That does seem odd. Would like to see the photos of the story behind that.
I couldn't provide those - but it's not as if you can be miles away from footpaths in the small forests in my vicinity. The many ditches and small brooks are a dominant feature in the forest closest to where I live - and after the last couple of days, many areas are practically waterlogged. However, while things are unusually wet at the moment, the ditch itself isn't a real problem, nor should navigating that particular area be: It's flat and mostly open with few trees and little undergrow. What's important is that water alone can't have carried the umbrella there - these aren't "streams"; mostly, it's slow running water you can jump across even in the worst of times.
Had the umbrella been bent or broken, I'd've had a theory: It could have been used as a kind of walking stick while crossing the ditch, failed and then left behind. But it's neatly rolled up, seemingly undamaged, looks almost as if it was dropped there on purpose. But it's not as if there was a path nearby - I myself was "ambling idly" ... well, not really - rather, carefully negotiating my way through this part of the woods, doing as little damage and causing as little disturbance as possible and inspecting things closely in order to find images. While there were some animal tracks, I didn't see much by the way of human activity *that'd be conducive to carrying an umbrella* (there is lumbering going on in the area, but ...).
So, all in all, this remains quite strange ... Though I can see one explanation: Sometimes, young people use the forest to hide less-than-desirable activities, and increasingly so in the ongoing situation! The umbrella could have been dropped at night while trying to walk across the area - and literally stumbling and/or falling into the ditch. What with the shock and the pain (the ditch is about one metre deep), the dropped umbrella was clear forgotten, i.e. all they could do was pick *themselves* up. All in all, this seems pretty likely: I've found the refuse of excessive partying more than once ...
Inexperienced people and their encounters with nature: This causes quite a few injuries and even deaths in our parts - usually, it concerns mostly tourists, but currently, there are lots of people who never before felt the urge to walk the woods or be out in nature, but do it now.
In any case, it's really irritating. Whoever dropped the umbrella had probably no business being there *and* no idea on how to behave in the woods (the latter being the core issue).
M.