Lower Cape River

From Dry Tropics Wiki
Jump to: navigation, search


Subcatchments

Smaller subcatchments within the Lower Cape River Catchment include:

  • Blowhard Creek
  • Boomerang Creek
  • Cape River
  • Bligh Creek
  • Suttor River

Vegetation

Riparian Habitat

iTRARC analysis of Riparian Habitat indicates that this subcatchment has decreased from very good to relatively good condition in the last 30 years. This change has been as a result of increasing gaps in the riparian corridor of small headwater and anabranching streams. The TRARC field survey scores support this assessment with the average score showing good condition.

iTRARC Scores

Catchment Class 3 A
Maximum iTRARC Score 22 (A+)
1970s Score 15 (A)
2004 Score 11 (B)
Reduction in Ecosystem Services Minor
Increase in Potential for Erosion Small
Reasons for Change in Score
  • Increased number of gaps in the headwater and anabranching reaches of the stream network
  • Increased amount of floodplain bare soil

TRARC (field survey) scores

Survey SiteScoreRegenerationWeeds
Cape R51.1 (C)1 (C)1 sp: 20% cover (B)
Hatfields Lagoon64.6 (B)1 (C)0 (A)
Top Surprise Waterhole77.1 (B)2 (B)1 sp: 15% cover (B)
Average 64.3 (B)

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

Wetlands

The condition of the Lower Cape River is considered to be fairly typical of upper Burdekin rangelands catchments, with cattle grazing being the dominant land use. Although permanent waterbodies are not common, there are a few significant permanent waterbodies in the lower reaches, particularly in the anabranches. These are in generally good condition. This sub-division has been the subject of significant NHT investment in riparian fencing and management through the Dalrymple Landcare Committee, and the water quality of two anabranch lagoons and the Cape River at the Gregory Developmental Road bridge, was monitored as part of that project (Burrows 2001). Fish surveys from here were reported in Burrows (2001) and riparian vegetation in Dowe (2004) and in Burrows (1999). Part of the lower Cape River is inundated by Lake Dalrymple (Burdekin Falls Dam), creating a highly modified habitat.

Reference: Assessing the condition of Wetlands in the Burdekin catchment

For more information see Lower Cape River wetland condition summary

Water

SedNet Modelling of Water Quality

Model results for the Lower Cape River subcatchment are summarized as follows:

  • Sub-catchment modelled area: 2,382 sq. km.
  • Source contributions: Hillslope = 71%; Gully = 22%; Streambank = 7%
  • Area of subcatchment with <50% ground cover: 927 sq. km or 39% of subcatchment
  • Hillslope sediment supply: 267 kg/ha/yr
  • Total suspended sediment (flow weighted) supply: 90 kt/yr
  • Total suspended sediment supply (flow weighted; normalized to area): 376 kg/ha/yr
  • Mean Annual Flow: 986,146 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 Rollston River subcatchment (71%), while gully erosion is also predicted to contribute substantially (22%) to the total load of 90 kt/yr. It is estimated that approximately 39% of the sub-catchment has poor ground cover (<50%). The rate of soil loss from all sources (supply) is considered moderate to low (376 kg/ha/yr) when compared to other sub-catchments. The Lower Cape receives waters from a number of upstream rivers and creeks, including the Campaspe River, resulting in a relatively large mean annual flow of 986,146 ML.

Water Quality Monitoring

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

Relevant information of Water Quality Monitoring in the Cape Campaspe River Basin:

Environmental Uses and Values

Aquatic Ecosystems

The aquatic ecosystem values of the Lower Cape 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 are identified in the subcatchment.

Stock Watering

Water supply for production of healthy livestock.

Visual Recreation

Camping along the Cape River.

Cultural and Spiritual

Custodial use of water resources by Jangga traditional owners.

References:

Landuse

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

  • Grazing: 91.7%
  • Conservation & minimal use: 5%
  • Water: 3.25%
  • Urban & semi urban: Limited urban & semi urban water activity use identified.

Grazing Land

Lower Cape River is a medium sized subcatchment where the land use is dominated by 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 Lower Cape River sub-catchment is proportioned as follows:

  • A Condition: 9%
  • B Condition: 42%
  • C Condition: 45%
  • D Condition: 4%

Data from the Lower Cape River River sub-catchment is based on 127 observations.

On the basis of the rapid assessment, the Lower Cape River sub-catchment is estimated to have the largest proportion of land in poor (C) condition (45%), followed by fair (B) condition (42%) and good (A) condition land (9%). 4% of observed land was in very poor (D) condition.

Ground Cover

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

  • ( BC) Bare Cover: 1%
  • ( LC) Low Cover: 16%
  • ( MC) Moderate Cover: 41%
  • ( HC) High Cover: 39%
  • (VHC) Very High Cover: 3%

Data from the Lower Cape River sub-catchment are based on 128 observations.

On the basis of the rapid assessment (2004-2007), the Allingham Creek sub-catchment is estimated to have the highest proportion of land within the moderate (MC) ground cover category (41%), followed by high (HC) cover (39%) and low (LC) cover (16%) categories. 1% of land was estimated to fall into the bare cover (BC) category.

Resource Condition Summary

Lower Cape River is a medium sized subcatchment where the land use is dominated by grazing on natural pastures. Approximately 5% of the land area is remnant native vegetation with minimal use. Riparian condition in this subcatchment has declined over the last 30 years, largely due to floodplain clearing, and is currently assessed to be in fair (B) condition. The lower Cape River itself is a largely dry, sandy and seasonal river channel and, while permanent waterbodies are not common, there are a few significant wetlands in the lower reaches, particularly in the anabranches. Part of the lower Cape River is inundated by Lake Dalrymple (Burdekin Falls Dam).

Hillslope erosion is identified by models as the major source of sediment and particulate nutrients affecting water quality within the Lower Cape River subcatchment, while gully erosion is also identified as a significant contributor. Both the rate of soil loss and total soil loss from the subcatchment are predicted to be comparatively low. Land condition is assessed as having high proportions of fair (B) and poor (C) condition land. This is also reflected in the rapid ground cover assessment (2004-07) and analysis of ground cover from satellite imagery (reference), which indicates that the mean ground cover has declined substantially from 1999 to 2006.

Water quality in the Lower Cape River subcatchment is predicted by models to be only slightly impacted by suspended sediment. There are no water quality monitoring data with which to compare the modelled concentrations, but monitored loads from the Cape River near the top of the subcatchment are lower than predicted by models.

Draft Environmental Values

The aquatic ecosystem values of the Lower Cape 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 are identified in the subcatchment. Little is known about the human use Environmental Values of the Basalt River subcatchment, which are thought to be limited to visual recreation, use for stock watering, and the cultural and spiritual values of the Jangga traditional owners.

Maps

References

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

This is a legacy website. Content is not being updated but is kept as an archive.
Updated NRM information is now held in the NQ Dry Tropics NRM Information Portal at http://nrm.nqdrytropics.com.au/.
while corporate information about NQ Dry Tropics is held on our main website at http://www.nqdrytropics.com.au
NQ Dry Tropics Website