As verbs the difference between ditch and swale. is that ditch is or ditch can be to discard or abandon while swale is (melt and waste away, or singe). As nouns the difference between ditch and swale. is that ditch is or ditch can be a trench; a long, shallow indentation, as for irrigation or drainage while swale is a low tract of moist or marshy land or swale can be (uk|dialect) a gutter in a candle.