3.4 Data Analyses
The following two statistical indices were used to evaluate the performance of the methods, which can be express as follows:
(9)
(10)
Where NSE is the Nash–Sutcliffe efficiency (Nash and Sutcliffe, 1970; Risse et al., 1994) and RMSE is the root mean square error;andare the ith observed and estimated runoff, respectively; is the mean observed runoff of events and N is the total number of events. higher NSE and lower RMSE values indicate that the model has performed better agreement with the observations.