What impacts groundwater levels?

Changes in climate

Changes in climate can impact groundwater levels in two ways – lower rainfall results in less recharge and higher temperatures increase the rate of evapotranspiration. On average, approximately 10% of rainfall becomes recharge to groundwater. This means that during periods of low rainfall or drought groundwater levels can decline, especially in areas where water is extracted for use.

Evapotranspiration

In some areas where groundwater is vital to the health of ecosystems evapotranspiration can account for more groundwater use than extraction from bore. During warm or hot weather trees and plants look for more water to survive and evaporation of water from the ground surface also increases. 

Pumping (bore interference)

If your bore occurs near another bore and is within its cone of influence interference can occur. This means that when the nearby bore is being pumped there may not be enough groundwater in your bore to achieve the usual yield.

When the total rate of extraction in an area exceeds the rate of recharge groundwater levels will drop on a regional scale. This can lead to consistently lower bore yields, increased pumping costs and environmental changes such as sea water intrusion.

Cone of influence

This diagram shows how a cone of influence is formed that extends outwards from a bore when groundwater is pumped. Diagram: ©Spatial Vision Innovations Pty Ltd (2015)