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 the Queensland Government, Healthy Land and Water, Lockyer Valley Regional Council, and Mulgowie Farming Company. Our Pilot Project was Queensland’s first scientifically-based and assessed offsite stormwater treatment project.
 

CURRENT PROJECTS

DOWNFALL CREEK RESTORATION PROJECT, 7TH BRIGADE PARK, CHERMSIDE

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

The Downfall Creek Restoration Project will provide 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.

The works, being delivered by BCC, have commenced and the first stage of the project is expected to be completed later in 2021. More information is available on BCC’s website.

LAIDLEY CREEK, LOCKYER VALLEY

To date, PBPL has invested $1 million to rehabilitate and stabilise 1.7km of Laidley Creek.
 
Works delivered include bank re-profiling, the planting and maintenance of 9,000 native 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 RESULTS

To date, rehabilitation of this upper catchment area has delivered significant environmental benefits including:

  • the prevention of 8,500 tonnes of sediment – approximately 445 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.

EXTREME WEATHER EVENTS

The Laidley Creek project has performed exceptionally well during significant stormwater events in recent years. The video below shows how the works have held up during these types of events.

PROJECT PARTNERS

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 $38,000 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*
 
Information current as at 27 April 2021
*Increase in ‘hectares remaining’ is due to PBPL’s investment in new offsite stormwater projects.