Logan Creek

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Vegetation

Riparian Habitat

iTRARC analysis of Riparian Habitat indicates that this subcatchment went from relatively good (B) condition to poor (C) condition in the last 30 years, primarily due to floodplain and riparian clearing and subsequent floodplain grazing. The field survey TRARC results support this assessment with all survey sites showing poor results with varying degrees of regeneration and low levels of weediness.

iTRARC Scores

Catchment Class 3 A
Maximum iTRARC Score 22 (A+)
1970s Score 11 (B)
2004 Score 2 (C)
Reduction in Ecosystem Services Large
Increase in Potential for Erosion Large
Reasons for Change in Score
  • Increased number and percentage of gaps on headwater streams and the main channel
  • Floodplain clearing
  • Increased bare soil on the floodplain
  • Increased number of low cover hill slopes next to the stream network

TRARC (field survey) scores

Survey SiteScoreRegenerationWeeds
Logan Ck [#1]50.3 (C)2 (B)1 sp: 15% cover (B)
Logan Ck [#2]51.7 (C)1 (C)1 sp: 20% cover (B)
Logan Ck, Suttor Lake60.1 (C)3 (A)1 sp: 10% cover (B)
Average 54 (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, so that significant habitat is present. Most of the waterholes present are likely to be highly and persistently turbid. Condition is not well known. Like much of the Belyando-Suttor sub-catchment, this area should be further explored for its aquatic resources. The limnology of a large waterhole on Logan Creek at Avon Downs was assessed by Loong et al. (2005).

Reference: Assessing the condition of Wetlands in the Burdekin catchment

For more information see Logan Creek wetland condition summary

Water

SedNet Modelling of Water Quality

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

  • Subcatchment modelled area: 3,372 sq. km.
  • Source contributions: Hillslope = 70%; Gully = 17%; Streambank = 13%
  • Area of subcatchment with <50% ground cover: 1,016 sq. km or 30% of subcatchment
  • Hillslope sediment supply: 193 kg/ha/yr
  • Total suspended sediment (flow weighted) supply: 93.3 kt/yr
  • Total suspended sediment supply (flow weighted; normalized to area): 277kg/ha/yr
  • Total suspended sediment end-of-subcatchment (flow weighted) yield: 66 kt/yr
  • Event Mean Concentration (EMC - flow weighted): 484 mg/L
  • Mean Annual Flow: 137,275 ML

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

Logan Creek is a relatively large subcatchment (over 3,000 sq. km) with approximately one third of its surface area showing less than 50% ground cover. This would account for the high proportion of sediment (70%) supplied from hillslope erosion. Due to the large size of the sub-catchment, the quantity of sediment loss per hectare is moderate to low compared to other Burdekin subcatchments. Flow is moderate to low due to low rainfall in this area, resulting in moderate concentrations of suspended sediment.

Water Quality Monitoring

The monitoring site in the Logan Creek catchment is located on the Avon Downs Station and has been sampled by NQ Dry Tropics Volunteers program for 2 years (2005/06 and 2006/07 wet seasons). The catchment area for this monitoring site is 3,325 sq km, of which 60.5% is used for grazing and 32% for cropping. Suspended sediment concentrations have been low to intermediate (mean concentration of 310 mg/L) over the monitoring period compared to other sites within the Burdekin rangelands. Additional monitoring data are required before a comparison with the SedNet model can be made. Filterable reactive phosphorus concentrations have been relatively high (mean concentration of 78 ug/L) in this waterway compared to other catchments within the Burdekin rangelands, probably explainable by the basalt soils within the catchment area.

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

Environmental Uses and Values

Aquatic Ecosystems

The aquatic ecosystem values of the Logan 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.

Irrigation

Extensive dryland cropping only.

Stock Watering

Water supply for production of healthy livestock.

Cultural and Spiritual

Custodial use of water resources by Wangan and Jagalingou traditional owners.

References:

Landuse

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

  • Grazing: 67%
  • Dryland agriculture: 26.7%
  • Water: 4.2%
  • Conservation & minimal use: 2%

Grazing Land

Logan Creek is a medium sized subcatchment where the major land use is grazing on, mostly, modified pastures, while there is a substantial 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 Logan Creek sub-catchment is proportioned as follows:

  • A Condition: 26%
  • B Condition: 44%
  • C Condition: 29%
  • D Condition: 1%

Data from the Logan Creek sub-catchment is based on 110 observations.

On the basis of the rapid assessment, the Logan Creek sub-catchment is estimated to have the largest proportion of land in fair (B) condition (44%), followed by poor (C) condition (29%) and good (A) condition land (26%). 1% of observed land was in very poor (D) condition.

Ground Cover

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

  • ( BC) Bare Cover: 0%
  • ( LC) Low Cover: 17%
  • ( MC) Moderate Cover: 15%
  • ( HC) High Cover: 49%
  • (VHC) Very High Cover: 19%

Data from the Logan Creek sub-catchment are based on 114 observations.

On the basis of the rapid assessment (2004-2007), the Logan 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 (19%) and low (LC) cover (17%) categories. 15% of land was estimated to fall into the moderate cover (MC) category.

Resource Condition Summary

Logan Creek is a medium sized subcatchment where the major land use is grazing on, mostly, modified pastures, while there is a substantial area of dryland cropping of cereals. The riparian habitat of the subcatchment has deteriorated over the last 30 years, principally due to clearing of riparian vegetation in headwater streams and along 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 water bodies not recorded. The waterways are understood to include numerous channel and off-channel water bodies 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 Logan Creek subcatchment, while gully and streambank erosion are also identified as significant contributors to the total sediment load. The rate of soil erosion is predicted to be low and considerably less than the Basin average, while the total soil lost from the subcatchment to waterways is also comparatively low. Land condition is assessed as having a high proportions in fair (B), poor (C) and good (A) condition. This is also reflected in the rapid ground cover assessment (2004-07). Analyses of satellite imagery identify extensive areas of vulnerable and marginal 'D' condition land, and show that the mean ground cover declined substantially from 73% in 1999 to 40% in 2004, but had recovered to 70% in 2006. The low cover may, in part, reflect the substantial land use for dryland cropping.

Water quality in the Logan Creek subcatchment is predicted by models to be slightly to moderately impacted by suspended sediment during wet season event flows, with elevated concentrations at the end-of-subcatchment. Water quality monitoring data from this subcatchment reflect model predictions.

Draft Environmental Values

The aquatic ecosystem values of the Logan 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 irrigation, stock watering, and the cultural and spiritual values of the Wangan and Jagalingou traditional owners.

Maps

References

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

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