Upper Lachlan
Issue: Catchments
This issue is discussed for these areas: [an error occurred while processing this directive]
For more inofrmation refer to the following Indicators:
Contaminated Sites | Discharge to Waters | Groundwater | Land Degradation | Land Use | Surface Water Quality
How has Catchment Quality Changed?
Upper Lachlan Shire is located on the Southern Tablelands of New South Wales (NSW) in the Lachlan, Hawkesbury-Nepean and Murrumbidgee Catchment Management Authorities. The Shire has an area of approximately 7,089 square kilometers. The Shire has a population of approximately 7,500 and is strongly rural in character. The Upper Lachlan Shire is currently experiencing a moderate shift in its agricultural practices, with the introduction of new farming methods and the diversification of many land holdings toward new ventures such as olive growing, alpaca wool and horse studs.
Insufficient data was available for Upper Lachlan Shire 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 water quality in Upper Lachlan Shire 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 those over 1895 to 1903 and 1938 to 1945. Previous extreme drought years include 1902, 1914, 1938, 1940, 1944, 1967, 1982 and 2002. The 2006–07 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 river 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 the majority of towns within the catchment. 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’?
Wastewater from Crookwell and Gunning is treated at Sewerage Treatment Plants (STP) located in each township. Construction of the Taralga Sewerage Scheme is programmed to commence in 2009. This Scheme will replace poorly performing septic systems with a centralised collection and treatment system, Tertiary treated effluent will be reused for agricultural irrigation. The Scheme is expected to substantially improve water quality in Corroboree Creek, a tributary to the Wollondilly River, and Sydney’s Drinking Water Supply via Warragamba Dam.
Tertiary treated effluent from the Crookwell STP is discharged to a constructed wetland which eventually discharges to the Crookwell River, a tributary of the Lachlan River. Tertiary Treated effluent from the Gunning STP discharges to Meadow Creek, also a Tributary of the Lachlan River, downstream of the Hume Highway. Stormwater infiltration and groundwater inflow is a shortcoming of both the Crookwell and Gunning Sewer Systems, with wastewater flows increasing as much as 7 times following storm events.
The Gunning plant exceeded its daily volume limit on two occasions, during 2004-05, due to heavy rainfall. However, all flows were treated by the plant and no bypass was required.
No land use change was reported for Upper Lachlan over the reporting period. However, it is expected that the rural residential development within the Shire continued to increase. As such, it is expected that the erosion and sedimentation related to this development would also increase.
Extensive areas of severe sheet erosion occurred within the Hawkesbury River catchment at Tarlo River and the Lachlan River catchment at Blakney and Prestons Creek. Minor areas of severe to extreme sheet erosion also occurred within Wollondilly, Abercrombie and Crookwell Rivers.
Dryland salinity occurred throughout Upper Lachlan Shire mainly within the Lachlan River Catchment at Blakney, Jerrawa and Prestons Creeks and Crookwell River.
Lachlan Catchment Management Authority identified some of the key challenges facing catchments in Upper Lachlan Shire as:
- the loss of native vegetation across the catchment and resulting land degradation. This is leading to stream and wetland sedimentation, increasing water turbidity, rising watertables and increased salinity levels in waters.
- rapidly increasing dryland salinity and some irrigation salinity, associated with rising water tables.
- the need for irrigation to remain viable. Irrigation was held to be necessary for agriculture in the river valley and a significant contributor to the catchment's prosperity.
- reduce remaining significant point-source pollution and urban and rural runoff, where this is causing water quality problems – particularly turbidity and increased levels of nutrients (DECC:1, 2008).
Murrumbidgee Catchment Management Authority identified some of the key challenges facing catchments in Upper Lachlan Shire:
- use of 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 water tables, 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 the efficiency of agricultural and urban water uses.
- increase efforts to control exotic plant and animal pests in rivers, particularly carp (DECC:2, 2008).
What has been done to address Catchment Quality?
Upper Lachlan Shire Council also promotes the NSW Government’s Rainwater Tank program to be used by residents to reduce potable water demand. The Shire Council also implemented water restrictions over the reporting period, however these were lifted in Crookwell and Taralga at the end of the current reporting period, due to good rainfall.
The Upper Lachlan Shire Council, in conjunction with the Lachlan Catchment Management Authority, Hawkesbury Nepean Catchment Management Authority and Sydney Catchment Authority, also undertook a number of projects to reduce land degradation over the reporting period.
What does this mean for Council?
The catchment data supplied from the Shire Council and the Department of Water and Energy is lacking for many indicators within Upper Lachlan Shire. This means that only partial assessment of the catchment quality is ever possible.
There is limited Shire Council monitoring of erosion, sedimentation, salinity and ground and surface water quality. Therefore the impacts from urban and rural development and significant natural pressures such as drought cannot be fully determined. The monitoring of the implemented Shire Council strategies and associated actions is also necessary to determine their effectiveness in achieving the desired catchment management outcomes.
The Upper Lachlan Shire Council should undertake the following actions to ensure environmental improvement in the catchment:
- continue to work closely with Lachlan, Hawkesbury Nepean and Murrumbidgee Catchment Management Authorities, to implement joint projects and ensure consistency in approach to land and water management and complementary actions.
- continue to build on the effective relationship with NSW State Government agencies to ensure the collection of up to date information regarding the condition of the catchments and 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 Shire 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:1 (2008) NSW Water Quality and River Flow Objectives: Lachlan River Community Comment on Objectives, Department of Environment and Climate Change viewed at http://www.environment.nsw.gov.au/ieo/Lachlan/report-01.htm on 22 October 2008.
DECC:2 (2008) NSW Water Quality and River Flow Objectives: Murrumbidgee River Community Comment on Objectives, Department of Environment and Climate Change viewed at http://www.environment.nsw.gov.au/ieo/Murrumbidgee/report-01.htm on 22 October 2008.
