Assessment and zoning of groundwater quality of Bojnord plain during drought and wet periods with using SPI, RAI and PN indices

One of the major consequences of climate change is the increasing severity of drought. Drought is a recurring natural phenomenon that is associated with a shortage of available water resources in a large area over a given period of time. In recent years, the increasing frequency of occurrence of extreme climatic phenomena such as floods and droughts, along with global warming evidence, has led to an increase in attention to climatic issues. In this research, by preparing climatic statistics of two stations in Bojnourd and Assadi, the drought condition of Bojnoord plain has been investigated according to drought indices SPI, RAI and PN. Then, using Piper and Wilcox diagram, the quality of groundwater resources has been compared during drought and wet periods. The results of the survey indicate that the Bojnourd plain has been in drought situations in recent years. The results show that the quality of water resources during the wet period was mostly mixed and sweet water, but in the drought period, the water type was more than the mixed and saline water. The results also show that in the drought period more than 50 percent of wells in saltwater conditions were unsuitable for agriculture.