18.5 Discharge to off-channel water storage

Supporting Information

Groundwater discharge to off-channel water storages could not be quantified in a way that is complete, neutral and free from material error.

There are 65 catchment dams within the Western Mount Lofty Ranges Prescribed Water Resources Area that are flagged as spring-fed dams with a combined storage capacity of 245 ML. A spring-fed dam receives a longer period of inflow than a pure local catchment runoff dam. In a typical year most local catchment runoff dams only fill once throughout winter and spring; but a spring-fed dam may receive inflow while the water is being taken. This allows more water to be taken than the capacity of the dam.

The volume of groundwater discharge to off-channel water storages provides important information regarding the amount of water available for use from spring-fed dams. Therefore the omission of this information is highly relevant to the users of the National Water Account. However its omission is not expected to have a material impact on the groundwater balance.