Water resources - Overview - New South Wales
Basin & Surface Water Management Area: Sydney Coast - Georges River
Introduction
This is a relatively small basin in the central coast area of New South Wales. It has a catchment area of about 1820 square kilometres and is extensively urbanised and industrialised. The city of Sydney covers most of this catchment.
The relief is generally low with maximum elevation up to only about 440 metres occurring in the extreme south of the Basin. Rainfalls are comparatively moderate, with average annual totals ranging from 1300 mm on the southern rim to 850 mm on the western fringe. The seasonal distribution is relatively uniform, but highest rainfalls occur during the summer months and the lowest during the spring months.
There are two major surface water storages plus a number of weirs all of which are operated by the Metropolitan Water Sewerage and Drainage Board for general distribution in the metropolitan area. The two storages are:
- Woronora Dam, with 72000 megalitres.
- Prospect Reservoir, with 50000 megalitres is the major onroute storage and distribution point in the Sydney's water supply network.
Vital Statistics:
| Area: | 1,820 Km2 |
|---|---|
| Total storage volume: | 53,342 |
| Total surface water use: | 0 ML/yr |
| Development category: | OVER DEVELOPMENT |
| Mean annual run-off: | 770,000 ML/yr |
Please note: No data were supplied about total surface water use for some river basins (eg. unregulated basins in NSW).
A four-class classification system was developed to provide a simple method to communicate the status of the use and allocation of Australia's water resources in relation to sustainable water management.
It is important to recognise that adequately quantifying a sustainable flow regime or sustainable yield and consequent operating rules is a complex matter. State, Territory and scientific agencies continue to develop and apply methods and measures for determining sustainable flow regimes and sustainable yields.
This categorisation provides a general guide only. Please refer to the State and Territory Overview and Technical reports for detail on the analysis methods used.
| Category | Development status | ||
|---|---|---|---|
| 1 | <30% | Low development | |
| 2 | 30 - 70% | Moderate development | |
| 3 | 70 - 100% | Highly developed | |
| 4 | 100% | Overdeveloped |
* Water use as a percentage of sustainable flow regime (surface water) and sustainable yield (groundwater)
PLEASE NOTE:
Sustainable Yield:
NSW is introducing volumetric licenses for the management of unregulated valleys and is currently collecting a wide range of data in unregulated basin.
The sustainable yield concept, ie the amount of water that can be diverted from rivers in perpetuity, is recognised in NSW. However NSW's current management practices views the sustainable yield as an allowable daily extraction volume as opposed to an annual yield figure. As well future reviews of the performance of the management rules to be adopted in each valley plus additional knowledge at that time may result in changes to the rules and hence changes to the "Sustainable Yield".
NSW has taken the approach that it is better to await the availability of data on the unregulated basins based on reliable and realistic analysis than to divert limited resources from this process to provide data based on unreliable information and inappropriate analysis. Accordingly the Sustainable Yield has not been calculated for the unregulated basins in NSW.
However an attempt was made to obtain a categorisation for the catchment based on the work done for the stressed streams.
A variable P was determined for the total catchment on the basis of the combined stress classsification results from the stressed streams analysis where P = (Total area of sub-catchments with high combined stress / Total area of classsified sub- catchments in basin)
Categorisation was on the basis that:
Category 1 applies for 0% <= P < 30% Category 2 applies for 30% <= P < 70% Category 3 applies for 70% <= P <100% Category 4 applies for P = 100%
Please refer to the Stressed Rivers Report(s) from the NSW Department of Land and Water Conservation's website for further information about this basin.
PLEASE NOTE:
Categorisation:
Cateogorisation of the SWMA has been based on the classification system developed for the NSW Stressed Rivers Approach to the management of unregulated streams.
The stressed rivers classification system separates subcatchments into nine categories (stressed and unstressed) based on assessments of both current environmental and hydrologic stress. This is illustrated by the matrix in Figure 1 of the Stressed Rivers Report(s) available from the NSW Department of Land and Water Conservation's website http://www.dlwc.nsw.gov.au . These reports also provides some of the rationale underlying the different categories.
In summary : Category 1 - comprises subcatchments with Low Combined Stress Category 2 - comprises subcatchments with Medium Combined Stress Category 3 - comprises subcatchments with High Combined Stress Category 4 - comprises Unresolved subcatchment
The distribution of categories across the SWMA is illustrated in the Figures in the Stressed Stream Report for the Basin at the NSW Department of Land and Water Conservation's website http://www.dlwc.nsw.gov.au .
How saline are the surface water resources in the Sydney Coast - Georges River surface water management area?
No data were available about the salinity of surface water resources in the Basin / SWMA for the Australian Water Resources Assessment 2000.
Major water storages
Table: Major water storage areas:
| Storage name: | Capacity (ML) |
|---|---|
| Centential Park Res 1 | 81 |
| South Bulli Stormwater | 62 |
| Honeysuckle Creek Dam | 12 |
| Coalcliff | 130 |
| Prospect Reservoir | 50,200 |
| Muirfield Golf Club | 10 |
| Asylum Dam | no data |
| Botany Dams (6) | no data |
| Brennans Creek Dam | no data |
| Bunnerong Dam | no data |
| Lachlan Swamps Dam | no data |
| Lake Toolooma | no data |
| Lane Cove Weir | no data |
| Lords Dam | no data |
| OHares Creek Weir | no data |
| Manly Dam | 2,000 |
| Stokes Creek Weir | no data |
| Stringybark Creek Dam | no data |
| Testers Weir | no data |
| Wedderburn Weir | no data |
| Lake Parramatta | 590 |
| Liverpool Weir | 168 |
| Centential Park Res 2 | 89 |
| Total | 53,342 |
Further Information
- View the New South Wales Water Resources Assessment 2000 Report
- View the New South Wales Water Resources Assessment 2000 Technical Report
- Link to data available for download on the:
- Surface Water Management Areas
- Data from the 1985 Review of Australia's Water Resources and Water Use
- Link to the Map Maker to make a map using this information.
- For more information about water and other natural resource issues link to www.dlwc.nsw.gov.au.
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