Carmichael River

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Subcatchments

Smaller subcatchments within the Carmichael River Catchment include:

  • Tomahawk Creek
  • Eight Mile Creek
  • Cabbage Tree Creek
  • Belyando River
  • Dunda Creek

Vegetation

Riparian Habitat

iTRARC analysis of Riparian Habitat indicates that this subcatchment has undergone a dramatic decrease in riparian condition from good (B+) to very poor (D) in the last 30 years. Every component of the riparian system has been impacted from the headwaters through to the floodplain. The limited field survey data show the riparian zones to be in poor condition too, although the absence of weeds is a good sign. High spatial resolution satellite imagery available on Google Earth ™ gully networks forming in areas that have been recently cleared. There are also fenceline contrasts that enable the observer to see what conditions were like pre-clearing.

iTRARC Scores

Catchment Class 2 A
Maximum iTRARC Score 24 (A+)
1970s Score 13 (B+)
2004 Score -4 (D)
Reduction in Ecosystem Services Very Large
Increase in Potential for Erosion Large
Reasons for Change in Score
  • Headwater clearing
  • Increased number and % of gaps on small streams
  • Increased number of gaps on the main channel and anabranching channels
  • Extensive floodplain clearing including riparian forest
  • Increased scald/gullies, low cover hillslopes, and floodplain bare soil

TRARC (field survey) scores

Survey SiteScoreRegenerationWeeds
Bully Ck Palm site50.2 (C)1 (C)0 (A)
Bully Ck Red Gum site55.1 (C)3 (A)0 (A)
Average 52.65 (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 the waterholes present are likely to be highly and persistently turbid. Their condition is not known (hence the low degree of confidence) but given the land use is typical of the Belyando-Suttor sub-catchment, it is assumed their condition is typical of other waterbodies in the region.

Reference: Assessing the condition of Wetlands in the Burdekin catchment

For more information see Carmichael River wetland condition summary

Water

SedNet Modelling of Water Quality

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

  • Subcatchment modelled area: 6,535 sq. km.
  • Source contributions: Hillslope =70 %; Gully = 24%; Streambank = 7%
  • Area of subcatchment with <50% ground cover: 3,266 sq. km or 50% of subcatchment
  • Hillslope sediment supply: 222 kg/ha/yr
  • Total suspended sediment (flow weighted) supply: 207 kt/yr
  • Total suspended sediment supply (flow weighted; normalized to area): 317kg/ha/yr
  • Total suspended sediment end-of-subcatchment (flow weighted) yield: 161 kt/yr
  • Event Mean Concentration (EMC - flow weighted): 674 mg/L
  • Mean Annual Flow: 238,807 ML

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

The Carmichael River subcatchment is the largest of the 51 Burdekin subcatchments with an area of 7,508 sq. km. (the Campaspe River being the largest at approximately 8,000 sq.km.). Fifty percent of the Carmichael River subcatchment is assessed as having less than 50% ground cover in 2004 with 70% of the total suspended sediment and associated nutrient supply entering the river is thought to originate from hillslope erosion (222 kg/yr). Event Mean Concentrations of sediments are predicted to be relatively high (674 mg/L), while the mean average flow is relatively low (238,807 ML) i.e. low rainfall is associated with this sub-catchment.

Water Quality Monitoring

The monitoring site on the Carmichael River is at Doongmabulla Station with an upstream catchment area of 2,279 sq km of which 75.9% is used for grazing. At present, the water quality data are too limited to draw any conclusions on this catchment.

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

Environmental Uses and Values

Aquatic Ecosystems

The aquatic ecosystem values of the Carmichael River subcatchment contains two areas that have been identified as containing High Ecological Value (HEV) waters by the BWQIP ecological values technical panel. These correspond to: (i) Nairana National Park in the north-eastern corner of the Carmichael River subcatchment; and (ii) Wilanspey Conservation Park, also near the bottom of the subcatchment. The aquatic ecosystem values of other parts of the subcatchment are considered to be Slightly to Moderately Disturbed (SMD) as a consequence of the surrounding land use for cattle grazing.

The Carmichael River subcatchment is contained mostly within the Desert Uplands bioregion. The condition of the waterways in this subcatchment is poorly known. Land cover is low, riparian condition is generally poor and erosion is widespread. Many areas of this subcatchment are susceptible to sheet and rill erosion. Three areas were identified by the WQIP ecological values technical panel that may be in relatively better condition and have high values. These included: the Cudmore National Park in the very south of the subcatchment; the sandstone country around Darkies Range; and, the area to the west surrounding the upper reaches of Dyllingo Creek. There was too little information on the condition of these areas for them to be considered to be “effectively unmodified” (ANZECC 2000) and be categorised as containing High Ecological Value (HEV) waters. These areas have not been categorised as HEV at this stage. However, these areas warrant further investigation.

The Directory of Important Wetlands also lists Doongmabulla Springs in this subcatchment. This is an important artesian spring that has suffered trampling and other impacts from grazing stock and feral animals.

Stock Watering

Water supply for production of healthy livestock.

Cultural and Spiritual

Custodial use of water resources by Jangga traditional owners.

References:

Landuse

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

  • Grazing: 89%
  • Conservation & minimal use: 10.4%
  • Water: Limited water activity use identified.
  • Urban & semi urban: Limited urban and semi urban activity use identified.

Grazing

Carmichael River is a very large subcatchment where land use is predominantly grazing on both 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 Carmichael River sub-catchment is proportioned as follows:

  • A Condition: 13%
  • B Condition: 54%
  • C Condition: 20%
  • D Condition: 13%

Data from the Carmichael River sub-catchment is based on 24 observations.

On the basis of the rapid assessment, the Carmichael River sub-catchment is estimated to have the largest proportion of land in fair (B) condition (54%), followed by poor (C) condition (20%) and good (A) condition land (13%). 13% of observed land was also in very poor (D) condition.

Ground Cover

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

  • ( BC) Bare Cover: 8%
  • ( LC) Low Cover: 4%
  • ( MC) Moderate Cover: 38%
  • ( HC) High Cover: 50%
  • (VHC) Very High Cover: 0%

Data from the Carmichael River sub-catchment are based on 24 observations.

On the basis of the rapid assessment (2004-2007), the Carmichael River sub-catchment is estimated to have the highest proportion of land within the high (HC) ground cover category (50%), followed by moderate (MC) cover (38%) and bare (BC) cover (8%) categories. 4% of land was estimated to fall into the low cover (BC) category.

Resource Condition Summary

Carmichael River is a very large subcatchment where land use is predominantly grazing on both natural and modified pastures. Approximately 10% of the land area is set aside for conservation and minimal use. Riparian habitat in this subcatchment has undergone a dramatic decline in condition over the last 30 years, principally as a result of widespread clearing in the headwaters, and along the main and anabranching channels, 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. However, 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 by models as the major source of sediment and particulate nutrients affecting water quality within the Carmichael River 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 proportion in fair (B) condition, while poor (C), very poor (D) and good (A) condition land was also observed. This is also reflected in the rapid ground cover assessment (2004-07). Analysis of ground cover from satellite imagery (reference) identifies extensive areas of degraded, and highly vulnerable and marginal 'D' condition land, particularly along the upper reaches of Dunda Creek and Carmichael River (Dylliwgo and Bimbah Creeks).

Water quality in the Carmichael River subcatchment is predicted by models to be moderately elevated, however there are no water quality monitoring data with which to compare the modelled concentrations. In light of reports of extensive gullying and poor land condition, water quality monitoring in this subcatchment would be useful to verify model predictions.

Draft Environmental Values

The Carmichael River subcatchment contains two areas that have been identified as containing High Ecological Value (HEV) waters by the BWQIP ecological values technical panel. These correspond to: (i) Nairana National Park in the north-eastern corner of the Carmichael River subcatchment; and (ii) Wilanspey Conservation Park, also near the bottom of the subcatchment. The aquatic ecosystem values of other parts of the subcatchment are considered to be Slightly to Moderately Disturbed (SMD) as a consequence of the surrounding land use for cattle grazing. Little is known about the human use Environmental Values of the Carmichael River subcatchment, which are thought to be limited to use for stock watering, and the cultural and spiritual values of the Jangga traditional owners.

Maps

References

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

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