Exploring ecohydrology – how vegetation and rainfall drive changes in groundwater

John Webb explores how rainfall, vegetation, and soil processes shape the composition of groundwater in Southern Australia.

The dominant source of the species in groundwater has come from rainfall, which contains varying amounts of dissolved sea spray and dust. There is a limited contribution from interaction between groundwater and aquifer minerals (carbonates and silicates), but no contribution from the inland sea that formerly covered parts of Australia.

Rainfall infiltrates downwards through the soil to become groundwater and is impacted by vegetation along the way. Groundwater salinity is much greater than rainfall salinity, largely due to transpiration by plants. Plants need particular species (K, S, C, Ca) for growth, and preferential uptake of these species alters the composition of soil water and therefore groundwater. They draw water from the soil and leave salts behind, increasing salinity, which remove water from the soil but leave many of the dissolved species behind.

Learn how these natural processes—and shifts in vegetation and climate—impact groundwater quality, salinity, and sustainability.