Passing water leaders swap places causing devastation (9)

I believe the answer is:

ruination

I'm a little stuck... Click here to teach me more about this clue!

'devastation' is the definition.
(I know that ruination is a type of devastation)

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for ruination that I've seen before include "Complete destruction or collapse" , "Crippling defeat" , "bankruptcy" , "State of loss" , "Utter destruction" .)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.