From Longman Dictionary of Contemporary Englishdredge something ↔ up phrasal verb1 DISCUSSto start talking again about something that happened a long time ago, especially something unpleasant Newsweek magazine dredged up some remarks which he made last year.2 to manage to remember something, or to feel or express an emotion, with difficulty Robertson tried to dredge up an image of her in his mind. From somewhere she dredged up a brilliant smile.3 TTWGETto pull something up from the bottom of a river, lake etc → dredge→ See Verb table
Examples from the Corpus
dredge up• As Izzie dredged it up again, her growing hair flopped forward over her face and hid what she was thinking.• I can't imagine what would prompt this woman to dredge it all up if there wasn't some truth in it.• The move follows reports that a new mechanised suction dredge is breaking up river banks, blocking rivers and killing fish. 