Link to the ditch = https://www.openstreetmap.org/way/977158185
Link to the stream = https://www.openstreetmap.org/way/506949983

According to me, the ditch should not have a name except if people around (or an official map of this area) give to it a name. I suspect an error from the creator of the first way. I have no official source for this ditch, do you have ?