A study into the low-flow characteristics of British rivers

This paper describes investigations currently being undertaken at the Institute of Hydrology into methods for predicting low flows from catchment characteristics. Different sources of errors in flow data are described which are all taken into account when selecting suitable flow records for analysis. A number of analytical techniques which incorporate both the magnitude and duration of low flows are described and some of their areas of application given. Preliminary results highlight the need for careful screening of the data, the significance of mean annual rainfall and the need for a geology index. Catchment characteristics used in the study are then outlined together with their effect on low flows. The paper is concluded by a discussion of the regression analyses to be used in developing formulae for predicting the low flow indices from catchment and climate characteristics.