Barratta Creek

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Vegetation

Riparian Habitat

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.

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

iTRARC Scores

Catchment Class
Maximum iTRARC Score 24 (A+)
1970s Score 23 (A+)
2004 Score 11 (B)
Reduction in Ecosystem Services Very Large
Increase in Potential for Erosion Large
Reasons for Change in Score
  • Floodplain cleared for sugar cane
  • Forest and closed forest cleared from floodplain
  • Bare soil on the floodplain
  • Increased scalding

TRARC (field survey) scores

Survey SiteScoreRegenerationWeeds
Major Ck71.2 (B)2 (B)1 sp: 5% cover (B)
East Barratta Ck72.6 (B)3 (A)2 spp; 90% cover (D)
Average 71.9 (B)

Wetlands

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 paragrass 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 DNRM 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).

For more information see Barratta Creek wetland condition summary

Reference: Assessing the condition of Wetlands in the Burdekin catchment

Water

SedNet Modelling of Water Quality

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

  1. Subcatchment modelled area: 1,009 sq. km.
  2. Source contributions: Hillslope = 68%; Gully = 15%; Streambank = 17%
  3. Area of sub-catchment with <50% ground cover: 61 sq. km or 6% of subcatchment
  4. Hillslope sediment supply: 407 kg/ha/yr
  5. Total suspended sediment (flow weighted) supply: 60 kt/yr
  6. Total suspended sediment supply (flow weighted; normalized to area):591kg/ha/yr
  7. Total suspended sediment end-of-subcatchment (flow weighted) yield: 49 kt/yr
  8. Event Mean Concentration (EMC - flow weighted): 272 mg/l
  9. Mean Annual Flow: 178,423 ML

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

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 Barratta Creek:

  1. 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.
  2. 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:

Environmental Uses and Values

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 Wetlands. Other parts of the subcatchment are considered to be Slightly to Moderately Disturbed (SMD as a consequence of the surrounding land use.

The aquatic ecosystems 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.

The Barratta Creek catchment contains a high number of highly significant and productive wetlands, with several listed on the Directory of Important Wetlands (DOIW), including: Jerona Aggregation, Barrattas Channel Aggregation, Haughton Balancing Storage, and the extensive Burdekin-Townsville Coastal Aggregation. However, most of the wetlands in the Barratta Creek systems have been highly modified. The upper catchment is relatively undeveloped with seasonally flowing streams but few persistent water bodies. The area is used for cattle grazing and this has affected water quality. In the lower freshwater reaches water flow and water quality have been modified by the introduction of supplemented irrigation waters from the Burdekin Falls Dam as part of the Burdekin River Irrigation Area (BRIA) distribution system and irrigation tailwaters. Riparian vegetation is largely continuous and in good condition in many places, maintaining wildlife habitat and ecological function, particularly a large corridor area in the centre of the catchment retained for natural values during the irrigation development (the Barratta Channels Aggregation DOIW). However, many of the freshwater wetlands are moderately to severely affected by aquatic and semi-aquatic and riparian weed infestations and receive agricultural contaminants carried in tailing and storm waters.

Despite their modified state, the wetlands in this catchment retain many natural ecological values, but only waters contained within the estuarine section of this catchment, within Bowling Green Bay National Park, have been assessed by the WQIP ecological values technical panel to be “effectively unmodified” (ANZECC 2000) and identified as High Ecological Value (HEV) waters. Bowling Green Bay National Park is recognised internationally as a Ramsar wetland, noted for its physiographic diversity and extent of wetland types and makes up part of the Burdekin-Townsville Coastal Aggregation (DOIW). The area provides important breeding and feeding habitat for water birds and other avifauna. Connor Island, in the Barratta Creek estuary is a noted for having the largest breeding colonies of fish-eating birds in eastern Australia. The area also provides important fish and crustacean nursery, providing critical habitat at particular lifecycle stages. In turn the area supports important estuarine and coastal fisheries, exporting carbon and other nutrients offshore and contributing to the productivity of the marine system. The adjacent Bowling Green Bay, a gazetted Fish Habitat Area (‘B’) and Dugong Protection Area (‘B’), has also been identified as a HEV coastal/marine 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 Spiritual

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

References:

Landuse

Principle land uses within the Barratta 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%

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, principally 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 assessment data for grazing land condition and ground cover available for the subcatchment. However, analysis of ground cover from satellite imagery 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 significant 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), irrigation, stock watering, human consumption of aquatic food, and the cultural and spiritual values of the Juru traditional owners.

Maps

Photos

References

References

Barratta Creek
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