ABSTRACT
A flood can be defined as the inundation of a normally dry area caused by an increased water level in a watercourse or in a body of water. Broadly, flooding can be classified as river flooding, coastal flooding and urban flooding. This study is limited to the floods in rivers, which can be characterised by the sudden or gradual increase in water levels, normally beyond the bank level of the river watercourse and subsequently inundating its surroundings. From the nature of its occurrence, floods in rivers can be further distinguished as flash flooding and simply river flooding. Flash flooding is characterised by a sudden and massive increase of water quantity (e.g. , caused by short intense bursts of rainfall, commonly from thunderstorms) often combined with mud or debris flows, leaving endangered communities only limited time to respond. River flooding, on the other hand, is marked by relatively slowly rising water levels of main rivers and a gradual inundation of floodplains due to generally continuous long duration rainfall. The former imposes a different and indeed more daunting challenge to the alertness of flood prone communities, whereas the larger scope and longer duration of the latter constitutes a major challenge to the scale and endurance of disaster management arrangements (Rosenthal et aI. , 1 998) . Various definitions of a flood and a comprehensive description of different types of flooding are presented by Ward ( 1 978).
