Climate change and groundwater

Groundwater losses are certainly not the first thing one thinks about when climate change is mentioned.

There is a connection: saltwater intrusion.

According to an article posted on Scitizen this is how the process works:

Saltwater intruding from the ocean into the aquifer due to sea-level rise mixes with inland freshwater and creates a zone of brackish water. Previous studies have shown that saltwater would penetrate underground only as far as it did above ground in aquifers consisting of coarse sands and create a relatively sharp boundary between saltwater and freshwater. Our research, however, shows that when saltwater intrudes into a fresh water aquifer they mix intensively. The size of this mixing zone greatly depends on the stratigraphic structures of the sand layers in the coastal aquifer.

In general, coastal aquifers are made of different sandy and silty layers that have formed over time. Some layers may contain coarse sand, and others may contain fine sand and silt. Fine sand and silt tend to permit less water flow, while coarse sand allows more water flow. We simulated coastal aquifers consisting of realistic layers containing sands and silt. The simulation results showed that more mixing occurs between the saltwater and freshwater as the complexity of the aquifer's stratigraphy increases. This is because different water velocities in layers create complex flow paths in the aquifer.