There are four types of water resources in Victoria:
1) Surface Water is water that occurs or flows on land, including waterways, lakes, reservoirs, dams and wetlands.
2) Groundwater is any water occurring underground.
3) Recycled water is derived from sewerage systems or industry processes and is treated to a standard appropriate for its intended use.
4) Desalination water is seawater treated to a standard appropriate for its intended use.
Victoria’s rivers and waterways can be broadly categorised as either regulated or unregulated systems. In regulated systems, the flow of water in the waterway is regulated and captured through the operation of large dams or weirs. In these systems, the dams, weirs and other flow-regulating structures significantly transform the natural variability of streamflow into a more reliable supply of water.
Unregulated systems are waterways that do not have large dams or weirs controlling the streamflow. Water is taken directly from these systems by pumps or diverted to off-stream storages. The volume of water available is based on rainfall and runoff, not on storage.
Groundwater is found in the spaces and fractures in rock and sediment underground. Ground water accumulates when rainfall, surface water or snowmelt seeps down from the surface and reaches the water table. When groundwater is held within a geological formation that allows water to flow through, known as an aquifer, it can be pumped to the surface for use.
The flow of groundwater can vary. Some users pump groundwater from a bore and store it for use. Elsewhere, groundwater is artesian, flowing naturally due to pressure in a deep aquifer. The salinity of the groundwater is often the key determinant as to whether it is suitable for consumptive use.
Highly treated wastewater can be treated for a range of non-drinking uses, including irrigation for agriculture.
Desalination is the process of removing salinity (dissolved salts) from water. Treated water can be used for a range of purposes, including irrigation.