The most common and most likely answer to this crossword clue is the 6 letter word EUREKA
I've seen this crossword clue in The Guardian
E
U
R
E
K
A
More clues leading to the result EUREKA
- Mistake rued, partly retracted in bingo?
- Potassium in European waste material: I found it
- Exultant cry on entering English country area?
- ‘Aha!‘, said solver, ‘A stinker!’
- I found it in Greece
- The thinking bather’s ejaculation
- I’ve found it in a Greek dictionary
- Call for displacement of ancient Greek
- Triumphant exclamation some mistake, ruefully served up
- Shout about headless fish and medicinal plant in county seat in 23
Buddy explains!
The straight part
We know that "legendary response to rising water level" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case legendary response to rising water level = eureka.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 EUREKA mean?
EUREKA noun- An alloy of copper and nickel whose resistivity is constant over a wide temperature range
- An exclamation indicating sudden discovery.