Broken River

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Subcatchments

Smaller Catchments within the Broken River Catchment include:

Topography

Vegetation

Riparian Habitat

The following information is summarized from the ACTFR report: Assessing the condition of riparian vegetation in the Burdekin catchment using satellitte imagery and field surveys by Leo Lymburner and John Dowe. 2006. This report can be accessed from the report section below.

The iTRARC analysis shows relatively little change between the 1970s and present in this catchment, the only difference being an increase in the number of low cover hill slopes adjacent to the stream network. Interestingly the field surveys indicate that many of riparian zones surveyed are in a very poor (1 site) poor (7 sites) or relatively good (3 sites) condition. This demonstrates that sub-canopy processes (cattle grazing in uncleared areas) can still have a impact on riparian condition even though there may be little change in the vegetation canopy cover within a catchment.

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Wetlands

The following information is summarized from the ACTFR report: Assessing the condition of Wetlands in the Burdekin catchment using existing GIS and field knowledge for CCI by Mirjam Maughan, Damien Burrows, Barry Butler, Leo Lymburner and George Lukacs. 2006. This report can be accessed from the report section below.

The Broken River begins in mountain rainforests west of Mackay, is impounded by Eungella Dam and then combines with sides streams from the eastern ranges (eg. Massey, Urannah and Grant Creeks) to provide an almost permanently flowing clear-water river system that drive the streamflow in the greater Bowen River catchment. Although artificial, Eungella Dam is listed in the Directory of Important Wetlands in Australia, but the reaches below the dam are greatly affected by restricted discharge from that dam. However, this effect is lost as the other tributaries enter the system. Much of the headwaters of this system are protected in National Parks and reserves, although there is also some significant land uses (eg, dairying, land clearing) which are likely to have had some effect on water quality and habitat function. The quality and variety of habitats here is very high and the area has high conservation value, though it requires further exploration to fully document these values.

Fishes of the upper reaches above Eungella Dam have been surveyed by McGill (2001) and Eungella Dam and reaches below have been subject to the introduction of translocated fishes for the purpose of boosting recreational fishing opportunities (Burrows 1999, Pusey 2006). This has further modified the naturalness of the system. The Broken River is home to a turtle (Elseya irwini) that is only known from the Bowen-Broken system, with the area around Urannah likely to be an important reach for this species. Waterholes in this area were described by Blackman et al. (2002) who considered them to be particularly ecologically valuable. Although the Broken River above the dam is affected by land use and below by the altered flow regime because of the dam, tributaries such as Massey and Urannah Creeks, which have high flow volumes are considered likely to be in a relatively natural condition, with unmodified flow regimes and limited public and cattle access. Other tributaries such as Grant and Emu creeks have more grazing so may be slightly more modified. Water quality data for some waterholes is available in Loong et al. (2004).

Broken River wetland condition summary...

Water

SedNet Modelling of Water Quality

The following statistics are summarized from the CSIRO report: Improved SedNet Modelling of Grazing Lands in the Burdekin Catchment by Kinsey-Henderson, A., Sherman, B. and Bartley, R. 2007. This report can be accessed from the report section below.

Model results for the Broken River subcatchment are summarized as follows:

Subcatchment modelled area: 2,193 sq. km.

Source contributions: Hillslope = 83%; Gully = 6%; Streambank = 11%

Area of sub-catchment with <50% ground cover: 86 sq. km or 4% of subcatchment

Hillslope sediment supply: 853 kg/ha/yr

Total suspended sediment (flow weighted) supply: 224 kt/yr

Total suspended sediment supply (flow weighted; normalized to area):1023kg/ha/yr

Total suspended sediment end-of-subcatchment (flow weighted) yield: 215 kt/yr

Event Mean Concentration (EMC - flow weighted): 228 mg/L

Mean Annual Flow: 942,374 ML

Hillslope erosion is identified as the major source of sediment and particulate nutrients affecting water quality within the Broken River subcatchment (83%), and is predicted to contribute 853 kg/ha/yr. Total suspended sediment loss from all sources is predicted to be very high (1,023 kg/ha/yr). A large proportion of this subcatchment has minimal use and is a designated conservation area (Eungella National Park) and levels of vegetated ground cover are high, with only 4% of the subcatchment showing less than 50% cover. The event mean concentration of suspended sediment is predicted to be relatively low (228 mg/L) because of the high annual flow (942,374 ML) which is due to the comparatively high rainfall experienced in the southern end of this subcatchment around Eugella. The estimated concentration of suspended sediment is consistent with the limited monitoring data.

Water Quality Monitoring

The monitoring site in the Broken River catchment is located near the Broken River Lodge and has been sampled by the BDTNRM Volunteers program for 1 year (2006/07). The catchment area for this monitoring site is 36 sq km, of which 34.3% is used for grazing. The Mean TSS concentration for the 2006/07 wet season was relatively low (181 mg/L) compared to the mean concentrations from other sites located in the Burdekin rangelands. TSS concentrations can be estimated for the extended Broken catchment using the monitoring data from the Bowen River at Dartmoor Station which is located just below the Little Bowen/Broken River junction and from the Little Bowen River site at Amberkolly Station which is located just upstream of this junction. The mean TSS concentration from the Little Bowen River (4,006 mg/L) is more than double that of the mean TSS concentration for the Bowen River at Dartmoor (1,125 mg/L). This result suggests that TSS concentrations in the Broken River catchment are probably in the low-intermediate range. Observations at the Little Bowen/Broken River junction in the 2006/07 wet season also support that the Broken River is a lower contributor of suspended sediments compared to the Little Bowen River.

Relevant information of Water Quality Monitoring in the Bowen Broken Bogie River Basin can be found by following these links:

Environmental Uses and Values

The following summary of environmental uses and values is based on information extracted from the following reports: Social, Economic, Cultural and Environmental Values of Streams and Wetlands in the Burdekin Dry Tropics Region by Greiner, R and Hall, N. 2006 and Burdekin Basin Draft Water Resource Plan by Queensland Dept. of Natural Resources, Mines and Water, 2006. The Greiner and Hall 2006 report may be accessed from the report section below.

Definition of Environmental Values in the Queensland Water Quality Guidelines

Aquatic Ecosystems:

The aquatic ecosystem values of a large portion of the Broken River subcatchment has been identified as containing High Ecological Value (HEV) waters by the BWQIP ecological values technical panel. These include the waters within the Eungella National Park and the Gamma, Crediton and Macartney State Forests. The majority of this subcatchment downstream of these areas to Emu Creek has intact remnant vegetation and also contains HEV waters. These waters closely match the area listed on the Directory of Important Wetlands as the Broken River, Urannah Creek and Massey Creek Aggregation. The aquatic ecosystems values of other parts of the subcatchment are considered to be Slightly to Moderately Disturbed (SMD) as a consequence of the surrounding land use or because of flow modification. Nevertheless, the biological communities are thought to remain in a healthy condition and ecosystem integrity is likely to be largely retained.

Broken River subcatchment draft HEV waters

Irrigation:

Improved pasture (80% of water) with some sorghum and horticulture. Mainly near the river in the upper reaches of the Broken River. It is possible that there will be increased demand for irrigation water in the future. There is a proposed dam site at Urannah. Water would be piped into Don River for use for irrigation near Bowen.

Farm Water Supply:

Use of water by dairy farms in the Eungella area.

Stock Watering:

Grazing in north western part of sub-catchment. Water supply for production of healthy livestock.

Primary Recreation:

Swimming is reported to occur in the Broken River.

Visual Recreation:

Camping, photography, bushwalking, wildlife viewing (Eungella National Park)

Drinking Water:

Eungella Dam supplies town water for Fitzroy Basin mining town.

Industrial Uses:

The Eungella Dam supplies water to several mines in Moranbah and Nebo coal mining areas (in the Fitzroy River Basin). Future mining water requirements from Eungella Dam are expected to include 3,100 ML/a each for the BHP coal mines at Moranbah and Goonyella, and up to 4,300 ML/a for Northern Developments.

Eungella Dam supplies water for industrial and domestic use at Collinsville and Newlands (Glenden). An inter-basin transfer is provided via two overland pipelines, one belonging to BHP Billiton and the other to the Eungella Water Pipeline Company (a subsidiary of SunWater).

Eungella Dam supplies coal-mining developments and associated urban infrastructure within the Bowen Basin around Moranbah and Goonyella.

Eungella Dam originally supplied water for irrigation development in the Lower Burdekin but currently supplies water for mines and supplements the water available at the Bowen River (or Collinsville) Weir. Water from the weir is pumped via a pipeline to supply the coal mine, power station and the Collinsville township. A separate pipeline feeds mining operations at Newlands and the township of Glenden within the catchment.

In contrast with other sub-catchments, current water use within the Broken as well as the Bowen subcatchments is dominated by industrial use, principally associated with coal-mining activities.

Cultural and Spirtual:

Traditional owners are the Wirri people at the headwaters of the Broken River and Birri people are traditional owners downstream.

Landuse

Principle land uses within the Broken River subcatchment as a proportion of total area:

Conservation & minimal use: 79.9%

Grazing: 9.7%

Production & Forestry: 8.4%

Water: 1%

Urban & semi urban: .9%

Irrigated horticulture & cropping: Limited irrigated horticulture activity use identified.

Grazing Land

Broken River is a relatively small subcatchment, although one of the largest in the Bowen Broken Bogie Basin, where the major land use is for conservation and other minimal use. Grazing on natural pastures and production forrestry comprise around 10% and 8% of the land area respectively.

Land Condition

Definition of ABCD land condition framework

Results of a Rapid Land Condition Assessment (adopted from Hassett et al. 2000) are presented below. The assessment has been devised to subjectively characterise condition while traversing the BDT region by vehicle. The data are based on a total of 4666 observations across the Burdekin region between 2004 and 2007.

The data were collected to provide independent information on land condition and provide a regional perspective. Resource assessment data are most useful when interpreted with other sources of data e.g. time-series remote sensing, modelling and water quality monitoring.

The estimated condition of the Broken River sub-catchment is proportioned as follows:

A Condition: 57%
B Condition: 29%
C Condition: 14%
D Condition: n/a

Data from the Broken River sub-catchment is based on 7 observations.

On the basis of the rapid assessment, the Broken River sub-catchment is estimated to have the largest proportion of land in Good (A) condition (57%), followed by fair (B) condition (29%) and poor (C) condition land (14%). No very poor (D) condition land was observed.

Ground Cover

No rapid assessment data are available for Ground Cover in the Broken River subcatchment.

Resource Condition Summary

Broken River is a relatively small subcatchment, although one of the largest in the Bowen Broken Bogie Basin, where the major land use is conservation and other minimal use. Grazing on natural pastures and production forrestry comprise around 10% and 8% of the land area respectively. Riparian habitat in the subcatchment has undergone relatively little change in the last 30 years and remains in very good (A) condition. The Broken River begins in mountain rainforest west of Mackay and provides a permanently flowing clear-water river system which is supplimented by tributories from the eastern ranges (eg. Massey, Urannah and Grant Creeks) where the headwaters are protected in National Parks, reserves and by native remnant vegetation. The quality and variety of habitats here is very high. Restricted discharge from Eungella Dam has limited effect on the environmental flows, while the dam is listed in the Directory of Important Wetlands.

Hillslope erosion is identified by models as the major source of sediment and particulate nutrients affecting water quality within the Broken River subcatchment. The rate of erosion is predicted to be high and above the Basin average, while the total soil loss from the subcatchment to waterways is also relatively high. Grazing land condition is assessed as having a high proportion in good (A) condition, while fair (B) and poor (C) condition land is also apparent. Analysis of ground cover from satelite imagery (reference) shows that the mean ground cover has been consistently very high throughout most of the subcatchment since 1997, except for the lower reaches of Broken River near its junction with Emu Creek.

Water quality in the Broken River subcatchment is predicted by models to be quite good, with relatively low concentrations of sediment at end-of-subcatchment during wet season event flows. Water quality monitoring data cannot be directly compared with model results for predicted sediment concentration. Nevertheless, while they are generally consistent with model results, based on the high ground cover it appears likely that the model is overestimating the rate of soil erosion and total soil loss from the subcatchment because of the steep terrain.

Draft Environmental Values

A large portion of the Broken River subcatchment has been identified as containing High Ecological Value (HEV) waters by the BWQIP ecological values technical panel. They include the waters within the Eungella National Park and the Gamma, Crediton and Macartney State Forests. The majority of this subcatchment downstream of these areas to Emu Creek has intact remnant vegetation and also contains HEV waters. These waters closely match the area listed on the Directory of Important Wetlands as the Broken River, Urannah Creek and Massey Creek Aggregation. The aquatic ecosystems values of other parts of the subcatchment are considered to be Slightly to Moderately Disturbed (SMD) as a consequence of the surrounding land use or because of flow modification. Nevertheless, the biological communities are thought to remain in a healthy condition and ecosystem integrity is likely to be largely retained. The human use Environmental Values of the subcatchment are understood to include recreation (swimming, boating & visual appreciation), irigation, farm supply, industry, stock watering, human consumption, drinking, and the cultural and spiritual values of the Birri and Wirri traditional owners.