TOPMODEL - A CRITIQUE

TOPMODEL (a TOPography based hydrological MODEL) is now 20 years old a nd has been the subject of numerous applications to a wide variety of catchments. This paper represents a critical review of some of the iss ues involved in application of the TOPMODEL concepts, including the ba sic assumptions involved; the derivation of topographic index distribu tions from digital terrain data; additional model components; meaning and calibration of the model parameters; and issues involved in model validation and predictive uncertainty. The aim is to provoke a thought ful approach to hydrological modelling and the interaction of modellin g and field work. Some recommendations are made for future modelling p ractice. (C) 1997 by John Wiley & Sons, Ltd.