Sellheim River

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Subcatchments

Smaller subcatchments within the Sellheim River Catchment include:

  • Sellheim River
  • Suttor River

Vegetation

Riparian Habitat

iTRARC analysis of Riparian Habitat indicates that this subcatchment was in poor condition (C) in the 1970s and has subsequently declined further to very poor (D) condition. This decline is the result of floodplain clearing (this catchment has very limited floodplains, but those have been cleared). There has also been an increase in low cover hill slopes and gullying/scalding. The field survey TRARC data also indicate poor condition at 3 of the 4 sites surveyed.

iTRARC Scores

Catchment Class 2 D
Maximum iTRARC Score 18 (A)
1970s Score 4 (C)
2004 Score -4 (D)
Reduction in Ecosystem Services Moderate
Increase in Potential for Erosion Large
Reasons for Change in Score
  • Floodplain clearing
  • An increase in the amount of floodplain bare soil
  • An increase in the amount of low cover hill slopes
  • An increase in gullying/scalding

TRARC (field survey) scores

Survey SiteScoreRegenerationWeeds
Coopers Ck53.9 (C)0 (D)0 (A)
Sellheim R54.6 (C)2 (B)2 spp: 25% cover (C)
Bells Ck57.4 (C)1 (C)0 (A)
Pyramid Ck65.8 (B)2 (B)1 sp: 2% cover (B)
Average 57.9 (C)

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

Wetlands

This sub-division is poorly known ecologically, though the creeks are considered to be generally dry with limited habitat availability. Condition is not well known though thought to be typical of sub-divisions in this area. Part of this sub-division is inundated by Lake Dalrymple (Burdekin Falls Dam), creating an artificial habitat.

Reference: Assessing the condition of Wetlands in the Burdekin catchment

For more information see Sellheim River wetland condition summary

Water

SedNet Modelling of Water Quality

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

  • Subcatchment modelled area: 1,404 sq. km.
  • Source contributions: Hillslope = 50%; Gully = 47%; Streambank = 3%
  • Area of subcatchment with <50% ground cover: 593 sq. km or 42% of subcatchment
  • Hillslope sediment supply: 439 kg/ha/yr
  • Gully sediment supply: 411 kg/ha/yr
  • Total suspended sediment (flow weighted) supply: 122 kt/yr
  • Total suspended sediment supply (flow weighted; normalized to area): 869kg/ha/yr
  • Total suspended sediment end-of-subcatchment (flow weighted) yield: 113 kt/yr
  • Event Mean Concentration (EMC - flow weighted): 1,166 mg/L
  • Mean Annual Flow: 97,280 ML

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

Selheim River produces a comparatively low annual flow (97,280 ML. This is due to low annual rainfall in this area. The Selheim River receives a moderate to high amount of suspended sediments and nutrients (122 kt/yr), resulting in very high event mean concentrations of sediments and nutrients (1,166 mg/L). Sediments are believed to be the result of both hillslope and gully erosion (50% and 47% respectively) with 42% of this subcatchment having less than 50% ground cover. On a kg per hectare per year basis, the Selheim River, a relatively small sub-catchment, receives more sediment from gullies than any other subcatchment in the greater Burdekin catchment(411 kg/ha/yr).

Water Quality Monitoring

There are no water quality monitoring data available for this catchment.

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

Environmental Uses and Values

Aquatic Ecosystems

The aquatic ecosystem values of the Sellheim River 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 Jangga and Birri traditional owners.

References:

Landuse

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

  • Grazing: 94.9%
  • Water: 5%
  • Conservation & minimal use: Limited conservation & minimal water activity use identified.
  • Urban & semi urban: Limited urban & semi urban water activity use identified.

Grazing Land

Sellheim River is quite a small subcatchment where land use is exclusively grazing on natural 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 Sellheim River sub-catchment is proportioned as follows:

  • A Condition: n/a
  • B Condition: 1%
  • C Condition: 78%
  • D Condition: 21%

Data from the Sellheim River sub-catchment is based on 82 observations.

On the basis of the rapid assessment, the Sellheim River sub-catchment is estimated to have the largest proportion of land in poor(C) condition (78%), followed by very poor (D) condition (21%) and fair (B) condition land (1%). Data not available for (A) condition land.

Ground Cover

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

  • ( BC) Bare Cover: 0%
  • ( LC) Low Cover: 41%
  • ( MC) Moderate Cover: 39%
  • ( HC) High Cover: 19%
  • (VHC) Very High Cover: 1%

Data from the Sellheim River sub-catchment are based on 80 observations.

On the basis of the rapid assessment (2004-2007), the Sellheim River sub-catchment is estimated to have the highest proportion of land within the low (LC) ground cover category (41%), followed by moderate (MC) cover (39%) and high (HC) cover (19%) categories. 1% of land was estimated to fall into the very high cover (VHC) category.

Resource Condition Summary

Sellheim River is quite a small subcatchment where land use is exclusively grazing on natural pastures. The condition of riparian habitat in this subcatchment has continued to decline over the last 30 years, with further clearing of the already limited floodplains, and is currently assessed to be in very poor (D) condition. The subcatchment waterways are poorly known ecologically and are thought to consist of dry, sandy ephemeral creeks with limited aquatic habitat. The lower part of the subcatchment is inundated by Lake Dalrymple (Burdekin Falls Dam), creating a highly modified habitat.

Hillslope and gully erosion are both identified by models as the major sources of sediment and particulate nutrients affecting water quality within the Sellheim River subcatchment. The rate of soil erosion is predicted to be high and well above the Basin average, while the total soil loss from the subcatchment to waterways is more moderate due to its relatively small area. Land condition is assessed to be mostly in poor (C) condition, while very poor (D) condition grazing land is also common. This is not well reflected in the rapid ground cover assessment (2004-07), which identifies large proportions of medium and high ground cover. Similarly, while analyses of satellite imagery do identify some areas of grazing land that are vulnerable to 'D' condition, the mean ground cover declined from a high of 91% in 1999 to 62% in 2004 and had recovered to 76% in 2006.

Water quality in the Sellheim River subcatchment is predicted by models to be heavily impacted by suspended sediment during wet season event flows, with highly elevated concentrations at the end-of-subcatchment. There are no water quality monitoring data with which to compare the modelled loads and concentrations. In light of the somewhat conflicting land condition assessments and elevated sediment concentrations and loads predicted by models, water quality monitoring in this subcatchment would be useful to verify model results.

Draft Environmental Values

The aquatic ecosystem values of the Sellheim River 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 stock watering, and the cultural and spiritual values of the Jangga and Birri traditional owners.

Maps

References

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

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