Ferdy jumping out of the lake
When 'the council' (presumably) beat down all the bracken that was covering the Sporting Club's land they piled up quite a bit of detritus in a heap on the side of the hill. Bits of car, vegetation, rocks. Note the greek chorus in the dead branches.
This (empty) keg is a recent addition. Ferdy was very apprehensive of it. Note his body language.
To quote Jimmy Webb/Richard Harris, someone left an umbrella stuck in the ground.