Learn more about the water fluxes in the Critical Zone

Underneath the soil surface, there is a place where water fills the free spaces left between sand, gravel, and other rock.
This is one of the places where water is stored within the Critical Zone.
This water has a special name: GROUNDWATER.
Groundwater can be very old. Or can be very young. This depends on how much water enters and how much water leaves this place of saturated underground material.

Groundwater is recharged by the water flowing from the surface. Rain, snow, glaciers’ melting, infiltration from rivers and lakes provide the water.
Groundwater is discharged by flowing to the surface. It can go back to the soil or flow back into rivers and lakes; it can be absorbed by plant roots and be transferred to the atmosphere; it can be withdrawn for human consumption.
The rate of recharge and discharge is different in different climates, soils, or land use types.

It is very important to understand the balance between recharge and discharge. And water stable isotopes can provide important information to help researchers and stakeholders to understand it.