The Key Question is based on an understanding of the hydrological processesoperating in the drainage basin. Students should obtain knowledge of thehydrological processes within the drainage basin and an understanding of how their linkage enables water to pass through the basin. This may be achieved through a systems analysis of inputs, stores, flows and outputs. Factors that influence the passage of water through the drainage basin should be studied within the context of human and physical aspects. Human factors such as urbanisation, agricultural practices, water resource and land use management will have an impact on the amount and speed of water passage through the basin. Physical factors will also have an impact and the investigation of influences such as precipitation, temperature, soil, geology, vegetation, slope and basin shape will enhance students understanding. The factor should be linked to their influence on the characteristics of flood hydrographs and regimes. It is not expected that candidates will have an exhaustive knowledge of hydrographs and regime; flashy and steady hydrographs plus the temperate deciduous river regime may form the basis of learning.

The heart of this Key Question lies in the acquisition of knowledge and understanding to compare the causes and consequences of flooding between and/or within drainage basins. Students should understand that floods are the result of physical and human factors and that the importance of each set of factors varies between and/or within drainage basins. It is not possible to cover all theoretical elements within the time allowed for this level so examples should be chosen to give a variety of human and physical causes that allows students to develop comparisons. The consequences of flooding should be investigated so that physical impacts are observed; such as those on landform and ecology. Human impacts are identified as demographic, economic and social. The Key Question does not demand a comparison of the impacts of flooding although this is often a more complete approach when analysing flood events.

Students should consider the concept that different groups within a drainage basin perceive floods in various ways. Some perceptions may be positive whilst many will be negative. There will also be different perceptions according to the location within the basin, economic impacts, the needs of the group to respond to the flood, political impacts etc. The actual content of learning will vary greatly according to exemplar material taken or investigation pursued. Learning should cover strategies such as technological developments, prediction, prevention, preparation, adaptation and land use planning. The strategies used to manage the flood hazard will depend upon the examples studied and it is not expected that there will be an exhaustive cover of content. It is important that students are given the opportunity to consider their effectiveness in managing the hazard including the roles of political organizations such as the Department of the Environment, Local Authorities and the water companies. The principles learned here are a useful introduction for G3 Theme 3.