Trend analysis of mean monthly, seasonally and annual streamflow of Daday Stream in Kastamonu, Turkey

Abstract

Water is one of the most important natural resource and assessment of the trends in water has a great importance to estimate the future of water resources. The main purpose of this study is to present a trend analysis of the streamflow of Daday Stream in Kastamonu, Turkey by monthly, seasonal and annual analyses. Monthly streamflow data were obtained from streamflow gauging station on the stream between 1988 and 2007. Trends of monthly, seasonal and annual runoff of Daday Stream were analysed by Trend analysis, non-parametric Mann-Kendall and Spearman tests. The results showed that mean annual streamflow of Daday Stream has a significant tendency to decrease for this period (p<0.01). Seasonal trend analysis results demonstrated statistically significant decreasing trends were found for all seasons. Trend analyses for monthly displayed that there were also statistically significant decreasing trends for all month excluding February, March, April, and June. In conclusion, decreasing trends in the streamflow of Daday Stream have been predicted for this period and for the future. The fluctuation in water resources could be affected by some reasons such as decreasing rainfall, rising temperature depending upon climate change.

Keywords

• climate change
• change-point analysis
• daday
• streamflow
• trend analysis