I think this might have been handled better by the TD. An interesting concept here would be to play it as a buncr and specify a drop zone maybe 1/2 to 2/3 of the way down the fairway just to the left side of the tree line. If the player shanked into the ditch, they would get free relief to the drop zone. Faster speed of play and a pretty fair for most shanks but still most likely a distance penalty.
I'm not sure the TD was thinking about the ditch when he made the rule of all water is casual. 90%+ of the time the ditch is dry. I think the TD was making the rule for all standing water on fairways and around the baskets and forgot to include or exclude the "normal" water hazards that are sometimes there. It's a good lesson to learn. Thanks Chuck.