Developing indicators to detect changes in the seasonality, frequency and duration of medium and high river flows

Indicators specifically designed to detect changes in the seasonality, frequency and duration of medium and high river flows have been developed to monitor river flow regimes. Four primary methods to display and interpret the indicator results have been developed to meet the needs of different target audiences. The variability in annual indicator values is accommodated by comparing the probability distributions of the annual values rather than seeking to identify trends in annual values themselves. Changes in the distribution of indicator values are consistent with those anticipated to arise as a result of climate change. This finding is confirmed by calculating the indicators from example flow data for catchments across England and Wales, which has been perturbed to reflect climate change scenario model outputs.