GROUNDWATER QUALITY ASSESSMENT WITH GRAPHICAL METHODS AND GQI INDEX IN HARAZ ALLUVIAL FAN, NORTHERN IRAN

Evaluation of ground water quality is important for assurance of safe and stable application of this source. However, quality conditions description is generally difficult with regarding to spatial variability of pollutants and a wide range of indicators (biological, physical and chemical substances) that can be measured. In this research, ground water quality of Haraz alluvial fan, located in the south part of Caspian Sea, has been investigated with Piper, Scholler, Wilcox and GQI methods. Piper diagram results showed ground water style and Calcium bicarbonate face at 90.3% groundwater samples, and Sodium bicarbonate at 9.7%. Scholler diagram shows acceptable quality of water and it has been determined by Wilcox method that 19.35% of the data are in class C2S1, 77.42% are in class C3S1 and 3.23% in class C3S2, indicating average water quality. Investigation of water samples with GQI method also showed that the study area in terms of the indicator is in the range of good.