Bega Valley

Issue: Catchments

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How has Catchment Quality Changed?

The Bega Valley Shire is located at the south-eastern extremity of New South Wales. The Shire contains 106 kilometres of coastline and lies within the Southern Rivers Catchment Management Authority area. Bega Valley covers an area of 6,279 square kilometres; however it has a relatively small population of approximately 32,500 people. The Shire has extensive natural areas including state forests.

Limited data was available for the Bega Valley to assess changes to, or impacts on, many aspects of catchment quality over the current reporting period.

Drought was a significant event impacting on catchment quality in Bega Valley over the current reporting period. The drought commenced in around 1997, and is as serious if not worse than other major prolonged droughts, such as the 1895 to 1903 and 1938 to 1945. Previous extreme drought years include 1902, 1914, 1938, 1940, 1944, 1967, 1982 and 2002. The 2006–07 irrigation season was a record dry season for much of the area (DECC, 2008).

As water availability has changed, water allocations within the catchment have been adjusted. Water allocations are made in a way that reflects the priority given to domestic and basic rights supplies, then to core environmental needs, then to irrigation and industry. Operational plans for 2007–2008 reflect that the catchment experienced one of the lowest inflow periods in history. In many cases, high security licences were permitted to carryover unused water for the first time.

Drought and/ or excessive water extraction can cause water bodies to dry out, water quality conditions to deteriorate and the fish within them may die or be eaten by birds. During this reporting period many of the rivers and smaller creeks did dry back and have had little or no surface flow.

Algal blooms can generally become more frequent during drought conditions due to low, slow flows and increasing water temperature. Major towns in the Shire have sufficient treatment facilities and treat all sewage before discharging to water. Unsewered towns in Bega Valley rely on septic systems and remained closely regulated by Council. No algal blooms were recorded over the reporting period. Council undertakes proactive algal monitoring on water storage dams at Yellow Pinch and Ben Boyd to ensure algal blooms are minimised and controlled.

During the drought, salinity levels have been relatively low. This is due to little or no inflows from higher salinity tributaries and no return flows. However, if dilution flows continue to reduce, river salinity levels may increase.

With reduced water availability for irrigation there is potential for substantial economic impacts. Irrigators who grow annual crops generally adjust their planting area depending on water availability. However, irrigators who grow perennial crops are impacted in the long term if they are unable to ensure crop survival.

Over the current reporting period, water allocations assigned in July 2006 had to be suspended in October and November 2006, due to the drought and inflows being below previous recorded low inflows. Domestic restrictions are used to raise awareness and understanding of the current drought and encourage people to conserve and use water more efficiently, resulting in lower water consumption.

Where are the ‘hot-spots’?

The Bega Valley catchment has ‘hot spots’ that have the potential to significantly damage sensitive coastal environments. This damage is generally caused by urban development. Stormwater volume and velocity, as well as sewage volume increases as the residential development increases, which has an impact on creeks, coastal vegetation, dune structures and the receiving waters.

All of the sewage treatment plants within Bega Valley experienced unlicensed discharges of sewage in each year of the reporting period. These discharges peaked in 2005-2006 and decreased over the rest of the reporting period. Council anticipates that the downwards trend in the number and volume of sewage discharges will continue into the future.

Southern Rivers Catchment Management Authority identifies some of the key challenges facing catchments in the Bega Valley region as:

managing water quality and quantity – sharing water with the environment and between people,
conserving, rehabilitating and sustaining aquatic and terrestrial biodiversity
protecting the soil,
maintaining sustainable production and development,
developing healthy urban environments,
recognising and protecting cultural heritage, and
maximising community participation in catchment health (Southern Rivers CMA, 2008).

The community also identified the following issues in relation to the Bega River Catchment in the Healthy Rivers Commission reports and in the consultation undertaken in preparation of the Draft Bega River Estuary Management Plan.

protection of drinking water, including:
- providing suitable ground and river water for drinking, needing only low-cost, minimal treatment by homesteads and small communities
- protecting subcatchment sources of drinking water and limited reaches upstream of licensed drinking water offtakes
- well-head protection of groundwater supply sources.
reducing, at source, the adverse pressures on water quality in the coastal lake systems-particularly where they involve entry of nutrients, suspended solids and bacteria. People wanted further development affecting the water quality of the coastal lakes to be avoided and current upstream water quality impacts identified and ameliorated.
improving effluent disposal in unsewered areas to minimise adverse impacts on water quality from poor maintenance and pump-out, leading to overflows.
reducing sedimentation of streams and wetlands throughout the catchment, particularly the lower Bemboka and Bega rivers and Wallaga Lake. Sediments that have built up in the rivers are being colonised by willows, which can divert higher flows and increase erosion. Sediments also smother aquatic habitats.
controlling stock access to streams. Uncontrolled access is causing increased erosion and elevated nutrient and bacteria levels in waters.
conserving riparian vegetation. Remaining riparian vegetation is degraded and threatened with accelerated rates of river erosion.
reducing the stress on systems that have been identified as being under stress
protecting rivers with high conservation values in the catchment. As a guide, such rivers should not be allowed to further degrade in water quality or flow regime, and may require restoration where water quality is poor, the flow regime has changed, they have suffered habitat loss or degradation, or a combination of these problems (DECC, 2008).

What has been done to address catchment quality?

Bega Valley Shire Council has implemented a Stormwater Plan, which included the following actions:

Prepare and implement vegetation management strategies.
Prepare and implement threatened species management strategies.
Prepare and implement a Soil and Water Management Policy.
Review and implement Council’s Weed Management Strategy.
Develop roadside vegetation management protocols and strategies.
Implement the drinking water monitoring program.
Implement the urban Stormwater Management Plan.

The Urban Stormwater Management Plan also included a number of actions that affected the quality of stormwater flowing into the creeks and rivers. These included:

Community Education – trailer containing a working model of Merimbula catchment which is used at local events and schools within Bega Valley.
Information brochures/educational kits distributed to the residents of Tura and Merimbula and available to other residents. Brochure information includes water tanks, community groups, water sensitive design and what a catchment is.
Introduction of rainwater tanks, with a policy to install tanks in all new dwellings and in renovated dwellings above a 50% increase in floor space. A rebate is also offered for residents under the NSW Climate Change Fund.
Construction/excavation of detention/retention ponds to retard the flow of stormwater.
Information logos stenciled on the drains.

Bega Valley has also completed the Bega Valley Sewerage Program during this reporting period. This program has comprised the following major elements:

Installing new sewerage systems in the villages of Cobargo, Wolumla, Candelo, Kalaru and Wallaga Lake; and
Upgrading 5 existing sewage treatment plants at Bega, Tathra, Tura Beach, Merimbula and Bermagui.

In addition this project has resulted in an increase and improvement in the reuse of treated across all plants. Impacts on the catchment from this project have been difficult to quantify at this stage but there has undoubtedly been an improvement through the connection of over 900 on site sewage systems (septics) to the sewerage system. More information on the Bega Valley Sewerage Program can be found under the Bega Valley Snapshot.

Council has in addition funded significant maintenance on many of the stormwater detention / quality improvement structures in the Shire. This funding has been sourced from the Bega Valley Shire Environment Levy. Council has also implemented a Stormwater Levy during this reporting period that has also provided a source of funding for further stormwater improvements including maintenance on sediment basins and the like.

What does this mean for Council?

The catchment data supplied from Council and the Department of Water and Energy is lacking for many indicators within Bega Valley. This means that only partial assessment of catchment quality is possible.

There is limited Council monitoring of land degradation and ground and surface water quality. Therefore impacts from urban and rural development and significant natural pressures, such as drought, cannot be fully determined. Monitoring of implemented Council strategies and associated actions is also necessary to determine their effectiveness in achieving the desired catchment management outcomes.

Bega Valley should undertake the following actions to ensure environmental improvement in the catchment:

Continue to work closely with Southern Rivers Catchment Management Authority, to implement joint projects and ensure consistency in approach to land and water management and complementary actions.
Continue to build on effective relationships with NSW State Government agencies to ensure up to date information regarding condition of the catchments environmental drivers such as salinity, and associated management issues relevant to them.
Monitor and adapt to the impacts of climate change to ensure no significant detrimental catchment effect is sustained from the changing conditions and any future actions.
Continue to ensure impacts on ground and surface water quality are considered in landuse zoning, development applications, sewage and water supply treatment.
Implement appropriate environmental monitoring programs to measure the effectiveness of Council's policies, strategies, and management activities.
Support and encourage sustainable land use and water management in the urban and rural communities. Approach business and industries regarding sustainable practices and monitoring.

References

DECC (2008) NSW Water Quality and River Flow Objectives: Bega River Community Comment on Objectives, Department of Environment and Climate Change viewed at http://www.environment.nsw.gov.au/ieo/Bega/report-01.htm on 14 October 2008.

Southern Rivers CMA (2008) Southern Rivers Catchment Management Authority, viewed at http://www.southern.cma.nsw.gov.au/index.html on 14 October 2008.

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Regional State of the Environment Report 2008