Bowen River

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Subcatchments

Smaller Catchments within the Bowen 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.

iTRARC analysis of Riparian Habitat indicates that this subcatchment has had a decrease in condition from fair (B) to poor (C) condition. The reduction in condition is primarily due to floodplain clearing and an increase in the number of erosional features visible within the imagery. The field surveys indicate that the sites visited are in fair to poor condition (B-C), with high levels of regeneration, and relatively high levels of weediness. High levels of regeneration and high levels of weediness may indicate lower grazing pressures at the sites at which these surveys were conducted.

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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.

This is one of the major tributaries of the Burdekin catchment, with many major waterholes and clear water flowing for most of the year in most years, providing very significant aquatic habitat. Condition is generally typical of the Burdekin rangelands, but ground cover has been poor in recent dry years, bank erosion is significant in the middle reaches and weeds are an ongoing riparian management issue. The sub-division includes the Bowen River Weir near Collinsville, providing a large, non-flowing deepwater habitat which creates a weir pool quite different from a natural waterhole. The weir is considered a barrier to upstream movement of fish and has a dysfunctional fishway on it (Hogan and Vallance 1999). Large deep waterholes are particularly common around Birralee and Myuna. The Bowen River is home to a turtle (Elseya irwini) that is only known from the Bowen-Broken system. Waterholes in this area were described by Blackman et al. (2002) who considered them to be particularly ecologically valuable and water quality data for some waterholes is available in Loong et al. (2004).

Bowen 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 Bowen River subcatchment are summarized as follows:

Subcatchment modelled area: 1,227 sq. km.

Source contributions: Hillslope = 47%; Gully = 29%; Streambank = 24%

Area of subcatchment with <50% ground cover: 445 sq. km or 36% of subcatchment

Hillslope sediment supply: 665 kg/ha/yr

Total suspended sediment (flow weighted) supply: 173 kt/yr

Total suspended sediment supply (flow weighted; normalized to area): 1,414 kg/ha/yr

Mean Annual Flow: 1,618,299 ML

Hillslope, gully and streambank erosion are all identified as significant sources of sediment and particulate nutrients affecting water quality within the Bowen River subcatchment (47%, 29% & 24% respectively). This subcatchment is largely a floodplain and a relatively high proportion of the sub-catchment has low ground cover (36%). Riparian habitat is reported to be in poor condition with extensive floodplain clearing and gullying. Total suspended sediment loss from all sources is predicted to be very high (1,414 kg/ha/yr).

Water Quality Monitoring

One monitoring site in the Bowen River catchment is located at Myuna Station and has been sampled by CSIRO and BDTNRM for 5 years. The second monitoring site is located just below the Little Bowen and Broken River junction (Dartmoor Station) and has been sampled by the BDTNRM Volunteers program for 1 year. The catchment area for Myuna is 7,112 sq km, of which 56.4% is used for grazing. Dartmoor is 3,889 sq km and with 31% grazing. As these sampling sites incorporte several other sub-catchments (e.g. Little Bowen, Broken, Glenmore Creek, Pelican Creek, Rosella Creek), the data are not useful for investigating the event water quality of Bowen River sub-catchment. However, the Bowen River at Myuna site provides data for the Bowen River Basin, while the Bowen River site at Dartmoor Station provides data from the both the Little Bowen and Broken River sub-catchments.

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., 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 Bowen River subcatchment are considered to be Slightly to Moderately Disturbed (SMD) as a consequence of the surrounding land use and flow modification, nevertheless, the biological communities are thought to remain in a healthy condition and ecosystem integrity is likely to be largely retained. No High Ecological Value (HEV) areas have been identified in the subcatchment.

Bowen River subcatchment draft HEV waters

Irrigation:

Irrigated horticulture around Birralee. Water supplied for irrigation from the Bowen River Weir. An area of approx. 20,000 ha of land has been identified as being suitable for irrigation

Stock Watering:

Extensive cattle grazing. Use of water for stock watering.

Primary Recreation:

Secondary Recreation:

Visual Recreation:

Bowen river supports swimming, fishing and has aesthetics value.

Drinking Water:

Collinsville and Glendon town water supply from Bowen River Weir.

Industrial Uses:

Bowen River Weir supplies mining operations at Newlands and Collinsville. Collinsville mine is expected to close in 2015 and Newlands mine in 2020. It also supplies water for the Collinsville Power Station.

Cultural and Spirtual:

Custodial use of water by Wirri traditional owners.

Landuse

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

Grazing: 95.6%

Water: 3.1%

Irrigated horticulture & cropping:.8%

Conservation & minimal use: .5%

Urban & semi urban: Limited urban & semi urban activity use identified.

Grazing Land

Bowen River is a relatively small subcatchment where land use is almost exclusively grazing on natural pastures.

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 Bowen River sub-catchment is proportioned as follows:

A Condition: 9%
B Condition: 44%
C Condition: 42%
D Condition: 4%

Data from the Bowen River sub-catchment is based on 97 observations.

On the basis of the rapid assessment, the Bowen River sub-catchment is estimated to have the largest proportion of land in fair (B) condition (44%), followed by poor (C) condition (42%) and good (A) condition land (9%). 4% of observed land was in very poor (D) condition.

Ground Cover

Ground Cover in the Bowen River sub-catchment is proportioned as follows:

( BC) Bare Cover: 2%
( LC) Low Cover: 8%
( MC) Moderate Cover: 43%
( HC) High Cover: 45%
(VHC) Very High Cover: 2%

Data from the Bowen River sub-catchment are based on 60 observations.

On the basis of the rapid assessment (2004-2007), the Bowen River sub-catchment is estimated to have the highest proportion of land within the high (HC) ground cover category (45%), followed by Moderate (MC) cover (43%) and low (LC) cover (8%) categories. 2% of land was estimated to fall into the bare (BC) and very high cover (VHC) category.

Resource Condition Summary

Bowen River is a very small subcatchment where land use is almost exclusively grazing on natural pastures. The condition of riparian habitat in the subcatchment has declined over the last 30 years due to floodplain clearing and gullying. The catchment was in fair (B) condition in the 1970s, but by 2004 its riparian condition had declined to poor (C). The Bowen River is one of the major tributaries of the Burdekin catchment, with many waterholes and clear flowing water for most of the year, thus providing very significant aquatic habitat. The Bowen River Weir, near Collinsville, is an artificial impoundment that provids a large, non-flowing deepwater habitat.

Hillslope, gully and streambank erosion are all identified by models as significant sources of sediment and particulate nutrients affecting water quality within the Bowen River subcatchment. The rate of soil erosion is predicted to be very high and well above the Basin average, while the total soil loss from the subcatchment to waterways is also comparatively high. Land condition is assessed as being fairly evenly divided between fair (B) and poor (C) condition. This is also reflected in the rapid ground cover assessment (2004-07), while analysis of ground cover from satelite imagery (reference) identifies large areas of land with low ground cover that are particularly vulnerable to 'D' condition. Bank erosion and gullying is reported to be significant in the middle reaches of the Bowen River.

Water quality in the Bowen River subcatchment is predicted by models to be moderately impacted during wet season event flows, with elevated concentrations of sediment at end-of-subcatchment. However, the sediment load at end-of-catchment is derived not only from this subcatchment, but also from others entering upstream. Water quality monitoring data from the Broken River at Myuna are not useful to specifically characterise water quality for the Bowen River subcatchment because it drains almost the entire Bowen Broken Basin.

Bowen River is identified as a priority subcatchment for rehabilitation on the basis of its poor land condition and vulnerability to 'D' condition, very high rate of soil erosion and predicted contribution to the total sediment load within the basin. The Bowen River is expected to contribute a considerable proportion to the suspended sediment export from the Burdekin River due to its close proximity to the Burdekin River mouth.

Draft Environmental Values

The aquatic ecosystem values of the subcatchment are considered to be Slightly to Moderately Disturbed (SMD) as a consequence of the surrounding land use and flow modification, nevertheless, the biological communities are thought to remain in a healthy condition and ecosystem integrity is likely to be largely retained. No High Ecological Value (HEV) areas have been identified in the subcatchment. The human use Environmental Values of Bowen River subcatchment are understood to include recreation (swimming, fishing & visual appreciation), irrigation, industry, stock watering, human consumption, drinking, and the cultural and spiritual values of the Wirri traditional owners.