Open AccessUsing Surface Time Domain Reflectometry Measurements to Estimate Subsurface Chemical Movement
Author(s) -
Gaur Anju,
Horton Robert,
Jaynes Dan B.,
Lee Jaehoon,
AlJabri Salem A.
Publication year - 2003
Publication title -
vadose zone journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.036
H-Index - 81
ISSN - 1539-1663
DOI - 10.2136/vzj2003.5390
Subject(s) - reflectometry , vadose zone , soil science , subsurface flow , groundwater , tracer , soil horizon , environmental science , surface layer , soil water , hydrology (agriculture) , geology , time domain , chemistry , layer (electronics) , geotechnical engineering , physics , computer science , nuclear physics , computer vision , organic chemistry
Chemicals that leach through soil pose threats to surface and groundwater quality. It is difficult and expensive to measure subsurface chemical transport and the transport properties required for extrapolating predictions beyond limited observations. The objective of our study was to evaluate whether solute transport properties measured at the soil surface could be used to predict subsurface chemical movement. The study was conducted in a greenhouse soil pit. The solute transport properties of the surface 2‐cm soil layer were determined by using time domain reflectometry (TDR) to measure the bulk electrical conductivity during a step application of CaCl 2 solution. The movement of chemicals in the subsurface was measured within the top 30 cm of soil following a pulse input of CaCl 2 solution. A comparison of the measured chemical transport properties in the surface and subsurface zones of the soil showed that the parameters were similar. Furthermore, the estimated parameters determined by the surface TDR method were used to predict the chemical concentration distributions within the 30‐cm soil layer, and it was found that the centers of mass of predicted chemical distributions were not significantly different from the measured ones. Therefore, the surface TDR measurements could be used to successfully predict subsurface chemical transport within the upper 30 cm of the soil. This surface measurement technique is a promising tool for vadose zone chemical transport studies.