Sorry for the inconvenience caused by my mistakes. I didn't change the attributes intentionally, no idea how that happened. It wasn't my intention to cause others work - so it's better to undo everything.
I entered the bridge areas because otherwise only the narrow line of the road is visible in the map, but not the entire width of the bridge. If there are also cycle paths on the sides, water can be seen between the cycle path and the road. As a water sports enthusiast, I also find the bridge area very helpful in the map, because some bridges are significantly wider than the crossing road/track, especially with railway bridges that are built for more than the currently available track.
I thought the bridge area plus the "bridge" attribute was redundant, but I now understand that this should remain an important attribute of the road.
I agree with "ditch", in nature it is often difficult to tell whether it is artificial or an actually natural but channeled watercourse.