Wellstead Estuary Project
Wellstead Estuary and Bremer Bay are synonymous with relaxed holidaymakers, fishing, boating and pristine deserted white sandy beaches with a backdrop of clear azure skies and undisturbed bushland. It is 185km east of Albany adjoining the Fitzgerald River National Park. The park is one of the largest and most botanically significant in Australia. Over 1800 species of flowering plants, or 20% of Australia's total plant species are found within it's boundaries, many of these endemic. The park has been given international recognition with Biosphere Reserve status. The Bremer River catchment and estuary form part of this Fitzgerald Biosphere.
Wellstead Estuary Foreshore vegetation
The town of Bremer Bay has a small but rapidly growing permanent population of 250 people, although at peak holiday times the population of the town can expand to 6500 people.
Wellstead estuary has a shallow and wide basin in its lower reaches, but narrows to form the typical flooded river valley in its upper reaches. The lower basin is some 2.5 km2 in size, with the navigable length of the estuary being some 13 km. The only river entering the estuary is the Bremer river, some 70 km long and with a catchment area of 716 km2 It is estimated 80% of this catchment has been cleared for agricultural use, mainly from the 1950's onwards.
The estuary is in many ways a typical South Coast estuary, being separated from the Southern Ocean by a sandbar generated by wave action and other coastal processes. For Wellstead estuary this sandbar is open every few years, and can often remain open for extended periods of time due to the protection offered by a granite headland at its mouth. This contrasts with the estuaries to the west that are generally either permanently open or open on an annual or frequent basis, due to their higher winter rainfall, and estuaries to the east that are generally either permanently closed or infrequently open to the sea due to their lower rainfall.
Salinity levels in the estuary vary greatly, from very fresh in times of heavy rainfall and high inputs from the Bremer river, to salinity levels more than twice that of seawater as a result of no river inputs and evaporation when the sandbar has not been breached for several years. Such alterations in salinity, often in a short period of time, limit the range of fish that can survive in the estuary. The estuary is, however, a very popular fishing destination, particularly for black bream.
Wellstead estuary has important ecological values, in particular offering open water, sandbanks, shallow water margins and foreshore vegetation habitats for many species of birds. Five hundred swans have been spotted at a time, and the estuary's sandbank and adjacent beaches provides one of the few breeding grounds for the hooded plover.
Wellstead estuary, as is normal with most estuaries, is shallowing as a consequence of sediment introduced by its inflowing river. Estuaries are constantly changing, and have a relatively short lifespan in comparison with many other landforms. Over a few thousand years, should sea levels not change greatly, the estuary can be expected to gradually infill and become a wetland and coastal plain.
Previous studies have indicated sediment depths of over five metres in the estuary, a consequence of sediment inputs from the catchment and decaying vegetation within the estuary. However, it is not known whether this sedimentation process has recently increased as a result of European settlement and the clearing of the catchment. As the catchment largely contains easily weathered sandstone, high sedimentation rates in the estuary could be natural. However, anecdotal information from indigenous people and long-term residents suggests the estuary has shallowed greatly in the past 20-30 years, and catchment clearing could be a contributing factor.
Clearing of vegetation in the catchment is also likely to have caused changes in the quantity of water entering the estuary, and as a consequence the frequency of sandbar openings. Anecdotal evidence suggests the sandbar has opened more regularly in recent times, a pattern that exists for many south coast estuaries.
Increased nutrient levels in incoming waters to the estuary are also expected as a result of vegetation clearing and the expansion of agriculture, particularly with the use of fertilisers and the keeping of livestock. Increased nutrient inputs can promote plant and algal growth in estuaries, and Wellstead estuary has a high level of plant growth, particularly Ruppia macrocarpa. Determining whether this plant growth is â€˜normal', or a recent development, is not possible given inadequate monitoring. However, the prolific plant growth and decay can be an inconvenience to boat users and local residents, and is a matter of concern.
Salinity levels in the Bremer River have increased, and again this increase is likely to be a consequence of the vegetation clearing and rising groundwater levels. Again, scientific information is limited but long-term residents have advised of increasing salinity levels in the catchment, with one long-term resident illustrating this change by the fact that yabbies are no longer caught in the upper reaches of the Bremer River.
With the increase in population of Bremer Bay, and increasing tourism and use of off road vehicles, come other environmental pressures. Increased vehicle and pedestrian access has caused some degree of damage to foreshore vegetation, as has the introduction of weeds.
Hooded Plover eggs on the beach are extremely vulnerable.
Photo: A. Gadsby
Sand dune damage from off road vehicles.
Photo: A. Gadsby
Until recently very little was known about the estuary and research and monitoring of the estuary negligible. There has been no coordinated management of the estuary and it is within this context that the Wellstead Estuary Management Plan was written and the project initiated.
The plan was prepared by the Wellstead Estuary Advisory Committee, a sub committee of the Shire of Jerramungup. Contributors to the plan were from a range of agencies and the original membership from the Shire of Jerramungup, Community, Fitzgerald Biosphere Group and the Department of the Environment. A 2004 survey of community attitudes and a literature survey informed an environmental status report which along with background papers formed the basis of the management plan which was launched in June 2006.
A new management group was formed from representatives of the Shire of Jerramungup, Department of Water, Department of Food and Agriculture, Department of the Environment and Conservation, Department of Indigenous Affairs and community. The management group decided at its first meeting to retain the name Wellstead Estuary Advisory Committee. A project coordinator was appointed and the Fitzgerald Biosphere Group selected to act as delivery agent for the project.
The plan details five strategies which each have specific actions which contain a timeframe for implementation, priority and identify the lead member agency.
The plan suggests long term resource condition targets and short term management action targets to monitor progress.
As part of the Bremer River Strategic Catchment the project has many overlaps with Bremer River Catchment Group initiatives and progress actioned within this overall context. Most of the 34 actions of the plan's strategy have now been implemented and are either completed or in progress.
To increase knowledge of the estuary and provide management tools for effective management many of the plans priority actions have been focussed on research and monitoring. A comprehensive foreshore condition survey has been completed and a report outlining recommendations published. Water quality surveying is being conducted quarterly. Fish stock research has been in progress since 2006 and a report due in June 2008. Similarly bird surveys have been conducted quarterly and a report due in June 2008. Cultural surveys were initiated in mid 2007. Sediment surveys carried out in mid 2006 and 2007 are contributing to our knowledge of estuarine ecological processes. A groundwater monitoring program began in October 2007 to monitor townsite nutrient levels and their estuary input.
Foreshore rehabilitation has been initiated for two priority sites identified in the Foreshore Condition report produced In early 2007.
A big focus of the project is community engagement with management and recognition of community values. Two community groups have been fostered by the project to address this: Friends of the Wellstead Estuary and the Bremer Bay Regional Trails Committee. The two groups are working cooperatively with the management plan to achieve its goals within a planned framework. The project has supplied a fully equipped trailer and tools to assist with this. The groups also initiate specific planning drafts for consideration by the wider community and agencies addressing actions such as foreshore protection, interpretive and educational material, habitat protection and planned access controls.
The Friends of the Wellstead Estuary, with the support of the FBG, organised a clean up event on Clean up Australia Day in 2007 and 2008