Collapse of residence into river (7)
I believe the answer is:
deflate
'collapse' is the definition.
(I know that deflate is a type of collapse)
'residence into river' is the wordplay.
'residence' becomes 'flat' (I've seen this before).
'into' indicates putting letters inside.
'river' becomes 'Dee' (River Dee).
'flat' put into 'dee' is 'DEFLATE'.
'of' acts as a link.
(Other definitions for deflate that I've seen before include "Let air out of, like balloon" , "Puncture, collapse like balloon" , "Cause to shrink or collapse" , "Take air" , "Release air from" .)