The most common and most likely answer to this crossword clue is the 9 letter word RIVERBANK
I've seen this crossword clue in The Daily Telegraph
R
I
V
E
R
B
A
N
K
More clues leading to the result RIVERBANK
Buddy explains!
The straight part
We know that "waterside area" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case waterside area = riverbank.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 RIVERBANK mean?
RIVERBANK noun- A sloped side of a river acting as a barrier between the water and level ground to either side.