Palerang
Issue: Catchments
This issue is discussed for these areas: [an error occurred while processing this directive]
For more information refer to the following Indicators:
Contaminated Sites | Discharge to Waters | Groundwater | Land Degradation | Land Use | Surface Water Quality
How has catchment quality changed?
Palerang Council is located in both the Murrumbidgee and Southern Rivers Catchment Management Authority areas. The Council has an area of 5,144 square kilometres and a population of approximately 13,000. Palerang is a rural shire with principal industries being beef and sheep production, stone fruit orchards and vineyards, and sand mining to supply the construction industry in nearby Canberra.
Insufficient data was available for Palerang to assess changes to, or impacts on, many aspects of catchment quality over the current reporting period. As a result, changes in erosion and groundwater quality are not reported.
Drought was a significant event impacting on catchment quality in Palerang over the current reporting period. The drought dates back to around 1997 and is as serious if not worse than other major prolonged droughts such as 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.
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 2007–08 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 or excessive water extraction causes water bodies to dry out, water quality conditions deteriorate and the fish within them may die or be eaten by birds. This scenario is unlikely for the main river channels, but is likely for many of the smaller creeks and tributaries. Indeed, many of the smaller creeks have already dried back to a series of disconnected pools.
Algal blooms are also more frequent during drought conditions due to low, slow flows. Most towns however have sufficient treatment facilities and treat all sewage before discharging to water and, where possible, manipulate flows to break up algal blooms.
During the drought, salinity levels are generally relatively low. This is due to little or no inflows from higher salinity tributaries and no return flows. Groundwater leakages from saline floodplains are generally also lower. However, if dilution flows continue to reduce, river salinity levels increase.
With little water available for irrigation, there is the 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 that were 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 water restrictions are currently in force in all three towns within Palerang that have a reticulated water supply. These 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 sewage treatment plants in Palerang discharge effluent to Millpost Creek, Molonglo River and Flood Creek. The Braidwood sewage treatment plant has an upward trend of Nitrogen concentrations, and Phosphorus concentrations to lesser degree. This may be caused by the limited capability of the existing sewage treatment plant which is scheduled to be replaced.
The Braidwood facility typically exceeds the maximum daily discharge volume on about 20 times each year due to moderate or significant rainfall events..
The Captains Flat sewage treatment plant also exceeded the volume limit on five occasions during 2005-06 and 19 days in 2006-07. No non-compliance reports were submitted for the Bungendore sewage treatment plant.
Scattered areas of extreme gully erosion occurred throughout all catchments within the council area.
The main landuse change during the reporting period was a relatively small decrease in agriculture, bushland and timber production, and an increase in conservation area. Urban development continued, particularly in Bungendore , however erosion and sedimentation was well managed. Other development included the conversion of some agricultural land from rural to rural-residential blocks, occasionally causing some localised impacts..
Murrumbidgee Catchment Management Authority identify some of the key challenges facing catchments in the Palerang Council area as:
- Use local knowledge and enthusiasm for social, environmental and economic sustainability, including continuing land care and improving water management.
- Continue scientific research, monitoring and reporting on river issues.
- Reverse the loss of native trees and other perennial vegetation across parts of the catchment that is leading to stream and wetland sedimentation, increased water turbidity, rising watertables, increased salinity levels in waters, and urban salinity.
- Reduce the causes of unnatural rates of river erosion and manage riparian zones to protect remaining native vegetation.
- Reduce remaining significant point-source pollution (e.g. sewage treatment plants, unsewered villages).
- Further reduce pollution of stormwater runoff from both urban and rural lands, and contamination of surface or groundwater with pesticides or other chemicals.
- Enable continuing improvements in efficiency of agricultural and urban water uses.
- Increase efforts to control exotic plant and animal pests in rivers, particularly carp (DECC, 2008).
Southern Rivers Catchment Management Authority identify some of the key challenges facing catchments in the Palerang Council area as:
- 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).
What has been done to address Catchment Quality?
Palerang Council encourages the NSW governments Rainwater Tank program to be used by residents to reduce potable water demand. Council also introduced an additional rainwater tank subsidy and broader WaterWise program, along with water restrictions, to reduce water use within the three villages that have a reticulated water supply.
Palerang Council has undertaken a Draft Development Servicing Plan for Braidwood Sewage Treatment Plant in accordance with the Developer Charges Guidelines for Water Supply, Sewerage and Stormwater (2002), which outlines the sewerage developer charges to be levied on development areas utilising a water utility's sewerage infrastructure. The Plan notes that it is proposed to replace the existing treatment plant in Braidwood because the quality of effluent does not meet the standard required by Department of Environment and Climate Change. It is also noted that the effluent from the new treatment plant will be of a quality suitable for reuse for irrigation, including potentially for the Braidwood golf course.
Over the reporting period, Council also adopted a number of Development Control Plans that establish detailed controls to guide the development in the Shire and as a supplement to the Local Environment Plan.
What does this mean for Council?
The catchment data available from Council and the Department of Water and Energy is lacking for many indicators within Palerang. This means that only partial assessment of the catchment quality is possible.
There is limited Council monitoring of erosion, sedimentation, salinity and ground and surface water quality. Therefore impacts from urban and rural development and significant natural pressures such as drought cannot be fully determined. The monitoring of the implemented Council strategies and associated actions is also necessary to determine their effectiveness in achieving the desired catchment management outcomes.
Palerang Council should undertake the following actions to ensure environmental improvement in the catchment:
- Continue to work closely with Murrumbidgee and Southern Rivers Catchment Management Authorities, to implement joint projects and ensure consistency in approach to land and water management and complementary actions.
- Continue and build on the effective relationship with 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: Murrumbidgee River Community Comment on Objectives, Department of Environment and Climate Change, http://www.environment.nsw.gov.au/ieo/Murrumbidgee/report-01.htm.
Southern Rivers CMA (2008) Southern Rivers Catchment Management Authority, http://www.southern.cma.nsw.gov.au/index.html.
