Test and Trend Analysis of Precipitation and Discharge in the North of Iran (Case Study: Polroud Basin)

2 Abstract: Present study investigated the type and time of discharge changes in relation to precipitation in the Polroud basin. This area is located in Guilan province, north of the Iran. The purpose of this paper is to inform on the precipitation and discharge fluctuations for the period 1968 - 2005 that it has been investigated by using the Man-Kendal non parametric test. These results suggest that data series have trend and abrupt change. On the other hand there is a good fitting between discharge and precipitation trend. There is also the same trend in autumn winter and spring, especially. These parameters have ascending and descending trends in the autumn and spring, respectively. The precipitation has ascending trend, whereas descending trend of discharge is seen in summer. The discharge diagrams presents descending trend in all of the seasons. Totally, the trends of parameters were similar with regard to prepared diagram and the changes of discharge are dependent to precipitation.