In the current research, we used the Mann-Kendall (MK) test to undertake trend analyses. This test is also known as a distribution-free (non-parametric) test. It is rigorous regarding missing values and is less sensitive to the swift breakpoints [59]. In hydrological or metrological temporal **data** series, it has a universal use since it can detect whether a trend is available in either dataset [60]. Nevertheless, the test is prone to the serial correlation that may influence the results [61]. In the present research, before proceeding to MK to probe the analytical magnitude and significance of the trends in the datasets, the sequential correlation approach was employed for the series.