Groundwater Management Unit
Groundwater Management Unit: Unincorporated Area - Lachlan
Introduction
The groundwater resource characteristics for the Unincorporated Area - Lachlan groundwater managment unit are presented below. This includes technical detail on aquifer properties and water level change for key monitoring bores.
What is the character of Unincorporated Area - Lachlan's groundwater resource?
Vital Statistics:
| Area | 86,500 km2 |
|---|---|
| Total Water Allocated | 23,140 ML/yr |
| Total Water Used | 15,950 ML/yr |
| Average Salinity | 11,400 mg/L |
| Sustainable Yield | 440,400 ML/yr |
| Depth to top of aquifer | 5 m |
Aquifer Description:
The major aquifers include alluvium (within major river valleys), basalts and bedrock consisting of fractured siltstone and sandstones. Minor aquifers include sandstones, siltstones, claystones and slates and granites and granodiorites.The aquifer systems are generally unconfined and occassionally semi- confined.
Method used for determining sustainable yield:
The sustainable yield is 440,000ML/year. This has been based on the 5% of the rainfall. The value does not take into account river recharge/discharge which is considered to be relatively insignificant.
Assumptions used for allocating development categories:
The allocations for the UA is 23,000 ML/yr or 0.5% of the sustainable yield. This indicates that this UA has a low level of development, and is a category 1 UA.
Are groundwater levels changing?
Technical information on the key groundwater bores and monitoring stations is presented below, including hydrographs where available. Link to a discussion on groundwater levels and trends at a State level as it relates to dryland salinity.
| Bore ID | Start record | End record | Depth of bore (m) | Reduced level (m) |
|---|---|---|---|---|
| VIC51213 | 20-Jul-78 | 15-Nov-99 | 76 | 212 |
| VIC55208 | 10-Oct-89 | 15-Nov-99 | 41 | 153 |
| VIC98414 | 31-Aug-77 | 22-Dec-99 | 31 | 193 |
The following groundwater management units also occur in Lachlan Province:
- Alexandra (VIC)
- Araluen Alluvium and Weathered Granite (NSW)
- Ascot (VIC)
- Bell Valley Alluvium (NSW)
- Belubula River Alluvium (NSW)
- Billabong Creek Alluvium (NSW)
- Bullarook (VIC)
- Bungaree (VIC)
- Cudgegong Valley Alluvium (NSW)
- Glengower (VIC)
- King Lake (VIC)
- Lancefield (VIC)
- Lower Macquarie Alluvium (NSW)
- Mid Murrumbidgee Alluvium (NSW)
- Mid and Upper Murrumbidgee Catchment Fractured (NSW)
- Molong Limestone (NSW)
- Moolort (VIC)
- Mudgee Limestone (NSW)
- Murrumbidgee (ACT)
- Namadgi (ACT)
- Orange Basalt (NSW)
- Queanbeyan and Molonglo (ACT)
- Spring Hill Groundwater Supply Protection Area (VIC)
- Tourello (VIC)
- Unincorporated Area - Lachlan Fold Belt Province (NSW)
- Upper Lachlan Alluvium (NSW)
- Upper Macquarie Alluvium (NSW)
- Wandin Yallock (VIC)
- Young Granite (NSW)
Further information
- Victoria Water Resources Assessment 2000 Report
- Victoria Water Resources Assessment 2000 Technical Report
- For more information about water and other natural resource issues link to www.dse.vic.gov.au .
- Link to data available for download on the Groundwater management units and provinces - ARC/INFO export
- Link to Map maker to make a map using this information.
Key
Links to an another web site
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