Little Bowen River

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Subcatchments

Smaller Catchments within the Little Bowen River Catchment include:

Topography

Vegetation

Riparian Habitat

The following information is summarized from the ACTFR report: Assessing the condition of riparian vegetation in the Burdekin catchment using satellitte imagery and field surveys by Leo Lymburner and John Dowe. 2006. This report can be accessed from the report section below.

iTRARC analysis of Riparian Habitat indicates that this subcatchment has gone from very good (A) condition to relatively good (B) condition as the result of increased gaps in the riparian zone and an increase in floodplain bare soil and gullying. The field survey indicates poor condition, however additional field survey sites are needed to fully characterise riparian conditions in this catchment.

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Wetlands

The following information is summarized from the ACTFR report: Assessing the condition of Wetlands in the Burdekin catchment using existing GIS and field knowledge for CCI by Mirjam Maughan, Damien Burrows, Barry Butler, Leo Lymburner and George Lukacs. 2006. This report can be accessed from the report section below.

This is a largely sandy, dry seasonal creek system with limited habitat availability, though the area is poorly known ecologically. Springs are present that create aquatic habitat in places. Condition is not well known though thought to be similar to adjoining sub-divisions. The diaries of Rachel Henning who lived on Exmoor station in the lower reaches of this sub-catchment from 1862-1865 provide interesting reading regarding the environment of that time, when it was first settled as sheep-grazing country. Water quality data for some waterholes in this area is available in Loong et al. (2004).

Little Bowen River wetland condition summary...

Water

SedNet Modelling of Water Quality

The following statistics are summarized from the CSIRO report: Improved SedNet Modelling of Grazing Lands in the Burdekin Catchment by Kinsey-Henderson, A., Sherman, B. and Bartley, R. 2007. This report can be accessed from the report section below.

Model results for the Little Bowen River subcatchment are summarized as follows:

Subcatchment modelled area: 1,455 sq. km.

Source contributions: Hillslope = 89%; Gully = 6%; Streambank = 5%

Area of subcatchment with <50% ground cover: 465 sq. km or 32% of subcatchment

Hillslope sediment supply: 737 kg/ha/yr

Total suspended sediment (flow weighted) supply: 121 kt/yr

Total suspended sediment supply (flow weighted; normalized to area): 832kg/ha/yr

Total suspended sediment end-of-subcatchment (flow weighted) yield: 115 kt/yr

Event Mean Concentration (EMC - flow weighted): 552 mg/L

Mean Annual Flow: 208,254 ML

Hillslope erosion is identified as the major source of sediment and particulate nutrients affecting water quality within the Little Bowen River subcatchment (89%), and is predicted to contribute 737 kg/ha/yr. Total suspended sediment loss from all sources is predicted to be high (832 kg/ha/yr). While gully erosion is predicted to contribute only 6% of the sediment load, extensive gully networks have been observed in this catchment and it is thought that the SedNet model may be significantly underestimating the contribution from this source. The event mean concentration of suspended sediment is predicted to be moderate (552 mg/L).

Water Quality Monitoring

The monitoring site on the Little Bowen River is located ~1 km upstream from the Little Bowen/Broken River junction on Amberkolly Station and has been sampled by BDTNRM Volunteers over 1 wet season (2006/07). The monitoring site drains a catchment area of 1,490 sq km, of which 58.8% is grazing. Suspended sediment concentrations were extremely high (mean concentration of 4,006 mg/L) in the 2006/07 wet season. The initial monitoring data are considerably higher than the predicted suspended sediment concentration in the SedNet model (552 mg/L), although additional monitoring is required to determine if this trend is consistent over sucessive wet seasons. However, the SedNet model appears to be underestimating the contribution of gully erosion and total soil loss from the sub-catchment.

Relevant information of Water Quality Monitoring in the Bowen Broken Bogie River Basin can be found by following these links:

Environmental Uses and Values

The following summary of environmental uses and values is based on information extracted from the following reports: Social, Economic, Cultural and Environmental Values of Streams and Wetlands in the Burdekin Dry Tropics Region by Greiner, R and Hall, N. 2006 and Burdekin Basin Draft Water Resource Plan by Queensland Dept. of Natural Resources, Mines and Water, 2006, The Greiner and Hall 2006 report may be accessed from the report section below.

Definition of Environmental Values in the Queensland Water Quality Guidelines

Aquatic Ecosystems:

The aquatic ecosystem values of the Little Bowen River Subcatchment are part of the upper catchment of Hazelwood Creek, which rises in rainforest headwaters at Criticon State Forest just west of Eungella, is identified as containing High Ecological Value (HEV) waters by the BWQIP ecological values technical panel. The flow generated from these headwaters support waterholes further downstream in Hazelwood Creek, providing aquatic habitat and refugia through some of the dry season in an otherwise dry catchment. 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.

Little Bowen River subcatchment draft HEV waters

Stock Watering:

Water supply for production of healthy livestock.

Cultural and Spirtual:

Custodial use of water resources by Wirri traditional owners.

Landuse

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

Grazing: 59%

Conservation & minimal use: 36%

Production forestry: 4.2%

Water: Limited water activity use identified.

Irrigated horticulture & cropping: Limited irrigated horitculture water activity use identified.

Grazing Land

Little Bowen River is a relatively small subcatchment where the principle land uses are grazing on natural pastures and conservation.

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 Little Bowen River sub-catchment is proportioned as follows:

A Condition: 14%
B Condition: 18%
C Condition: 56%
D Condition: 12%

Data from the Little Bowen River sub-catchment is based on 43 observations.

On the basis of the rapid assessment, the Little Bowen River sub-catchment is estimated to have the largest proportion of land in poor (C) condition (56%), followed by fair (B) condition (18%) and good (A) condition land (14%). 12% of observed land was in very poor (D) condition.

Ground Cover

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

( BC) Bare Cover: 0%
( LC) Low Cover: 38%
( MC) Moderate Cover: 46%
( HC) High Cover: 17%
(VHC) Very High Cover: 0%

Data from the Little Bowen River sub-catchment are based on 24 observations.

On the basis of the rapid assessment (2004-2007), the Little Bowen River sub-catchment is estimated to have the highest proportion of land within the moderate (MC) ground cover category (46%), followed by low (LC) cover (38%). 17% of land was estimated to fall into the high cover (HC) category.

Resource Condition Summary

Little Bowen River is a relatively small subcatchment and, while the principle land use is grazing on natural pastures, approximately 36% of the land area is set aside for conservation and minimal use. Riparian habitat in the subcatchment has declined over the last 30 years because of clearing in the riparian zone and an increase in floodplain bare soil and gullying, and is currently assessed to be in fair (B) condition. The subcatchment is a largely sandy, dry seasonal creek system with limited habitat availability, although springs are present that create aquatic habitat in places. However, very little is known about the ecology and condition of aquatic habitats.

Hillslope erosion is identified by models as the major source of sediment and particulate nutrients affecting water quality within the Little Bowen River subcatchment. The rate of soil erosion is predicted to be high and close to the Basin average, while the total soil loss from the subcatchment is at an intermediate level compared to other basin subcatchments. Land condition is assessed as having the highest proportion in poor (C) condition, with roughly equal proportions of good (A), fair (B) and very poor (D) condition land. This is also reflected in the ground cover assessment (2004-07). Analyses of ground cover from satellite imagery (reference) show that ground cover has been in decline over the last decade and identify large areas of chronic and vulnerable 'D' condition land along the Little Bowen River.

Water quality in the Little Bowen River subcatchment is predicted by models to be poor, with relatively high concentrations of sediment at end-of-subcatchment. Water quality monitoring below the Little Bowen/Broken River junction recorded extremely high suspended sediment concentrations in the 2006/07 wet season; much higher than predicted by models. Extensive gully networks have been observed in this subcatchment and it is thought that the models may be significantly underestimating the contribution from this source and, consequently, the total soil loss from the subcatchment.

Little Bowen River is identified as a priority subcatchment for rehabilitation on the basis of its chronic and vulnerable 'D' condition land, high rate of soil erosion and contribution to the total sediment load within the basin.

Draft Environmental Values

Part of the upper catchment of Hazelwood Creek, which rises in rainforest headwaters at Criticon State Forest just west of Eungella, is identified as containing High Ecological Value (HEV) waters by the BWQIP ecological values technical panel. The flow generated from these headwaters support waterholes further downstream in Hazelwood Creek, providing aquatic habitat and refugia through some of the dry season in an otherwise dry catchment. 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. The human use Environmental Values of the subcatchment are understood to be limited to stock watering, and the cultural and spiritual values of the Wirri traditional owners.