SDLAM Determination Modelling 28 June 2018
Operation of the mechanism Basin Plan scenario in the model (2750 GL water recovery) Add package of supply projects Run supply package modelling scenario Check ecology scores Reduce water recovery Check limits of change Check reliability of supply metrics Final adjustment volume PPMs must be in place by 30 June 2019
Environmental equivalence • Supply measures must achieve equivalent or better environmental outcomes • Compares SDLAM package to benchmark modelling runs • Scoring method was developed by CSIRO to compare environmental outcomes = ‘ecological elements’ • Overall score must be equal or better • Trade-off allowed between elements and reaches • Limits of change (constrain the trade-off) • The determination also cannot have detrimental impacts on reliability
The components of the framework used to determine the SDL adjustments are:
Modelling • MDBA has a modelling framework representing rivers in the Murray– Darling Basin • It includes dams, weirs, water supply for towns, irrigators and agriculture, etc • Modelling period: 114 years historical record (1895 – 2009)
Benchmark Scenario With Hydrology Basin Plan 2,750 GL — fully Flow Modelling implemented Without Framework Basin Plan Basin Plan 2012 Time Translate flow into Environmental Outcomes Coorong Baseflows Lower Lakes Murray Mouth Freshes Ecological Elements Bankfull Limits of Change (environmental score) Overbank
Assessing environmental water needs
Ecological elements Twelve biological elements of the ecosystem, the ‘ecological elements’ are used by the framework to capture flow-related environmental outcomes.
Ecological elements – spatial
Preference curves – benthic herb lands 1 1 0.8 0.8 0.6 0.6 Value Value 0.4 0.4 0.2 0.2 0 0 0 1 2 3 4 5 6 7 8 9 0 1 2 3 Years since SFI last met Consecutive years SFIs met Good Medium Poor Critical
Example – short lived fish Ave = 0.68 Score Federation drought, Wet 1950s and Millennium ‘bad’ for short lived 1970s – ‘good’, drought– bad for fish, low score high score short lived fish, low score
Types of limits of change Baseflow and freshes • Relate to SFIs • Requires no reduction in outcomes achieved in the benchmark run Bankfull and overbank • Relate to SFIs • Seven different rules can be applied to determine LoC Coorong, Lower Lakes and Murray Mouth • Five outcomes are required • Relate to salinity, barrage flows and mouth openness
A Simple Example Application Benchmark Scenario – Ecological Elements – Reach 1 EE EE Reach Class Ecological Element Score Score Score Waterbirds (health) 6786 Bitterns, crakes & rails 5526 Bird 5348 Colonial nesting waterbirds 4395 Waterbirds (breeding) 4684 Reach 2 Reach 1 River Red Gum forests 7896 River Red Gum woodlands 8086 7002 Blackbox forests and woodlands 8719 Vegetation 7571 Shrublands na Tall grasses, sedge & rushlands 6425 Benthic herblands 7270 Short-lived fish 8117 Fish 8086 Long-lived fish 8055 Benchmark Scenario – Ecological Elements – Reach 2 EE EE Reach Class Ecological Element Score Score Score …. …. …. …. 6200
Benchmark Limits of A Simple Example Application Scenario Results Change EE Scores EE Scores Reach 1: 7002 Combined: no decrease Reach 2: 6200 (trade-off allowed Combined: 6846 between reaches) Baseflow Baseflow Reach 1: 93% Reach 1: no decrease Reach 2 Reach 2: 82% Reach 2: no decrease Reach 1 SFIs (freshes, bankfull, SFIs (freshes, bankfull, overbank) overbank) SFI 1 (lower FP): 72% SFI 1 (lower FP): 68% SFI 2 (upper FP): 63% SFI 2 (upper FP): 61% SFI 3: …… SFI 3: …… Coorong (EOS) Coorong (EOS) Salinity, flow, openness Salinity, flow, openness
Benchmark Limits of A Simple Example Application Scenario Results Change EE Scores EE Scores Reach 1: 7002 Combined: no decrease Reach 2: 6200 (trade-off allowed Combined: 6846 between reaches) Baseflow Baseflow Reach 1: 93% Reach 1: no decrease Reach 2 Reach 2: 82% Reach 2: no decrease Reach 1 SFIs (freshes, bankfull, SFIs (freshes, bankfull, overbank) overbank) SFI 1 (lower FP): 72% SFI 1 (lower FP): 68% SFI 2 (upper FP): 63% SFI 2 (upper FP): 61% SFI 3: …… SFI 3: …… Coorong (EOS) Coorong (EOS) Salinity, flow, openness Salinity, flow, openness Supply measure 1 Environmental works Supply measure 2 Constraints, EWM & operations
Benchmark Supply Measure A Simple Example Application Scenario Results Scenario Results EE Scores EE Scores Reach 1: 7002 Reach 1: 7246 Reach 2: 6200 Reach 2: 6047 Combined: 6846 Combined: 6846 Baseflow Baseflow Reach 1: 93% Reach 1: 93% Reach 2 Reach 2: 82% Reach 2: 82% Reach 1 SFIs (freshes, bankfull, SFIs (freshes, bankfull, overbank) overbank) SFI 1 (lower FP): 72% SFI 1 (lower FP): 69% SFI 2 (upper FP): 63% SFI 2 (upper FP): 65% SFI 3: …… SFI 3: …… Coorong (EOS) Coorong (EOS) Salinity, flow, openness Salinity, flow, openness Supply measure 1 Environmental works Supply measure 2 Constraints, EWM & operations
SDL adjustment proposals 5
SDL adjustment timeline Independent Reviews • 2013 – Benchmark model, ecological elements development Brooks et al. • 2014/15 – Trial of the model/EE framework with 6 measures – wide exposure of the SDLAM method • 2015/16 – Progress towards 19 measures Bewsher • Late 2016 – States advised to propose more Expert Panel projects to bring new water into the system → Menindee Lakes, HydroCues (EEWD), Constraints Bewsher • 2017 – Finalisation of determination – 605 GL
Ecological Elements scoring method Scores for: Waterbirds (4) Each flow indicator score is weighted by the proportional area Reach Regional Vegetation (6) within the reach of that scores score element and combined to give a EE score for Fish (2) the reach. Each EE score is averaged to get a reach EC score Compare } Basin Plan benchmark Increase SDL until achieve to environmental equivalence Increased SDL with supply within agreed safeguards measures
Menindee Lakes Purchase of major high security Copi Hollow entitlements Lake Pamamaroo Pipeline to supply Broken Hill Menindee Inlet Regulator New outlet – Lake Menindee Pamamaroo Outlet Main Weir Regulator Lake Regulator separates Lakes Menindee Menindee and Cawndilla Menindee Lake Cawndilla – largely dry Menindee Outlet Regulator Weir 32 Constraint management 14 000 ML/day Weir 32 Lake Cawndilla • Evaporative savings Darling River • Higher release rates Cawndilla Outlet • Less dead storage Regulator To Lake Tandou and Darling Anabranch
Enhanced Environmental Water Delivery Hydro cues = a water delivery strategy
floodplain Targeted trigger Lower River operators Flow trigger Regulated flow boundary (constraint) channel In June July August September October November
Constraints relaxation Address physical and policy constraints to allow higher regulated flows. • Hume to Yarrawonga key focus area (40 000 ML/d) • Yarrawonga to Wakool junction key focus area (50 000 ML/d) • South Australian Murray key focus area (80 000 ML/d) • Murrumbidgee key focus area (40 000 ML/d) • Goulburn – not a supply project - (stage 1 - 20 000 ML/d)
Ecological Elements Reach Scores Without Assessment Reach Baseline Benchmark SDL 605 Development Upper-Murray – Barmah-Millewa Forest 6935 4003 5100 5017 Upper-central Murray – Gunbower- 7030 3405 5567 Koondrook-Perricoota 6376 Mid-Murray – Hattah Lakes 5577 2738 3387 3955 Lower-Murray - Chowilla 6080 2791 3970 4271 Edward Wakool 6292 3224 4169 4120 Lower Darling 4271 2637 2791 2805 Mid- Murrumbidgee 6360 4163 4646 4495 Lower Murrumbidgee 7524 5094 6502 6331 Lower Goulburn Floodplain 8641 6814 8219 8038 Southern basin region score 6523 3874 4928 5045
Site-specific flow indicators’ performance against the limits of change KEY TO SYMBOLS SFI breaching LoC SFI within 1% of LoC SFI >1%,<5% away from LoC SFI >5% away from LoC Lower Darling Floodplain Lake Lower Murrumbidgee Victoria Floodplain Mid-Murrumbidgee Riverland-Chowilla Floodplain Wetlands Murrumbidgee freshes Edward-Wakool River System Barmah-Millewa Hattah Forest Lakes Coorong, Lower Lakes Gunbower- Lower Goulburn and Murray Mouth Koondrook- Floodplain Perricoota Forest
Why is the Lower Darling limit of change not being achieved? • Key proposed changes to Menindee Lakes: • New infrastructure • Regulator between Menindee and Cawndilla • Weir 32 expansion • Inlet and regulator between the Lower Darling and Darling Anabranch • Higher managed flows • Increased flow rate at Weir 32 • Fill and spill pattern changes • Menindee and Cawndilla • Weir 32 • More flows in the Darling Anabranch
Model scenarios comparison at Weir 32
Model scenarios comparison at Wycot
Thank you. Office locations Office locations Adelaide Adelaide Albury-Wodonga Albury-Wodonga Canberra Canberra Toowoomba Toowoomba mdba.gov.au mdba.gov.au 1800 630 114 1800 630 114 engagement@mdba.gov.au engagement@mdba.gov.au
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