sdlam determination modelling

SDLAM Determination Modelling

28 June 2018

Operation of the mechanism

Add package of supply projects

Run supply package modelling scenario

Basin Plan scenario in the model (2750 GL water recovery)

Final adjustment volume

Check ecology scores Reduce water recoveryCheck limits of change

Check reliability of supply metrics

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)

Hydrology Modelling

Framework

Time

FlowBenchmark Scenario

2,750 GL — fully implemented

Basin Plan 2012Without

Basin Plan

WithBasin Plan

Translate flow into Environmental Outcomes

Baseflows

FreshesBankfull

Overbank

CoorongLower LakesMurray Mouth

Ecological Elements(environmental score) Limits of Change

Assessing environmental water needs

Ecological elementsTwelve 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 landsVa

lue

Valu

e

0 1 2 3 4 5 6 7 98 3210

0

0.2

0.4

0.6

0.8

1

0

0.2

0.4

0.6

0.8

1

Years since SFI last met Consecutive years SFIs met

Good CriticalMedium Poor

Scor

eAve = 0.68

Example – short lived fish

Federation drought, ‘bad’ for short lived

fish, low score

Wet 1950s and 1970s – ‘good’,

high score

Millennium drought– bad for

short lived fish, low score

Types of limits of changeBaseflow 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

Reach 1Reach 2

Class Ecological Element EE Score

EE Score

Reach Score

Bird

Waterbirds (health) 6786

5348

7002

Bitterns, crakes & rails 5526Colonial nesting waterbirds 4395Waterbirds (breeding) 4684

Vegetation

River Red Gum forests 7896

7571

River Red Gum woodlands 8086Blackbox forests and woodlands 8719Shrublands naTall grasses, sedge & rushlands 6425Benthic herblands 7270

Fish Short-lived fish 8117 8086Long-lived fish 8055

Benchmark Scenario – Ecological Elements – Reach 1

Class Ecological Element EE Score

EE Score

Reach Score

…. …. …. …. 6200

Benchmark Scenario – Ecological Elements – Reach 2

A Simple Example Application

Reach 1Reach 2

Benchmark Scenario Results

EE ScoresReach 1: 7002Reach 2: 6200

Combined: 6846

BaseflowReach 1: 93%Reach 2: 82%

SFIs (freshes, bankfull, overbank)

SFI 1 (lower FP): 72%SFI 2 (upper FP): 63%

SFI 3: ……

Coorong (EOS)Salinity, flow, openness

Limits ofChange

EE ScoresCombined: no decrease

(trade-off allowed between reaches)

BaseflowReach 1: no decreaseReach 2: no decrease



SFI 3: ……



Reach 1Reach 2

Supply measure 1Environmental works Supply measure 2

Constraints, EWM & operations



Combined: 6846




SFI 3: ……


Limits ofChange

EE ScoresCombined: no decrease

(trade-off allowed between reaches)

BaseflowReach 1: no decreaseReach 2: no decrease



SFI 3: ……



Reach 1Reach 2

Supply measure 1Environmental works Supply measure 2

Constraints, EWM & operations



Combined: 6846




SFI 3: ……


Supply Measure Scenario Results


Combined: 6846




SFI 3: ……



SDL adjustment proposals

5

• 2013 – Benchmark model, ecological elements development

• 2014/15 – Trial of the model/EE framework with 6 measures – wide exposure of the SDLAM method

• 2015/16 – Progress towards 19 measures• Late 2016 – States advised to propose more

projects to bring new water into the system→ Menindee Lakes, HydroCues (EEWD), Constraints

• 2017 – Finalisation of determination – 605 GL

SDL adjustment timeline

Brooks et al.

Independent Reviews

Bewsher

Expert Panel

Bewsher

Scores for:

Fish (2)

Vegetation (6)

Waterbirds (4)

Reach scores

Each flow indicator score is weighted by the proportional area

within the reach of that element and combined to give a EE score for the reach. Each EE score is averaged to get a reach EC score

Regional score

Ecological Elements scoring method

Compare Basin Plan benchmark

to Increased SDL with supply

measures} Increase SDL until achieve

environmental equivalence within agreed safeguards

Menindee LakesPurchase of major high security entitlements

Pipeline to supply Broken Hill

New outlet – Lake Menindee

Regulator separates Lakes Menindee and Cawndilla

Lake Cawndilla – largely dry

Constraint management 14 000 ML/day Weir 32

• Evaporative savings• Higher release rates• Less dead storage

Lake Menindee

Lake Cawndilla

Lake Pamamaroo

Copi Hollow

Darling River

Weir 32

Menindee Outlet Regulator

Pamamaroo Outlet Regulator Main Weir

Menindee Inlet Regulator

To Lake Tandou and Darling Anabranch

Cawndilla Outlet Regulator

Menindee

Enhanced Environmental Water Delivery

Hydro cues =

a water delivery strategy

June November

Low

er

flood

plai

nIn

ch

anne

l

July August September October

Regulated flow boundary (constraint)

River operators Targeted trigger

Flow trigger

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)

Constraints relaxation

Assessment ReachWithout

DevelopmentBaseline Benchmark SDL 605

Upper-Murray – Barmah-Millewa Forest 6935 4003 5100 5017

Upper-central Murray – Gunbower-Koondrook-Perricoota

7030 3405 55676376

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

Ecological Elements Reach Scores

KEY TO SYMBOLS

Lake Victoria

Hattah Lakes

Coorong, Lower Lakes and Murray Mouth

Riverland-Chowilla Floodplain

Edward-Wakool River System

Gunbower-Koondrook-

Perricoota Forest

Barmah-MillewaForest

Lower Murrumbidgee Floodplain Mid-Murrumbidgee

Wetlands

Lower Darling Floodplain

Site-specific flow indicators’ performance against the limits of change

Lower GoulburnFloodplain

SFI breaching LoCSFI within 1% of LoC

SFI >5% away from LoCSFI >1%,<5% away from LoC

Murrumbidgeefreshes

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

Office locationsAdelaideAlbury-WodongaCanberraToowoomba

mdba.gov.au 1800 630 [email protected]

Office locationsAdelaideAlbury-WodongaCanberraToowoomba

mdba.gov.au 1800 630 [email protected]

Thank you.

sdlam determination modelling

Documents