Brine causing wet areas to be redeveloped (8)
I believe the answer is:
seawater
'brine' is the definition.
('seawater' can be a synonym of 'brine')
'wet areas to be redeveloped' is the wordplay.
'to be redeveloped' is an anagram indicator.
'wet'+'areas'='wetareas'
'wetareas' is an anagram of 'SEAWATER'.
'causing' acts as a link.
(Other definitions for seawater that I've seen before include "Drink" , "What breaches dyke, perhaps" , "Brine" .)