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Publications
Supervising Scientist Report 168
Koehnken L
Supervising Scientist, 2001
ISSN 1325-1554
ISBN 0 642 24374 3
The hard copy is not available from SSD publications, but can be ordered from Tasmanian Department of Primary Industries, Water & Environment, GPO Box 44, Hobart, Tasmania 7001. A CD-ROM will be available from SSD publications Publications, Supervising Scientist Division.
A full list of SSD publications including prices is available on the publications page. An order form can be downloaded and faxed or posted back. Alternatively, you can email your order to publications_ssd@environment.gov.au or phone +61 08 8920 1100.
The north-east of Tasmania encompasses the South Esk River basin, rivers draining into Bass Strait east of the Tamar, and rivers discharging to the east coast of Tasmania north of Scamander. The area incorporates a wide range of riverine environments, ranging from small streams draining high plateau regions, to large rivers that are highly regulated and impacted by land use activities. This report provides a summary of the environmental status of waterways in the north-east region based on published information. Current water quality issues and current water management activities are presented on a catchment basis.
Overall there is a lack of long-term water quality information available for north-east waterways. The recent 'State of the River' reports (Bobbi et al 1996, 1999a,b,c,d) have greatly improved the understanding of water quality and riverine health in a number of waterways, but more information is required to assist catchment managers and the community in identifying issues and priorities.
Riverine water quality issues identified in this review include run-off from agricultural and forestry land, high levels of bacteriological indicators due to stock access to rivers, leaching from septic tanks, poorly performing sewage treatment facilities, and acidic discharges from historic mining centres. Generally, industrial wastewater discharges were not identified as a significant water quality issue except where occasional accidental releases occurred.
The region is characterised by a dispersed population, with the largest towns having fewer than 5000 residents. The low population density has limited local Councils’ ability to provide adequate sewage treatment to all residents. Septic tank usage is high outside of the major population centres and although not quantified, it is believed they are impacting downstream water quality.
Impacts from land use practices are a major issue in north-east Tasmania. Turbidity and elevated nutrient and bacteriological loads have been documented during and following rainfall events in many rivers in the north-east. These impacts are most pronounced in agricultural areas where riparian vegetation has been damaged or lost and stock has direct access to waterways. Habitat destruction threatens several aquatic species, such as the giant freshwater lobster and freshwater snails. NHT (Natural Heritage Trust) funded projects are beginning to address these issues in most catchments through the implementation of Rivercare plans.
Many of the sewage lagoon systems in the north-east have been upgraded in the past few years through the NHT Clean Quality Water Program. Notable exceptions are the Longford sewage lagoon system and Scottsdale sewage treatment plant. The Longford facility discharges into Back Creek which is also severely impacted by intensive agricultural practices in the catchment. The Scottsdale STP discharges to Cox’s Creek, which is impacted by dairying, forestry and direct stock access.
Storys Creek, tributaries of the Ringarooma/Boobyalla system, and the George River catchment receive acid drainage from historic tin mining sites. Some remediation work has been completed at these sites, but elevated metal concentrations and low pH values continue in parts of the catchments. Near Gladstone, acid drainage affects waterways used for recreation.
Coastal areas in the north-east are used extensively for recreation. An analysis of the estuaries has indicated that most are impacted to moderately impacted, and except for the Boobyalla and Tamar, are of little conservation value. The presence of introduced marine pests in Henderson Lagoon and elevated levels of Tributyl-tin in sediments in Georges Bay are newly recognised additional stresses on these estuarine waterways.
Summary table of activities and impacts in north-east Tasmania
| Category of activity | Municipality | Site | Issue(s) | Affected river(s) | Suspected pollutants/impacts |
| Septic tanks | All | Widespread | Seepage contaminating waterways | Believed to be widespread with coastal areas of particular concern | Bacteria, pathogens, nutrients, BOD |
| Agricultural activities | All | Widespread impact on riparian zones | Run-off from agricultural land and unrestricted stock access to rivers | Widespread | Damage/loss of riparian communities; loss of habitat for aquatic species including rare and vulnerable giant freshwater crayfish, freshwater snails and frogs, bacteria, pathogens, nutrients, BOD, TSS |
| Sewage treatment plant | Northern Midlands | Longford STP | Inadequate sewage treatment | Back Creek | Bacteria, pathogens, nutrients, BOD |
| Sewage treatment plant | Dorset | Scottsdale | Large loading to small waterway | Cox’s Creek | |
| Old mine site | Northern Midlands | Storys Creek | Acid mine drainage | Storys Creek, South Esk | Metals, acidity |
| Old mine site | Break O’Day | Anchor Mine | Acid mine drainage | George River | Metals, acidity |
| Old mine site | Dorset | Arba, Briseis, Pioneer, Endurance, Blue Lake | Acid mine drainage | Ringarooma/Boobyalla | Metals, acidity |
| TBT-paints | Break O’Day and possibly others | Georges Bay | Tributyl-tin entering and damaging ecosystem and marine farms | Georges Bay, possibly other estuaries | Tributyl-tin |
| Introduction of marine pests | Break O’Day | Henderson Lagoon | Introduced North Pacific sea star (Asterias amurensis) | Impact native shellfish populations and aquaculture | |
| Introduction of marine pests | All | Estuaries | Introduced European green crab (Carcinus maenas) | Impact native crab and bivalve populations, impact on marine farming operations | |
| Waste disposal sites | Potentially all | Numerous | Seepage from waste disposal sites is contaminating groundwater; coastal areas are of particular concern | MRT finalising report identifying areas | Various organic and inorganic pollutants |
| Dams, weirs | Northern Midlands | Various | Physical structures impeded fish and eel passage | Various | Migration of eels and native fish disrupted |
The full report can be ordered from publications_ssd@environment.gov.au
Koehnken L 2001. North-east rivers environmental review: A review of Tasmanian environmental quality data to 2001. Supervising Scientist Report 168, Supervising Scientist, Darwin NT.
This report is available as a PDF file. You will need Adobe Acrobat Reader installed on your computer to view the PDF files. Figures 1, 5 and 6 are provided as separate PDF files because they are large files and will be slow to download.
A print resolution PDF of the report is also available.
If you are unable to access the report, please contact the Supervising Scientist Division (telephone 61 (0)8 8920 1100; email enquiries_ssd@environment.gov.au) to organise a suitable alternative format.
