FOCUS CATCHMENTS

Brisbane River

The Catchment at a Glance

The Brisbane River Catchment has a sub-tropical climate, with 1.5m of rainfall a year, mostly as intense summer storms. The catchment area is 13,500km2 in size and extends from Moreton Bay to the Great Dividing Range. This catchment includes the sub-catchments of the Upper Brisbane, Stanley, Lockyer and Bremer Rivers. It includes 850kms of river and lake banks as well as 50 major creeks.

The Brisbane River is the largest river in the Catchment. Eighty kms of the river’s lower reaches are tidal and flood prone with 11 ‘major floods’ recorded in Brisbane since 1840.

Only 14% of the catchment is currently uncleared. Land use is varied, including significant areas of urban, grazing, cropping and forested lands. The upper catchment is mainly rural, while the lower catchment is urbanised. The Brisbane River Catchment supports the largest population of any catchment in Queensland (in excess of one million), and being part of SE Queensland, is currently experiencing rapid population growth. For example, from 1991 to 2031 it has been estimated that there will be a 78% increase in the population of Brisbane City. As a consequence of this population, there are 40 sewage treatment plants (STPs) in the catchment. In Brisbane City alone, there are over 2,100km of enclosed urban stormwater drains and 8,200km of ‘kerb and channel’ stormwater drainage.

The Brisbane River Catchment drains to Moreton Bay (1,523km2 in area), a shallow bay sheltered from the Pacific Ocean by the islands of Moreton and North Stradbroke to the east. The Bay plays a major role in the economy of the region and the lifestyle of its people. Brisbane in the only place in the world where 700-900 dugong graze on seagrasses within sight of a major City. The Bay also hosts internationally recognised sites for migratory birds and supports a significant fishing industry. The Bay’s recreational fishing industry alone is worth over $400M p.a.
Key Waterway-Related Issues

The following issues are nominated by the Author as currently being the most significant waterway-related issues facing the catchment (in no particular order):

• Flooding (regional and local).
• Sediment loads/turbidity in creeks, the river and bay (from urban stormwater and rural land uses).
• Nutrient loads in creeks, the River and Bay (e.g. algal blooms in the Western Bay are principally linked to nitrogen discharges from STPs).
• Weeds (aquatic and riparian).
• Degradation and discontinuity of riparian vegetation.
• High concentrations of nutrients, bacteria and phytoplankton in creeks within the upper catchment.
• Sewer overflows and urban stormwater impacting upon urban creeks.
• Water supply and environmental flows.
• Litter and toxicants (e.g. pesticides and heavy metals) in creeks, the River and Bay.
• Bank erosion (particularly creeks in the upper catchment).

Largely because of the widely recognised work of the SE Qld Regional Water Quality Management Strategy (SEQRWQMS or ‘The Moreton Bay Study’), catchment managers now have a good understanding of cause-effect relationships in tidal waterways, and are implementing suitable actions. However, scientific investigations are still in their infancy in freshwater areas via the SEQRWQMS (with help from CRCs and others). There is still much to learn about the health of these systems, the key threats, sources of pollutants and importantly, necessary management actions.

Key Stakeholders Involved with Catchment Management and Research

• Local governments and their various reference groups.
• Numerous community/catchment groups (e.g. in Brisbane City Council alone there are currently 16 formally recognised catchment groups).
• Commonwealth Government (e.g. through NHT funded projects).
• State Government (e.g. the Environmental Protection Agency, Department of Natural Resources and Mines, Department of Primary Industries, Queensland Transport).
• Port of Brisbane Corporation.
• SEQ Water Board.
• CRCs (i.e. Catchment Hydrology, Coastal Zones, Freshwater Ecology).
• Local universities (University of Qld, Griffith, Qld University of Technology).
• Industry associations (SIA, IEAust, HIA, QMBA, UDIA, etc.) and local groups such as the Urban Stormwater Information Group which represents key urban stormwater managers from across SE Qld.
• The SEQRWQMS (the Strategy will continue until 2001).

Want More Information?

The Crew Member's Guide to the Health of Our Waterways (SEQRWQMS, 1998) is an excellent layperson's summary of the SEQRWQMS's scientific findings involving the lower catchment (contact the SEQRWQMS on 07 3403 4206).

The Moreton Bay Study - A Scientific Basis for the Healthy Waterways Campaign (SEQRWQMS, 1999) is a companion document to the above, but aimed at the scientific community (contact the SEQRWQMS on 07 3403 4206).

The Moreton Bay Catchment Water Quality Management Strategy (SEQRWQMS, 1998) summarises those actions being taken by stakeholders in the region to address the findings of the SEQRWQMS for tidal waters (contact the SEQRWQMS on 07 3403 4206). This Strategy is being updated as scientific investigations now involve the Catchment's freshwater areas.

The Urban Stormwater Management Strategy (BCC, 1999) summarises those actions being taken by Brisbane City Council to manage urban waterways within its jurisdiction (contact Council on 07 3403 9402).

Tony Weber
Focus Catchment Coordinator (Brisbane River Catchment)
trweber@wbmpl.com.au