Fitzroy River
Coordinator: Chris Carroll,
Natural Resources, Mines and Energy, Queensland
Introducing the Fitzroy River Catchment
The Fitzroy River Catchment in Queensland is one of the CRC’s five focus catchments. The information given below is intended to give readers a feel for the physical nature of the catchment, the key issues facing catchment managers in the region, and key stakeholder groups involved in catchment management and waterway-related research.
Location and size
The catchment of the Fitzroy River stretches from the Carnarvon Gorge National Park in the West to Rockhampton on the central Queensland coast. The Fitzroy catchment is the second largest in Australia, nearly 150,000km2, and is dominated by agriculture (grazing, dryland cropping, irrigated cotton and horticulture) and by mining (coal production of 100 million tonnes/year, magnesite, nickel and historically gold and silver).
Hydrologic aspects
The river flow is highly episodic with seasonal bias to higher flows in summer. Limited data indicates annual sediment delivery to the estuary is 5 million tonnes with high levels of nutrients and some pesticides. The catchment has recognised land degradation problems including all forms of soil erosion by water, and soil fertility decline. Several existing industries and communities are barely viable in the current economic environment.
Land use in the Fitzroy catchment
- Grazing
Grazing is the largest contributor (over 50 %) to rural income into Queensland’s Central West Region. The grazing industry manages vast areas of the Fitzroy region (more than 13 million ha). Productivity is low by world standards, and in some cases poor management has led to resource degradation and possibly off-site impacts. Soil erosion and related problems of sediment and nutrient delivery are perceived to be major problems. It is likely that off-site impacts are small on a per hectare basis, but grazing is possibly the largest contributor to the Fitzroy Catchment water quality problems, due to its massive area.
- Dryland cropping
The second largest area managed is dryland cropping, roughly 0.8 to 1 million hectares. Dryland cropping productivity in the region is low (grain production is about 700,000 tonnes/year), but recent estimates suggest there is potential to produce 2,000,000 tonnes/year. Again, soil erosion is perceived to be a dominant natural resource problem for this land use. Local practice, plus the unreliable rainfall, result in long periods with cropping land lying fallow and thus venerable to soil erosion. Other land resource degradation issues include soil compaction and fertility decline. It is widely recognised by catchment groups that the decline in these natural resources is linked to reduced farm productivity. There has been slow uptake of previous research, so careful consideration of the socio-economics of this sector is vital to uptake of any future research results.
- Irrigated cropping
Irrigated cropping although small in area, may have an impact on water quality; the major concerns are pesticides and nutrients. Although irrigation accounts for a small percentage of the total catchment area (45,000 ha), the rapid expansion and high inputs required by the industry has a significant effect on resources and downstream water quality. There is considerable potential for the adoption of best management practices in this sector. Note that the Fitzroy River is currently subject to a Water Allocation Management Plan (WAMP). Aspects of this issue will be covered in the CRC’s Sustainable Water Allocation program.
- Mining
Mining, although small in area, may have impacts on acidity and salinity of surface water. In central Queensland the area disturbed by open-cut coal mining exceeds 50,000 ha. The area subjected to underground long-wall mining is less, but increasing. The primary aim with open-cut rehabilitation is to produce a post-mining landform that is resistant to geo-technical failure and with minimal off-site impact on water quality.
In-stream problems
The Fitzroy River has periodically high levels of sediment (turbidity), pesticide and nutrient levels, toxic algal blooms and widespread occurrence of exotic weeds and threatened habitats, in particular flood plains and riparian areas.
Soil erosion and related sediment movement appear to be having a major impact
on the Fitzroy Catchment. In two isolated events,
NRME staff estimated that approximately 20 million
tonnes of topsoil was eroded from the surface
of the catchment, predominantly from agricultural
land. An unknown portion of this eroded sediment
reaches the river network. Further, an unknown
portion of this material is transported through
the complex river/floodplain environment and its
associated sediment storages. It is not clear
what the trends are in measures of river health.
There is a need to quantify the source, amount,
and quality of sediment generated across the catchment,
the pollutants carried with it, and the effects
of the practical management options.
Riverine, riparian, estuarine and marine health
Riverine and riparian areas in the Fitzroy have been disturbed by agricultural and mining activities. The estuary hinterlands have been generally cleared for grazing and urban development except for a considerable area of near pristine marine wetlands near the southern mouth. From limited water quality data, the downstream end of the estuary is in good condition but with high turbidity. Near Rockhampton, the estuary has high nutrient levels probably associated with upstream inputs, reduced tidal mixing due to the barrage, and to local sewage outfalls. Keppel Bay supports a major scallop, prawn and fish industry.
The way forward
There is considerable existing knowledge about the functioning of this and similar
catchments. Natural Resources, Mines and Energy,
Queensland has had a long-term presence in the catchment.
The Fitzroy is also a focus catchment of the CRC
for Coastal Zone, Estuary, and Waterway management,
LWRRDC’s National Eutrophication Management
program and a site for investigations by several
Universities including Central Queensland University
and The University of Melbourne.
The challenge for the CRC for Catchment Hydrology is to consider this vast, diverse catchment in a holistic way taking into consideration the existing knowledge and the parallel research of other organisations.
Chris Carroll
Focus Catchment Coordinator (Fitzroy River Catchment)
Mr Chris Carroll
Natural Resources, Mines and Energy, Queensland
PO Box 736
Rockhampton Qld 4700 Australia
Tel: (07) 4938 4240
Fax: (07) 4938 4010
chris.carroll@dnr.qld.gov.au
|
