assessment and prediction of qezelozan and shahroud rivers discharge

the aim of this study was the analysis of discharge variations of two rivers i.e. qezelozan and shahroud, regarding the sustainable rice production in guilan province. to achieve this purpose four trend analysis tests including sen, mann-kendall, linear regression and spearman were used. in this study, river discharge data of 49 and 37 years for respectively qezelozan and shahroud rivers were used. the results of all tests in quarterly and annual periods were similar. the results of all tests showed a significant decrease in river discharge of qezelozan and shahroud. furthermore, for monthly periods the man-kendall and the spearman tests were used that during the periods both tests showed similar results i.e. reducing discharge during the studied periods. in both rivers, the annual river discharge was reducing by 60% from the first year to the last year of the study period. in this study, the changes in both precipitation and temperature were also investigated; the results showed a significant reduction in the amount of rainfall and a significant increase in the temperature. the results of this research could be used in predicting future drought, irrigation planning and management of integrated water resources.