Diamond Creek

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Subcatchments

Smaller subcatchments within the Diamond Creek Catchment include:

  • Logan Creek

Vegetation

Riparian Habitat

iTRARC analysis of Riparian Habitat indicates that this subcatchment has undergone a large decrease in condition from relatively good (B+) to poor (C). This reduction in condition is due to tree clearing along headwater streams and on the floodplains. The field survey results also indicate very poor condition, however additional sites would be required to capture the full range of conditions that may be encountered in this subcatchment.

iTRARC Scores

Catchment Class 2 B
Maximum iTRARC Score 20 (A+)
1970s Score 12 (B+)
2004 Score 1 (C)
Reduction in Ecosystem Services Very Large
Increase in Potential for Erosion Moderate
Reasons for Change in Score
  • Forest and woodland clearing along headwaters and tributaries
  • Floodplain clearing including riparian forests
  • Bare soil on the floodplain
  • Increased number of low cover hill slopes

TRARC (field survey) scores

Survey SiteScoreRegenerationWeeds
Diamond Ck44.3 (D)2 (B)0 (A)
Average 44.3 (D)

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 (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 Diamond Creek wetland condition summary

Water

SedNet Modelling of Water Quality

Model results for the Diamond Creek subcatchment are summarized as follows:

  • Subcatchment modelled area 2,417 sq. km.
  • Source contributions: Hillslope = 65%; Gully = 20%; Streambank = 15%
  • Area of subcatchment with <50% ground cover: 1,220 sq. km or 50% of subcatchment
  • Hillslope sediment supply: 149 kg/ha/yr
  • Total suspended sediment (flow weighted) supply: 55 kt/yr
  • Total suspended sediment supply (flow weighted; normalized to area): 229kg/ha/yr
  • Total suspended sediment end-of-subcatchment (flow weighted) yield: 37 kt/yr
  • Event Mean Concentration (EMC - flow weighted): 432 mg/L
  • Mean Annual Flow: 86,013 ML

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

Half of the Diamond Creek subcatchment has less than 50% ground cover. Although the total amount of suspended sediments and associated nutrients that are carried by Diamond Creek are low (55 kt/yr) compared to other Burdekin subcatchments, most of the sediment is derived from hillslope erosion (65%) with a substantial portion from gully erosion (20%). The moderate concentrations of sediment (432 mg/L) are likely due to the relatively low annual flow (86,013 ML) of Diamond Creek as a consequence of low rainfall in this area.

Water Quality Monitoring

There are no water quality monitoring data available for the Diamond Creek catchment.

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

Environmental Uses and Values

Aquatic Ecosystems

The aquatic ecosystem values of Diamond 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.

Stock Watering

Water supply for production of healthy livestock.

Cultural and Spiritual

Custodial use of water by Wangan and Jagalingou traditional owners.

References:

Landuse

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

  • Grazing: 96%
  • Dryland agriculture: 3.3%
  • Water: Limited water activity use identified.

Grazing Land

Diamond Creek is a relatively small subcatchment where the land use is dominated by grazing on, mostly, modified pastures, while there is a small area of dryland cropping of cereals.

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 Diamond Creek sub-catchment is proportioned as follows:

  • A Condition: 29%
  • B Condition: 44%
  • C Condition: 27%
  • D Condition: n/a

Data from the Diamond Creek sub-catchment is based on 127 observations.

On the basis of the rapid assessment, the Diamond Creek sub-catchment is estimated to have the largest proportion of land in fair (B) condition (44%), followed by good (A) condition (29%) and poor(C) condition land (27%). Data not available for (D) condition land.

Ground Cover

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

  • ( BC) Bare Cover: 0%
  • ( LC) Low Cover: 4%
  • ( MC) Moderate Cover: 14%
  • ( HC) High Cover: 49%
  • (VHC) Very High Cover: 33%

Data from the Diamond Creek sub-catchment are based on 70 observations.

On the basis of the rapid assessment (2004-2007), the Diamond Creek sub-catchment is estimated to have the highest proportion of land within the high (HC) ground cover category (49%), followed by very high (VHC) cover (33%) and moderate (MC) cover (14%) categories. 4% of land was estimated to fall into the low cover (LC) category.

Resource Condition Summary

Diamond Creek is a relatively small subcatchment where the land use is dominated by grazing on, mostly, modified pastures, while there is a small area of dryland cropping of cereals. The riparian habitat of the subcatchment has deteriorated over the last 30 years, principally due to clearing along headwater streams and on the floodplains, and is currently assessed to be in poor (C) 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 by models as the major source of sediment and particulate nutrients affecting water quality within the Diamond Creek subcatchment, while gully erosion is also identified as a significant contributor to the total sediment load. The rate of soil erosion is predicted to be very low and considerably less than the Basin average, while the total soil loss from the subcatchment to waterways is also comparatively low. Land condition is assessed as having a high proportions in fair (B), good (A and poor (C) condition. This is also reflected in the rapid ground cover assessment (2004-07). Analyses of satellite imagery also identify extensive areas of vulnerable and marginal 'D' condition land, and show that the mean ground cover declined substantially from 86% in 1999 to 45% in 2004, but had only recovered to 67% in 2006 when large areas of poor ground cover were common.

Water quality in the Diamond Creek subcatchment is predicted by models to be slightly impacted by suspended sediment during wet season event flows. There are no water quality monitoring data with which to compare the modelled concentrations and loads. Water quality monitoring in this subcatchment would be useful to verify model predictions in light of the extensive areas of vulnerable and marginal 'D' condition land identified.

Draft Environmental Values

The aquatic ecosystem values of the Diamond 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 traditional owners.

Maps

References

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

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