What causes flooding?Riverine flooding occurs in relatively low-lying areas adjacent to streams and rivers. In the flat inland regions of Australia, floods may spread thousands of square kilometres and last several weeks, with flood warnings sometimes issued months in advance. In the mountain and coastal regions of Australia flooding can occur rapidly and warning times are short, perhaps only a few hours.
Flash floods can occur almost anywhere where there is a relatively short intense burst of rainfall such as during a thunderstorm. During these events the capacity of the drainage system has insufficient time to cope with the downpour. Although flash floods are generally localized, they pose a significant threat to the loss of human life because of their unpredictability and the short duration of an event.
Floodplains in many catchments have been extensively encroached upon, thereby increasing the number of buildings vulnerable to flooding. In addition, the construction of new buildings on the floodplain in one location can increase flood levels at another location by increasing the amount of runoff from the floodplain.
Simply because an area has not been flooded in the past does not necessarily exclude the possibility of the area being flooded in the future.
there are some pictures of some flooded towns and the effects it can makeWhat is a flood?A simple definition of flooding is water where it is not wanted (Chapman 1994). Flooding occurs most commonly from heavy rainfall when natural watercourses do not have the capacity to convey the excess water.
Floods however do not necessarily need to be caused by heavy rainfall. In coastal areas, inundation may occur because of a storm surge, tsunami, or a high tide coinciding with higher than normal river levels. Storm surges are most commonly caused by tropical cyclones. Tsunamis are triggered...