Study of drought with SPI index (case study: Ghareh Chai and Karkheh basins)

ABSTRACT: To geo location and climate condition of Iran, in recent years, some hydro meteorological problems have emerged for different parts of Iran because of Low rainfall, it’s inappropriate distribution and drought. The goal of this study is the investigation of the Meteorological drought in Ghareh chaiand Kharkhe watershed in Hamadan province, location in Western part of Iran. In this study, flow and precipitation data series of hydrometric and climatology station with 37 years dataset was used. Then drought period were extracted using SPI index and the results were analyzed. Results showed that drought periods have taken place, and influenced water resources and few years were without drought, but in many years drought were occurred even for a short period. Finally assessment of SPI drought with using correlation between Runoff and SPI index show high accuracy SPI index.