Depending on the rate and magnitude of climate change, the increasing rainfall may seriously affect society. For instance, the normal conveyance of rainwater to rivers or brooks will change. Higher precipitation intensity leads to faster saturation of the soils, and increases in runoff volumes. In combination with a decrease of the buffering capacities (channelisation due to deforestation, urbanisation, draining wetlands, etc.), higher peak water levels can be expected, with an increase in the frequency of flooding events.
Water-related disasters, i.e. floods and droughts, are known to cause devastating death tolls, suffering and economic damages. Due to these implications, the topic of extreme hydrological events has drawn increasing attention in the literature. Compare, for example, the coverage in the IPCC report of 1990 with that of its supplement (1992), and with the agenda of the forthcoming IPCC 1995 report. The purpose of the present literature review is to reveal state-of-the-art knowledge on whether and how extreme events in precipitation will affect river regimes and flooding frequencies. An extreme weather event can be defined as an event sufficiently anomalous, in comparison with the mean weather, to cause substantial socio-economic damage (Tol et al., 1994). Clearly, the impact of a rainfall event depends on its characteristics (such as geographical pattern, total amount, duration, intensity, etc.) in relation to the responding ability of the area (location, size, soil type etc.) affected.
In the following, a review of recent literature in relation to possible changes in flooding patterns is given. After an introduction of the characteristics of the climate models, predictions on (extreme) rainfall are compared with meteorological observations (global and regional scale), and investigated for their implications on flooding behaviour. The review starts with a concise discussion of the origins of flooding, and of the mechanisms leading to rainfall and possible changes therein.
