ABOUT THE FOCUS CATCHMENT

In south-eastern Queensland (SEQ) around

Brisbane, the population, currently about 2.8 million,

is expected to reach over 4 million by 2031. Most

growth is expected to occur in the Logan-Albert

catchments to the south, and in the catchments

of the Bremer and Lockyer rivers, tributaries of the

Brisbane River. These catchments, and several

others, drain into Moreton Bay, parts of which

are ‘internationally significant’ under the Ramsar

Convention.

Poor water-quality and aquatic ecosystem health

in areas of Moreton Bay have been identified as

being largely caused by diffuse contamination with

sediment and nutrients from the non-urban areas

west of Brisbane. Research has found that these

‘non-urban’ sources are largely the river and creek

channels themselves and gully erosion. In-channel

works that slow the movement of runoff during and

after heavy rain can reduce channel erosion, but

resources are limited, confining the restoration to

soil types and areas where it can have best effect.

For urban growth areas to the south, current

water supply sources may be augmented

in the future by options such as harvesting

rainwater and stormwater, recycling wastewater,

desalinating seawater, or pumping groundwater, to

accommodate changing population and climate.

Urban water managers need to decide how to

combine these options, both to maximise water

supply and to ensure the best possible ecosystem

health of the waterways carrying urban water

discharges to Moreton Bay.

eWater is trialling software in these areas aiming

to help our partners with these two distinct river-

erosion and urban-supply challenges.

• Using modelling trials and field based studies we

are helping the SEQ Healthy Waterways Partnership

(SEQHWP, at least 10 members of which are also

eWater partner organisations) to consider restoration

works to reduce channel erosion, and to monitor the

effects on ecosystems in the streams leading to the

bay.

• With our prototype urban models, we are showing

the SEQ Urban Water Security Research Alliance (all

of which are eWater partners) how it could explore

options for improving both the security of urban

water supply and the quality of receiving waters.

 APPLICATION

eWater CRC’s next-generation software tools are

being demonstrated and further developed via this

application:

(i) predicting sediment yields under rehabilitation

options;

(ii) developing predictive models for ecosystem

health, based on stream condition;

(iii) enabling optimal spacing of restoration works;

(iv) exploring urban water supply options, including

wastewater and stormwater recycling.

In meeting the specific needs of this region, this

application will also expand the models’ functionality

for use in other situations.

eWater CRC is working on water management issues in partnership

projects with organisations in south-eastern Queensland.

The project teams are focusing on the rapidly growing urbanised area

in catchments draining into Moreton Bay near Brisbane. They are ‘road-

testing’ eWater software in relation to water security for the urban areas,

as well as the water quality and ecosystem health of the bay itself and the

streams that run into it.

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South East Queensland

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QLD

 

RUNOFF AND EROSION CHALLENGES

Studies show that the bay is receiving about 300,000 t/year

of fine sediment, and that 80% of this sediment comes

from 20% of its catchment area, mostly from streambank

and gully erosion. The challenge is to place erosion control

works where they will be most effective.

HOW eWATER IS HELPING

eWater teams are adapting our catchment modelling

framework to help optimise rehabilitation so that it reduces

the supply of sediment to the waterways.

For the various stream-rehabilitation options, eWater is

using modelling and local data to predict the effects of a

range of possible spatial configurations across the whole

region – a very complex challenge.

 And our ecological modelling software is helping predict

how ecosystems in the catchments’ streams will respond

to the rehabilitation options. The team is also developing a

monitoring and evaluation plan for the essential tracking of

the results of restorative work.

OUTCOMES

The outcome of this runoff/erosion application will be

an integrated set of software the SEQHWP could use to

decide between spatial patterns (local and regional) of

rehabilitation activities which are compatible with good

ecological health in streams and estuaries around the bay.

The software could potentially help the Partnership achieve

its target of a 50% reduction of sediment inflow to Moreton

Bay by the year 2026.

URBAN WATER-SYSTEM CHALLENGES

Urban water planners need to understand how complex

urban water systems would perform under a mixture of

urban water management options. For that they need

software tools to help them model the whole urban water

system and explore and optimise supply security over the

long term.

HOW eWATER IS HELPING

The eWater team is developing urban modelling software

capable of analysing a water and nutrient balance for

a whole-of-urban water system at regional-catchment

scales. eWater is trialling this software tool in collaboration

with a project of the SEQ Urban Water Security Research

 Alliance. The water supply strategies considered are those

identified in the draft SEQ Water Strategy released in

March 2008.

With eWater’s urban modelling tool, planners potentially

can explore the implications of using recycled water,

rainwater, desalinated water and stormwater for urban

and agricultural purposes. For example: how might the

various supply options affect the dynamics of supply-

system storage levels and system reliability, resilience

and vulnerability; and what might be the various options’

effects on the quality of receiving waters?

OUTCOMES

This urban water system application demonstrates a

decision-support system that could help urban water

planners develop a range of strategies for water supply

planning and operations.

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South East QueenslandFOCUS CATCHMENT

EROSION URBAN

ORGANISATIONS INVOLVED

These eWater partner organisations are involved in this application project:

Brisbane City Council, Department of Environment & Resource Management (formerly the Dept

of Natural Resources & Water, and the Environmental Protection Agency), Department

of Primary Industries & Fisheries, Griffith University, The University of Queensland,

CSIRO (through the Water for a Healthy Country National Research Flagship).

KEY CONTACT

Professor Jon Olley 

SEQ Focus catchment (restoration)

 Australian Rivers Institute, Griffith University 

 j.olley@griffith.edu.au

KEY CONTACT

Dr Shiroma Maheepala

SEQ Focus catchment (urban)

CSIRO Water for a Healthy Country 

shiroma.maheepala@csiro.au

 All eWater tools demonstrated in focus catchments are part of our integrated modelling suite.

 August 2009