Long‑term water resource assessments (LTWRAs) help us monitor the state of our water resources. Under the Water Act 1989 (the Act) we perform a LTWRA every 15 years so we have the best information available when we’re creating water policy.

The first LTWRA started for Victoria in August 2018.

Requirement under the Water Act 1989

Under the Water Act 1989 s.22(L), a long-term water resources assessment must identify whether either or both of the following has occurred:

  1. there has been any decline in the long-term availability of surface water or groundwater and whether the decline has fallen disproportionately on the environmental water reserve or on the allocation of water for consumptive purposes;
  2. there has been any deterioration in waterway health for reasons related to flow.


The assessment will use the best available data and modelling to see if long-term water availability has declined, and if there has been a disproportionate effect either on the environment or allocations to people and industries consuming water.  These assessments will also check if waterway health has deteriorated because of changing streamflow patterns.  

If the assessment identifies that either of these two issues has happened, we will hold a review to see how we can balance the needs of the environment and everyone in Victoria who needs water for drinking, farming or other business (also called “consumptive use”) The review will be open and consultative and will consider relevant social, environmental and economic needs.

More information

Download methodology fact sheet (DOCX, 797.9 KB)

Page last updated: 25/07/19