Document Type : Original Article

Authors

• Monireh Faghani ¹
• Tohid Aligholinia ²

¹ PhD graduate in Water Science and Engineering-Irrigation and Drainage, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.

² PhD graduate in Water Science and Engineering-Irrigation and Drainage, Environmental researcher and university lecturer, Saba University of Urmia, Iran.

Abstract

In order to develop any planning in water resources management, statistical distributions should be used. Among the basic goals of water management, we can mention the activities of developing the use of water resources, improving the efficiency of consumption, protecting water resources and improving their quality and quantity, preserving the environment, and improving the level of management. In this research, in order to investigate the above conditions, the average annual flow data of 15 hydrometric stations in West Azarbaijan province were used for a period of 25 years (1365-1390). In order to investigate the trend, four non-parametric methods Man-Kendall, Spear-Man, Thiel-Sen and Sens-T were considered. The results showed a significant decreasing trend in 4 hydrometric stations of Tashnad, Nazarabad, Tamer and Yalguz-Aghaj. In this regard, the comparison of the results of all four methods has shown the low accuracy of SENS-T method in the process. Also, regarding the randomness of the data, the W-W test was used, and the Wilcoxon test was used to check the homogeneity of the data, and a suitable statistical distribution was performed on the annual series of flow of the stations in question according to the Kolmogorov-Smirnov statistic. The results showed that the data were more and better matched with multi-parameter distributions such as GEV, Normal, Pearson 6, Wakeby.

Keywords

• Keywords: non-parametric test
• distribution function
• trend analysis
• flow regime

Main Subjects

• ًQanat and aquifer