Lolworth Creek

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Vegetation

Riparian Habitat

iTRARC analysis of Riparian Habitat indicates that this subcatchment has experienced little change in the riparian condition since the 1970’s, with the riparian areas remaining in relatively good condition. The field based TRARC data however indicates that many of the riparian zones are in poor (8 sites) or very poor (3 sites) condition, this is due to limited regeneration and pervasive weediness (two aspects of riparian condition that remote sensing cannot detect).

iTRARC Scores

Catchment Class 3 B
Maximum iTRARC Score 18 (A)
1970s Score 14 (B+)
2004 Score 13 (B+)
Reduction in Ecosystem Services No Change
Increase in Potential for Erosion Small
Reasons for Change in Score
  • Increase in the number of low cover hill slopes next to the stream channel network

TRARC (field survey) scores

Survey SiteScoreRegenerationWeeds
Fletcher Ck41.2 (D)0 (D)1 sp: 50% cover (C)
Toomba Lake43.1 (D)1 (C)0 (A)
Lolworth Ck, Causeway Spring49.4 (C)3 (A)2 spp: 21% cover (C)
Fletcher Ck, Red Bend51.5 (C)1 (C)1 sp: 10% cover (B)
Lolworth Ck, Red Falls52.4 (C)1 (C)0 (A)
Lolworth Ck, Big Bend52.6 (C)2 (B)2 sp: 6% cover (C)
Lolworth Ck [#1]53.8 (C)0 (D)2 sp: 15% cover (C)
Dry Lagoon58.8 (C)1 (C)0 (A)
Lolworth Ck [#2]61 (C)1 (C)2 spp: 80% cover (D)
Lolworth Ck [#3]64.4 (B)1 (C)2 spp: 30% cover (C)
Lolworth Ck, Top Camp Waterhole68.1 (B)3 (A)1 sp: 10% cover (B)
Lolworth Ck, Basalt Spring70.9 (B)3 (A)0 (A)
Lolworth Ck, Horse Lagoon overflow73.5 (B)2 (B)0 (A)
Average 56.9 (C)

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

Wetlands

This sub-division is based around the Great Basalt Wall, a major basalt feature with numerous springs. These springs drive the permanency or semi-permanency of many major in-channel waterbodies and large off-channel lakes and swamps. The Great Basalt Wall is a National Park and many of the waterbodies in this sub-division are listed in the Directory of Important Wetlands in Australia. Fletcher Creek on the north side of the basalt wall, and Toomba Creek on the south side, have permanent surface flow, at least in their upper reaches, with near-permanent flow along much of the rest of their length. Lolworth Creek contains a number of deepwater lagoons, especially in the reaches downstream of Toomba Creek. All systems here either have clear water or relatively so. Fletcher Creek is considered to have the most extensive aquatic habitat in this sub-division (and among the highest in the entire Burdekin catchment), hence its high ecological value rating.

The sub-division also includes a number of large, significant shallow lakes that create significant waterbird habitat, especially as many have extensive aquatic plants communities. They are usually filled by overland run-off rather than springwater and may last for several years once full, though drying back significantly during long dry periods. The limnology of Lake Toomba was assessed by Loong et al. (2005). Unlike the lower Lolworth Creek, the upper sections are not spring-fed and are largely dry sandy streambeds, thus having lesser value than most other habitats in this sub-division. Lake Cargoon, in the upper reaches of Lolworth Creek, is also unlike other lake in this sub-division, being turbid rather than clear, reflecting its more eroding catchment area (Burrows and Butler 2003). Its values are thus considered to be less than for other lakes in this sub-division as are Horse and Horseshoe Lagoons which are more ephemeral than the lakes further down the catchment.

A number of the waterbodies in this sub-division were investigated and sampled (though only on one occasion) for water quality and macroinvertebrates by Burrows and Butler (2003). Pusey et al. (1998) and Pusey (2004) surveyed the freshwater fish of Fletcher Creek at the Gregory Developmental Road on several occasions. The exotic fish, tilapia, have been present in the lower reaches of Fletcher Creek since 2005 (Veitch et al. 2006). Apart from this work, and the descriptions of the wetlands in the Directory of Important Wetlands in Australia, little is known about the aquatic ecology and resources of these very valuable wetlands. Grazing is the dominant land use in this sub-division, but the country is good grazing country and the condition and functionality of all major waterbodies listed here is generally considered to be relatively good, with relatively minor departure from their natural condition.

Lolworth Creek wetland condition summary

Reference: Assessing the condition of Wetlands in the Burdekin catchment

Water

SedNet Modelling of Water Quality

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

  • Subcatchment modelled area: 3,220sq. km.
  • Source contributions: Hillslope = 51%; Gully = 29%; Streambank = 20%
  • Area of subcatchment with <50% ground cover: 857 sq. km or 27% of subcatchment
  • Hillslope sediment supply: 161 kg/ha/yr
  • Total suspended sediment (flow weighted) supply: 103 kt/yr
  • Total suspended sediment supply (flow weighted; normalized to area): 319 kg/ha/yr
  • Total suspended sediment end-of-subcatchment (flow weighted) yield: 87 kt/yr
  • Event Mean Concentration (EMC - flow weighted): 385 mg/L
  • Mean Annual Flow: 225,206 ML

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

Hillslope, gully and streambank erosion are all identified as significant sources of sediment and associated nutrients affecting water quality within the Lolworth Creek subcatchment (51%, 29% & 20% respectively). Overall, however, the total supply of suspended sediments and nutrients is moderately low compared to other Burdekin sub-catchments (319 kg/ha/yr). The event mean concentration of sediments is predicted to be low to moderate (385 mg/L) when compared to other subcatchments.

Water Quality Monitoring

The monitoring sites in the Lolworth Creek subcatchment include:

  • Fletcher Creek is located upstream from the Gregory Developmental Road on FletcherVale Station and has been sampled by the NQ Dry Tropics Volunteers program for 3 years. The catchment area for this monitoring site is 884 sq km, of which 54.1% is used for grazing.
  • Lolworth Creek is located upstream from the Gregory Developmental Road on Lockwall Station and has been sampled by the NQ Dry Tropics Volunteers program for 3 years. The catchment area for this monitoring site is 2,296 sq km, of which 85.1% is used for grazing.

Suspended sediment concentrations have been relatively low for Fletcher Creek (mean concentration of 252 mg/L) and intermediate for Lolworth Creek (mean concentration of 646 mg/L) over the monitoring period. The monitoring data compare reasonably well with the SedNet model outputs.

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

Environmental Values

Aquatic Ecosystems

Three separate areas within the Lolworth Creek subcatchment have been identified as having High Ecological Value (HEV) waters by the BWQIP ecological values technical panel. These include: (i) two sections of the Basalt Wall National Park, including areas adjacent to each section; and (ii) part of the Dalrymple National Park at the very eastern end of the subcatchment. The aquatic ecosystems values of other parts of the subcatchment are considered to be slightly to moderately disturbed as a consequence of the surrounding land use for cattle grazing. Nevertheless, the biological communities are thought to remain in a healthy condition and ecosystem integrity is likely to be largely retained. The human use Environmental Values of Lolworth Creek subcatchment are understood to include recreation (swimming, fishing & visual appreciation), stock watering, human consumption, drinking, and the cultural and spiritual values of the Kudjala traditional owners.

The aquatic ecosystem values of Lolworth Creek

High Ecological Value (HEV)

Slightly to Moderately Disturbed (SMD) - remaining areas of the subcatchment.

Stock Watering

Water supply for production of healthy livestock.

Secondary Recreation

The Great Basalt Wall Wetlands are understood to support some recreational fishing.

Visual Recreation

Bush walking in the Basalt Wall National Park. Torrens Creek.

Camping along Fletchers Creek, on Charters Towers, Greenvale Road.

Drinking Water

Suitability of raw drinking water supply.

Cultural and Spiritual

Great Basalt Wall National Park protects 35,200ha of land surrounding Great Basalt Wall and is one of the most rugged and inaccessible parks of west Queensland.

The area is home to The Kudjala Aboriginal people.

References:

Landuse

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

  • Grazing: 77.65%
  • Conservation & minimal use: 21.05%
  • Water: 1.3%
  • Urban & semi urban: Limited urban & semi urban water activity use identified.

Grazing Land

Lolworth Creek is a medium sized subcatchment where the major land use is 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 Lolworth Creek sub-catchment is proportioned as follows:

  • A Condition: 31%
  • B Condition: 43%
  • C Condition: 22%
  • D Condition: 4%

Data from the Lolworth Creek sub-catchment is based on 77 observations.

On the basis of the rapid assessment, the Lolworth Creek sub-catchment is estimated to have the largest proportion of land in fair (B) condition (43%), followed by good(A) condition (31%) and poor (C) condition land (22%). 4% of observed land was in very poor (D) condition.

Ground Cover

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

  • ( BC) Bare Cover: 4%
  • ( LC) Low Cover: 15%
  • ( MC) Moderate Cover: 30%
  • ( HC) High Cover: 30%
  • (VHC) Very High Cover: 21%

Data from the Lolworth Creek sub-catchment are based on 71 observations.

On the basis of the rapid assessment (2004-2007), the Lolworth Creek sub-catchment is estimated to have the highest proportion of land within the high (HC) and Moderate (MC) ground cover category (30%), followed by very high (VHC) cover (21%) and low (LC) cover (15%) categories. 4% of land was estimated to fall into the bare cover (BC) category.

Resource Condition Summary

Lolworth Creek is a medium sized subcatchment where the major land use is grazing on native pastures. However, approximately 21% of the land area is set aside for conservation and minimal use, while there are a relatively small number of abandoned and operational mines within the subcatchment. Riparian condition in the subcatchment has undergone relatively little change over the last 30 years and remains in fair (B) condition. The subcatchment is based around the Great Basalt Wall, a major basalt feature with numerous springs. These springs supply many permanent in-channel, deepwater lagoons and large off-stream lakes and swamps that provide significant waterbird habitat. The upper sections of Lolworth Creek are not spring-fed and are largely dry, sandy streambeds. Many of the water bodies in this subcatchment are listed in the Directory of Important Wetlands in Australia. The ecology and condition of aquatic habitats has been quite well studied.

Hillslope, gully and streambank erosion are all identified by models as significant sources of sediment and associated nutrients affecting water quality within the Lolworth Creek subcatchment. However, the rate of soil erosion is predicted to be well below the basin average, while the total soil loss to waterways is also comparatively low. Grazing land condition is assessed as having quite similar proportions in fair (B), good (A) and poor (C) condition. This is also reflected in the ground cover assessment (2004-07). Analysis of ground cover from satellite imagery (reference) identifies some areas of land along Lolworth Creek with poor cover. Nevertheless, the mean ground cover across the entire subcatchment declined from 93% in 1999 to 76% in 2004, and had recovered to 90% in 2006.

Water quality in the Lolworth Creek subcatchment is predicted by models to be quite good, with only slightly elevated sediment concentrations and loads during wet season event flows. Water quality monitoring data compare reasonably well with model results and indicate higher sediment concentrations coming from Lolworth Creek compared to Fletcher Creek, in which concentrations were quite low over the monitoring period.

Draft Environmental Values

Three separate areas within the Lolworth Creek subcatchment have been identified as having High Ecological Value (HEV) waters by the BWQIP ecological values technical panel. These include: (i) two sections of the Basalt Wall National Park, including areas adjacent to each section; and (ii) part of the Dalrymple National Park at the very eastern end of the subcatchment. The aquatic ecosystems 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. Nevertheless, the biological communities are thought to remain in a healthy condition and ecosystem integrity is likely to be largely retained. The human use Environmental Values of Lolworth Creek subcatchment are understood to include recreation (swimming, fishing & visual appreciation), stock watering, human consumption, drinking, and the cultural and spiritual values of the Kudjala traditional owners.

Maps

References

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

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