Stochastic Modeling of Salt Accumulation in the Root Zone Due to Capillary Flux from Brackish Groundwater

Authors

S. H.H. Shah, Wageningen University & Research
R. W. Vervoort, The University of Sydney
S. Suweis, Ecole Polytechnique Fédérale de Lausanne
Andrew J. Guswa, Smith CollegeFollow
A. Rinaldo, Ecole Polytechnique Fédérale de Lausanne
S. E.A.T.M. Van Der Zee, Wageningen University & Research

Document Type

Article

Publication Date

9-13-2011

Publication Title

Water Resources Research

Abstract

Groundwater can be a source of both water and salts in semiarid areas, and therefore, capillary pressure-induced upward water flow may cause root zone salinization. To identify which conditions result in hazardous salt concentrations in the root zone, we combined the mass balance equations for salt and water, further assuming a Poisson-distributed daily rainfall and brackish groundwater quality. For the water fluxes (leaching, capillary upflow, and evapotranspiration), we account for osmotic effects of the dissolved salt mass using Vant Hoff's law. Root zone salinity depends on salt transport via capillary flux and on evapotranspiration, which concentrates salt in the root zone. Both a wet climate and shallow groundwater lead to wetter root zone conditions, which in combination with periodic rainfall enhances salt removal by leaching. For wet climates, root zone salinity (concentrations) increases as groundwater is more shallow (larger groundwater influence). For dry climates, salinity increases as groundwater is deeper because of a drier root zone and less leaching. For intermediate climates, opposing effects can push the salt balance either way. Root zone salinity increases almost linearly with groundwater salinity. With a simple analytical approximation, maximum concentrations can be related to the mean capillary flow rate, leaching rate, water saturation, and groundwater salinity for different soils, climates, and groundwater depths.

Volume

47

Issue

9

DOI

10.1029/2010WR009790

ISSN

00431397

Rights

Copyright 2011 by the American Geophysical Union

Comments

Archived as published.

Recommended Citation

Shah, S. H.H.; Vervoort, R. W.; Suweis, S.; Guswa, Andrew J.; Rinaldo, A.; and Van Der Zee, S. E.A.T.M., "Stochastic Modeling of Salt Accumulation in the Root Zone Due to Capillary Flux from Brackish Groundwater" (2011). Engineering: Faculty Publications, Smith College, Northampton, MA.
https://scholarworks.smith.edu/egr_facpubs/32