Native Companion Creek

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Vegetation

Riparian Habitat

iTRARC analysis of Riparian Habitat indicates that this subcatchment has had a very large reduction in the riparian condition. Condition has decreased from good (B+) in the 1970s to very poor (D) in 2004. This is primarily due to extensive clearing of riparian zones and floodplains throughout this subcatchment. The field survey TRARC data also indicate that riparian zones are in poor condition with 6 out of 8 sites surveyed falling into the poor category. The low degree of weediness is good, but may indicate high grazing pressure.

iTRARC Scores

Catchment Class 2 A
Maximum iTRARC Score 24 (A+)
1970s Score 13 (B+)
2004 Score -1 (D)
Reduction in Ecosystem Services Very Large
Increase in Potential for Erosion Small
Reasons for Change in Score
  • Clearing of woodland and forest from headwater streams and anabranching streams
  • Extensive floodplain clearing including forest
  • Increased bare soil on the floodplain and increased numbers of low cover hillslopes

TRARC (field survey) scores

Survey SiteScoreRegenerationWeeds
Native Companion Ck [#1]58.4 (C)1 (C)0 (A)
Native Companion Ck [#2]62.8 (C)2 (B)1 sp: 1% cover (B)
Native Companion Ck [#3]63.4 (C)1 (C)0(A)
Native Companion Ck [#4]70.9 (B)2 (B)0(A)
Alpha Ck [#1]59.1 (C)1 (C)0(A)
Alpha Ck [#2]59.5 (C)2 (B)0(A)
Alpha Ck [#3]71.2 (B)2 (B)0(A)
Average 63.6 (C)

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

Wetlands

This sub-division is poorly known ecologically, with even basic knowledge on the number and location of permanent or significant waterbodies not recorded. The system here includes numerous channels and off-channel waterbodies, and waterholes present are likely to be highly and persistently turbid. Condition is not well known, but assumed to be similar to that of other sub-divisions in the Belyando-Suttor sub-catchment.

Reference: Assessing the condition of Wetlands in the Burdekin catchment

For more information see Native Companion Creek wetland condition summary

Water

SedNet Modelling of Water Quality

Model results for the Native Companion subcatchment are summarized as follows:

  • Subcatchment modelled area 5,460 sq. km.
  • Source contributions: Hillslope = 62%; Gully = 25%; Streambank = 13%
  • Area of subcatchment with <50% ground cover: 2,812 sq. km or 52% of subcatchment
  • Hillslope sediment supply: 210 kg/ha/yr
  • Gully sediment supply: 88 kg/ha/yr
  • Total suspended sediment (flow weighted) supply:184,075 kt/yr
  • Total suspended sediment supply (flow weighted; normalized to area): 337kg/ha/yr
  • Total suspended sediment end-of-subcatchment (flow weighted) yield: 141.5 kt/yr
  • Event Mean Concentration (EMC - flow weighted):629 mg/L
  • Mean Annual Flow: 224,908 ML

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

Native Companion Creek is the fifth largest of the Burdekin subcatchments. It is located in an area of low average annual rainfall, receiving less than 660 ml/yr. Despite the low annual rainfall, this sub-catchment experiences medium to high rates of mean annual flow (224,908 ML). Despite the high flow, Native Companion Creek receives high mean event concentrations of suspended sediments and nutrients (629 mg/L) corresponding to approximately 184,075 kt/yr of sediment.

The high levels of sediments and nutrients entering Native Companion Creek are mainly the result of hillslope erosion (62%), most likely the result of more than 50% of this sub-catchment being exposed to less than 50% ground cover. Gully erosion provides 25% of the sediments and nutrients.

Water Quality Monitoring

The monitoring site in the Native Companion Creek catchment is located on Surbiton Station and has been sampled by NQ dry Tropics Volunteers program for 2 years (2005/06 and 2006/07 wet seasons). The site drains a catchment area of 5,443 sq km of which 99.9% is used for grazing. Suspended sediment concentrations have been in the intermediate to high range (mean concentration of 823 mg/L) compared to other catchments within the Burdekin rangelands over the monitoring period. Additional monitoring data are required to validate against the SedNet model.

Relevant information of Water Quality Monitoring in the Belyando River Basin:

Environmental Uses and Values

Aquatic Ecosystems

The aquatic ecosystem values of the Native Companion subcatchment are poorly known and, while considered to be Slightly to Moderately Disturbed (SMD) as a consequence of the surrounding land use for cattle grazing, 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) waters have been identified in the subcatchment.

Stock Watering

Water supply for production of healthy livestock.

Cultural and Spiritual

Custodial use of water resources by Bidjara traditional owners.

References:

Landuse

Principle land uses within the Native Companion Creek subcatchment as a proportion of total area:

  • Grazing: 99.9%
  • Water: Limited water activity use identified.
  • Urban & semi urban: Limited urban & semi urban water activity use identified.

Grazing Land

Native Companion Creek is a large subcatchment where the land use is exclusively grazing on natural and modified 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 Native Companion Creek sub-catchment is proportioned as follows:

  • A Condition: 52%
  • B Condition: 36%
  • C Condition: 9%
  • D Condition: 3%

Data from the Native Companion Creek sub-catchment is based on 92 observations.

On the basis of the rapid assessment, the Native Companion Creek sub-catchment is estimated to have the largest proportion of land in good (A) condition (52%), followed by fair (B) condition (27%) and poor (C) condition land (9%). 3% of observed land was in very poor (D) condition.

Ground Cover

Ground Cover in the Native Companion Creek sub-catchment is proportioned as follows:

  • ( BC) Bare Cover: 0%
  • ( LC) Low Cover: 7%
  • ( MC) Moderate Cover: 36%
  • ( HC) High Cover: 53%
  • (VHC) Very High Cover: 4%

Data from the Native Companion Creek sub-catchment are based on 92 observations.

On the basis of the rapid assessment (2004-2007), the Native Companion Creek sub-catchment is estimated to have the highest proportion of land within the high (HC) ground cover category (53%), followed by moderate (MC) cover (36%) and low (LC) cover (7%) categories. 4% of land was estimated to fall into the very high cover (VHC) category.

Resource Condition Summary

Native Companion Creek is a large subcatchment where the land use is exclusively grazing on natural and modified pastures. Riparian habitat in this subcatchment has undergone a dramatic decline in condition over the last 30 years, principlly due to extensive clearing of riparian zones and floodplains throughout the subcatchment, and is currently assessed to be in very poor (D) condition. The subcatchment waterways are poorly known ecologically, with even basic knowledge on the number and location of permanent or significant waterbodies not recorded. The waterways are understood to include numerous channel and off-channel waterbodies that are likely to be highly and persistently turbid.

Hillslope erosion is identified as the major source of sediment and particulate nutrients affecting water quality within Native Companion Creek subcatchment, while gully erosion is also identified as a significant contributor to the total sediment load. The rate of soil loss is predicted to be quite low and close to the Basin average, while the total amount of soil loss from the subcatchment to waterways is moderately high due to its large area. Land condition is assessed as having a high proportions in good (A) and fair (B) condition, while poor (C) condition land is also apparent. This is also reflected in the rapid ground cover assessment (2004-07). However, analyses of ground cover from satellite imagery (reference) identify extensive areas of vulnerable and marginal 'D' condition land, particularly in the central part of the subcatchment. The mean ground cover declined substantially from 1999 to 2006 and areas of poor ground cover were common in 2006.

Water quality in the Native Companion Creek subcatchment is predicted by models to be moderately impacted by suspended sediment during wet season event flows. This is also reflected in water quality monitoring data that recorded similarly elevated concentrations of suspended sediments at end-of-catchment.

Draft Environmental Values

The aquatic ecosystem values of the Native Companion Creek subcatchment are poorly known and, while considered to be Slightly to Moderately Disturbed (SMD) as a consequence of the surrounding land use for cattle grazing, 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) waters have been identified in the subcatchment. Little is known about the human use Environmental Values of the subcatchment, which are thought to be limited to use for stock watering, and the cultural and spiritual values of the Bidjara traditional owners.

Maps

References

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

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