See Administration in the contextual statement for legal instruments for environmental flow provisions and environmental flow release arrangements in the rivers.
The Sydney Catchment Authority and Delta Electricity managed environmental flow releases in the rivers for which they are responsible as specified in their respective water management licences. The following table provides details of volumes released, categorised as purely environmental flows during 2009–10.
Breakdown of water releases as environmental flows during 2009–10 in the Sydney Region
Managing authority |
Storage reservoir/weir | Streams benefiting from environmental flow release | Environmental flow release during 2009–10 (ML) | Volume from the release reaching sea |
|---|---|---|---|---|
| Delta Electricity | Lake Lyell | Coxs River up to Lake Burragorang (Warragamba Dam) | 1,963 | 0* |
| Sydney Catchment Authority | Cataract | Cataract River up to Broughtons Pass Weir | 475 | |
| Cordeaux | Cordeaux River up to its confluence with the Avon River, and the Avon and Nepean rivers below that up to Pheasants Nest Weir | 693 | ||
| Avon | Avon River up to its confluence with the Nepean River, and the Nepean River below that up to Pheasants Nest Weir | 6,995 | ||
| Nepean | Nepean River up to Pheasants Nest Weir | 1,606 | ||
| Wingecarribee | Wingecarribee River up to Lake Burragorang (Warragamba Dam) | 1,095 | ||
| Lake Burragorang (Warragamba Dam) | Warragamba, Nepean and Hawkesbury rivers downstream of Lake Burragorang (Warragamba Dam) up to the sea | 12,154 | 12,154 | |
| Pheasants Nest Weir | Nepean and Hawkesbury rivers downstream of the weir up to the sea | 7,835 | 7,835 | |
| Broughtons Pass Weir | Cataract, Nepean and Hawkesbury rivers downstream of the weir up to the sea | 588 | 588 | |
| Woronora | Woronora River up to its confluence with the Georges River, and the Georges River below that up to the sea | 6,078 | 6,078 | |
| Fitzroy Falls | Yarrunga Creek up to Lake Yarrunga (Tallowa Dam) | 3,665 | 0* | |
| Lake Yarrunga (Tallowa Dam) | Shoalhaven River downstream of Lake Yarrunga (Tallowa Dam) up to the sea | 55,727 | 55,727 | |
| Total | 82,382 | |||
| * Releases from relevant reservoirs contributed to environmental flows from downstream reservoirs/weirs. Releases from these downstream reservoirs/weirs have been accounted separately in the table. |
The environmental flow release from Woronora Reservoir includes 2,450 ML released from the banked environmental flow (see Line item 8.1.9.7 Allocation on regulated flows remaining). Line item 14.2 includes quantification information for all the other volumes provided in the above table.
The above table provides details of volumes released to meet environmental flow obligations specified in water management licences issued to water utilities. In addition to these obligatory flows, the following releases were made to rivers in the Sydney Region during 2009–10:
The Sydney Catchment Authority and Delta Electricity must monitor and assess the effectiveness of environmental flow releases detailed in their water management licences. The NSW Office of Water, on behalf of the Water Administration Ministerial Corporation, oversees management authority compliance with environmental flow provisions.
Both the Sydney Catchment Authority and Delta Electricity report that they satisfied all necessary compliance requirements associated with environmental flow management for 2009–10.