Schedule 6—Default method for calculation of supply contribution
Note: See section 7.15.
Part 1—Description
(a) identify the hydrological model of the Basin that is to be used for the calculations (the benchmark model—this is the model that was used to arrive at the unadjusted SDL, with some modifications);
(b) identify the indicator sites and regions that are to be used in applying the method (these will be chosen to be representative, while ensuring that areas of high ecological value are given due weight);
(c) identify the flow regime characteristics that are to be used as a measure of environmental outcomes, and that are to be measured or assessed in relation to those indicator sites;
(e) identify the method of comparison between the benchmark environmental outcomes and another set of environmental outcomes—this will use a scoring method, including preference curves and weightings for environmental significance. A higher score will represent a preferable environmental outcome;
(f) identify the limits of changes in score or outcome that ensure that supply contributions maintain environmental outcomes within identified limits;
(iii) compare the environmental outcomes against the benchmark environmental outcomes and assess whether the score is equivalent or higher;
(v) repeat with successive test supply contributions until the largest contribution is found that still results in an equivalent or higher score;
Part 2—Method
(b) incorporate appropriate rules for delivery of water from the Lower Lakes into the Coorong, including relating Lake level to release volumes;
(d) incorporate updated environmental watering event time‑series for without development and baseline model runs in the environmental event selection tool;
(e) remove the operation of the Living Murray works and use the component of the Living Murray water that was used by the works for floodplain outcomes;
(g) set environmental flow demands for the Goulburn River consistent with the flow event targets described in MDBA 2012a.
Note: Refinements to the MDBA model run 847 will be undertaken in consultation with Basin jurisdictions through the Basin Officials Committee.
(2) The benchmark pattern of reliability of supply to entitlement holders for subparagraph 7.15(1)(d) is that provided for in the benchmark model run.
Note: As the Living Murray works and measures have been removed from the benchmark model under S6.02(1)(e) above, the full benefit of them can be considered for an SDL adjustment.
(b) must take into account the following policy settings included in the benchmark model to the extent that, at the time the method is applied, the specific settings used in the benchmark model are not expected to be, or were not, implemented by 2019:
Schedule Sch 6 - Basin Plan 2012 - Default method for calculation of supply contribution | Zoe
Note: In finalising these policies, Basin States and the Commonwealth would need to ensure any associated third party impacts associated with these policies are assessed and addressed as appropriate.
(1) The indicator sites, and corresponding river reaches and associated floodplains, that are to be used are those used in the development of the Environmentally Sustainable Level of Take (ESLT) method (the ESLT method) for which detailed assessments of environmental water requirements were done.
(2) Each reach is to incorporate one hydrologic indicator site (HIS) used in the ESLT method for which detailed assessments of environmental water requirements were done.
(a) the Northern Basin region, which includes all rivers in the Basin upstream of the upstream extent of the Menindee Lakes; and
(b) the Southern Basin region, which includes the River Murray upstream of the boundary of the Coorong, Lower Lakes and Murray Mouth Ramsar site and all connected tributaries apart from the Northern Basin; and
(c) 2 disconnected rivers regions, the Lachlan and Wimmera Rivers, if supply contributions are proposed within these valleys.
Note: The Coorong, Lower Lakes and Murray Mouth Ramsar site cannot be scored in the same way as other sites and reaches. Paragraph S6.07(c) provides limits for changes in score or outcomes for this site.
(3) The benchmark environmental outcomes are those scores calculated in accordance with this section based on the application of the method set out in this Schedule for the benchmark model.
Note: Preference curves describe a relationship between environmental outcome and a flow statistic such as frequency or dry spell. For example, achievement of a target frequency of inundation may score 100 points, with this score reducing towards zero for frequencies below the achievement of the target.
(2) Science based, independently reviewed, fit for purpose metrics for weighting environmental significance of the flood dependent area will be used in the method.
Note: The choice of preference curves and metrics and weightings for environmental significance will involve both scientific advice and consultation with Basin jurisdictions and be those regarded as the best available for the method.
(3) The metrics to be used for weighting environmental significance in subsection (2) may include consideration of the following:
(i) are formally recognised in international agreements or, with environmental watering, are capable of supporting species listed in those agreements; or
(b) a run with an SDL adjusted for the supply contribution together with the improved environmental outcomes associated with the supply measures being considered.
(2) For any model run the score for each reach, and cumulatively the overall score, is that resulting from the following steps:
(c) combine flow event frequency and dry spell measures of environmental outcome according to a science based, independently reviewed, fit for purpose rules‑based approach, to derive a single measure for each flow target;
(e) combine, according to a science based, independently reviewed, fit for purpose approach, the scores for each flow event target to ascertain the score for the reach; and
Note: Scoring will need to occur separately for areas with environmental works and for areas without works and then combined within the scoring method.
(3) Hydrologic modelling under the method to establish a supply contribution will start with the benchmark environmental flow events and these will only be modified as necessary to reflect the outcomes of the proposal and potential supply contribution.
Note: The method may be applied using separate modelling runs for the northern and southern Basin, or parts thereof, as necessary to determine relevant supply contributions. For example, if there are no proposed supply contribution measures for a tributary, it would not be necessary to develop scoring metrics for that tributary provided that the in‑valley recovery volume is maintained.
(a) for each region of the Basin—no reduction in the benchmark environmental outcome scores, although some reductions in individual elements may be permitted if they are offset by increases in other elements;
(i) where the benchmark model run achieves or exceeds the target frequency range for a flow indicator, achievement of the target frequency range must be retained and the frequency result must not vary by more than 10% of the benchmark result; and
(ii) where the benchmark model run does not achieve the target frequency range for a flow indicator, the frequency result must not vary by more than 10% of the benchmark result, and not fall below the baseline model result; and
(iii) where the benchmark model run provides little improvement in frequency for a flow indicator (less than 50% progress toward the target range from the baseline model result), the frequency result must not vary by more than 15% of the benchmark result, and not fall below the baseline model result; and
Note: Where a flow indicator exceeds these limits of change, but other indicators at the site are within the limits of change, modelling under the method will redistribute the use of environmental water amongst flow indicators to balance outcomes with respect to subparagraphs (i) to (iii). Consistent with section S6.06(3) redistribution of environmental water will occur to the minimum extent necessary to ensure that the limits of change are met and not to otherwise affect environmental flow outcomes in the benchmark model.
(iv) where a supply measure or combination of measures can achieve the ecological outcomes sought by the plan as represented by an ecological target or targets, and a flow indicator or indicators and associated benchmark model results, then subparagraphs (i) to (iii) do not apply to that flow indicator or indicators;
(ii) Barrage flows: greater than 2000 GL per year on a three year rolling average basis with a minimum of 650 GL in any year, to be achieved for 95% of years;
(v) Mouth openness: Mouth open to an average annual depth of 1 metres (‑1.0 m AHD) or more for at least 90% of years and 0.7 metres (‑0.7 m AHD) for 95% of years;
Note: These limits of change are for the purpose of modelling SDL adjustment and do not necessarily represent environmental watering or management targets.
MDBA 2011, The proposed “environmentally sustainable level of take” for surface water of the Murray‑Darling Basin: Methods and outcomes, MDBA publication no: 226/11, Murray‑Darling Basin Authority, Canberra.
MDBA 2012a, Hydrologic modelling to inform the proposed Basin Plan: Methods and results, MDBA publication no: 17/12, Murray‑Darling Basin Authority, Canberra.
(a) identify the hydrological model of the Basin that is to be used for the calculations (the benchmark model—this is the model that was used to arrive at the unadjusted SDL, with some modifications);
(b) identify the indicator sites and regions that are to be used in applying the method (these will be chosen to be representative, while ensuring that areas of high ecological value are given due weight);
(c) identify the flow regime characteristics that are to be used as a measure of environmental outcomes, and that are to be measured or assessed in relation to those indicator sites;
(e) identify the method of comparison between the benchmark environmental outcomes and another set of environmental outcomes—this will use a scoring method, including preference curves and weightings for environmental significance. A higher score will represent a preferable environmental outcome;
(f) identify the limits of changes in score or outcome that ensure that supply contributions maintain environmental outcomes within identified limits;
(iii) compare the environmental outcomes against the benchmark environmental outcomes and assess whether the score is equivalent or higher;
(v) repeat with successive test supply contributions until the largest contribution is found that still results in an equivalent or higher score;
Part 2 Method
Schedule 6—Default method for calculation of supply contribution
Note: See section 7.15.
Part 1—Description
(a) identify the hydrological model of the Basin that is to be used for the calculations (the benchmark model—this is the model that was used to arrive at the unadjusted SDL, with some modifications);
(b) identify the indicator sites and regions that are to be used in applying the method (these will be chosen to be representative, while ensuring that areas of high ecological value are given due weight);
(c) identify the flow regime characteristics that are to be used as a measure of environmental outcomes, and that are to be measured or assessed in relation to those indicator sites;
(e) identify the method of comparison between the benchmark environmental outcomes and another set of environmental outcomes—this will use a scoring method, including preference curves and weightings for environmental significance. A higher score will represent a preferable environmental outcome;
(f) identify the limits of changes in score or outcome that ensure that supply contributions maintain environmental outcomes within identified limits;
(iii) compare the environmental outcomes against the benchmark environmental outcomes and assess whether the score is equivalent or higher;
(v) repeat with successive test supply contributions until the largest contribution is found that still results in an equivalent or higher score;
Part 2—Method
(b) incorporate appropriate rules for delivery of water from the Lower Lakes into the Coorong, including relating Lake level to release volumes;
(d) incorporate updated environmental watering event time‑series for without development and baseline model runs in the environmental event selection tool;
(e) remove the operation of the Living Murray works and use the component of the Living Murray water that was used by the works for floodplain outcomes;
(g) set environmental flow demands for the Goulburn River consistent with the flow event targets described in MDBA 2012a.
Note: Refinements to the MDBA model run 847 will be undertaken in consultation with Basin jurisdictions through the Basin Officials Committee.
(2) The benchmark pattern of reliability of supply to entitlement holders for subparagraph 7.15(1)(d) is that provided for in the benchmark model run.
Note: As the Living Murray works and measures have been removed from the benchmark model under S6.02(1)(e) above, the full benefit of them can be considered for an SDL adjustment.
(b) must take into account the following policy settings included in the benchmark model to the extent that, at the time the method is applied, the specific settings used in the benchmark model are not expected to be, or were not, implemented by 2019:
Note: In finalising these policies, Basin States and the Commonwealth would need to ensure any associated third party impacts associated with these policies are assessed and addressed as appropriate.
(1) The indicator sites, and corresponding river reaches and associated floodplains, that are to be used are those used in the development of the Environmentally Sustainable Level of Take (ESLT) method (the ESLT method) for which detailed assessments of environmental water requirements were done.
(2) Each reach is to incorporate one hydrologic indicator site (HIS) used in the ESLT method for which detailed assessments of environmental water requirements were done.
(a) the Northern Basin region, which includes all rivers in the Basin upstream of the upstream extent of the Menindee Lakes; and
(b) the Southern Basin region, which includes the River Murray upstream of the boundary of the Coorong, Lower Lakes and Murray Mouth Ramsar site and all connected tributaries apart from the Northern Basin; and
(c) 2 disconnected rivers regions, the Lachlan and Wimmera Rivers, if supply contributions are proposed within these valleys.
Note: The Coorong, Lower Lakes and Murray Mouth Ramsar site cannot be scored in the same way as other sites and reaches. Paragraph S6.07(c) provides limits for changes in score or outcomes for this site.
(3) The benchmark environmental outcomes are those scores calculated in accordance with this section based on the application of the method set out in this Schedule for the benchmark model.
Note: Preference curves describe a relationship between environmental outcome and a flow statistic such as frequency or dry spell. For example, achievement of a target frequency of inundation may score 100 points, with this score reducing towards zero for frequencies below the achievement of the target.
(2) Science based, independently reviewed, fit for purpose metrics for weighting environmental significance of the flood dependent area will be used in the method.
Note: The choice of preference curves and metrics and weightings for environmental significance will involve both scientific advice and consultation with Basin jurisdictions and be those regarded as the best available for the method.
(3) The metrics to be used for weighting environmental significance in subsection (2) may include consideration of the following:
(i) are formally recognised in international agreements or, with environmental watering, are capable of supporting species listed in those agreements; or
(b) a run with an SDL adjusted for the supply contribution together with the improved environmental outcomes associated with the supply measures being considered.
(2) For any model run the score for each reach, and cumulatively the overall score, is that resulting from the following steps:
(c) combine flow event frequency and dry spell measures of environmental outcome according to a science based, independently reviewed, fit for purpose rules‑based approach, to derive a single measure for each flow target;
(e) combine, according to a science based, independently reviewed, fit for purpose approach, the scores for each flow event target to ascertain the score for the reach; and
Note: Scoring will need to occur separately for areas with environmental works and for areas without works and then combined within the scoring method.
(3) Hydrologic modelling under the method to establish a supply contribution will start with the benchmark environmental flow events and these will only be modified as necessary to reflect the outcomes of the proposal and potential supply contribution.
Note: The method may be applied using separate modelling runs for the northern and southern Basin, or parts thereof, as necessary to determine relevant supply contributions. For example, if there are no proposed supply contribution measures for a tributary, it would not be necessary to develop scoring metrics for that tributary provided that the in‑valley recovery volume is maintained.
(a) for each region of the Basin—no reduction in the benchmark environmental outcome scores, although some reductions in individual elements may be permitted if they are offset by increases in other elements;
(i) where the benchmark model run achieves or exceeds the target frequency range for a flow indicator, achievement of the target frequency range must be retained and the frequency result must not vary by more than 10% of the benchmark result; and
(ii) where the benchmark model run does not achieve the target frequency range for a flow indicator, the frequency result must not vary by more than 10% of the benchmark result, and not fall below the baseline model result; and
(iii) where the benchmark model run provides little improvement in frequency for a flow indicator (less than 50% progress toward the target range from the baseline model result), the frequency result must not vary by more than 15% of the benchmark result, and not fall below the baseline model result; and
Note: Where a flow indicator exceeds these limits of change, but other indicators at the site are within the limits of change, modelling under the method will redistribute the use of environmental water amongst flow indicators to balance outcomes with respect to subparagraphs (i) to (iii). Consistent with section S6.06(3) redistribution of environmental water will occur to the minimum extent necessary to ensure that the limits of change are met and not to otherwise affect environmental flow outcomes in the benchmark model.
(iv) where a supply measure or combination of measures can achieve the ecological outcomes sought by the plan as represented by an ecological target or targets, and a flow indicator or indicators and associated benchmark model results, then subparagraphs (i) to (iii) do not apply to that flow indicator or indicators;
(ii) Barrage flows: greater than 2000 GL per year on a three year rolling average basis with a minimum of 650 GL in any year, to be achieved for 95% of years;
(v) Mouth openness: Mouth open to an average annual depth of 1 metres (‑1.0 m AHD) or more for at least 90% of years and 0.7 metres (‑0.7 m AHD) for 95% of years;
Note: These limits of change are for the purpose of modelling SDL adjustment and do not necessarily represent environmental watering or management targets.
MDBA 2011, The proposed “environmentally sustainable level of take” for surface water of the Murray‑Darling Basin: Methods and outcomes, MDBA publication no: 226/11, Murray‑Darling Basin Authority, Canberra.
MDBA 2012a, Hydrologic modelling to inform the proposed Basin Plan: Methods and results, MDBA publication no: 17/12, Murray‑Darling Basin Authority, Canberra.
(b) incorporate appropriate rules for delivery of water from the Lower Lakes into the Coorong, including relating Lake level to release volumes;
(d) incorporate updated environmental watering event time‑series for without development and baseline model runs in the environmental event selection tool;
(e) remove the operation of the Living Murray works and use the component of the Living Murray water that was used by the works for floodplain outcomes;
(g) set environmental flow demands for the Goulburn River consistent with the flow event targets described in MDBA 2012a.
Note: Refinements to the MDBA model run 847 will be undertaken in consultation with Basin jurisdictions through the Basin Officials Committee.
(2) The benchmark pattern of reliability of supply to entitlement holders for subparagraph 7.15(1)(d) is that provided for in the benchmark model run.
Note: As the Living Murray works and measures have been removed from the benchmark model under S6.02(1)(e) above, the full benefit of them can be considered for an SDL adjustment.
(b) must take into account the following policy settings included in the benchmark model to the extent that, at the time the method is applied, the specific settings used in the benchmark model are not expected to be, or were not, implemented by 2019:
Note: In finalising these policies, Basin States and the Commonwealth would need to ensure any associated third party impacts associated with these policies are assessed and addressed as appropriate.
S6.03 Indicator sites and regions that a S6.03 Indicator sites and regions that are to be used
(1) The indicator sites, and corresponding river reaches and associated floodplains, that are to be used are those used in the development of the Environmentally Sustainable Level of Take (ESLT) method (the ESLT method) for which detailed assessments of environmental water requirements were done.
(2) Each reach is to incorporate one hydrologic indicator site (HIS) used in the ESLT method for which detailed assessments of environmental water requirements were done.
(a) the Northern Basin region, which includes all rivers in the Basin upstream of the upstream extent of the Menindee Lakes; and
(b) the Southern Basin region, which includes the River Murray upstream of the boundary of the Coorong, Lower Lakes and Murray Mouth Ramsar site and all connected tributaries apart from the Northern Basin; and
(c) 2 disconnected rivers regions, the Lachlan and Wimmera Rivers, if supply contributions are proposed within these valleys.
Note: The Coorong, Lower Lakes and Murray Mouth Ramsar site cannot be scored in the same way as other sites and reaches. Paragraph S6.07(c) provides limits for changes in score or outcomes for this site.
S6.04 Things that are to be measured or S6.04 Things that are to be measured or assessed
(3) The benchmark environmental outcomes are those scores calculated in accordance with this section based on the application of the method set out in this Schedule for the benchmark model.
S6.05 Ecological elements of the scoring S6.05 Ecological elements of the scoring method
Note: Preference curves describe a relationship between environmental outcome and a flow statistic such as frequency or dry spell. For example, achievement of a target frequency of inundation may score 100 points, with this score reducing towards zero for frequencies below the achievement of the target.
(2) Science based, independently reviewed, fit for purpose metrics for weighting environmental significance of the flood dependent area will be used in the method.
Note: The choice of preference curves and metrics and weightings for environmental significance will involve both scientific advice and consultation with Basin jurisdictions and be those regarded as the best available for the method.
(3) The metrics to be used for weighting environmental significance in subsection (2) may include consideration of the following:
(i) are formally recognised in international agreements or, with environmental watering, are capable of supporting species listed in those agreements; or
S6.06 How the method is to be applied S6.06 How the method is to be applied
(b) a run with an SDL adjusted for the supply contribution together with the improved environmental outcomes associated with the supply measures being considered.
(2) For any model run the score for each reach, and cumulatively the overall score, is that resulting from the following steps:
(c) combine flow event frequency and dry spell measures of environmental outcome according to a science based, independently reviewed, fit for purpose rules‑based approach, to derive a single measure for each flow target;
(e) combine, according to a science based, independently reviewed, fit for purpose approach, the scores for each flow event target to ascertain the score for the reach; and
Note: Scoring will need to occur separately for areas with environmental works and for areas without works and then combined within the scoring method.
(3) Hydrologic modelling under the method to establish a supply contribution will start with the benchmark environmental flow events and these will only be modified as necessary to reflect the outcomes of the proposal and potential supply contribution.
Note: The method may be applied using separate modelling runs for the northern and southern Basin, or parts thereof, as necessary to determine relevant supply contributions. For example, if there are no proposed supply contribution measures for a tributary, it would not be necessary to develop scoring metrics for that tributary provided that the in‑valley recovery volume is maintained.
S6.07 Limits of changes in score or outc S6.07 Limits of changes in score or outcomes
(a) for each region of the Basin—no reduction in the benchmark environmental outcome scores, although some reductions in individual elements may be permitted if they are offset by increases in other elements;
(i) where the benchmark model run achieves or exceeds the target frequency range for a flow indicator, achievement of the target frequency range must be retained and the frequency result must not vary by more than 10% of the benchmark result; and
(ii) where the benchmark model run does not achieve the target frequency range for a flow indicator, the frequency result must not vary by more than 10% of the benchmark result, and not fall below the baseline model result; and
(iii) where the benchmark model run provides little improvement in frequency for a flow indicator (less than 50% progress toward the target range from the baseline model result), the frequency result must not vary by more than 15% of the benchmark result, and not fall below the baseline model result; and
Note: Where a flow indicator exceeds these limits of change, but other indicators at the site are within the limits of change, modelling under the method will redistribute the use of environmental water amongst flow indicators to balance outcomes with respect to subparagraphs (i) to (iii). Consistent with section S6.06(3) redistribution of environmental water will occur to the minimum extent necessary to ensure that the limits of change are met and not to otherwise affect environmental flow outcomes in the benchmark model.
(iv) where a supply measure or combination of measures can achieve the ecological outcomes sought by the plan as represented by an ecological target or targets, and a flow indicator or indicators and associated benchmark model results, then subparagraphs (i) to (iii) do not apply to that flow indicator or indicators;
(ii) Barrage flows: greater than 2000 GL per year on a three year rolling average basis with a minimum of 650 GL in any year, to be achieved for 95% of years;
(v) Mouth openness: Mouth open to an average annual depth of 1 metres (‑1.0 m AHD) or more for at least 90% of years and 0.7 metres (‑0.7 m AHD) for 95% of years;
Note: These limits of change are for the purpose of modelling SDL adjustment and do not necessarily represent environmental watering or management targets.
MDBA 2011, The proposed “environmentally sustainable level of take” for surface water of the Murray‑Darling Basin: Methods and outcomes, MDBA publication no: 226/11, Murray‑Darling Basin Authority, Canberra.
MDBA 2012a, Hydrologic modelling to inform the proposed Basin Plan: Methods and results, MDBA publication no: 17/12, Murray‑Darling Basin Authority, Canberra.