Riverine Flood Recovery Reconnaissance Project

Riverine Flood Recovery Reconnaissance Project

 

Assessing the 2022 floods' environmental impacts and delivering the best recovery and resilience solutions.

 Assessing and addressing environmental impacts and conditions with a focus on waterways, wetlands, gullies, and riparian zones. Assessing and addressing environmental impacts and conditions with a focus on waterways, wetlands, gullies, and riparian zones. Following the 2022 South East Queensland flood events, this project is focused on assessing the environmental impacts as well as delivering on-ground works to build environmental resilience.

The program has been run in two stages: reconnaissance and action. Stage one has been completed and has assessed the impacts and conditions of specific sites that were damaged in the significant floods of late 2021 and multiple flood events in 2022. This work looked at flood damage of riparian areas throughout South East Queensland (SEQ) and collaborated with a wide range of stakeholders to compile a robust picture of the damage sustained across the region. While not all areas with flood damage assessed were able to be put forward for funding, we identified those areas with high potential to build long-term environmental resilience at a reach scale of 5 kilometres or more.

The results from the first stage, summarised in a report identifying a program of works for recovery activities to address streambank erosion and environmental recovery, lead to the start of stage two, which sees the deployment of those on-ground works.

 

The project stages:

Riverine Recovery icon 1 Riverine recovery arrow icon Riverine flood recovery icon 2
RECONNAISSANCE PROGRAM OF WORKS   DETAILED DESIGN & APPROVALS WORKS DELIVERY & MONITORING
  • Fields assessment and consultation with relevant stakeholders in flood-affected areas.
  • Research, mapping, data collection, and reporting on flood-related environmental impacts.
  • Identify opportunity for long-term co-investment at a reach scale and multiple co-benefits such as improving koala and lungfish habitat.
  • Creation of a program of works for recovery activities to address streambank erosion and build riparian resilience.
  • Landholder and stakeholder engagement.
 
  • Detailed engineering designs and ecological surveys.
  • Site assessments including flood modelling, geotechnical and bathymetry surveys.
  • Approvals for works including development applications, landholder access, surveys and modelling required.
  • Deploying on-ground works and actions aimed at addressing impacts and creating future resilience for the areas.
  • Monitoring and evaluation.

Stage 1 focused on:

  • Surveying areas affected by flooding events through research, data collection, consultation and mapping.Gully eroded by the floods, Mark Waud walking in itReconnaissance of flood damage on the Logan River.
  • Environmental impacts and conditions, with a focus on waterways and riparian zones.
  • Identify opportunity for long-term co-investment at a reach scale and multiple co-benefits such as improving koala and lungfish habitat.
  • Report and detail potential recovery works required to address impacts at each site.
  • Landholder and stakeholder engagement.

Stage 2, currently underway, will focus on:

  • Detailed engineering designs and ecological surveys.
  • Site assessments including flood modelling, geotechnical, bathymetry and ecological surveys.
  • Approvals for works including development applications and landholder access.
  • Deploying on-ground works and actions aimed at addressing impacts and creating future resilience for the areas.
  • Monitoring and evaluation.

What we are doing

Gully eroded by the floods, Mark Waud walking in itGeotechnical surveys being undertaken at the Borallon reach.

Stage one (concluded):

  • 8-week reconnaissance.
  • Fields assessment and consultation with relevant stakeholders in flood-affected areas.
  • Research, mapping, data collection, and reporting on flood-related environmental impacts.
  • Creation of a program of works for recovery activities to address streambank erosion and build riparian resilience.

Stage Two:

  • 5 selected sites from stage one to undergo recovery actions.
  • Detailed designs, surveys assessments, approvals for works including development applications, landholder access,
  • surveys and modelling required.
  • On ground works including targeted riverbank battering, and pile field construction and revegetation.
  • Rehabilitation and restoration of flood-affected environments to maintain healthy ecosystems and other environmental values.
  • Improve resilience for future disaster events. 

 Healthy Land & Water flood impacts reporting and mapping portal. Healthy Land & Water flood impacts reporting and mapping portal.

 

Measuring success

This project is achieving great impacts for flood-affected areas with stage one completed and stage two rolling out to achieve riparian restoration and flood resilience for the future.

 Stage Location Findings/Actions Recovery outcomes deriving from Stage 2 works

Stage 1

($246,000)

Logan River
  • Stream banks and surrounding floodplains poorly vegetated.
  • Widespread erosion resulting in tall vertical banks along most of the river. 
Woogaroo Creek
  • Extensive streambank and riparian vegetation loss along with measurable degradation in aquatic habitat condition and water quality during the 2021-22 SEQ floods.
  • Channel deepening and widening throughout the reach.
  • Loose soil structure associated with this reach suggests the presence of areas where potential mass bank failure from steeper upper banks may occur under future flooding. 
Lockyer Creek/Laidley Creek
  • Surface soil losses from overland flows and erosion within the streambank and channel.

Impacts observed post 2022 flooding include:

  • Degradation of channel.
  • Incision/bed lowering within the creek.
  • Bank erosion.
  • Reduction in bed grade.
Brisbane River - Borallon Reach Downstream
  • Substantial erosion of inset flood plain from 2022 flooding events.
  • Channel widening, floodplain stripping, neck/meander cut-offs and channel deepening.
  • Loss of vegetation and previous revegetation on inset floodplain.
  • Extensive loss of large established trees.
  • Damage to infrastructure. 
Brisbane River - Pine Mountain
  •  Channel widening and deepening and stripping of the floodplain is evident from 2022 assessments.
  • Damage from the February 2022 flood event was exacerbated by the May 2022 flood event before the site could stabilise or vegetation re-establish.
South Pine River - Eatons Hill 
  • Bank erosion and damage to riparian areas of the South Pine River.
  • Land slip which removed riparian vegetation, disturbing area of approx. 500 m2 and scouring to depth of 0.5 m.
  • Mobilisation of sediment and undercutting of significant trees.
Upper Brisbane River - Harlin
  • Significant bed and bank scouring within the channel and inset floodplain.
  • Upstream pile fields have been outflanked on river side and sustained significant deposition around pile fields.
  • The 2022 flooding events left minimal riparian vegetation coverage.
Brisbane River - Borallon Reach Upstream
  • Substantial erosion of inset flood plain from 2022 flooding events.
  • Channel widening, floodplain stripping, neck/meander cut-offs and channel deepening.
  • Loss of vegetation and previous revegetation on inset floodplain.
  • Extensive loss of large established trees.
  • Damage to infrastructure.

 Stage 2

($3.65m)

Logan River Revegetating approx. 4ha of riparian land.

Nature-based or green solutions proposed for this reach include:

  • Active native revegetation.
  • Stock fencing.
  • Landholder engagement in partnership with Resilient Rivers Initiative.
  • Building catchment scale recovery and resilience by implementing green solutions in less degraded areas:
  • Improve vegetation connectivity and reduce degradation.
  • Exclude stock from riparian areas to aid vegetation establishment and reduce further erosion.
Woogaroo Creek

Two priority sites with a range of engineering works increase overall the vegetation density. Works include:

  • Bank reprofiling.
  • Incorporation of fallen trees with support of pile fields.
  • Toe protection.
  • Revegetation and weed management.
  • Activities aim to actively encourage natural bank stability, reduce channel widening by slowing flow rates and volumes of overland flow.
  • Increased width of the riparian vegetation buffer along with increased overall vegetation density at a reach scale.
  • The above will be delivered in partnership with Ipswich City Council.
 Lockyer Creek

Laidley Creek, targeted at Reach 2 to expand reach scale resistance to flooding:

  • Limit bed incision which causes a deepening and widening of the channel.
  • Build upon previous restoration efforts provided for Reach 1.
  • Installation of three grade control structures (combined rock grade control and cross channel pile fields).
  • Revegetation (in collaboration with other partners).
  • Reduced stream power, sediment transport capacity and erosion.
  • Improved riparian resilience.
Brisbane River - Borallon Reach Downstream

Engineering works to reduce hydraulic energy while vegetation establishes on the inset floodplain.
Works include:

  • Installation of timber pile fields with rock armouring around selected pile fields.
  • Revegetation within eroded corridor, focusing on both bank stability and establishment of "living pile fields".
  • Restored riparian vegetation to improve riparian connectivity and assist in hydraulic energy dissipation to reduce erosion.
  • Improving resilience.
Brisbane River - Pine Mountain

Engineering works to reduce hydraulic energy while vegetation establishes.
Works include:

  • Installation of timber pile fields with rock armouring around selected pile fields.
  • Revegetation within eroded corridor.
  • Stock exclusion fencing.
  • Prevent a permanent cut-off channel from forming.
  • Restore riparian vegetation to improve riparian connectivity and assist in hydraulic energy dissipation.

Why this project is important

Recent 2022 floods described as a “one-in-100 event” by the Bureau of Meteorology, have dramatically affected the waterways, wetlands, gullies, and riparian zones in South East Queensland.

The environmental impacts deriving from the floods have immense repercussions on wildlife, habitat, and water quality.

Research has shown that baseline water quality in the Brisbane River has deteriorated due to an increase in sediment and pathogen pollution caused by historic vegetation clearing and grazing practices that have left most of the banks vulnerable to erosion during floods.

To preserve water quality and flora and fauna we need to assess the severity of the floods’ impact, determine emergency actions and deploy on-ground works that guarantee future resilience.

 

Project snapshot

Project name: 

Riverine Flood Resilience Project

Stage 1 - Reconnaissance (2022-2023) $246,000

Stage 2 - Works (2024) $3.65m

Project manager:  Samille Loch-Wilkinson, Healthy Land & Water
Project team:  Hannah Sherlock, Healthy Land & Water
Catchment:  South East Queensland
Partnerships: 

This project is supported by Healthy Land & Water, with assistance provided through the jointly funded Commonwealth-State Disaster Recovery Funding Arrangements (DRFA).
Partners include the Resilient Rivers Initiative, ICC, Port of Brisbane and Lockyer Valley Regional Council.

 

What's next

There is huge potential to build on the success of this project with potential to attract more investment partners to deliver larger-scale results and resilience for the region.

Project collaborators

This project is supported by Healthy Land & Water, with assistance provided through the jointly funded Commonwealth-State Disaster Recovery Funding Arrangements (DRFA).
Partners include the Resilient Rivers Initiative, ICC, Port of Brisbane and Lockyer Valley Regional Council.

AUS_GVT_LOGO.jpeg QLD_GVT_LOGO.jpeg

Jointly-funded Commonwealth-State Disaster Recovery Funding Arrangements (DRFA) Environmental Recovery Program – Sub-package A Riverine Recovery Program Stage 1 and 2