Hydrogeological drought management index (HDMI) as a tool for groundwater resource management under drought conditions, Case study: Dayyer-Abdan district, Boushehr province

Drought has major negative effects on water resources and its related environments. Sometimes the drought damages are irreparable. Groundwater drought is one of the most important droughts that caused by insufficient groundwater recharge. This study aims to evaluate the effect of drought on groundwater resources of Dayyer- Abdan district, south of Boushehr province. Data and information such as rainfall, groundwater level, well discharge rates and groundwater quality data were used to this purpose. The Standardized Precipitation Index (SPI) and Groundwater Resource Index (GRI) were used to assess the drought situation. A new index called Hydrogeological Drought Management Index (HDMI) is introduced in this research. The HDMI index is a combination of Groundwater Resource Index (GRI), the Modified Standardized Electrical Conductivity Index (MSECI) and Standardized Well Discharge Index (SWDI). According to the achieved results, the average of GRI index is less than -1, that indicates a moderate groundwater drought. Groundwater drought also has destroyed the groundwater quality. From the groundwater quality view point (MSECI index), the most critical zone of the aquifer is located in the southern part of the study area. From the aquifer potential view point (SWDI index), the most suitable groundwater zone is the northern parts of the study area. The southern parts of the Dayyer-Abdan district (adjacent to the Persian Gulf) have the lowest amounts of HDMI index (less than -4). So the exploitation of groundwater is not recommended in these areas.