Investigation of the Effects of Drought and Salinity on the Chemical Quality of the Water Resources in the Zanjans' Plain Aquifers

Due to the occurrence of dry season and exploitation of water resources for higher agricultural yields, the groundwater level in the Zanjan plain has subsided. The lowered of water level of aquifer have reduced the efficiency of wells and paralleled with water quality degradation. The underground structure of aquifer was destroyed and the quality of water resources contains more salt than fresh waters.

In order to survey on the salinity of water in this region, data from 45 sampling wells (1384-1394) has been used. In the first step by collecting valid information about the chemical quality of related aquifer, investigation on fluctuation trends of ions concentrations of Ca, Mg, Na, HCO3, Cl, SO4, from 1384 to 1394has been conducted. Then, pH and EC have been surveyed for ten years (1384-1394) to determine the general chemical quality of region groundwater. Finally, fluctuation trends of elements and water salinity have been plotted on descriptive diagrams, piper, statistical models, and other plans. In this study, all the ethical considerations have been observed and no conflict of interest was reported by the authors.

The data of this study demonstrated that average concentrations of sulfate and chloride are2.3 and 1.1meq/lit respectively. The concentration of these ions in water samples indicated the desirable quality of groundwater at present. However, if the current trend regarding the subsiding of groundwater level in the Zanjan plain, we could face a decrease in water quality and an increase in salinity in the coming years.

According to the results of the study, it can be said that the increasing trend in the concentrations of salts in the water and the declining trend of the output of the wells could reduce the chemical quality of water in near future