Pejar Dam

Pejar Dam is not the main water supply for the New South Wales, Australia, inland city of Goulburn,in fact Sooley Dam is the major water supply for the city of goulburn which is released into the water supply via Rossi Weir. [ [http://waterinfo.nsw.gov.au/cgi-bin/wqis.pl?site_id=570000576 NSW Water Quality Data Availability ] ]

The dam was completed in 1980 by the New South Wales Department of Works for the Goulburn City Council to augment the water supply. It can store 9,000 megalitres over 1.55 square kilometres collected from a catchment of 142 square kilometres. The dam wall is 25 metres high.

Water is released from the dam down the Wollondilly River where due to issues of loss the water fails to arrive at Rossi weir, upstream from Goulburn. Water is actually pumped to the city's water treatment works from Rossi Weir which is pumped down from Sooley Dam then and distributed to Goulburn's reticulation system for consumption.

In theory Pejar Dam represents 60% of Goulburns’ water, because that’s its size in proportion to the total storage. In practice Pejar Dam doesn’t perform any were near this level because it isn’t catching and then delivering that amount of water to Goulburn. This is because Pejar Dam has no engineered link to the City and no engineered link to the river.

In March 2006, in the drought, Council released all the remaining water from Pejar (about 900ML or 10% of its storage) when Sooley Dam was full. This was a clear breach of the operating rules. Council figures show that over the period of this release from Pejar, the City experienced the largest amount of water lost from storage on record. About 600ML of water was unaccounted for, or about 4 months supply at that time. This is the equivalent of 70% of what was in Pejar, lost.

It’s also become evident from Councils’ 2007 hydrology studies, that Pejar Dam doesn’t yield as much water as it was originally estimated to yield, particularly in drought years. Pejar Dam was last full in November 2000. Five years later, in May 2006, it was empty. It remained empty until heavy, specific rain in June 2007. Pejar is now about half full.

During this same period Sooley Dam didn’t ever drop below 70% of storage. Sooley obviously has a better yield than Pejar as a result of its catchment location and ability to draw flood water back form the river for storage. In addition Sooley Dams’ pipeline and short water transfer to Goulburn also contributes to its better supply performance.

In May 2005, the council of the city of Goulburn announced that storage had reached a crisis point as dam levels fell to 10% of capacity this was simply not true. Even though there had been no significant rain since December 2004 Sooley Dam had maintained a capacity of 70%. Despite this the council enforced the strictest of water restrictions, and released a political motivated statement that the city was likely to run out of water by early-2006....The last time the dam was full was in November 2000 however as the water released from Pejar Dam cannot due to loss ever supply Sooley Dam the need for a pipeline is required. In November 2005, although the drought has broken in districts surrounding the region, the dam is still 11% full. By April 2006, this level has dropped to 0.1% of capacity. [http://goulburn.local-e.nsw.gov.au/files/3917/File/waterstoragesat10April2006.pdf]

On April 21, 2006 the Pejar Dam was declared officially empty after the local water authority emptied the Dam. [cite news | first=David | last=Braithwaite | author= | url= http://www.smh.com.au/news/national/dam-dries-up-for-first-time-in-25-years/2006/04/21/1145344266879.html | title=Dam dries up for first time in 25 years | work= | publisher=Sydney Morning Herald | pages= | page= | date=21 April 2006 | accessdate=2006-04-21]

References

Pejar pipeline plan - Goulburn Water

http://groups.google.com.au/group/Goulburn-Water/web/pejar-pipeline

External links

* [http://www.abc.net.au/worldtoday/content/2005/s1370499.htm ABC radio program on Goulburn's low dam levels in May 2005]
* [http://www.agric.nsw.gov.au/reader/drt-area New South Wales Department of Agriculture drought maps (viewed 14 November 2005)]
* [http://goulburn.local-e.nsw.gov.au/roads/1439/1858.html Goulburn Mulwaree Council Water update as at early November 2005]