Don River

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Vegetation

Riparian Habitat

iTRARC analysis of Riparian Habitat indicates that this subcatchment has undergone a large decrease in condition from good (A) to relatively poor (C+). This change is due to an increased number of gaps in the riparian corridor along all stream sizes and floodplain clearing. There has also been an increase in the amount of gullying/scalding within the catchment.

iTRARC Scores

Catchment Class 1 B
Maximum iTRARC Score 22 (A+)
1970s Score 16 (A)
2004 Score 6 (C+)
Reduction in Ecosystem Services Large
Increase in Potential for Erosion Large
Reasons for Change in Score
  • Increased gaps in the riparian zones of headwaters and tributaries and main channel
  • Floodplain clearing for cropping including forest
  • Increased gullying/scalding and low cover hillslopes

TRARC (field survey) scores = No TRARC scores for this subcatchment

Reference:Assessing the condition of Riparian Vegetation in the Burdekin catchment

Wetlands

The Don River is an ephemeral system flowing for short periods after significant rainfall. No major permanent waterholes are known though some smaller holes are likely present and these may be vulnerable to disturbance. The coastal freshwater wetlands are also mostly ephemeral or seasonal. The area is poorly known ecologically, especially the coastal freshwater wetlands. Hogan and Vallance (1998) surveyed the freshwater fish of the river, finding low diversity which is not surprising given the low amount of permanent freshwater available

Reference: Assessing the condition of Wetlands in the Burdekin catchment

For more information see Don River wetland condition summary

Water

SedNet Modelling of Water Quality

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

  • Subcatchment modelled area: 1,037sq. km.
  • Source contributions: Hillslope = 45%; Gully = 7%; Streambank = 48%
  • Area of subcatchment with <50% ground cover: 119 sq. km or 11% of subcatchment
  • Hillslope sediment supply: 610 kg/ha/yr
  • Streambank sediment supply: 647 kg/ha/yr.
  • Total suspended sediment (flow weighted) supply: 140 kt/yr
  • Total suspended sediment supply (flow weighted; normalized to area): 1350kg/ha/yr
  • Total suspended sediment end-of-subcatchment (flow weighted) yield: 134 kt/yr
  • Event Mean Concentration (EMC - flow weighted): 625 mg/L
  • Mean Annual Flow: 214,461 ML

Reference: Improved SedNet Modelling of Grazing Land in the Burdekin Catchment

Although relatively small, the Don River sub-catchment contributes a proportionally large amount of suspended sediment (140 kt/yr) to the greater Burdekin catchment, compared to other sub-catchments of similar size (eg. Kirk River, Fanning River and Allingham Creek). Approximately 11% of the Don River subcatchment has less than 50% ground cover. This relatively small proportion may be due, in part, to the large horticultural industry that extends throughout this sub-catchment. The greatest contribution of suspended sediment, however, is provided by streambank erosion (48%). This is likely the result of large scale clearing of riparian areas along the Don River. Hillslope erosion is also important, contributing 42% of the suspended sediment and associated nutrients. Both of these sources, streambank and hillslope, provide relatively high amounts of suspended sediment per hectare compared to other sub-catchments (610 kg/ha/yr and 647 kg/ha/yr respectively).

Water Quality Monitoring

The monitoring site in the Don River catchment is located near the Bruce Highway and has been sampled by the NQ Dry Tropics Volunteers program for 2 years. The catchment area for this monitoring site is 1,078 sq km, of which 93.8% is used for grazing. Suspended sediment concentrations for the Don River have been relatively high (mean concentration of 476 mg/L) over the monitoring period compared to other coastal catchments in the Burdekin Region. A flow-weighted annual suspended sediment load of 86,500 tonnes/year was calculated using the monitoring data from the 2005/06 wet season. This load is lower than that predicted by the SedNet model (140,000 tonnes/year), although comparisons are difficult to make based on one wet seasons monitoring data.

Herbicide residues of atrazine and hexazinone have been detected in the Don River, although these concentrations were low.

Environmental Uses and Values

Irrigation

Use of waters of the Don River for irrigated horticulture.

Stock Watering

Water supply for production of healthy livestock.

Cultural and Spiritual

Custodial use of water resources by Juru traditional owners.

References:

Landuse

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

  • Grazing: 86.9%
  • Irrigated horticulture & cropping: 5.3%
  • Water: 3.5%
  • Conservation & minimal use: 2.2%
  • Urban & semi urban: 1.8%
  • Mining: Limited mining water activity use identified.
  • Dryland agriculture: Limited Dryland agriculture water activity use identified.
  • Production & forestry: Limited Production & forestry water activity use identified.

Land Condition

Definition of ABCD land condition framework

No data available for land condition in the Don River subcatchment.

Ground Cover

No data available for Ground Cover in the Don River subcatchment.

Maps

Photos

References

LanduseDonRiver.jpg
Download Catchment Layer as *.kml (requires Google Earth)

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