Wordnet 3.0
VERB (1)
1. 
 obstruct with, or as if with, a dam; 
- Example: "dam the gorges of the Yangtse River"[syn: dam, dam up]
WordNet (r) 3.0 (2006):
dam up
    v 1: obstruct with, or as if with, a dam; "dam the gorges of the
         Yangtse River" [syn: dam, dam up]