Possible Clues:

• Battlefield furrow
• Ditch or river full of fish? Quite the contrary
• Long to make such a dugout
• Fish around river-ditch
• Are shortly in something fishy in such a dugout
• Source of raw fish found outside the channel
• A turnover in spades may get along down this
• A ditch dug by soldiers
• Ditch dug by soldiers
• Fish around river and ditch