Barratta Creek

From Knowledge Base

Jump to: navigation, search

Subcatchments

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 declined from excellent condition (A+) in the 1970s to relatively good condition (B) in 2004. The decline in condition is the result of floodplain clearing including forest, an increase of bare soil on the floodplain and an increase in scalding. Despite the changes that have occurred within the catchment it continues to provide a wide range of riparian habitats (hence the B iTRARC score), and the field survey results are consistent with this assessment. The level of regeneration is high, indicating good riparian condition into the future. However the weed species, particularly the high cover encountered at East Barratta Creek are of concern.

more...

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.

The upper part of the catchment (above Woodhouse Lagoon) is relatively undeveloped, being used for rangeland cattle grazing. Although some large waterholes are present, this part of the catchment is mostly dry and although little is known about it, it is considered that changes to water quality and aquatic habitat are typical for this type of land use. From Woodhouse downstream to the Bruce Highway, and in fact downstream of the highway to the estuary, the flow regime has been altered to one of perennial flow by the tailwater discharge from the development of extensive agriculture (mostly sugar cane). Although this change from a seasonal to a perennial stream is a very significant departure from its natural condition, we believe Barratta Creek to be one of the most important, healthy and productive creek systems in the Burdekin catchment, and in fact along the coast between Mackay and Ingham (Burrows and Butler 2007). It includes many large, permanent wetlands and long lengths of perennially-flowing creek contained within a environmental corridor retained when the irrigation area was first developed in the early 1990’s (see ACTFR 1994, BBIFMAC 1999, Tait and Perna 2001). Unlike most other coastal creek systems in the region, there are no major fish passage barriers. Riparian habitat condition is generally good though threatened by weeds (especially rubber vine, guinea grass, paragrass and hymenachne) and inappropriate fire management. The idea that although it has departed significantly from its natural condition, but retains (and has probably enhanced) its functional values, is further discussed in Burrows and Butler (2007).

Tributary streams such as Pelican Creek and the Collinsons Lagoon systems, are surrounded by intensive land use and are in very poor condition, with loss of riparian vegetation and domination by aquatic weeds such as para grass and water hyacinth, but are worthy of rehabilitation. The series of deepwater lagoons that make-up the Didgeridoo Lagoon system are similarly affected by surrounding land use development but have retained better condition than Pelican Creek or Collinsons Lagoon. Many significant wetlands in the catchment are listed in the Directory of Important Wetlands in Australia, and the lesser known wetlands of the coastal complex are part of the Bowling Green Bay National Park and Ramsar site (QDEH 1991). These are also subject to altered flow regime, but less surrounding intensive land use development (much of this land is cattle grazing) and have generally retained better condition. The freshwater fish of the catchment have been surveyed by Perna (2003, 2004), confirming their high levels of diversity and productivity. Several exotic fish species have been caught in the catchment, including mosquitofish and three-spot gourami which are quite well-established in the lower half of the catchment, as far upstream as Woodhouse Lagoon. A considerable amount of water quality data is available for the irrigation area (Congdon and Lukacs 1995). The limnology of two sites within this sub-division (Barratta Creek at Northcote and East Barratta Creek, bit at DNRW (now DERM) gauging stations) were assessed by Loong et al. (2005) and the lower reaches of the creek by Davis et al. (2005). Management issues for Barratta Creek featured strongly in the lower Burdekin sub-regional strategy (BBIFMAC 1999).

Barratta Creek wetland condition summary...

Water

SedNet Modelling of Water Quality

The following statistics are summarized from the CSIRO report: Improved SedNet Modelling of Grazng 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 Barratta Creek subcatchment are summarized as follows:

Subcatchment modelled area: 1,009 sq. km.

Source contributions: Hillslope = 68%; Gully = 15%; Streambank = 17%

Area of sub-catchment with <50% ground cover: 61 sq. km or 6% of subcatchment

Hillslope sediment supply: 407 kg/ha/yr

Total suspended sediment (flow weighted) supply: 60 kt/yr

Total suspended sediment supply (flow weighted; normalized to area):591kg/ha/yr

Total suspended sediment end-of-subcatchment (flow weighted) yield: 49 kt/yr

Event Mean Concentration (EMC - flow weighted): 272 mg/l

Mean Annual Flow: 178,423 ML

Barratta Creek is a relatively small subcatchment compared to others within the greater Burdekin catchment.

Hillslope erosion is believed to be the major source of sediment and particulate nutrients influencing water quality within this sub-catchment, although total sediment supply is relatively low at 60 kt/year. This is probably due to the fact that only 6% of the sub-catchment has less than 50% ground cover. Flow is artificially sustained within the Barratta system, providing irrigation water for sugar cane crops, resulting in relatively low concentrations of sediment compared to other sub-catchments.

Water Quality Monitoring

The monitoring sites in the Baratta Creek:

Upper Barratta Creek is located at the Viv Cox Bridge and has been sampled by the ACTFR for 3 years. The catchment area for this monitoring site is 691 sq km, of which 84.2% is used for grazing and 14.68% for cropping.
East/ West Barratta Creek are located along the Bruce Highway and has been sampled by the ACTFR for 4 years. The catchment area for this monitoring site is 912 sq km, of which 72.1% is used for grazing and 24.72% for cropping.

Suspended sediment concentrations at the three monitored Barratta sites have, on average, been relatively low (mean concentrations from event flow samples range between 73 to 107 mg/L) over the monitored period compared to other catchments on the coastal plain in the Burdekin Region. Oxidised nitrogen concentrations (nitrate + nitrite) have been consistently high in this catchment over the monitored period (mean concentrations from event flow samples range between 413 to 439 ug/L) compared to other coastal catchments in the Burdekin Region. These high concentrations are indicative of fertiliser runoff. Flow-weighted average annual suspended sediment loads for the Barratta Creek have been calculated at 13,500 tonnes using the monitoring data from the 2004/05, 2005/06 and 2006/07 wet seasons which is considerably lower than the annual load predicted by the SedNet model of 60,000 tonnes. Flow-weighted average annual dissolved inorganic nitrogen loads for the Barratta Creek have been calculated at 72 tonnes using the monitoring data.

Several herbicide residues have been detected in the Barratta Creek system including ametryn, atrazine, diuron, and hexazinone which have been detected regularly in the waters while other herbicides which include 2,4-D, simazine, bromacil, prometryn and metolachlor have been detected with less regularity. All these herbicides (with the possible expection of simazine) are sourced to the sugar and horticultural industres. Of these herbicides, diuron and atrazine are considered to be of the most concern in the region due the higher concentrations measured compared to the other herbicides. In addition, diuron and atrazine also exceeded set ANZECC guidelines in some samples and have been traced into the adjacent marine environment (Bowling Green Bay). In general, concentrations of most herbicides at the Barratta Creek monitoring sites were highest in low flow conditions and on the rising limb of the flow hydrograph. Using the 2005/06 and 2006/07 wet season data, an annual average of 192 kg of atrazine, 112 kg of diuron, 6.9 kg of Ametryn, 20 kg of 2,4-D and 4.4 kg of hexazinone was estimated to be exported from the Barratta Creek catchment.

Relevant information of Water Quality Monitoring in the Lower Burdekin 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., Burdekin Basin Draft Water Resource Plan by Queensland Dept. of Natural Resources, Mines and Water, 2006, and Draft Environmental Values and Water Quality Objectives for the estuarine and coastal areas of the Lower Burdekin by Lankester, A., Dight, I., Brodie, J., Bainbridge, Z. and Lewis, S. 2007. Two of these reports may be accessed from the report section below.

Definition of Environmental Values in the Queensland Water Quality Guidelines

Aquatic Ecosystems:

A single area of the Barratta Creek subcatchment has been identified as containing High Ecological Value (HEV) waters by the BWQIP ecological values. This area corresponds to the estuarine wetlands within Bowling Green Bay National Park, which is recognised internationally as a Ramsar wetland that provides important breeding and feeding habitat for water birds and other avifauna. The aquatic ecosystems values of the middle and lower reaches of Barratta Creek, below where irrigation tailwater enters the main channel, is considered to be Highly Disturbed (HD) notwithstanding its significant ecological value and inclusion in the Directory of Important Wetalnds. Other parts of the subcatchment are considered to be Slightly to Moderately Disturbed (SMD as a consequence of the surrounding land use.

The aquatic ecosystem values of Barratta Creek: Protected status: GBRWHA; Fish Habitat Area of management level A. Upstream connectivity disrupted by diversion channels and drop boards; fish barriers; use of waterway as irrigation and tail water channel; elevated concentrations of sediments, nutrients and pesticides entering the waterway; freshwater flows from irrigation tail water into "naturally" saline areas; modified flow regime.

Baratta Creek subcatchment draft HEV waters

Irrigation:

Use of Barratta Creek for irrigation, mostly sugarcane.

Stock Watering:

Water supply for production of healthy livestock.

Secondary Recreation:

Major fishing area-considered the most popular estuarine fishing area in the catchment.

Visual Recreation:

Barratta and Sheep Station Creek Estuary is used for visual appreciation.

Human consumers of Aquatic food:

Fish from recreational and commercial fishing and shellfish consumption. Subsistence hunting, fishing and collecting by Juru Traditional Owners.

Cultural and Spirtual:

Heritage; traditional resource use; traditional values and attributes of natural resources (plant and animal) by Juru Traditional Owners.

Landuse

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

Grazing: 60.4%

Irrigated Sugar: 30.9%

Conservation & minimal use: 5.6%

Water: 2.8%

Urban & semi urban: .17%

Irrigated horticulture & cropping: .07%

Grazing Land

Land Condition

Definition of ABCD land condition framework

No data available for land condition in the Barratta Creek sub-catchment.

Ground Cover

No data available for Ground Cover in the Barratta Creek sub-catchment.

Resource Condition Summary

Barratta Creek is a small subcatchment where the major land use is grazing on natural pastures, while approximately 31% of the land area is used for irrigated sugar production. Less than 6% of the land is set aside for conservation and other minimal use. The riparian habitat of the subcatchment has deteriorated over the last 30 years, principly due to floodplain clearing, and is currently assessed to be in fair (B) condition. Despite the changes that have occurred within the subcatchment, it continues to provide a wide range of riparian habitats. The upper part of the subcatchment is a mostly dry, ephemeral creek system and, although some large waterholes are present, little is known about the ecology and condition of aquatic habitats. The flow regime of the middle and lower reaches of Barratta Creek subcatchment have been altered to perennial flow by the tailwater discharge from the development of extensive system of irrigation channels for agriculture. Although this change from a seasonal to a perennial stream is a very significant departure from its natural condition, Barratta Creek is considered to be one of the most important, healthy and productive creek systems in the Burdekin region and includes many large, permanent wetlands and long lengths of perennially-flowing creek where there are no major fish passage barriers.

Hillslope erosion is identified by models as the major source of sediment and particulate nutrients affecting water quality within the Barratta Creek subcatchment, while both streambank and gully erosion are also predicted to contribute to the total sediment load. The rate of soil erosion is predicted to be moderate and well below the Basin average, while the total soil loss from the subcatchment to waterways is comparatively low. There are no rapid assesment data for grazing land condition and ground cover available for the subcatchment. However, analysis of ground cover from satelite imagery (reference) shows that the mean cover on grazing land was quite high in 2006.

Water quality in the Barratta Creek subcatchment is predicted by models to be only slightly impacted by suspended sediment during wet season event flows. However, water quality monitoring data show still lower concentrations and loads of suspended sediment than predicted by models, thus indicating that the models are likely to be overestimating sediment erosion. In contrast, disproportionately high dissolved inorganic nitrogen concentrations and loads have been recorded from the Barratta Creek subcatchment. Several herbicide residues have regularly been detected in Barratta Creek, including atrazine, diuron, ametryn and hexazinone. Very many samples contained atrazine and diuron concentrations that exceeded ecosystem health guidelines.

The area of sugar production in the Barratta Creek subcatchment is identified as a priority focus for improved management practice to reduce fertilizer and herbicide loss to waterways on the basis of the disproportionately high dissolved inorganic nitrogen concentrations and loads, and elevated concentrations of several herbicides that are associated with sugar production.

Draft Environmental Values

A single area of the Barratta Creek subcatchment has been identified as containing High Ecological Value (HEV) waters by the BWQIP ecological values. This area corresponds to the estuarine wetlands within Bowling Green Bay National Park, which is recognised internationally as a Ramsar wetland that provides important breeding and feeding habitat for water birds and other avifauna. The aquatic ecosystems values of the middle and lower reaches of Barratta Creek, below where irrigation tailwater enters the main channel, is considered to be Highly Disturbed (HD) notwithstanding its signigicant ecological value and inclusion in the Directory of Important Wetlands. 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 waters are understood to include recreation (boating & visual appreciation), irigation, stock watering, human consumption of aquatic food, and the cultural and spiritual values of the Juru traditional owners.