Wonderland Billabong #1, Victoria, Australia

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A billabong (/ˈbɪləbɒŋ/ BIL-ə-bong) is a small body of water, usually permanent. It is most likely derived from the Wiradjuri language of southern New South Wales, which "describes a pond or pool of water that is left behind when a river alters course or after floodwaters recede". It is often an oxbow lake caused by a change in course of a river or creek, but other types of small lakes, ponds or waterholes are also called billabongs.

In this case it is a terrace in the course of Stony Creek, the bottom of which is lower than the water outlet seen in the lower left of the photograph. The depression retains water even when no water flows through Stony Creek. When Stony Creek is flowing strongly a waterfall deep inside a narrow stone channel beyond the right side of the photograph supplies water, and the small cascade and stones in the lower half of this photograph are covered with flowing water.