Offsite Stormwater

OFFSITE STORMWATER TREATMENT PROJECTS 

THE SEDIMENT PROBLEM

Sediment run-off – soil that runs off degraded land, creeks and riverbanks into waterway catchments – impacts waterway health in Brisbane and within the SEQ regional catchment. In fact, it’s a problem in many areas around Queensland and Australia. 
  
In SEQ, sediment travels from regional waterways into the Brisbane River, ultimately depositing in Moreton Bay and the Port of Brisbane’s navigational channel, requiring it to be removed through maintenance dredging (conducted under strict permit conditions) to ensure safe commercial shipping. 

THE APPROACH 

PBPL worked with a number of partners to develop a new approach to tackling sediment pollution and improving waterway health which seeks to stop sediment run-off ‘at the source’ and substantially reduce the amount of sediment that enters the waterway in the first instance - offsite stormwater treatment. 
 
This new approach was developed and implemented with a range of partners including Healthy Land and Water, Lockyer Valley Regional Council, Mulgowie Farming Company, Queensland Government (Department of Environment and Science, Department of Infrastructure, Local Government and Planning), Planfuture, Alluvium, BMT WBM, Griffith University (Australian Rivers Institute). 

Our Pilot Project was Queensland’s first scientifically-based and assessed offsite stormwater treatment project. 

Our PROJECTS

Since 2016, we’ve worked with partners to complete projects within the Lockyer Valley, Brisbane and Ipswich Council areas.  These works are delivering real benefits to the local environment and community and has reduced the overall amount of sediment being washed into our waterways.    

These benefits include: 

  • 5 completed projects, 1 project nearing completion 

  • 3.3 km of degraded creek and river bed rehabilitated 

  • improved instream habitat connectivity and improved water quality outcomes at the site 

  • planting 15,000 native trees and plants 

  • approximately 14,630 tonnes of sediment avoided annually 

  • Investment in scientific research and monitoring 

Represents the combined outcomes of all offsite stormwater projects completed as at February 2024. 

Read our project case studies below for more detail.  

To date, PBPL has invested $1 million to rehabilitate and stabilise 2.8km of Laidley Creek over three stages of work. A fourth project commenced in late-2023. 
  
Works delivered so far include bank re-profiling, the planting and maintenance of 9,000 native trees and plants and the installation of 4 cross-bed grade control structures as well as a major research component with scientists using innovative techniques to identify and monitor the sources of sediment pollution. 

The benefits 

To date, the four stages of rehabilitation work completed in this upper catchment area has delivered significant environmental benefits including: 

  • the prevention of 14,280 tonnes of sediment – approximately 714 truckloads of dirt – from entering Laidley Creek, anticipated each year 

  • significant water quality improvements to the Brisbane River and Moreton Bay 

  • improved flora and fauna habitats at the site 

  • increased agricultural productivity at the site by improving land security and providing protection from future flood events. 

Completed in 2023, this was a partnership between PBPL, Brisbane City Council (BCC) and South East Queensland Council of Mayors  to rehabilitate a section of Downfall Creek to improve waterway health, reduce erosion and stabilise the creek system, which was  identified by BCC as a priority site for rehabilitation and enhancement works through the Resilient Rivers Initiative. 

The benefits

The Downfall Creek Restoration Project has provided many benefits including: 

  • stabilising the creek landscape to reduce sediment loss and erosion, avoiding approximately 375 tonnes of sediment movement downstream annually 

  • planting native creek vegetation including over 2,500 new trees to increase and connect habitat for land and aquatic wildlife 

  • improving instream habitat and water quality within the creek 

  • improving ‘natural’ visual amenity. 

In 2023, PBPL and Ipswich City Council completed a project to rehabilitate two sections of Woogaroo Creek in Ipswich.  

The benefits 

The Woogaroo Creek rehabilitation has delivered benefits including: 

  • 110m of degraded creek bed rehabilitate 

  • around 3,250 native plants and pile fields constructed to slow the flow of water and help protect banks during significant weather 

  • creation of instream habitat for fish species 

  • approximately 325 tonnes of sediment and associated nutrient pollution avoided annually. 

EXTREME WEATHER EVENTS

Our works at Laidley Creek have performed exceptionally well during significant storm and flood events in recent years. Check out the video below to see how the works have held up during these types of events.

VIDEOS

AWARDS

  • 2018 International RiverFoundation Australasia Riverprize Finalist

  • 2016 Healthy Waterways Awards - Sustainable Water Management Award and the Minister’s Grand Prize

  • 2016 Australian Engineering Excellence Awards - Queensland Environmental Excellence Award

  • 2016 Australian Shipping and Maritime Industry Awards - Environmental Transport Awards

MORE INFORMATION

DEVELOPMENT AT THE PORT

Developers at the Port need to comply with the Port of Brisbane Technical Guidelines which require developers to manage and treat stormwater.
 
Qualifying developers can partially meet stormwater quality requirements by investing into PBPL’s offsite program at a rate of $32,000 per hectare.
 
PBPL tracks development at the Port that is utilising offsite investment. The below tables summarises the investments made in catchment management and the area of port development ‘treated offsite’.

Table 1: This table summarises the investment made by the Port of Brisbane offsite and the amount of land at the Port that has utilised the investment.
 

Year
Offsite Investment
Hectares Used
Hectares Remaining
2015/16
$500,000
17.8
2.2
2016/17
$503,635
6.87
15.48*
2017/18
$0
5.48
10
2018/19
$84,000
17.57
-4.21
2019/20
$242,000
6.42
-1.67*
2020/21
$839,000
6.27
23.13*
2021/22
$579,000
10.58
30.52
2022/23
$421,925
20.29
36.63
 

Information current as at 27 April 2021
*Increase in ‘hectares remaining’ is due to PBPL’s investment in new offsite stormwater projects.