A revised approach to the UKIH method for the calculation of baseflow

A revised approach to the calculation of baseflow using the method originally proposed by the United Kingdom Institute of Hydrology is presented. The revisions resolve two aspects of the method that lead to less than optimal results; that is, the calculation of values of baseflow that exceed the corresponding values of strearnflow and the dependence of the calculated values on the origin of the five-day segmentation of the input streamflow data. The approach is illustrated using strearnflow monitoring information that is typical for areas of southern Ontario, Canada, where baseflow is primarily the result of groundwater discharge.