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Introduction
Condition
Pressure
Response
Acknowledgment
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Introduction
 The Lake Fenton/Lady Barron Creek water catchment is, in effect, a relatively pristine system in that for much of the time water quality is maintained at a very high level. Water quality impacts that are of major concern in developed areas do not constitute a problem in this catchment (e.g. nutrient enrichment, septic tank leachate, sewage overflows, industrial effluent, leachate from landfill sites, car exhaust fumes and industrial particulates). Nevertheless, the draft catchment management study highlights that comparatively minor human activities can pose significant threats to drinking water supplies (Hobart Water 2000). The draft catchment management plan for Lake Fenton/Lady Barron Creek provides an overview of the general characteristics of the catchment, the existing jurisdiction that covers the land and water resources of the area, and management actions related to the issues that directly affect or have the potential to directly affect water quality and quantity. The issues include potential turbidity increases resulting from road run-off, landslips, recreational activities, bushfires and forestry operations, and the presence of bacterial and pathogenic contamination of the catchment water resources. 
Condition The water supplied from the system is highly valued as a drinking water supply because it is relatively free from atmospheric and other environmental pollutants. Hobart Water has a water licence to draw 8,000 ML per annum (average of 22 ML per day) from the Lake Fenton/Lady Barron Creek system. The actual amount of water drawn from the system rarely exceeds 7,000 ML per annum. Water quality monitoring programs are used by Hobart Water to check the physical, chemical and biological conditions of the Lake Fenton/Lady Barron Creek system. Micro-biological, physical and chemical water quality parameters are currently monitored on a weekly basis in the catchment. Giardia and Cryptosporidium are monitored quarterly and during heavy rainfall events. Turbidity monitors linked to telemetry raise the alarm of rapidly rising turbidity in Lady Barron Creek, such that the water may be diverted from the water supply system. Hobart Water staff inspect Lake Fenton by boat to look for any potential sources of contamination (e.g. animal carcases, erosion or human interference). Staff also perform emergency inspections of the catchment areas based on poor water quality results. Physical environmental changes that may have adverse effects on water quality in the catchments are monitored. These include natural occurrences such as landslips and accelerated erosion caused by heavy rainfall. Environmental damage and waste pollution caused by animals, pesticides, fertilisers, people and vehicles are also monitored. Other measures include the upcoming installation of on-line water monitoring stations both at the water intake weir and at Lake Fenton. Measurement of flow and rainfall data is also planned. On a quarterly basis, a full analysis of water quality is performed on the water yielded from the Lake Fenton/Lady Barron Creek catchment. The water samples for these analyses are taken from the Fenton pipeline at New Norfolk. In response to suspected turbidity impacts from the Lake Dobson Road, a targeted water monitoring strategy has been proposed for major drainage lines. Details of the monitoring strategy will enable decisions to be made regarding appropriate locations and management actions for road maintenance and stormwater/snowmelt run off Pressure Despite its relatively protected status, there are a number of significant pressures in the catchment requiring management action. The pressures for which the draft management plan is seeking to respond are generally as a result of heavy rainfall or after snowmelt when contaminants are delivered to waterways by overland flow or leaching into the water table. - The most likely water quality impact is the potential for increased suspended solids, colour and turbidity, which may be derived from a variety of sources in the catchment including road run-off, logging operations, erosion of walking tracks, fires and landslips. Suspended solids are particles of soil or other substances that do not dissolve, but are suspended in the water column.
- Lady Barron Creek is susceptible to rapid increases in turbidity and colour after relatively minor rainfall events. The water from Lady Barron Creek is at times diverted out of the water supply system due to turbidity levels exceeding the water quality limit of one NTU (turbidity units). High turbidities limit the penetration of chlorine, which acts as a disinfectant on micro-organisms, including those that are harmful to human health such as E. coli. Turbidity can have a significant effect on the micro-biological quality of drinking water. High turbidity can both interfere with the detection of bacteria and viruses, by absorbing them onto the particulate matter and thus shielding them, and promote bacterial growth through the nutrients, which are absorbed. High turbidity has also been shown to protect micro-organisms from the action of disinfectants.
- There is a risk of contamination of yielded water with faecal matter, or by dead carcasses, at some point upstream of the water intake. The risk is increased if there is inappropriate recreational use of the catchment. There has been evidence of faecal contamination (by humans or other warm-blooded animals) in water entering Lake Fenton from Wombat Moor.
- There have been several recordings of low levels of Giardia and Cryptosporidium parvum in Lake Fenton and in Lady Barron Creek (unpublished information). Giardia and Cryptosporidium parvum are protozoans that are found in the faeces of warm-blooded animals. Ingestion of these organisms in water can lead to diahorrea and gastroenteritis. Short circuiting (especially during storm events) of water flow in Lake Fenton between the catchment and the extraction point could increase the risk of contamination of the water prior to disinfection with chlorine.
- There is also potential for water contamination from spillages of diesel and use of chemicals such as pesticides, herbicides and 1080 in nearby logging coupes. Additionally, weed management as identified in the draft Mt Field National Park management plan, has the potential to affect water quality if herbicides are used along the verges of the Lake Dobson Road.
- Road run off risks include oil, grease and exhaust fume contamination from vehicular traffic using the Lake Dobson Road, and fuel spill contamination from accidents on the road (diesel fuel is delivered in 200 litre drums to Lake Dobson to run generators for ski lodges and tows). There is also risk of pollution caused by transportation of organic waste disposal (sewage waste) or chemical spills on the Lake Dobson Road.
- Forestry operations have some potential to contaminate water entering Lady Barron Creek due to the close proximity of the harvesting operation to the water catchment. Burning of the coupe for regeneration will have potential to start a wildfire in the catchment and may cause ash contamination in Lady Barron Creek. Wildlife poisoned with 1080 will have the potential to travel from the coupe and die in the catchment of Lady Barron Creek, creating a water quality problem. There is concern over the use of herbicides and fertilisers. There will be planned applications of both chemicals, however they will be manually applied during the life of the proposed plantation and when completing forest regeneration work.
Response It is the objective of Hobart Water to meet the NHMRC Australian guidelines for recreational use of water "schedule 1, primary contact recreation" guidelines relating to micro-biological faecal indicators for catchment waters prior to intake into the Hobart water system. Following chlorination, it is Hobart Water's objective to meet the NHMRC Australian drinking water guidelines (1996) for post chlorination water supplied from the catchment via the Fenton pipeline to consumers. Specific management actions of the Lake Fenton/Lady Barron Creek catchment management plan are: - Water monitoring: in response to suspected turbidity impacts from the Lake Dobson Road, a targeted water monitoring strategy has been proposed for major drainage lines. Details of the monitoring strategy will enable decisions to be made regarding appropriate locations and management actions for road maintenance and storm water/snow melt run-off.
- Management of State forest: requirement for ongoing negotiations with Forestry Tasmania to reach consensus on appropriate long-term management within the catchment to protect water quality.
- Recreational activities: prohibition of recreational activities such as swimming, fishing, boating and camping in the catchment in order to minimise the risk of bacteria and pathogens entering the water supply. Appropriate toilet facilities need to be planned for the area. Use of the Lake Fenton to Lake Webster track to be discouraged.
- Education program: introduction of an education program to inform PWS staff, visitors and locals of the existence and extent of coverage of the water catchment and the role they are expected to play in protecting it. This program will include the production of information brochures and installation of water catchment signs.
- Access and safety considerations: access to Lake Fenton, Lady Barron Creek and catchment is to be restricted through the minimisation of car parks in the catchment, construction of fencing where appropriate and installation of security gates on private access roads. Bushwalking is to be managed to minimise the risk of water contamination.
- Hydrology program: undertake a hydrology study of Lake Fenton to determine water inflows from Wombat Moor and water detention times and circulation characteristics within the lake. Such a study would provide an understanding of the residence time of pathogenic micro-organisms in the water supply system and the associated health risks.
- Fire management: to protect catchment water quality, a bushfire management plan is to be developed by PWS and Forestry Tasmania in conjunction with Hobart Water for the catchment and surrounding land.
- Annual review: implementation of several actions in this catchment management plan have been initiated through the cooperative involvement of stakeholders. A test of the effectiveness of the actions will come with continued water monitoring programs within the catchment and periodic performance review. The review process will involve the periodic re-convening of the Lake Fenton/Lady Barron Creek catchment management committee.
- Forestry Tasmania has set aside the majority of the catchment under the informal reserves system and no harvesting operations are planned to occur. The remaining area has been recognised as being available for multiple use forestry with special consideration for water values.
Acknowledgment Hobart Water |
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