Lake and river rose catastrophically (9)
I believe the answer is:
reservoir
'lake' is the definition.
(reservoir is a kind of lake)
'river rose catastrophically' is the wordplay.
'catastrophically' is an anagram indicator.
'river'+'rose'='riverrose'
'riverrose' is an anagram of 'RESERVOIR'.
'and' acts as a link.
(Other definitions for reservoir that I've seen before include "Store for water etc" , "Man-made lake of stored water" , "water over a wide area?" , "Area for storage, of water say" , "River rose (anag.)" .)