Resumen
It is often reported that simpler models, due to their low parameter requirements, perform better than more complex models. To test this, the current study compared a simple rainfall-runoff model (IHACRES) with a complex watershed model (SWAT). Based on these two approaches, six models were developed for three climatically distinct (arid, semi-arid and semi-humid) watersheds in Iran. The coefficient of determination (R2) and the Nash-Sutcliffe model efficiency coefficient (NS) were calculated in each case. In arid, semi-arid, and semi-humid watersheds the SWAT model (R2 = 0.52, 0.68, 0.66; NS = 0.54, 0.63, 0.64, respectively) outperformed the IHACRES model (R2 = 0.37, 0.70, 0.57; NS = 0.22, 0.57, 0.56, respectively) for the same respective climate zones. Overall, SWAT performed better than IHACRES, although both models had acceptable performances in the semi-arid and semi-humid watersheds. In the arid watershed, the IHACRES model performed poorly compared to SWAT.