Identification and separation of major base flow components from a stream hydrograph

A method is given for the separation of the major base flow components in a river hydrograph using simple models. Simplifying assumptions are made which enable the models to be used without rainfall data if necessary, suitable information being deduced from the river hydrograph. Lumped parameter hydrological models are used for the calculations of actual transpiration, soil moisture deficit, and aquifer recharge rates. The base flow components are each identified in terms of a recession time constant, an initial value, and an infiltration contribution. The techniques are applied to the River Severn, for which flow components are separated and then used to illustrate applications to a study of the behavior of conservative water quality determinants.