A Novel GIS-Based Approach to Assessment Suitable Irrigation Water Using a fuzzy-Multi Indices Method in Astaneh-Kuchesfahan Plain, Iran

Increasing soil salinity decreased soil permeability and reduced water absorption by plant roots leading to reduced agricultural productivity. For this reason, water quality must be tested before it can be used for agricultural purposes. Accordingly, the currentresearch aimed to assess suitable irrigation water (IW)using a new GIS-basedapproach in Astaneh-Kuchesfahan plain, Iran.Fuzzy logic (FL) via GISwas used to reduce the uncertainty. Four steps were performed to receive this aim. In step 1, the values of nine indices used for agricultural water quality classification were calculated based on chemical analysis of 19 water samples in wet and dry seasons.In step 2, these indices were interpolated via ArcGIS 10.8 software. In the following, fuzzy membership functions (FMF) were used for the standardization of parameters in step 3. Finally, in step 4, foraggregation of the indices, several fuzzy overlay operations were used. Eventually, to identify the most accurate overlay operation,the correlations between the fuzzy memberships and operation maps were used.The results showed that the sum of absolute values for correlations (SAVC) in the dry season is higher than in the wet season.The results also showed that the "GAMMA 0.9" and"GAMMA 0.95"withthe highest SAVCare the bestoverlay operations in dry and wet seasons, respectively. According to the best operation maps, only a small southeast area has"good" groundwater quality for IWin both dry and wet seasons.

Heavy Metals in Fresh Waters of Kazakhstan and Methodological Approaches to Developing a Regional Water Quality Classification

The study aimed to define the classes in the Heavy Metals Section of the Regional Environmental Ranking System based on long-term data (1997-2017). When distinguishing water quality classes, the following factors were taken into account: background content of heavy metals, content of heavy metals in water bodies exposed to different levels and character of anthropogenic pollution, and response of biological communities to toxic pollution of their natural habitats. According to the proposed classification, the non-contaminated water of Сlass 1 contains the following: Cd<0.2, Cu<2.5, Zn<4, Pb<3, Cr<0.5, and Ni<0.5 μg dm-3. Class 2 water is characterized by Cd<0.5, Cu<6, Zn<6, Pb<7, Cr<1, and Ni<2 μg dm-3 content. Moderately polluted water of Class 3 contains Cd<3, Cu<10, Cr<10, Ni<10, Zn<20, and Pb<20 μg dm-3. Concentrations of all heavy metals increase proportionally and exceed 30-100 μg dm-3 in the most polluted water of Class 6. The proposed methodological approach assesses not only the local content of heavy metals in water bodies of Kazakhstan but also the degree of toxic pollution of their vast catchment basins. The proposed methods are applicable to other arid regions with similar physical and climatic conditions.