Choose a cardinal direction from your
water site. Forcefully
move all enemies from your water site one
step in the chosen direction and
flood that
site. Trigger and resolve any effects related to minions entering or the site being
flooded. Then repeat the process until
you reach the edge of the
realm.
The flood and push effect will continue even across a
void, but minions cannot be forcefully moved across regions. Each site will be flooded at the same moment as the minions arrive, so a submerged
minion being evicted will also be submerged on the new site (and
there will never be a moment where it's pushed onto the new site without the new site also being flooded).