Unconfined aquifers
These aquifers are very responsive to rainfall and pumping. They exhibit a seasonal pattern that mimics rainfall and pumping –
Semi-confined and confined aquifers
These aquifers are less susceptible to changes in rainfall and pumping as they are protected by overlying
Very deep confined aquifers
These aquifers show no relationship at all to rainfall patterns as they are buried under many layers of aquifers and aquitards. They do respond to pumping, however the effects may not be seen immediately as there is generally vast volumes of groundwater held in storage which balance out any extraction.
Groundwater flow systems and response to change
How groundwater responds to change is also influenced by flow systems as discussed on our How does groundwater move page. Groundwater that flows through local flow systems reacts quickly to changes in pumping or climate and the impact is greater. In regional flow systems the impact may not be seen for many, many years and the impact will be more subdued.
Response to change
This graph show how groundwater responds to change in different flow systems over time. Diagram: ©Spatial Vision Innovations Pty Ltd (2015)