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Newsletter #1, February 2011
South East Q ueen
Satellite image of
Moreton Bay on 15
January 2011, with
the flood plume visibly
The 2011 Queensland floods were devastating to concentrated in western
the people and economy, with lives lost and homes and northern portions of
and infrastructure destroyed. As communities across Moreton Bay.
Queensland rebuild their homes and businesses,
the impact of the floods on the ecosystems that
support commercial and recreational activities of
the state are unknown. The flood has already had a
short term impact on water quality in the rivers and
Moreton Bay, with increased risks associated with
human contact and shipping.
This newsletter is the first in a series that will
provide an overview of the environmental impacts
of the January 2011 floods on the catchments and
waterways. The impacts of sediments, nutrients
and toxicants delivered to Moreton Bay by the flood
plume may influence both the ecosystems and the
ecosystem services. This newsletter will provide
information on the location of the flood plume, the
types of impacts expected, and the frequency of
UQ - MODIS Image
flood events.
6 Jan 2011 15 Jan 2011 21 Jan 2011
CSIRO
A pilot hydrodynamic model of the Moreton Bay region developed for Healthy Waterways has been run throughout the flood and recovery
period. Although the model is not yet fully calibrated, maps of the salt content of the water (salinity) generated by the model appear to provide
a useful predictor of the flood plume (low salinity flood plume = purple color).
Snapshot of S the flood The features that will require monitoring are depicted in the diagrams below (e.g. gully erosion, riparian
outh East Queensland during vegetation integrity, water quality, seagrass, coral, and dugongs). A collection of the Healthy Waterways’
partners are undertaking this monitoring using remote sensing, in situ sensors and direct measurements.
The integration and communication of this monitoring effort will be important for establishing the short and
long term impacts of the flooding, both in the catchment and in Moreton Bay.
A conceptual diagram of the South East Queensland flood event is depicted, illustrated with aerial
photographs taken during the flood. The diagram was developed by the Healthy Waterways Flood Analysis of the monitoring results will inform Healthy Waterways and its partners of the efficacy of various
Response Taskforce. This conceptualisation includes the impacts and effects on rural and urban rural and urban waterway health management investments. This includes the ability of these investments to
landscapes as well as Moreton Bay. The basic principles depicted in the diagram are applicable a) mitigate flooding and flood impacts, b) protect the water quality, living resources and habitats of South
throughout the east coast of Queensland, including Hervey Bay and the Great Barrier Reef. East Queensland waterways, c) enhance the recovery from the 2011 flooding or future flooding.
Rural areas Urban areas Moreton Bay
• Runoff of sediments , nutrients and toxicants from • Runoff from upper catchment • Flood waters enter the Bay with high levels of sediments, nutrients and toxicants
agricultural lands and vegetated areas • Runoff of sediments , nutrients and toxicants • Freshwater flood plume sits on top of the saltier water with distinct inner brown and outer green plumes which move slowly
• Severe bed and bank scouring and gully erosion • Bank and bed scouring leads to collapse of banks and across the Bay
increases sediment load damage to mangroves • Sediments block light in the water column
• Resuspension of sediments • Resuspension of sediments • Seafood may become contaminated with toxicants
• Groundwater recharge • Groundwater recharge • Deposition and resuspension of sediments
• Sewage treatment plants release high nutrient and • Seagrass is smothered by sediment
pathogen loads
12 Jan 15 Jan 15 Jan
Wivenhoe Dam
reaches 190% Brown water
at northern
The Australian
Lockyer Creek Bribie Island end of
Piet Filet
Piet Filet
peaks at 17.25m Full Wivenhoe Dam releasing Pontoons and other debris along Pumicestone
water downstream Nudgee Beach Passage
Deception Bay
Redcliffe
24 Jan
Bramble Bay
Moreton Island
Bremer River
peaks at 19.5m Brisbane River
peaks at 4.46m
Seqwater
Junction of the Lockyer Waterloo Bay
and Brisbane Rivers
12 Jan 14 Jan 15 Jan 15 Jan
Troy Hansen, Qld State Library
North Stradbroke
Island
Martin Howard
Nicola Udy
Floodwaters entering Brisbane
Piet Filet
Flood plume expanding into Waters off the northern end of North
Water over the rail tracks in Gailes City financial precinct Waterloo Bay to King Island Stradbroke Island remain clear
Historical flood events
Australia’s climate means that drought, punctuated
by intense rain events, will lead to future flooding.
The El Nino/Southern Oscillation climatic pattern
results in cycles of drought and intense rain in
Queensland. This pattern will likely be exacerbated
Flooding in Brisbane city
by climate change. Thus flooding is something
that South East Queensland residents, businesses 9
and governments will need to cope with now and 8.8
into the future. In addition, the rivers, estuaries and 8.6
1841
embayments of South East Queensland will be
Qld State Library
8.4 5 Feb,1893
threatened by more frequent and severe floods.
8 19 Feb,1893
The January 2011 flood was only the ninth highest 7.8 Albert St, 1893
flood since recording began in the 1840’s. Even 7.6
before recording began, in 1824, the explorer John 7.4
Oxley noted evidence of recent flooding near the
juncture of the Bremer and Brisbane Rivers. While 7 1844
6.8
flooding is a regular and natural occurrence in
6.6 1845
South East Queensland, the substantial amount of
Qld State Archives
6.4
infrastructure damage by the 2011 flood is unique.
Previous floods have also had devastating impacts, 6
major
with bridges, homes and buildings destroyed. But 5.8 Albert St, 1974
the growth of Brisbane, particularly in flood prone 5.6 1974
areas, makes the 2011 flood especially damaging. 5.4 1890
5 1898
4.8
4.6 2011
news.com.au
tt e rs 4.4
U pco min g n e ws le 4 Albert St, 2011
erbanks 1887,1864 1889
• Creeks, riv
3.8
3.6
s
and paddock 3.4 1908 1863,1931 1857
moderate
• Impacts o
n the Bay 3 1852 1870
2.8 1843 1873
2.6
2.4 1955
minor
2 1928
1996 1968 1967
1929 1991 Historical flooding
levels and images
1.8 1956
as measured at the
1.6 Brisbane City gauge
1.4
Healthy Waterways Authors: Bill Dennison, James Udy, Peter Schneider, Piet Filet. Design: Kate Moore
PO Box 13086, George St, Brisbane, QLD 4003 For more information about the waterways of South East Queensland please visit Healthy Waterway’s website:
Phone: (07) 3123 1682 Fax: (07) 3103 4573 www.healthywaterways.org
www.healthywaterways.org Front banner: Road washed away in Lockyer Creek, SEQ Catchments
Back banner: 1974 floods in Chelmer, Queensland State Library