Table 18: Risk matrix adopted to identify the Sustainability Factor (from CSIRO and SKM 2010, page 17) Showing results for the Western Porous Rock SDL resource unit (MDBA 2013a) Step A* Step B Step C Risk Productive Sustainability Environmental Assets or Ecosystem function or Key environmental outcome Degree of uncertainty Ranking base factor (SF) High EA that is highly In the current state, Storage / 0.1 No risk to the key No reduction to Step A risk ranking high or groundwater dependent groundwater discharge recharge environmental SF for any salinity medium and highly sensitive to provides baseflow to ratio <20 outcome (i.e. class Uncertainty No reduction take the unregulated river groundwater is low to SF reach. Groundwater salinity) extraction is likely to There is risk to the Salinity class 1 Uncertainty SF reduced – result in streamflow key environmental SF reduced by is high by 50% depletion outcome (i.e. 20% groundwater Medium EA that is highly The rivers in the SDL Storage / 0.5 Salinity class 2 – salinity) groundwater dependent unit are regulated and recharge SF reduced by and moderately they are highly ratio 20 40 10% – sensitive to take connected to groundwater (i.e. >50% EA that is moderately impact of pumping on groundwater dependent streamflow) and highly sensitive to take Low EA that has low The rivers in the SDL Storage / 0.7 Step A risk ranking is low groundwater unit are regulated or recharge dependence and low unregulated and they ratio > 40 Uncertainty No reduction sensitivity to take have low-moderate is low to SF connection with the EAs do not exist in the groundwater system SDL unit Uncertainty SF reduced (i.e. <50% impact of is high by 50% pumping on streamflow * Overall risk set to the highest ranking across the three criteria.
Table 18: Risk matrix adopted to identify the Sustainability Factor (from CSIRO and SKM 2010, page 17) Step A* Risk Ranking Environmental Assets or Ecosystem function or Productive base Sustainability factor (SF) High EA that is highly groundwater dependent and highly sensitive to take In the current state, groundwater discharge provides baseflow to the unregulated river reach. Groundwater extraction is likely to result in streamflow depletion Storage / recharge ratio <20 0.1 Medium EA that is highly groundwater dependent and moderately sensitive to take EA that is moderately groundwater dependent and highly sensitive to take The rivers in the SDL unit are regulated and they are highly connected to groundwater (i.e. >50% impact of pumping on streamflow) Storage / recharge ratio 20 – 40 0.5 Low EA that has low groundwater dependence and low sensitivity to take EAs do not exist in the SDL unit The rivers in the SDL unit are regulated or unregulated and they have low-moderate connection with the groundwater system (i.e. <50% impact of pumping on streamflow Storage / recharge ratio > 40 0.7 * Overall risk set to the highest ranking across the three criteria. Showing results for the Western Porous Rock SDL resource unit (MDBA 2013a) Step B Step C Key environmental outcome Degree of uncertainty No risk to the key environmental outcome (i.e. groundwater salinity) No reduction to SF for any salinity class Step A risk ranking high or medium Uncertainty is low No reduction to SF There is risk to the key environmental outcome (i.e. groundwater salinity) Salinity class 1 – SF reduced by 20% Salinity class 2 – SF reduced by 10% Uncertainty is high SF reduced by 50% Step A risk ranking is low Uncertainty is low No reduction to SF Uncertainty is high SF reduced by 50%
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