For over 20 years the health of South East Queensland’s waterways has been monitored and reported on via a comprehensive Ecosystem Health Monitoring Program (EHMP), providing a snapshot of the health of waterways of the region in the form of an annual Report Card.
The internationally recognised program provides a regional picture of the state of Quandamooka (Moreton Bay), the region’s waterways, catchments and community quality of life, enabling a coordinated approach to catchment management.
Healthy Land and Water is the current entity coordinating the EHMP in collaboration with a diverse range of community, industry and government partners.
The release of the 2021 ‘Report Card’ for South East Queensland marks the 21st birthday of this large-scale monitoring and reporting program, the model that has since been emulated around Australia and the world.
Charting the waters – early and continued investment in science
The EHMP we know today was largely developed from a series of scientific studies completed in the late 1990s and early 2000s. This research initially focused on the region’s estuaries and Moreton Bay and eventually expanded to include freshwater reaches in the following years.
The outcome of this research was the design of a cost-effective, coordinated monitoring program for estuarine, marine and freshwaters of the region that was able to measure and report on current and future changes in ecological health at a catchment scale and, where necessary, guide management actions.
This marked the conception of the EHMP and ultimately led to the first Report Card published in 2000.
In 21 Years the EHMP has measured:
334 monitoring sites (129 freshwater sites, 182 estuarine/marine sites, 17 seagrass depth range sites & 6 event monitoring sites).
Over 800,000 water samples and observations.
26,963 responses to community survey.
More than 90 model runs.
Today, Healthy Land and Water continues to coordinate cutting edge science and monitoring through a partnership program with local government, state government and water utilities.
The fact that the program has endured over 20 years is a testament to the value the people of South East Queensland place on waterways, and the success of the program in driving coordinated investment to improve waterway health.
Quick story by time:
Early 2000s – The beginning
- The first Report Card was launched in 2000.
- Monitoring showed high levels of nutrient pollution from treated wastewater, such as sewage, was impacting waterway health.
- This led to investment from local government and utilities to improve treatment plants.
- Investment resulted in reduced nutrients in the estuaries, particularly the Brisbane River.
Mid-late 2000s – Changes occurring
- Estuarine condition remained ‘above guideline’ in many estuaries and for this reason the changes weren’t reflected in the grade.
- Pollution that does not originate from a single source (also known as diffuse sources), was identified as a big issue and needed to be addressed.
Early 2010s – Shifting
- It was recognised that South East Queensland residents deeply valued local waterways, not just Moreton Bay. Local waterways on their own generate the emotional connection that is needed to generate support for their protection and conservation.
- Shift in communication and engagement approach.
- Grades weren’t getting worse, but they weren’t changing significantly, wanted ways to acknowledge on-ground catchment management and provide guidance for actions.
Mid 2010s – Adapting
- Technological advances and the now long-term data set enabled us to build models that could enhance our catchment environmental condition assessment.
- New indicators – stream bank vegetation, wetland extent, pollutant loads, social and economic – were added to the program.
Early 2020s – Resilience
- Two decades of population increase and the waterways have held the line – no dramatic declines evident.
- The best and worst performing catchments become clearer with two decades of data across varying climate.
- Catchment resilience of freshwater reaches evident in some areas.
- Moreton Bay resilience evident.
Over 21 years the region has grown, and the pressures have changed
The climate has changed
In the last 30 years; Winter and spring rainfall has decreased. The number of hot days (>30°C) has increased
Increase in STP inflows
Inflows to STPs across SEQ have increased over the last 20 years.
Urban footprint growth
Urban footprint increased from 1 million to 1.34 million residential dwellings.
Between 100,000 and 1,000,000 tonnes of sediment delivered every year to waterways
60% population increase
SEQ increased from 2.4 to 3.8 between 2000 and 2021.
Tree clearing and wetlands loss
107,000 ha of woody vegetation cleared over 20 years (150,000 soccer fields) & 1,940 ha wetlands lost (2717 soccer fields) over 16 years.
An evolving monitoring and evaluation program
The Ecosystem Health Monitoring Program (EHMP) has taken advantage of major advances in predictive modelling and today, not only reports on condition, but also on the drivers of ecosystem health and management responses. The program measures social and economic benefits informing the waterway benefit rating given to each catchment.
The social and economic benefits of waterways
The creeks, rivers, lakes, bays and beaches of South East Queensland provide significant value to the region’s residents and visitors alike. Most South East Queensland residents have a deep connection with nature, reporting that it is an important part of their lives.
- Department of Environment and Science, Queensland (2021) Queensland Wetlands Program, WetlandInfo website, accessed 23 November 2021. Available at: https://wetlandinfo.des.qld.gov.au/wetlands/about-us/qld-wetland-program.html
- Queensland Department of Environment and Science. 2020. Statewide Landcover and Trees Study (SLATS).
- Bureau of Meteorology, 2018. South East Queensland Regional Weather and Climate Guide.
Figure 1. Brisbane estuary total nitrogen (eight months per year only) 2001 – 2021. Total nitrogen concentrations reduced following major wastewater (sewage) treatment plant upgrades (2000s), although remain above guideline (red line). While slightly improved in 2021, there are indications that nitrogen has been trending up over the last 5 years or more in a few estuaries of SEQ.
Rarely seen anywhere in the world, seagrass has returned to western Moreton 20 years after the EHMP identified water quality issues in Moreton Bay.
There has been significant long-term recovery of seagrass in southern Deception Bay which were lost entirely in 1996. Seagrass meadows in Bramble Bay, which have not been seen since the 197s, have also recovered over the past two years and are now widespread off the southern Redcliffe peninsula and Nudgee Beach.
These improvements in the Bay’s ecological condition, are likely the result of a reduction in nutrient loads to the Bay over an extended period. While also in part a factor of prolonged drought, the recovery of seagrass shows that the Bay has resilience and can recover.
The Bay ‘mud patch” is shrinking
Moreton Bay acts as a sink for sediments, nutrients and other pollutants transported by rivers to the coast. Mud deposited in the Bay can smoother key habitats including, seagrass, corals and oyster reefs. Currents and wave energy can also resuspend mud into the water column impacting water quality.
The 2011 and 2013 Brisbane River floods delivered a substantial volume of mud to Moreton Bay, resulting in an expansion in the area of mud within the Bay . However, between 2015 and 2019 the total area of mud reduced significantly. This was a result of the gradual flushing of mud to deeper parts of or out of the Bay entirely.
The amount of mud delivered to the Bay has increased as a result of land-use changes in the catchment . This increase has impacted the health of the Bay over the long-term.
The reduction in the area of mud illustrates that the Bay can recover over the medium term, with subsequent improvements in water quality and seafloor habitats driving improvements in overall ecosystem health.
Figure 3. Moreton Bay bottom sediment mud content percentage (1998, 2011, 2015 and 2019).
Freshwater habitats and catchments – Freshwater stream health declining as the long-dry continues
Confirming if the freshwater habitat of a region is getting better or worse is difficult to disentangle from the very strong effect of the climate. But as we move in and out of dry and wet periods, long-term data can be used to identify the key drivers of condition in South East Queensland and help guide on ground action.
Stream health in the western catchments has declined over the last several years and is now comparable to 2007, at the end of the Millennium Drought. However, the Australian Government Bureau of Meteorology has predicted a 70% chance of La Niña forming in the coming months (the 2021/22 Summer).
What drives stream health in South East Queensland?
Across the region a higher percentage of mid-dense forest in the upstream catchment has a positive effect on stream health site scores. Stream health is also generally negatively impacted by urbanised and/or pasture land in the upstream catchment. This suggests that maintaining natural areas and restoring waterway vegetation will result in better stream health .
Both rainfall and forest cover work in concert to maintain good freshwater stream health. Lower than average rainfall typically results in lower stream health, while average and higher than average rainfall generally increases stream health scores. The presence of forest cover appears to provide resilience to fluctuations in rainfall.
Western catchments show a high degree of annual variability in overall stream health. This variability may be a consequence of dry and wet periods which are typically more pronounced in the western catchments. For this reason, returning vegetation to waterways, particularly in the western catchment is a priority to improve the stream health of the region.
Figure 3. Western catchment (Bremer, Lockyer, Upper Brisbane) macroinvertebrate and fish scores from 2002 to 2021. Low scores are observed during period of low rainfall and river flow (2005-2007) (2020-2021), while higher scores are observed during high rainfall years (2011-2013).
Fine sediment pollution – protecting and restoring our catchments
|Figure 4. Satellite image of Southern Moreton Bay in March 2021, showing the Logan River flood plume mixing with freshwater draining off the freshwater wetlands of Minjerribah (North Stradbroke Island).|
Unfortunately, fine sediment pollution resulting from land-use changes continues to affect South East Queensland’s waterways. The impact of fine sediment pollution is greatest on receiving waterways such as Moreton Bay.
Research commissioned by Healthy Land and Water in the 2000s demonstrated that channel erosion is the dominant process supplying fine sediments to Moreton Bay. Gully erosion and hillslope erosion is also important in some catchments.
The SEQ Healthy Waterways Strategy (2001) set an overall target of a 50% reduction in fine sediment loads entering receiving waters by 2020 to address these declines in health.
Currently, over 1000 km of rivers and creeks in South East Queensland pose a high level of channel erosion risk (less than 5% of total length).
Control of channel erosion has been identified as the highest priority action for reducing fine sediment pollution. This can be achieved by restoring waterway vegetation to improve bank stability.
Re-introducing vegetation on floodplains and hillslopes can also reduce the erosive power of floodwaters. Bringing back stream bank vegetation to 15% of stream length (6,000 km across South East Queensland) would restore the resilience to many freshwater streams and reduce sediment loads to coastal areas by 50% .
Waterway vegetation is under continued threat from invasive weeds, for this reason protecting steam bank vegetation by controlling weed infestations will protect what we already have.
Healthy Land and Water has continued to work with its partners and membership network to drive investment in restoring catchments. There has been a significant amount of work and investment occurring across the region to help control fine sediment pollution.
Scenario Planning- What does the future look like?
The waterways in South East Queensland and Quandamooka (Moreton Bay) are highly valued by local residents and visitors alike. Waterways are culturally important and deliver social and economic benefits. Using scenario planning tools, we know in order to maintain these values we need continued coordination and investment.
By 2032 there is expected to be an additional 1 million residents in South East Queensland (4.8 million) compared to present. This will likely translate to an increase in the urban footprint and other land-use changes across the catchments. Climate projections indicate annual average temperatures will be between 0.6 and 1.3 °C above climate observed between 1986-2005 by 2030, with intense rainfall events becoming more frequent .
Without action fine sediment loads are likely to increase by approximately 50%. However, we can achieve an approximate 50% reduction in fine sediment loads entering waterways if we invest in restoring our catchments and adopt best management practice .
This will reduce the overall pressure our waterways under a rapidly changing climate.
Through continued action and investment, South East Queensland can hold the line against predicted increases in pollutant loads and other impacts on waterways, between now and 2030.
What action can we take?
Celebrate our rivers, wetlands and bay
Moreton Bay is visited more than the Great Barrier Reef! Overall South East Queensland waterways provide approximately $3.2b worth of recreational value to residents and provide significant emotional and cultural value. Highlighting the value of waterways to the community can improve feelings of responsibility and willingness to engage in or support waterway protection activities.
Conserve, protect and restore
Protect high value creeks, wetlands, floodplains and coastal areas that provide vital habitat for native species, reduce flood impacts, improve water quality and are beloved by residents for their emotional and cultural value.
Control and minimise impacts of existing and growing urban areas
New development in South East Queensland must meet expectations to protect creeks, wetlands, tree cover and stream bank vegetation. Using erosion and sediment controls that stop pollutants running off development and construction sites into local waterways through stormwater, is an easy and inexpensive way to minimise impacts of urban areas on waterways.
Improve waterway vegetation
Replant and protect vegetation in the western catchments, particularly Lockyer and Upper Brisbane. Many parts are impacted by the historic loss of tree cover and bringing back stream bank vegetation would restore the resilience to many freshwater streams and reduce pollutant loads.
Much work has been done, but there is much left to do. 1000km of streams have been identified as posing high erosion risk. Bringing back stream bank vegetation to 15% of stream length (6,000 km across South East Queensland) would restore the resilience to many freshwater streams and reduce sediment loads to coastal areas by 50%.
Maintain ground cover and apply best management practice
Our catchments support many activities, such as grazing, cropping, mining and forestry that support local economies. How land is managed across the catchment can effect the health of waterways. A large area of south-east Queensland is managed as grazing land.
Maintaining ground cover and applying best management practices can improve the water quality of run-off from these land-uses.
Limit wastewater pollutants
Manage projected increases in nutrient inputs to waterways as the population grows by maximizing nutrient removal efficiencies of wastewater (sewage) treatment plants.