Assessment of Meteorological and Hydrological Drought and its Effect on Water Quality: (Case Study: Godarkhosh River)

Drought is a natural phenomenon that causes water resources shortage in various sectors such as drinking water, industry and agriculture. Drought is one of the climatic phenomena that can be observed not only in arid and semi-arid regions, but also alternately in wet areas. It should be noted that aridity and drought are different, aridity is a climatic trait specific to arid and semi-arid regions and is a permanent feature of the climate of the dry region (Eslamian et al, 2012). Liu et al (2011) with the study of meteorological and hydrological droughts in Oklahoma State discovered the two-day drought incidence of 2 months and the correlation coefficient between SPI and SDI profiles in an optimal state was 0.63. Eskandari-Damaneh (2015) investigated temporal and spatial relationships between meteorological and hydrological droughts in Tehran province. The results showed a correlation of 99% between meteorological and hydrological droughts and the increasing trend of drought in Tehran province. Mahmoudi et al. (2015) assessed the drought of meteorology in Sistan and Baluchestan Province using a standard score index and its impact on water quality in the province. Delpla et al (2009) examined the impact of climate change on the quality of surface waters in relation to drinking water production and concluded that climate change has reduced the quality of drinking water that has potential health impacts. Also, Mosley (2015) indicated that drought increased salinity, algae and soluble ions, which greatly reduced the quality of freshwater. According to drought studies, the main objective of this study is to study the drought of meteorology and hydrology, as well as to determine the probable delay between the occurrence of these two types of drought and their impact on river water quality, for water resources management in Godarkhosh basin which is one of the most important basins in Ilam province.