Dry River

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Vegetation

Riparian Habitat

iTRARC analysis of Riparian Habitat indicates that this subcatchment was in poor (C) condition in the 1970’s however the clearing of floodplain and riparian vegetation and installation of pivot arm irrigation on the floodplain have lead to a decrease in condition to very poor (D). The field surveys show a range of 2 very poor (D), 7 poor (C) and 2 good (B) sites reflecting the overall poor condition of this subcatchment. The absence of weeds is promising however the coincidence of zero regeneration and zero weeds may be indicative of heavy grazing pressure.

iTRARC Scores

Catchment Class 3 D
Maximum iTRARC Score 16 (A)
1970s Score 2 (C)
2004 Score -4 (D)
Reduction in Ecosystem Services Moderate
Increase in Potential for Erosion Small
Reasons for Change in Score
  • Clearing of riparian vegetation on the main channel
  • Clearing of floodplain vegetation for cropping
  • Removal of forest from the floodplain

TRARC (field survey) scores

Survey SiteScoreRegenerationWeeds
Wyandotte Ck43.9 (D)0 (D)0 (A)
Forester Ck46.7 (D)1 (C)0 (A)
Dry R/Wyandotte Ck junction52.3 (C)0 (D)0 (A)
Fig Tree Spring53.3 (C)0 (D)0 (A)
Dry R53.4 (C)2 (B)1 sp: 1% cover (B)
Conjuboy Springs56.2 (C)2 (B)0 (A)
Chalk Hole57.3 (C)1 (C)0 (A)
Round Spring57.3 (C)2 (B)0 (A)
Wyandotte Ck, Chalkhole67.1 (B)2 (B)0 (A)
Eight Mile Ck68.7 (B)1 (C)0 (A)
Average 55.6 (C)1 sp: 5% cover (B)

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

Wetlands

The waterbodies of this sub-division are poorly known ecologically. The Dry River is a largely dry sandy creek. A variety of small springs are known to be present in the sub-division, which is also part of a basalt province, but large waterholes are not apparent. The aquatic habitats of this sub-division should be further explored.

For more information see Dry River wetland condition summary

Reference: Assessing the condition of Wetlands in the Burdekin catchment

Water

SedNet Modelling of Water Quality

Model results for the Dry River sub-catchment are summarized as follows:

  • Sub-catchment modelled area: 1,946 sq. km.
  • Source contributions: Hillslope = 62%; Gully = 31%; Streambank = 6%
  • Area of sub-catchment with <50% ground cover: 384sq. km or 20% of sub-catchment
  • Hillslope sediment supply: 283 kg/ha/yr
  • Total suspended sediment (flow weighted) supply: 88 kt/yr
  • Total suspended sediment supply(flow weighted; normalized area): 454 kg/ha/yr
  • Total suspended sediment end-of-subcatchment (flow weighted) yield: 81 kt/yr
  • Event Mean Concentration (EMC - flow weighted): 477 mg/L
  • Mean Annual Flow: 169,257 ML

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

Hillslope erosion is identified as the major source of sediment and particulate nutrients affecting water quality within the Dry River sub-catchment (62%). This is thought to be associated with the relatively large proportion of hillslope with low ground cover (20%) and comparatively steep sloping topography. Nevertheless, loss of sediment and associated particulate nutrients from hillslopes (supply) is considered to be relatively low (283 kg/ha/yr). The sediment contribution from gully erosion is estimated to be quite substantial (31% of the total supply or 28 kt/yr). Loss of sediment and associated particulate nutrients from all sources (supply) is considered to be moderate (454 kg/ha/yr). The event mean concentrations of sediment are predicted to be moderately high (477 mg/L) due to the relatively lower rainfall and mean annual flow.

Water Quality Monitoring

The monitoring site in the Dry River catchment is located at Jervoise Station which drains a catchment area of 682 sq km and has been sampled by BDTNRM volunteers over two wet seasons (2003/04 and 2006/07). The land use in this catchment area is predominately grazing (98.9%). Suspended sediment concentrations in the Dry River have been relatively high over the monitoring period (mean concentration of 3,395 mg/L), although comparisons with the modelling data are difficult to make due to the limited monitoring dataset (i.e. low number of samples and the high variability in the Burdekin).

Relevant information of Water Quality Monitoring in the Upper Burdekin River Basin:

Environmental Values

Aquatic Ecosystems

The aquatic ecosystem values of a small section of the Undara Volcanic National Park, which lies along the north-west edge of the subcatchment, has been identified as containing High Ecological Value (HEV) waters because of its protected status and condition assessment by the BWQIP ecological values technical panel. While this part of the subcatchment is dry with few drainage channels, it is representative of the small seasonal or ephemeral channels and any other waters present in this area. The aquatic ecosystem values of other parts of the Dry River subcatchment are poorly known and are considered to be Slightly to Moderately Disturbed (SMD) as a consequence of the surrounding land use for cattle grazing.

Stock Watering

Water supply for production of healthy livestock.

Cultural and Spiritual

Custodial use of water by Gugu and Badhun traditional owners.

References:

Landuse

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

  • Grazing: 99.5%
  • Conservation & minimal use: .40%
  • Water: Limited water activity use identified.
  • Urban & semi urban: Limited urban and semi urban water activity use identified.
  • Irrigated horticulture & cropping: Limited irrigated horticulture & cropping water activity use identified.
  • Mining: Limited mining water activity use identified.

Grazing Land

Dry River is a relatively small sub-catchment where land use is almost exclusively for 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 Dry River sub-catchment is proportioned as follows:

  • A Condition: 40%
  • B Condition: 44%
  • C Condition: 16%
  • D Condition: 0%

Data from the Dry River sub-catchment is based on 105 observations.

On the basis of the rapid assessment, the Dry River sub-catchment is estimated to have the largest proportion of land in fair (B) condition (44%), followed by good (A) condition (40%) and poor (C) condition land (16%).

Ground Cover

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

  • ( BC) Bare Cover: 0%
  • ( LC) Low Cover: 1%
  • ( MC) Moderate Cover: 5%
  • ( HC) High Cover: 44%
  • (VHC) Very High Cover: 50%

Data from the Dry River sub-catchment are based on 94 observations.

On the basis of the rapid assessment (2004-2007), the Dry River sub-catchment is estimated to have the highest proportion of land within the very high (VHC) ground cover category (50%), followed by high (HC) cover (44%) and moderate (MC) cover (5%) categories.

Resource Condition Summary

Dry River is a relatively small subcatchment where land use is almost exclusively for grazing on native pastures, while there are many abandoned and operational mines throughout most of the subcatchment. The condition of riparian habitat in the subcatchment has declined over the last 30 years, with clearing of riparian vegetation on the main channel and floodplain vegetation for cropping, and is currently assessed as very poor (D). The absence of weeds is promising, however the coincidence of zero regeneration and zero weeds may be indicative of heavy grazing pressure. The Dry River is an ephemeral, sandy creek and, while a variety of small springs are known to be present in the subcatchment, large waterholes are not apparent. Very little is known about the ecology and condition of aquatic habitats in the Dry River subcatchment.

Hillslope and gully erosion are both identified as major sources of sediment and particulate nutrients affecting water quality within the Dry River subcatchment. The rate of soil erosion is predicted to be moderate and just below both the basin and BWQIP region averages, while the total soil loss to waterways from the subcatchment is comparatively low due to its small area. Grazing land condition is assessed as having high proportions of land in good (A) and fair (B) condition, while there is also a substantial proportion of poor (C) condition land. This is not well reflected in the rapid ground cover field assessment (2004-07). Analysis of satellite imagery (reference) identifies areas of high vulnerability to 'D' condition land along the middle and lower reaches of the Dry River, while the mean ground cover over the entire subcatchment fluctuated relatively little between 1999 and 2006 (between 97% and 89%).

Water quality in the Dry River subcatchment is predicted by models to have moderately elevated sediment concentrations and loads during wet season event flows. Water quality monitoring data, however, have recorded very high concentrations of sediment in the water. Comparisons are difficult to draw between the monitoring and modelling datasets due to the small number of samples collected over only two wet seasons, but support continued water quality monitoring. The high monitored concentrations may reflect more extensive gullying than predicted.

Draft Environmental Values

A small section of the Undara Volcanic National Park, which lies along the north-west edge of the subcatchment, has been identified as containing High Ecological Value (HEV) waters because of its protected status and condition assessment by the BWQIP ecological values technical panel. While this part of the subcatchment is dry with few drainage channels, it is representative of the small seasonal or ephemeral channels and any other waters present in this area. The aquatic ecosystem values of other parts of the Dry River subcatchment are poorly known and 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 Dry River subcatchment, which are thought to be limited to use for stock watering, and the cultural and spiritual values of the Gugu and Badhun traditional owners.

Maps

References

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

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