Analysis of monthly flow discharge occurrence pattern using Power Laws Analysis in some hydrometric stations of Mazandaran Province

摘要: The assessment of hydrologic wet and dry periods is the primary and necessary basis of water resources management and planning, which needs to be studied and understood in the case of drought occurrence. The aim of this study is the use of Power Law Analysis and analyzing wet and dry periods’ patterns of river flow in a number of gauge stations of Mazandaran province. With this purpose, the wet and dry periods of monthly discharge time series in 26 hydrometric stations have been analyzed through a 36-year study period. Therefore, the average monthly discharge, the threshold limit and the starting and ending of the wet and dry spells were calculated and then the number of wet and dry spells’ occurrence sequences from 1 to 41 months were determined. The research results showed that there were a straight relationship between the severity and the duration of dry and wet spells. The minimum severity of dry and wet spells were observed in Polur and Hanisk stations with the linear slope of -0.87 and -1.29 in southwest and western parts of the Mazandaran province. The maximum flow duration for dry and wet periods (122.09 and 145.89) were identified in Qoran Talar station at the center of the study area. In other words, the stations in the main branches of the southeast and center of Mazandaran province had dry and wet flow durations more than the other studied stations. The proximity of scatter plots to the straight line or parallel lines without intersection in the study area represented a homogeneous regime of dry and wet periods and significant changes with time were not observed. In this regard, it can be noted that the periodic …