Evaluation of Hydrologic Models Used to Quantify Major Land‐Use Change Effects

Abstract

An evaluation was made of the capabilities of watershed models when applied in the absence of site calibration data and limited validation data to predict the effects of major land‐use changes upon hydrology. Members of the task committee were surveyed for representative models and asked to assess the accuracy to be expected from each. A total of 28 surface hydrology models were considered and most were judged capable of providing “good” accuracy. The reasons for this confidence were explored and appear to be based upon personal experience, possibly tempered by belief in the model originators. In view of the limited number of model comparison studies conducted and the less than encouraging results often obtained, it appears that when models are applied at sites without hydrologic data, considerable care must be taken if reasonable results are to be expected. In addition, there appears to be little justification for using a model more complicated than necessary under these conditions.