Soil water movement estimated from isotope tracers

Open Access
Publisher Website
Google Scholar
Abstract
The natural isotope oxygen-18 and artificially injected tritium are used for studying the percolation of soil water. Particle velocity, progression rate and soil moisture flux are distinguished from each other. Water particle velocities and seasonal groundwater recharge are determined in glacio-fluvial deposits and in till soils. In the glacio-fluvial deposits of the Uppsala Esker it is found that the groundwater recharge is distributed rather uniformly over the year, although high soil moisture flux near the ground surface is caused by single episodes. The travel time of a water particle from the ground surface to the groundwater level at about 4 m depth is two to three years. In the more heterogeneous moraine areas, the dispersion of the marked water is considerable. However, the origin of water recharging the groundwater can be determined. The vertical distance travelled by the fastest moving water particles in one year does not exceed 10 m.