Investigating Low Flows trend Assessment in Isfahan Province

Although there are many studies on meteorological drought in Isfahan province, there is no specific study on hydrologic droughts. In this study, trend analysis of low flows as the most important hydrologic drought indicators for Isfahan province watersheds is carried out for the first time. Mean daily stream flow as a hydrologic indicator and 1-, 7-, 15-, 30- and 90-day low flows as hydrologic drought indicators for 22 gauging stations with at least 20 years of data record were calculated and their trends were estimated over the province. Results of trend analysis using Mann-Kendall and Spearman correlation indicated that mean daily stream flow and low flows have negative trend at many gauging stations. Apart from Ghaleh Shahrokh station, Low flow indices in Zayandehrud dam basin have negative trend so that Eskandari station show highest degree of negative trend. Daily stream flow and low flows reduction especially in recent years is a warning for water resources management in Zayandehrud basin.