In many ways Bart Brassica is a model farmer, but in others, particularly his laissez-faire attitude to bodies of water, as has been put to him in various subpoenas, he tends towards the criminally negligent and is liable to come unstuck. In this case you might notice the blurring around his pitchfork is due not so much to drowning but to waving to attract attention. As we've seen before Bart is, for all purposes, undrownable but can neither swim nor float. Here he  has fallen in while attempting to scoop out a batch of his oversized Prawns from the Old School Baths he had installed to take advantage of the recent flood. This interlude, where Bart waits for someone to come and haul him out, gives him time for more complex ponderings.