Flooding is the bursting of water from over-swollen rivers/lakes or the deliberate release of water trapped underground. The former is a matter of divine whim, extreme weather or elemental interplay and generally not something mortals can influence; the latter is released by digging under the surface of the land (typically with legions) and, in doing so, breaking through to underground caves in which a river is passing or a lake has been trapped. The breaking through has potential to release a pent-up pressure that causes the flood-water to roar through the newly opened access route - filling a succession of adjacent locations, roughly following a downhill path, and potentially causing fatalities on its way to eventually settling or being absorbed back into the landscape.