بررسي هيدروشيميايي دشت ميان‌آب با استفاده از روش‌هاي آماري، نمودارهاي هيدروشيميايي و منطق فازي

Hydrogeochemical assessment of Mian-Ab plain using statistics, hydrochemical diagrams and Fuzzy partitioning methods

A robust classification scheme for partitioning water chemistry samples into homogeneous groups is an important tool for the characterization of hydrologic systems. Geological and hydro-chemical systems are sometimes too complex to analyze easily using conventional graphical or statistical methods. Often, the chemical and physical properties of the natural system vary continuously, rather than abruptly. In other words, these underlying physical and chemical processes do not always produce discrete outcomes. Because of this continuity, statistical clusters may not be completely separated and instead may form a sequence of overlapping clusters. Therefore, methods related to "fuzzy logic" may be useful for modeling and classification purposes. In this research, 30 groundwater samples of Mian-Ab plain classified into three groups by using Fuzzy partitioning (FP) method. The groups with respect to total dissolved solid and water type were analyzed. The ions concentration of groundwater displays an increasing trend from the first group towards the third group. The first and second group exhibit sodium chloride water type while in the third group sulfate and calcite are dominant. In order to identify governing geochemical processes of aquifer, composite diagrams, and ionic ratio and saturation indices of calcite, dolomite and gypsum of water samples were evaluated. The results show that chemical composition of groundwater intensively under influence of recharge water from river, lithological constituents of aquifer and evaporation from aquifer.