Under the provisions of the Murray Darling Basin Plan (the Basin Plan) 2012, Victoria is required to prepare Water Resource Plans (WRPs) for five WRP areas.
Alluvium was engaged to undertake a preliminary risk assessment to inform the development of these WRPs. The WRP areas are set out in the following figure.
The approach adopted for the risk assessment aligns with international and national standards for risk assessment, with risk being assessed as the product of the likelihood and consequence of a threat impacting on an asset. In accordance with the provisions of the Basin Plan, levels of risk assigned to events and their consequences have been defined in a manner consistent with AS/NZS ISO 31000:2009 Risk management – Principles and guidelines.
Over 7,000 individual risk assessments were generated, comprising discreet assessments of the probability of a cause occurring, the susceptibility of each threat to that cause and the sensitivity of the beneficial uses to each threat in each of the five WRP areas. However not all discreet assessments generate plausible risks. Some combinations of cause, threat and beneficial use will not create a risk. As an example changes to the timing of surface water delivery, will not impact on groundwater quality. The exclusion of the non-plausible risks resulted in the identification of over 3,300 plausible discrete risks across the five WRP areas.
These plausible risks were compiled and amalgamated based on three broad categories of threat (water availability, water quality condition and water resource structural condition) and four broad beneficial use categories (environment, consumptive, social and indigenous). Approximately 500 risks have been identified based on this grouping of threats and beneficial uses. These risks include approximately 300 moderate to very high risks across the five WRP areas.
Over 95% of the discrete risks identified were found to be associated with at least one of the following eight (8) themes:
- climate change
- extreme drought
- continuation of existing land use practice
- suspended sediments and nutrients
- other water quality issues (DO, pH, water temperature)
- a reduction in the volume of water
- Beneficial uses
- the availability (or absence) of water for Indigenous cultural use