Abstract:

In this study, interannual change in riverflows of Porsuk Creek Basin was revealed by using long-term minimum, maximum and mean riverflow data of stations located within the basin. Statistical methods were applied to hydroclimatological data which are grouped as (1) data completion , (2) data control, (3) trend analysis and (4) correlation analyses. By adopting this multiple-method use, it is aimed to increase reiability of results and also reveal several varability components (inhomogeneity, persistence, periodicity, trend) in the time series. Significant decreasing trends were detected in riverflow data (both in mean, minimum and maximum series) for the 42 years period between 1970 and 2011. These significant decreasing trends were observed at 56.7% of mean riverflows, 48.3% of minimum riverflow and 65% of maximum riverflows at 0.05 significance level. According to results of test graphs of Mann-Kendall Rank Correlation, the starting point for detected negative trend in the time series is concentrated at 1980s. Keywords: Hydroclimatology, data completion, trend analysis, Porsuk Creek Basin.

Keywords: