Tracking Temporal and Spatial Changes in Underground Water Quality for Potable and Agricultural Purposes (Case Study: Yazd, Ardakan Plain)

In recent decades, the quality of groundwater in most areas of Iran has become critical. In this regard, water resources management, especially groundwater resources has a great importance. The aim of existence research was to investigate the temporal and spatial process of underground water quality changes in Ardakan plain, Yazd Province for drinking and agricultural purposes, according to water quality classification systems of Wilcox and Schuler. In this paper, electrical conductivity, sodium absorption ratio (SAR), magnesium, calcium, chlorine, acidity, sulphate and sodium were measured and then interpolated and subsequently classified according to the Kriging, Wilcox and Schuler methods, respectively. The results showed that, except for the parts of the North-East, the rest of the plain have reasonably suitable quality for drinking and with the passage of time, the quality of underground water has been deteriorated. In the case of agricultural, the same setting exists and most of the pollution has been associated with the northern and Eastern parts of the area, which has been expanding over the recent decades. The main reasons of decreasing water quality, on the one hand, can be due to the over-exploitation of water resources as the result of the expansion of urban areas and industrial activities, particularly in the city of Ardakan and Meybod, dominance of traditional agriculture and extensive cultivation of pistachio trees. On the other hand, this reduction in water quality could be attributed to the recent droughts which has diminished groundwater recharge as well.