Preprints
https://doi.org/10.5194/hess-2020-527
https://doi.org/10.5194/hess-2020-527

  21 Oct 2020

21 Oct 2020

Review status: a revised version of this preprint was accepted for the journal HESS and is expected to appear here in due course.

Simulation of reactive solute transport in the critical zone: A Lagrangian model for transient flow and preferential transport

Alexander Sternagel1, Ralf Loritz1, Julian Klaus2, Brian Berkowitz3, and Erwin Zehe1 Alexander Sternagel et al.
  • 1Karlsruhe Institute of Technology (KIT), Institute of Water Resources and River Basin Management, Hydrology, Germany
  • 2Luxembourg Institute of Science and Technology (LIST), Environmental Research and Innovation Department, Catchment and Eco-Hydrology Research Group, Luxembourg
  • 3Department of Earth and Planetary Sciences, Weizmann Institute of Science, Israel

Abstract. We present an approach to simulate reactive solute transport within the Lagrangian Soil Water and Solute Transport Model framework (LAST). The LAST-Model is based on a Lagrangian perspective describing the (1-D) movement of discrete water particles, which travel at different velocities and carry solutes through a heterogeneous, partially saturated soil that is separated into a soil matrix and structural macropore domain.

In this study, we implement an approach to represent non-linear sorption and first-order degradation processes of reactive solutes under well-mixed and preferential flow conditions in the critical zone. The intensity of the two reactive transport processes may vary with the soil depth, to account for topsoil that facilitates enhanced microbial activity (and hence sorption) as well as chemical turnover rates. This expanded LAST-Model is evaluated with simulations of conservative tracer transport and reactive transport of the herbicide Isoproturon, at different flow conditions, and compared to data from field experiments. Additionally, the model is compared to simulations from the commonly used HYDRUS 1-D model. Both models show equal performance at a matrix flow dominated site, but LAST better matches indicators of preferential flow at a macropore flow dominated site. These results demonstrate the feasibility of the approach to simulate reactive transport in the LAST-Model framework, and highlight the advantage of the structural macropore domain to cope with preferential bypassing of topsoil and subsequent re-infiltration into the subsoil matrix.

Alexander Sternagel et al.

 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Alexander Sternagel et al.

Alexander Sternagel et al.

Viewed

Total article views: 463 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
357 99 7 463 6 12
  • HTML: 357
  • PDF: 99
  • XML: 7
  • Total: 463
  • BibTeX: 6
  • EndNote: 12
Views and downloads (calculated since 21 Oct 2020)
Cumulative views and downloads (calculated since 21 Oct 2020)

Viewed (geographical distribution)

Total article views: 287 (including HTML, PDF, and XML) Thereof 280 with geography defined and 7 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 05 Mar 2021
Download
Short summary
Key innovation of this study is an approach to simulate reactive solute transport in the vadose zone within a Lagrangian model. The new reactive solute transport routine accounts for sorption and degradation processes during transport of reactive substances through a partially saturated soil domain. Model evaluation using bromide and IPU data from field experiments under different flow conditions shows the feasibility of the approach. Comparisons to HYDRUS 1-D results corroborate this finding.