SYDNEY, AUSTRALIA | 14 -18 October 2018 MANAGED BY

Technology and Rural Floodplain Management: future-proofing flood-dependent wetlands

Joanna Taylor, Simon Morton, Dan Mawer and Neal Albert

J. Taylor/OEH

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• Facilitate the orderly passage of floodwater through the system

• Manage risks to life and property from the effects of flooding

• Maintain flood connectivity to ecological and cultural assets.

Floodplain management: guiding principles

GwydirBarwon-DarlingPlans in prep.

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J. Taylor/OEH J. Taylor/OEH

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Boobera Lagoon in the Border Rivers (G. Pezzimenti/OEH)

Bungle Gully Dam in the Lower Namoi (J. Taylor/OEH)

Brolga near the Gwydir wetlands (J. Taylor/OEH)

Lake Goran in the Upper Namoi (G. Pezzimenti/OEH)

Macquarie Marshes in the Macquarie (S. Hunter/OEH)

Horseshoe Lagoon in the Barwon-Darling (S. Hunter/OEH)

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Hydraulic models:

• mainly 2D MIKE 21 Flexible Mesh models

• built using 1 m LiDAR Digital Elevation Model or DEM

• account for developments and structures

• fit-for-purpose strategic models

• cover approx. 44,000 km2 , 5 % of NSW or 1.4 Belgiums!

Capture, use, share: location-based flood information

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Managing cumulative impacts

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Managing cumulative impacts

ArcGIS Online for public scrutiny of draft management zones.

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https://trade.maps.arcgis.com/apps/webappviewer/index.html?id=8040c99bb63646c7b0d12d63dec69595

(G. Pezzimenti/OEH)

Infrastructure protection works (ADS40))Below-ground supply channel (G. Pezzimenti/OEH))

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Managing cumulative impacts

Only minor works can be built in MZ A/DWindella

Crinolyn

Goddard’s Lease

Old Dromana

Levee-protected cotton crops(J. Taylor/OEH))

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Managing cumulative impacts

Larger works can be built in MZB/C, subject to rigorous assessment.

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• Sections are drawn across floodplain

• Peak design flood flows were estimated

• Compared existing model flows with proposed model flows to ensure flows are ± 5%.

Managing cumulative impacts

Floodplain scale

MANAGED BY

Property scale

Existingdevelopment

conditions

Proposeddevelopment

conditions

Pre-development

conditions

a) Overall change

b) Current change

c) Proposed change

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Property scale

Existingdevelopment

conditions

Proposeddevelopment

conditions

Pre-development

conditions

a) Overall change

b) Current change

c) Proposed change

SYDNEY, AUSTRALIA | 14 -18 October 2018

SYDNEY, AUSTRALIA | 14 -18 October 2018 MANAGED BY

Better information and technology includes:

• Improvements in available elevation data sets

• Flexible Mesh modelling approach

• Use of Graphical Processing Units (GPUs) to speedup simulations

Lesson Learnt – start with good LiDAR

Better technology, better assessments

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J. Taylor/OEH J. Taylor/OEHJ. Taylor/OEH J. Taylor/OEH

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Acknowledgements

This work was undertaken as part of the Healthy Floodplains Project, which is funded by the Australian Government’s Sustainable Rural Water Use & Infrastructure Program as part of the implementation of the Murray-Darling Basin Plan

The project team is the work of more names than can be listed here – with representatives from the Office of Environment & Heritage (OEH), Department of Industry Water, Department of Primary Industries – Fisheries, the Natural Resources Access Regulator and WaterNSW.

We would like to acknowledge our immediate OEH project team: Dan Mawer and Neal Albert who helped write the abstract, as well asGeoff Simpson, Mal Ridges, Michelle Cavallaro, Peter Sobinoff and Simon Hunter.

More information can be found at: https://www.industry.nsw.gov.au/water/plans-programs/healthy-floodplains-project/plans