River with a bore? (4)

I believe the answer is:

ebro

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

'river' is the definition.
(I know that Ebro is a river)

'a bore?' is the wordplay.
'bore' can be anagrammed to 'EBRO'.
However, I'm unsure how this is indicated.

'with' is the link.

Can you help me to learn more?

(Other definitions for ebro that I've seen before include "Spanish river" , "River of northeast Spain" , "flower" , "European river" , "Longest river in Spain" .)

I've seen this clue in the Evening Standard.

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