 1172-1178 ◽  
Author(s):  
Francis X. M. Casey ◽  
Robert Horton ◽  
Sally D. Logsdon ◽  
Dan B. Jaynes
Keyword(s):  
Solute Transport ◽  
Field Soil ◽  
Transport Parameters ◽  
Soil Hydraulic

scholarly journals Field scale variability of solute transport parameters and related soil properties

1997 ◽  
Vol 1 (4) ◽  
pp. 801-811 ◽  
Author(s):  
B. Lennartz ◽  
S. K. Kamra ◽  
S. Meyer-Windel
Keyword(s):  
Soil Properties ◽  
Solute Transport ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Preferential Flow ◽  
Type I ◽  
Transport Parameters ◽  
Undisturbed Soil ◽  
Soil Hydraulic

Abstract. The spatial variability of transport parameters has to be taken into account for a reliable assessment of solute behaviour in natural field soils. Two field sites were studied by collecting 24 and 36 small undisturbed soil columns at an uniform grid of 15 m spacing. Displacement experiments were conducted in these columns with bromide traced water under unsaturated steady state transport conditions. Measured breakthrough curves (BTCs) were evaluated with the simple convective-dispersive equation (CDE). The solute mobility index (MI) calculated as the ratio of measured to fitted pore water velocity and the dispersion coefficient (D) were used to classify bromide breakthrough behaviour. Experimental BTCs were classified into two groups: type I curves expressed classical solute behaviour while type II curves were characterised by the occurrence of a bromide concentration maximum before 0.35 pore volumes of effluent (MI<0.35) resulting from preferential flow conditions. Six columns from site A and 8 from site B were identified as preferential. Frequency distributions of the transport parameters (MI and D) of both sites were either extremely skewed or bimodal. Log-transformation did not lead to a normal distribution in any case. Contour maps of bromide mass flux at certain time steps indicated the clustering of preferential flow regions at both sites. Differences in the extent of preferential flow between sites seemed to be governed by soil structure. Linear cross correlations among transport parameters and independently measured soil properties revealed relations between solute mobility and volumetric soil water content at time of sampling, texture and organic carbon content. The volumetric field soil water content, a simple measure characterising the soil hydraulic behaviour at the sampling location, was found to be a highly sensitive parameter with respect to solute mobility and preferential flow situations. Almost no relation was found between solute transport parameters and independently determined soil properties when non-preferential and preferential samples were considered separately in regression analyses. Future work should concentrate to relate integrated parameters such as the infiltration rate or the soil hydraulic functions to solute mobility under different flow situations.

scholarly journals Inverse modelling for predicting both water and nitrate movement in a structured-clay soil (Red Ferrosol)

PeerJ ◽  
2019 ◽  
Vol 6 ◽  
pp. e6002 ◽  
Author(s):  
James M. Kirkham ◽  
Christopher J. Smith ◽  
Richard B. Doyle ◽  
Philip H. Brown
Keyword(s):  
Adsorption Isotherm ◽  
Solute Transport ◽  
Water Flow ◽  
Hydraulic Properties ◽  
Transport Processes ◽  
Inverse Modelling ◽  
Diffusion Experiment ◽  
Soil Hydraulic Properties ◽  
Soil Columns ◽  
Soil Hydraulic

Soil physical parameter calculation by inverse modelling provides an indirect way of estimating the unsaturated hydraulic properties of soils. However many measurements are needed to provide sufficient data to determine unknown parameters. The objective of this research was to assess the use of unsaturated water flow and solute transport experiments, in horizontal packed soil columns, to estimate the parameters that govern water flow and solute transport. The derived parameters are then used to predict water infiltration and solute migration in a repacked soil wedge. Horizontal columns packed with Red Ferrosol were used in a nitrate diffusion experiment to estimate either three or six parameters of the van Genuchten–Mualem equation while keeping residual and saturated water content, and saturated hydraulic conductivity fixed to independently measured values. These parameters were calculated using the inverse optimisation routines in Hydrus 1D. Nitrate concentrations measured along the horizontal soil columns were used to independently determine the Langmuir adsorption isotherm. The soil hydraulic properties described by the van Genuchten–Mualem equation, and the NO3–adsorption isotherm, were then used to predict water and NO3–distributions from a point-source in two 3D flow scenarios. The use of horizontal columns of repacked soil and inverse modelling to quantify the soil water retention curve was found to be a simple and effective method for determining soil hydraulic properties of Red Ferrosols. These generated parameters supported subsequent testing of interactive flow and reactive transport processes under dynamic flow conditions.

scholarly journals HYDRUS-2D Simulations of nitrate nitrogen and potassium transport characteristics under fertilizer solution infiltration of furrow irrigation

2020 ◽  
Author(s):  
Wei-Bo Nie ◽  
Kun-Kun Nie ◽  
Yi-Bo Li ◽  
Xiao-Yi Ma
Keyword(s):  
Solute Transport ◽  
Water Content ◽  
Nitrate Nitrogen ◽  
Sandy Loam ◽  
Furrow Irrigation ◽  
Distribution Range ◽  
Transport Parameters ◽  
Empirical Parameter ◽  
Vertical Range ◽  
Soil Hydraulic

Abstract Understanding the characteristics of soil solute transport is fundamental to the design and management of furrow irrigation systems. This study determined the soil hydraulic and solute transport parameters by inverse solution with HYDRUS-2D and then verified them. The experimental data were obtained from the infiltration of clay loam and sandy loam of different potassium nitrate (KNO3) concentrations under furrow irrigation. Then, the initial soil water content (θ0), KNO3 concentration, and water depth (h0) affecting the transport characteristics of nitrate nitrogen (NO3−-N) and potassium (K+) were analyzed. The results indicated that the soil hydraulic and solute transport parameters determined from the inversion solution with HYDRUS-2D were reliable. The soil saturated water content, saturated hydraulic conductivity, and empirical parameter n in the van Genuchten–Mualem model increase with the increase of KNO3 concentrations, whereas the empirical parameter a shows a decreasing tendency. The distribution range of NO3−-N increased with the increases of θ0 and the KNO3 concentration, which had barely any effect on the range of K+ distribution. The horizontal distribution range of NO3−-N and K+ increased with the increase of h0, but it had no obvious influence on the vertical range.

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