Watergate clues I cracked (6)
I believe the answer is:
sluice
'watergate' is the definition.
(I've seen this before)
'clues i cracked' is the wordplay.
'cracked' is an anagram indicator.
'clues'+'i'='cluesi'
'cluesi' is an anagram of 'SLUICE'.
(Other definitions for sluice that I've seen before include "Water-controlling gate" , "Flush" , "Drain channel; quick wash" , "Drench copiously" , "Sliding gate for controlling flow of water in stream" .)