Investigation of temporal changes in groundwater quality of Neishaboor Plain and its possible causes

Water resource limitations in the Neishaboor Plain, together with significant increase in water demand in this area due to the urban, agricultural and industrial development, make it a necessity for researchers to investigate and provide the base information for establishing a sustainable water resource management program. In this study the temporal changes in groundwater quality and the possible causes of these fluctuations were studied. The water quality data used in this investigation included a 9 year (2001-2009) periodically measurements of TDS, total hardness, Na+, Ca2+, Mg2+, Cl- and SO42- concentrations. The results indicated a significant degradation of groundwater quality over the period of the study, as was shown by the increase in concentrations of the quality parameters. The TDS concentration in 77% of the investigated wells raised sharply over the above mentioned period, with an annual mean rate of 19.63 mg/L. In reagard to possible causes of groundwater deterioration, geological formations, the decline in groundwater level, and agricultural activities were realized to be the most important factors. The results showed that with every 0.81m mean annual decline in groundwater level, the TDS concentration increased by a value of 19.63 mg/l. The geological tertiary formations (Miocene) and volcanic rocks were also affecting the spatial quality changes observed in some parts of the Nayshaboor's aquifer.