The most common and most likely answer to this crossword clue is the 9 letter word BILLABONG
I've seen this crossword clue in The Sunday Telegraph
B
I
L
L
A
B
O
N
G
More clues leading to the result BILLABONG
- Put a water pipe on account for Australian backwater
- . A drug pipe overlooked by police in Aussie backwater
- A backwater in global Britain amazingly
- Illegal delivery over in major Victorian backwater
- Shocking no-ball I belted back across stagnant pool
- Charge for a water pipe by branch of a river in Australia
- Invoice Gabon produced for flooded channel in Oz
- Measure a ring found in pool
Buddy explains!

The straight part
We know that "flooded channel in Oz" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case flooded channel in oz = billabong.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does BILLABONG mean?
BILLABONG noun- A stagnant pool of water.
- A streambed that is only filled with water during the rainy season.
- A channel that dead-ends which extends from the main part of a river.
- An oxbow lake.