Reactive transport modelling to infer changes in soil hydraulic properties induced by non-conventional water irrigation

Research output: Contribution to journalArticlepeer-review

Authors

  • Javier Valdes-Abellan
  • Joaquín Jiménez-Martínez
  • Lucila Candela
  • Diederik Jacques
  • Claus Kohfahl
  • Karim Tamoh

Institutes & Expert groups

  • University of Alicante
  • ETHZ - Eidgenösslsche Technische Hochshule Zürich
  • UPC - Universitat Politècnica de Catalunya
  • IGME - Geological Survey of Spain

Documents & links

Abstract

The use of non-conventional water (e.g., treated wastewater, desalinated water) for different purposes is increasing in many water scarce regions of the world. Its use for irrigation may have potential drawbacks, because of mineral dissolution/precipitation processes, such as changes in soil physical and hydraulic properties (e.g., porosity, permeability), modifying infiltration and aquifer recharge processes or blocking root growth. Prediction of soil and groundwater impacts is essential for achieving sustainable agricultural practices. A numerical model to solve unsaturated water flow and non-isothermal multicomponent reactive transport has been modified implementing the spatio-temporal evolution of soil physical and hydraulic properties. A long-term process simulation (30 years) of agricultural irrigation with desalinated water, based on a calibrated/validated 1D numerical model in a semi-arid region, is presented. Different scenarios conditioning reactive transport (i.e., rainwater irrigation, lack of gypsum in the soil profile, and lower partial pressure of CO2 (pCO2)) have also been considered. Results show that although boundary conditions and mineral soil composition highly influence the reactive processes, dissolution/precipitation of carbonate species is triggered mainly by pCO2, closely related to plant roots. Calcite dissolution occurs in the root zone, precipitation takes place under it and at the soil surface, which will lead a root growth blockage and a direct soil evaporation decrease, respectively. For the studied soil, a gypsum dissolution up to 40 cm depth is expected at long-term, with a general increase of porosity and hydraulic conductivity.

Details

Original languageEnglish
Pages (from-to)114-124
Number of pages11
JournalJournal of Hydrology
Volume549
DOIs
Publication statusPublished - 1 Jun 2017

Keywords

  • soil, non-conventional water, reactive transport, physical properties, hydraulic properties

ID: 3051133