Reed, D.W., Johnson, P., Firth, J.M. 1975. A non-linear rainfall/runoff model providing for variable lag time. J. Hydrol., 25 295–305.
The cascading reservoir analogue of the rainfall-runoff process is extended, by the introduction of an additional parameter, to permit application to catchments exhibiting variable lag times. A semi-empirical relationship between lag time and storage is incorporated, and the total-runoff hydrograph provided for.
The resulting non-linear model leads to improved representation of the observed events against which it has been assessed.