Risk Management
Risk management approaches are commonly used in the management of surface water reservoirs. For example, dams are drawn down during drought periods based on the assessment that there is a high probability that dam levels will recover during the planning timeframe. This acknowledges the high variability of rainfall in Australia. Similar risk management approaches can be taken for connected water resources, to take advantage of the different characteristics of surface and aquifer storages.
Taking a risk management approach in conjunctive water management can involve:
- using aquifers as a drought reserve by allowing temporary depletion of groundwater storage beyond the rate of recharge, based on the assessment that there is adequate provision for groundwater dependent ecosystems, that groundwater recovery can be achieved over the planning timeframe and that there is no long-term impacts on the water quality (REM, 2002). In many catchments, aquifers can provide greater storage volumes than existing surface water reservoirs;
- coordinating the replenishment and withdrawal of both surface water and groundwater storages in the catchment to better management climate variability. This can mean switching between these storages depending on catchment conditions. During non-drought periods water is released from surface reservoirs for water users and for aquifer replenishment while groundwater is the dominant water source during drought periods; and
- using climate predictions or long-term rainfall forecasts, such as correlations between El Nino/Southern Oscillation (ENSO) or Inter-Decadal Pacific Oscillation (IPO) indices and water availability to assess future risk.
Relevant Links
BRS Rainfall Reliability Wizard
BRS National Agricultural Monitoring System
LWA Managing Climate Variability
References
REM 2002. Watermark: Sustainable groundwater use within irrigated regions. Project 2: Conjunctive resource management, milestone 2 final report. Prepared for the Murray Darling Basin Commission, Australia.