Effects of Climate Type and Temporal Variability in Meteorological Input Data in Modeling of Salt Transport in Unsaturated Soils

Oilfield produced brine is a major source of salt contamination in soil and groundwater. Salt transport in the upper soil layers is controlled by the atmospheric interactions via infiltration of meteoritic water. In lower layers, it is controlled by fluctuations in groundwater table, which are also linked to atmospheric interactions via groundwater recharge. Therefore, climate is an important factor in the movement of contaminants in the unsaturated zone. A one-dimensional variably saturated flow and transport model with soil atmospheric boundary condition was used to estimate the effect of climate type and soil texture on soil water and salt dynamics in variably saturated soils. Numerical simulations were run with Hydrus-1D, using daily and sub-daily climate. Simulations were run for nine-year climate datasets for ten different ecoclimatic locations in Alberta, Canada. Results show that flow and transport are function of climate type. Results also indicated that higher temporal resolutions of precipitation data resulted in higher net infiltration values. Higher net infiltration values resulted in faster solute displacement, especially, if the precipitation events were assumed to occur outside the evaporation hours. Minimal to no interaction was observed between groundwater table and atmosphere in coarse-grained soil material, especially in wetter climatic conditions. Keywords: Variably saturated soils, climate, soil-atmosphere boundary, water and salt dynamics, groundwater table