>>64461753
Trebuchets and cannons were laid down and operated by trained professionals. So if one can afford to field them, the operation is included.
>The cannon would need to be within rifle range to hit the castle.
And? What are trenches, gabbions, sandbacks etc.?
>Rivers naturally drain while lakes that drain quickly don't stay lakes.
Rivers also have a stronger current than lakes and you don't need to drain and fill in the whole lake.
And ultimately - it is the mcmansion of some polish richfag so it won't stand up to any kind of organised siege.