Impacts of trends and uncertainties in river flooding due to climate change

Projected climate changes will have an effect on frequencies and duration of river flooding and therefore on design criteria for dikes or on risk assessment. In addition to existing sources of uncertainty, extremes and variability of climatological input will change. To deal with this problem the purpose of this project can be split into two main parts. First, to identify possible effects of climate changes on extreme discharges of rivers and particularly the uncertainty involved. Second, to determine the appropriate level of modelling needed to predict such effects taking into account the uncertainties. The major subsystems are climate, catchment and river. Important aspects are the additional uncertainty introduced by each subsystem and the appropriate level of modelling a subsystem. In this paper some preliminary excersises to address these questions with respect to catchment and river are shown, based on very schematic models not representing any particular catchment.