The great imperial pond seems like an enormous extravagance by the emperor in a floating palace with no natural water sources of its own other than rain or at least so it would appear for the lake is filled annually during the 'dip' when the floating island is lowered by the Order of the Silent Chanters into lake until the palace is submerged several meters in water before being lifted back up and the excess drained away. Great aquatic creatures are kept in the lake by the emperor and it is no place to tread without being accompanied by a whisperer talented in the Beast Murmurs.