Changes in Physical and Chemical Indices of Groundwater in Minab Plain, Iran, Caused By Water Level Decline
This study set out to investigate changes in physical and chemical indices of groundwater in Minab Plain caused by groundwater level decline. To this end, 12 groundwater samples were drawn from different wells across this plain between 22 November and 22 December 2015. Then, the parameters of acidity, electrical conductivity, and temperature were measured in situ and the major anions and cations at the Regional Water Laboratory of Hormozgan. Comparison of these parameters with EC and Cl, and other parameters measured in 2006 indicates increased concentrations of EC, Cl, Na, HCO3, TDS, as well as TH, and decreased concentration of SO4 over time. In addition, groundwater level and reservoir capacity decreased by 11.33 m and 287.179 million m3, respectively, resulting in lower groundwater quality and higher groundwater salinity. The characteristics and quality diagrams of water and maps were evaluated using AQ.QA and GIS. Comparison of the concentrations of major cations and anions in the regional groundwater showed the dominant cationic and anionic conditions were (Na>Mg>Ca>K) and (Cl>HCO3>SO4>CO3), respectively. Results suggested that the regional waters had good, acceptable, and average qualities for drinking. In terms of agricultural use, the dominant cations in the regional groundwater were Na followed by Mg.
Keywords- Minab Plain, groundwater quality decline, groundwater level decline.