Day 27, Swan Hill to Sydney

Today, we headed north to survey the wetlands of the Lachlan River which flows into the Murrumbidgee River in really wet years. This year was pretty dry.

There are two parts to the extensive lower wetlands on the Lachlan River: the wetlands of the main Lachlan River, down to the Great Cumbung Swamp and the Booligal Creek wetlands to the west of the Lachlan River.

We came in from the west to the Great Cumbung Swamp. The big lakes to the west were dry. 

The Great Cumbung Swamp is one of the Murray-Darling Basin’s more important wetlands and particularly important for the Lachlan River. There was some flooding in river red gum forests, south of the reed beds, with quite a few herons, ducks, egrets and spoonbills, feeding along the channels.

Video: Surveying the channels through the redgum forest south of the reedbeds on the Great Cumbung Swamp

We then moved on to surveying the reedbed area, south of the main channel of the Great Cumbung Swamp. There were a few of its channels with water, with hundreds of egrets, spoonbills and herons and only a few Black Duck and Grey Teal. 

Video: Flooded areas of the Great Cumbung Swamp, south of the main channel.   

We then flew up the main channel of the Cumbung Swamp, where there were only a few Pelican and cormorant flocks, as well as a few small flocks of Black Duck and Grey Teal. 

From the Cumbung, we flew north, flying over the mostly dry swamps and lakes along the Lachlan River, including Peppermint Swamp and then on to the Booligal Creek system which includes the distributaries Merrimajeel and Muggabah Creeks. 

We then flew down the Merrowie Creek system, where there was a small amount of water confined to the main channel, with a little more in Cuba Dam. There were only a few waterbirds, mostly Wood Ducks and Black Duck. 

From here, we went to Lake Brewster. This is a great place for waterbirds when it is full but, at only 14% capacity, the lake was drying back fast.

The lake covered about 60-70% of its full surface area, with hundreds of Grey Teal, some Black Duck, Black Swans and the different cormorant species. Pelicans were there in big numbers. This is a key place for their breeding but unlikely to happen this year, given the dropping water levels. 

From here, we went to Lake Cargelligo, which is regulated, making it permanent. There were the usual small numbers of cormorants and Pelicans.

The lake was drying back, probably only about 70% of the lakebed covered by water. When it is drying, it has tens of thousands of waterbirds on the shallow water. Today was no different, there were more than five thousand waterbirds with about 80-90% of Grey Teal. There were also hundreds of Pied Stilts, Pelicans, cormorants, Black Duck and Australian Shelduck. There were no breeding rookeries, dependable in big floods. The lake is on its way to drying completely by next year, unless we have more flooding.  

The diversity and number of waterbirds reflect the importance of this wetland. It continues to be threatened by gold mining, which is taking over more of the footprint of the lake. It is unfortunate that one of our more important lakes continues to be threatened by this development, through the removal of lake habitat.