US Salinity Laboratory Research Articles

Hydro-chemical characteristics of Biring and Tangting Rivers (Nepal) and evaluation of water quality for drinking and irrigation purposes

Although river water is vital for drinking, irrigation and domestic needs, it faces threats from natural processes and human activities. Small and medium-sized rivers, especially in Nepal, remain understudied despite their vital importance in providing water to densely populated areas. This study evaluated the suitability for drinking and irrigation and the hydro-chemical characteristics of the Biring and Tangting rivers in Koshi province, Nepal. The results showed that turbidity, pH, EC, TDS, TH, NH4+, K+, Ca2+, Mg2+, Na+, Cl−, SO42−, HCO3− and NO3− values of all sampling sites in the Biring and Tangting rivers, except for the turbidity value of 10.39 NTU recorded in the PT9 site of the Tangting River, did not exceed maximum limit values set for drinking water. However, according to Water Quality Index results, the water of both rivers was in poor condition for drinking due to domestic wastewater discharges and cremation activities which caused high NH4+ levels. The major cations in both rivers were listed as Ca2⁺ > Na⁺ > K⁺ > Mg2⁺, while the major anions were listed as HCO₃⁻ > Cl⁻ > SO₄2⁻ > NO₃⁻. Gibbs and Piper diagrams showed that geogenic weathering of carbonate rocks prevailing in the region affected the hydrochemistry in both rivers. Evaluation based on seven different irrigation indices and US salinity laboratory diagram revealed that the water of both rivers was suitable for irrigation despite some magnesium-related limitations.

Novel approach evaluating powdered raw and hydrothermally treated syenite as stonemeal for tropical environments: Potential effects on groundwater quality and agricultural suitability

Soluble fertilizers, particularly potash, are often prohibitively expensive or unavailable in Africa. Consequently, alternatives such as powdered silicate rocks, both raw and hydrothermally treated, are being explored as potential solutions, especially for acidic tropical soils. This study investigates the possible impacts of these rocks (syenite) on groundwater quality, which is a critical factor for agricultural activities. The powdered raw material underwent chemical and mineralogical characterization, including X-ray fluorescence and X-ray diffraction, followed by quantitative evaluation of materials by scanning electron microscopy. Both raw and 46 hydrothermally treated materials were subjected to sequential leaching cycles (1, 24, and 192 h) using deionized water, and the resulting leachates were analyzed by inductively coupled plasma atomic emission spectroscopy. Parameters such as electrical conductivity, total dissolved solids, soluble sodium percentage, sodium adsorption ratio, magnesium hazard, Kelly's ratio, and permeability index were also evaluated. Results from the 47 leachates indicated that 64 % of the samples exhibited excellent to acceptable water quality for irrigation purposes across all parameters. Conversely, 6 % to 13 % fell into the doubtful category, and 2 % to 24 % were classified as unsuitable. Consistency index and ratios of approximately 0.07 and 0.042, respectively, were determined using multi-criteria decision analysis (analytic hierarchy process: AHP), confirming the coherence of the decision and pairwise comparison matrix. The weighted coefficients for each criterion ranged from 0.06 to 0.2. Consequently, the optimal sample (Treatment 23) was identified, showing a hydrothermal temperature of 176 °C, a time of 3.9 h, a normality of 4.62, and a liquid-solid ratio of 0.24. This treatment met all high-water quality standards, including low salinity and sodium hazard, as corroborated by the US salinity laboratory and Wilcox diagrams. Furthermore, due to their nutrient release, low concentration of toxic elements, and effective buffering capacity (pH ∼ 10.6), these powdered syenites are suitable for application in acidic soils.

Mamdani-type fuzzy inference system for irrigational water quality

This paper aims to evaluate the quality of groundwater resources used for irrigation purposes using a Mamdani-type fuzzy inference system (MFIS). The MFIS is used to resolve ambiguities and uncertainties in economic, social, and natural systems and also facilitates the capture of expert knowledge in ways similar to human reasoning and thought processes. In this study, 20 groundwater samples were collected from various locations within the Mayiladuthurai district, Tamil Nadu, India, between January 2016 and December 2019. These samples underwent physical and chemical analyses to assess the suitability of the collected water resources for irrigation. The analysis utilizes the Mamdani Fuzzy Inference System, which combines values of Electrical Conductivity (EC) and Sodium Adsorption Ratio (SAR). Additionally, methods from the US Salinity Laboratory Staff were also employed. Ultimately, the groundwater quality in Mayiladuthurai is graded for irrigation use by this method. The results indicate that the MFIS reduces imprecision and uncertainty in data handling through the fuzzy membership function. The comparison of irrigation suitability results clearly demonstrates that the proposed MFIS method offers an improved assessment of the irrigation water quality level of the studied groundwater resources.

Geochemical processes, salinity sources and utility characterization of groundwater in a semi-arid region of Iraq through geostatistical and isotopic techniques.

Identifying factors contributing to water salinity is paramount in efficiently managing limited water resources in arid environments. The primary objective of this study is to enhance understanding regarding the hydrochemistry, source, and mechanism of water salinity, as well as to assess the suitability of water for various uses in southern Iraq. The groundwater samples were collected from water wells and springs and analyzed for major cations and anions along with stable isotopes (δ18O and δ2H) to accomplish the objective. The analysis of major ion chemistry, hydrochemical techniques, principal component analysis (PCA), and isotope signatures were adopted to determine the primary factors contributing to water mineralization. The study inferred that evaporation and geological processes encompassing water-rock interactions, such as dissolution precipitation and ion exchange, were key processes. The stable isotope analysis revealed that the water originated from meteoric sources and underwent significant evaporation during or before infiltration. The utility assessment of water samples indicates that most samples are not appropriate for consumption and are significantly below the established standards for potable water. In contrast, a significant portion of the groundwater samples were found to meet the criteria for irrigation suitability by adopting Wilcox and the US Salinity Laboratory criteria. The groundwater could be considered for irrigation with proper salinity control management. Overall, this study has significantly improved the understanding of the hydrogeochemical regimes and acts as a first step toward the sustainable utilization of water resources.

Irrigation Water – Quality Issues, Limits, and Way Forward

Depending on how groundwater has been collected and used, the severity of the rainfall, and the following aquifer recharge, the quality of irrigation fluids differs between regions, nations, and even towns. In hot, arid regions with limited rainfall, the salinity of groundwater used for agriculture rises, limiting the variety of crops that may be produced. Therefore, determining the quality of the irrigation water is essential. How well water works for irrigation relies on how much and what kinds of soluble salts are present in the solution. In regard to the four fundamental standards of water salinity (electrical conductivity), sodium risk (sodium adsorption ratio-SAR), residual sodium carbonates (RSC), and ion toxicity, the amount and make-up of soluble salts in a solution are reviewed. We talk about the risks associated with boron and chlorides. For convenience, several plant species' boron tolerance levels are given. The updated water quality diagram created by the US Salinity Laboratory Staff in 1954 is the most significant section of this review. The salinity of most irrigation fluids is more than 2250 S cm-1, which is not represented in this picture. The water classification diagram was expanded to include salinities up to 30,000 S cm-1 in order to handle EC values larger than 2250 S cm-1. The categories for salinity and sodicity presented here can be used to select and manage crops in an educated manner. Methods for controlling water sodicity with gypsum and lowering water salinity by combining different waters are described with examples.

Hydrogeologic characteristics of groundwater in the Kızılırmak graben (Nevşehir–Turkey) and its evaluation in terms of irrigation water quality

Abstract In this study, an area of 150 km2 with important settlements and agricultural areas within the Kızılırmak and Kuyulukışla grabens, in the north of Nevşehir province (Turkey), was investigated. This study aimed to evaluate the hydrochemical properties and water quality of the vital groundwater in the study area, determine effective utilisation methods, and make recommendations for sustainable use. From the data obtained as a result of these analyses, sodium adsorption ratio (SAR) and sodium percentage (%Na) values were calculated and compared with WHO (World Health Organization) and TS-266 (Turkish Standards) quality standards to determine the characteristics of water for human consumption and irrigation for agricultural purposes. Based on these values, Wilcox diagrams and US Salinity Laboratory diagrams were used. According to these evaluations, it was found that sample SMP1 is not suitable for use as drinking water according to the basic parameters in the reference standards, while the other samples are suitable for drinking and human consumption. Electrical conductivity, %Na, SAR values, US Salinity Laboratory, and Wilcox diagrams were used to evaluate the use of water resources for irrigation purposes. According to the results obtained, all samples except sample SMP1 were found to be suitable for use as irrigation water.

Hydrogeochemical Quality of Groundwater used for Irrigation in Ziban Region, Algeria

The present study focuses on the hydrogeochemical characteristics of groundwater in order to assess their irrigation suitability. The samples collected from 28 boreholes intended for irrigation chosen from two localities (El Outaya and Ain Naga) in the Ziban region (Algeria), were analyzed for nine different physicochemical water quality parameters (which include EC, pH, Ca2+, Mg2+ , Na+, K+, Cl-, SO42-and HCO3-). The laboratory results indicate that most of the groundwater samples of the both locations show high value of EC which exceed as per FAO Standards. The classification of hydrochemical facies by Piper diagram shows dominance of chloride and calcium sulfate (CaSO4) and magnesium groundwater type (in Ain Naga) and potassium chloride water type (in El Outaya). The majority of groundwater samples analyzed of the both location are unsuitable for irrigation purpose according to the interpretation of graphical plots such as Wilcox and US Salinity Laboratory for the classification of groundwater. In Ain Naga location, the better class of water quality is C3S1 with only 14.28%.The rest is unsuitable for irrigation C4S1 (71.42%) and C4S2 (14.28%). However, all groundwater samples analyzed of El Outaya location are unsuitable for irrigation with C4S2 (28.57%), C4S3 (28.57%) and C5S3 (42.85%).

Wolf prize awarded to Rien van Genuchten

Martinus Th. (“Rien”) van Genuchten has been awarded the 2023 Wolf Prize in Agriculture. The Wolf Prize is awarded to “outstanding scientists and artists from around the world for achievements in the interest of humanity and friendly relations among people.” The prize is awarded in the disciplines of medicine, agriculture, mathematics, chemistry, and physics. For agricultural sciences, the Wolf Prize is widely considered one of the world's most prestigious recognitions. Rien van Genuchten was born in 1945 in Vught, The Netherlands. He received his early education at the Agricultural University of Wageningen, The Netherlands, and his PhD at New Mexico State University in the United States. He then spent most of his career at the US Salinity Laboratory in Riverside, CA, before moving to the University of Rio de Janeiro, Brazil, and to Utrecht University, The Netherlands. One of his most influential publications describes a closed-form equation for predicting the hydraulic conductivity of unsaturated soils, known as the van Genuchten equation (van Genuchten, 1980). He was, together with Jirka Simunek, the developer of the widely used HYDRUS software package for simulating the movement of water, heat, and solutes in variably saturated media (Šimůnek et al., 2016). Early in his career, he also published a compendium on analytical solutions of the one-dimensional convection–dispersion equation (van Genuchten & Alves, 1982), a resource widely used to analyse solute transport at the column and field scale. Rien van Genuchten was the founding editor of Vadose Zone Journal, when he, 21 years ago, had the insight to initiate a new, multi-disciplinary journal to promote research related to the vadose zone, the zone between the soil surface and the groundwater table. This was at a time when environmental research was still in its infancy, and the new journal provided a common outlet for agronomy, soil science, hydrology, hydrogeophysics, biogeochemistry, civil engineering, and the emerging environmental sciences. Rien van Genuchten's foresight paved the way for innovative research and helped elevate vadose zone science to an established and respected field of research. The Wolf Prize was awarded to Rien van Genuchten “for his ground-breaking work in understanding water flow and predicting contaminant transport in soils.” On behalf of the editorial board of Vadose Zone Journal, we congratulate and celebrate Rien van Genuchten and his receipt of the Wolf Prize. Venkataraman Lakshmi: Conceptualization; writing—review and editing. Markus Flury: Conceptualization; writing—original draft; writing—review and editing.

Kırklareli Yöresindeki Atıksuların Tarımda Sulama Amaçlı Kullanılabilirliğinin Belirlenmesi

Turkiye’s water resources are getting increasingly polluted and the need for per capita water is increasing rapidly from year to year with population growth. With the increasing population, the increase in the need for food, the increase in water consumption, and the reuse of wastewater in various fields, especially as irrigation water, by treating it with appropriate methods, come to the fore today.The sewage waters of the city of Kırklareli are treated in the existing domestic and industrial treatment plants and discharged into the Kırklareli stream. This study was carried out in order to determine the irrigation water quality and pollution status of the waters released from the waters of the creek and treatment plants and to reveal their suitability for agricultural use. Waste water samples taken from stations determined on Kırklareli Stream were taken seasonally. Physical and inorganic-chemical parameters were investigated. The results from the study was determined according to the Classes of Inland Surface Water Resources (KYSKK) in the Water Pollution Control Regulation. Accordingly; In terms of physical and inorganic-chemical parameters of Kırklareli stream water samples, it is seasonally classified as IV. class has been determined. It has been determined to be in the C3S1 class according to the US Salinity Laboratory Classification system based on electrical conductivity (EC) and sodium adsorption rate (SAR) values. According to the results obtained, it has been determined that it should be used with caution due to its excessive salt content. Analysis of variance, one-way analysis of variance (ANOVA) and correlation analysis were performed in a repeated measurement experiment on the measurement values of water samples. Significant differences and relationships between parameters were determined statistically.

Isotopic, Geophysical, and Hydrogeochemical Investigations of Groundwater in West Middle Upper Egypt.

The groundwater of the west Assiut and El-Minia districts was evaluated in this paper using geoelectrical, hydrogeochemical, and stable isotope (oxygen-18 and deuterium) studies. In the studied localities, 42 vertical electrical soundings (VES) were taken to evaluate groundwater potential, and the analysis, as well as collection, of 74 samples of Eocene groundwater was carried out. In accordance with the vertical electrical soundings' interpretation, there are four geoelectrical formations and two major water-bearing units that act as aquifers (Pleistocene and Eocene). To determine irrigation suitability, the sodium absorption ratio (SAR), electrical conductivity (EC), residual sodium carbonate (RSC), sodium percentage (Na %), magnesium hazard (MH), Kelley's ratio (KR), and permeability index (PI) were evaluated as irrigation quality parameters. The EC, Na %, and the diagram of the US salinity laboratory indicated that most of the collected samples of groundwater were suitable for irrigation, whereas the RSC and PI pointed out that all of the collected water samples were safe for irrigation. The oxygen and hydrogen isotope values in groundwater samples showed that the Eocene aquifer was recharged by both surface water and the Nubian aquifer.

Quantification of Gypsum in Soils: Methodological Proposal

Gypsum is widely found in soils under arid and semi-arid climates due to its semi-soluble nature. In spite of that, they are less known than other soils, and this has generated some misunderstandings in some initial pedological concepts and in soil classification systems. In addition, the quantification of gypsum, and in particular of its secondary accumulations is affected by the sampling procedures and sample handling in the lab; besides by the methods used for the determination of gypsum themselves, since they differ on the accuracy, cost, and expertise needed. The objective of our research is to improve some laboratory procedures in order to determine and quantify gypsum in the soil, especially secondary accumulations. We applied several methods of sample handling and gypsum analysis to a loess profile in the Ebro Valley (NE Iberia), consisting of 10 horizons containing gypsum in varying amounts (0 to about 50%); of different sizes and morphologies. We propose a protocol considering procedures (sieving or not), qualitative determinations and two methods (turbidimetry and dehydration of crystallization water) for an optimal determination of gypsum depending on the characteristics of the sample and compared them with the acetone method (US Salinity Laboratory Staff, Agric. Handb., 1954, 60, 175; Nelson, 1978, 181), as it is the reference method in the main Classification Systems. The results obtained after applying the different methods for the analysis of gypsum in bulk samples have allowed us to propose a decision tree procedure for the determination of gypsum in soil materials. This procedure includes, determination of gypsum in all fractions, coarse and fine, the estimated amount of gypsum in the field (as a major or minor component) and the presence of other components that may interfere with the results. The most accurate results are obtained with those methods based on the loss of gypsum water upon heating when gypsum content is >4%, and with the turbidimetric method in case of lower amounts of gypsum. Finally, we discuss the implications of these analyses when a soil is classified according to the main soil classification systems (WRB 2014; Soil Survey Staff, SSS- NRCS, 2014).

Water quality assessment of Noyyal river using water quality index (WQI) and multivariate statistical techniques

ABSTRACT Noyyal River is an important river that flows through the districts of Coimbatore, Tirupur, and Erode in Tamil Nadu, India. This river is the prime source of water for agricultural and domestic purposes in the above districts. This study evaluates the surface water quality of the Noyyal river and its suitability for drinking and agricultural uses. For this study, samples were collected from 27 locations along the Noyyal river from its source to sink. The water quality index (WQI) values were designated and, except for two samples out of 27, all the other samples were categorized as poor, very poor, and unfit for consumption. The parameters evaluated to assess the water quality of the Noyyal river for irrigation include Electrical conductivity (EC), Sodium adsorption ratio (SAR), Soluble sodium percentage (SSP), Residual sodium carbonate (RSC), Magnesium hazard (MH), Kelly’s ratio (KR), and Permeability index (PI). USSL (U.S. Salinity Laboratory) diagram analysis helped to classify the samples 1 and 2 of the Noyyal river in the C1S1 and C2S1 category, which indicates low salinity-low sodium and medium salinity-low sodium, respectively. The rest of the samples fall under the category of very high salinity and very high sodium waters. Other indices like RSC, magnesium hazard, soluble sodium percentage, Kelly’s ratio, and permeability index signified that majority of the collected samples fall in the category of unsuitable for agricultural use and they need special management practices. The Principle component analysis determined the four PCs that explained 84.88% of the total variance in the data structure. The present study concludes that we cannot use the surface water of the Noyyal river directly without treatment and strict management practices should be implemented for the sustainable use of the resource.

Spatiotemporal evaluation and assessment of shallow groundwater quality for irrigation of a tropical coastal groundwater basin.

The present study aims at analyzing groundwater quantity and quality simultaneously to identify its availability and suitability for irrigation. Various water quality indices were used to assess (i) origin of the groundwater sources (Gibbs diagram); (ii) salinity, alkalinity, and sodium hazard (sodium adsorption ratio, exchangeable sodium percentage, Kelly's ratio, US Salinity Laboratory diagram, Wilcox diagram); (iii) magnesium hazard (magnesium absorption ratio); (iv) carbonate and bicarbonate hazard (residual sodium carbonate); (v) hydro-chemical facie and evaluation (Piper diagram and Expanded Durov diagram); and (vi) statistical relationship among the variables, sample sites, and spatiotemporal grouping (principal component analysis and cluster analysis). The overall objective is to quantify the irrigation suitability of groundwater reserves. Gibb's diagram suggests that the groundwater quality is mainly controlled by rock-water interaction. Piper trilinear showed the presence of various types of hydro-chemical facies such as Ca-Mg-HCO3, mixed, and sodium bicarbonate. The expanded Durov diagram revealed the hydro-chemical evolution, grouping, and areal distribution of the groundwater samples. USSL diagram, Wilcox diagram, Kelly's ratio, magnesium hazard, and permeability index suggest that the groundwater quality is suitable for irrigation. Kaiser-Meyer-Olkin (KMO) and Bartlett's tests confirmed the applicability of principal component analysis (PCA), which indicates that groundwater quality is controlled by rock-water interaction mainly. It also suggests that the groundwater has carbonate dissolution, which indicates the groundwater's hardness increased. Cluster analysis (CA) from the year 2000 to 2010 shows 4 to 8 groups present within the study area. Irrigation water quality suitability map and predicted groundwater potential zone map together act as a master tool for deciding tube well location, pumping schedule, and crop planning for the sustainability of the agriculture eco-system in the study area. The implementation of the aforementioned activities in the study area will further stop the advancement of the seawater intrusion front. The methodology shows the potential applicability for similar coastal groundwater basins worldwide with or without modification.

USE OF ACTIVE MICROORGANISM IN IMPROVING POND WATER QUALITY: CASE STUDY OF BEYTEPE POND

Water resources have been seriously polluted in terms of quality in the last hundred years, especially due to anthropogenic effects. The quality of the water in the storage structures (dam, lake, pond, etc.) has started to deteriorate due to the deterioration in the drainage basin, especially the insufficient feeding. In recent years, researches on the protection and improvement of the quality of water in storage structures have begun to increase. In this study, it was aimed to improve the water quality of Beytepe Pond located in the campus of the Turkish National Botanic Garden Directorate (TNBG) by using Active Microorganism (EM) in laboratory conditions. In the study, Baykal EM1, active microorganism, was used. For improvement water quality was used aerobic (A) and anaerobic (AN) systems in containers with a volume of 10 liters. EM was administered in 3 doses as 5, 10 and 20 ml L-1. pH, conductivity (EC), Dissolved Oxygen (DO), Chemical Oxygen Demand (COD) and chlorophyll-a values were measured in the pond water. Beytepe Pond water is 3rd class according to the US salinity laboratory salinity classification (USSL). COD and chlorophyll-a values exceed eutrophication limit values. At the beginning of the study, the raw water COD value was measured as 263 mg L-1. It was determined that 5 ml L-1 EM application was reduced up to 2 mg L-1 in anaerobic system application. The same application provided the best improvement in chlorophyll-a values. As a result of the study, it was observed that the EM application provided an improvement in the quality of the Beytepe Pond water.

Isotopic signatures and hydrochemistry in assessing groundwater occurrence in the desert environs west Qena, Egypt

BackgroundDeveloping the desert zone outside the flood plain of the Nile River and targeting the reclamation of about 12,500 feddan in the desert environs of Qena governorate are considered one of the top priorities of both government and the private sectors. The present study is based on qualitative analyses of the groundwater of the Quaternary aquifer in the desert environs west Qena. Groundwater was chemically and isotopically analyzed to determine the origin of groundwater and assess its occurrence.ResultsThe obtained results indicate that the Quaternary aquifer represents the most important groundwater aquifer in the area. The water level ranges from + 40 to + 67 m above sea level. The groundwater movement direction in the study area is mainly from southeast to northwest direction, with some local flow groundwater directions from Nile River at the north to old alluvial plain and desert environs at the south. The hydraulic conductivity of the aquifer is determined from the pumping test range from 17.63 to 42.86 m/day, with an average value of 27.04 m/day, while the transmissivity ranges between 2142.8 and 1128.3 m2/day, with an average value of 1456.74 m2/day. The total dissolved solids range from 589 to 3832 mg/L. Isotopic analysis (oxygen eighteen and deuterium) of fifteen groundwater samples was carried out to define the recharge source of the Quaternary aquifer. The groundwater isotopic data reflect variability in recharge conditions during different ages and different climatic regimes. According to the minor and trace elements concentration and US Salinity Laboratory Staff nomogram, most water samples are suitable for drinking purposes, domestic use and irrigation.ConclusionThe current research concluded that from the foregoing hydrological study and the determined values of hydraulic conductivity and transmissivity, the Quaternary aquifer is classified as ranging between moderate and high potential aquifer. The high potentiality of the aquifer is detected close to the Nile River. In addition to the representative groundwater samples showing the isotope signature of the Nile River sample, this means that all these wells have the same source of recharge (meteoric water of the Nile River).

Groundwater quality of arsenic contaminated aquifers in the Munshiganj district, Bangladesh using water quality index

About 47% shallow tubewells (STWs) in Munshiganj district, Bangladesh, contain arsenic (As) concentrations above 50 ppb. The groundwaters with elevated arsenic (As) concentrations are using for domestic (principally for drinking) and irrigation (principally for rice cultivation) purposes. STWs water qualities have been assessed for both domestic and irrigation purposes. A total of 45 (43 from Munshiganj and 2 from Dhaka city) groundwater samples were collected and analyzed for chemical constituents on 2015 (January and March), 2016(February) and 2017(September). The ions abundances for cations and anions were Na+ > Ca2+ > Mg2+ > Fe2+ > K+ > Mn2+ and HCO3− > Cl− > SO42− > NO3−, respectively. Based on piper diagram, 68.89% samples were Ca-Mg-HCO3 type (68.89%). About 40.00% samples were “unsuitable” for drinking purpose according to WQI. The sodium hazards were assessed by Wilcox and The US salinity laboratory staff (USSL) diagrams showed that most of the samples were suitable for irrigation except for 13.33% (6 samples) with EC values exceeded 2000 μS/cm. STWs are not suitable for drinking purposes, although suitable for irrigation purposes based on the quality of the water.

Hydrochemical characteristics, hydraulic connectivity and water quality assessment of multilayer aquifers in Western Suzhou City, Northern Anhui Province, China

Abstract The present study focuses on the shallow phreatic aquifer (SA) and the upper confined aquifer (CA) developed in Cenozoic loose strata, which are the major regional groundwater resources for drinking, irrigation, industry and other water-related activities. Seven samples from SA and seventeen samples from CA were analyzed to depict the hydrochemical characteristics, categorize the hydrochemical facies, evaluate the hydraulic connectivity, and appraise the drinking water and irrigation water quality. The abundance of cations is Na+ > Ca2+ > Mg2+ > K+ and the anions is HCO3− > SO42− > Cl− in both aquifers, respectively. Groundwater chemistry is controlled by water-rock interactions such as halite dissolution, ion exchange, reverse ion exchange, silicate weathering, and followed by the dissolution of Glauber's salt. The low connectivity and moderate connectivity between these two aquifers has engendered. The majority of the ion concentrations are within the limit for drinking, only one sample from the shallow aquifer was greater than the limit of 250 mg/L, a total of 29% from the shallow unconfined aquifer and 14% from the confined aquifer are not within the limit of 250 mg/L. The sodium absorption ratio (SAR), residual sodium carbonate (RSC) and soluble sodium percentage (%Na) values reveal that all the samples are appropriate for irrigation uses. The the US salinity laboratory (USSL) diagram shows that sixteen CA samples and all the SA samples fall in the C3S1 zone, implying high salinity hazard and low alkalinity hazard.

Presenting the spatial-temporal model for assessing and predicting qualitative changes of the groundwater resources in Shahriar, Tehran, Iran.

The quality of surface and groundwater are fundamental concerns. The World Health Organization (WHO) reports that 80% of diseases are waterborne. This percentage mostly lies in developing nations and underdeveloped countries. Determining the relationship between land-use patterns and groundwater quality changes is one of the methods to evaluate the impact of land-use on the hydrological condition of each region which ultimately assists in managing natural resources. In the present study, the spatial-temporal model via satellite images of Landsat TM, ETM, and OLI for2002, 2007, 2012, and 2017 are used to investigate all these modalities in Shahriar Plain, Tehran, Iran. Following image processing and analysis, the land-uses of the study area are classified into urban, farming, and bare lands. In order to assess the water quality of the study area, the periodic sampling data of piezometric wells in the plain were used from 2002 to 2017. Based on the US Salinity Laboratory (USSL) diagram, water qualities for agricultural uses are classified. Results demonstrated that land area has changed over time indicating an increase in urban land area and declines in agricultural and bare lands. Additionally, the results of the groundwater quality indicated C3S1 class in the second and third periods have increased to 3.58% (1025.93ha) and 12.82% (9367.85ha) while C2S1 class has been decreased in second and third periods to 3.58 and 12.82%. C1S1 and C4S1 classes during the three periods have been 0.

Robust clustering for assessing the spatiotemporal variability of groundwater quantity and quality

The long-term spatiotemporal assessment of groundwater resources through robust clustering techniques can be used to promote remediation measures for groundwater depletion and contamination. To fully understand the variability of groundwater quantity and quality due to anthropogenic activities and climate changes, a new ensemble clustering framework based on the Combining Multiple Clusters via Similarity Graph (COMUSA) method was developed. This new approach was applied and evaluated in the context of groundwater well systems on the Ghorveh-Dehgolan Plain (GDP), which is located in western Iran, for groundwater level (GWL) and 13 physicochemical parameters during four periods (the average of data from 1988–1990, 1997–1999, 2006–2008, and 2015–2017). The classification was confirmed by using the cluster validity index of the silhouette coefficient (SC), which indicated that the cluster ensemble method could improve the performance of individual clustering methods for groundwater quantity and quality by up to 12% and 20%, respectively. Piper plots, US Salinity Laboratory Staff (USSL) diagrams, and the pollution index of groundwater (PIG) were assessed for all clusters of physicochemical variables to analyse groundwater suitability for drinking and irrigation purposes. The results of the cluster ensemble showed that a critical pattern of groundwater depletion occurred in the western half of the GDP, while the eastern part was recognized as the most polluted zone on the plain. It could be concluded that the decline in GWL was not the only reason for the increase in groundwater quality variables, but other factors, such as noticeable cropland expansion and the overuse of chemical fertilizers and pesticides, were also influential factors related to these patterns. Taken together, the results of this study contribute to better recognizing the spatiotemporal changes in groundwater quantity and quality under the intense pressure of anthropogenic activities.

QUALITY ASSESSMENT AND HYDROGEOCHEMICAL PROPERTIES OF GAZLIGÖL (İHSANIYE-AFYONKARAHISAR, TURKEY) WATER RESOURCES

The study area includes Gazlıgöl (İhsaniye) and its surroundings located approximately 21 km north of Afyonkarahisar province. In this study, it is aimed to determine the hydrochemical properties of the water resources in the study area and their usability for different purposes. With this scope, pH, electrical conductivity (EC), main anion-cation and NO3 contents of a total of 19 groundwater samples in the region were determined. According to the results obtained, the pH values of the water resources in the region vary between 7.1 and 8.1 and the average is 7.7, which is basic water. The electrical conductivity values are between 110 and 1927 µS/cm, with an average of 461 µS/cm. The dominant water types in the region are Ca-Na-HCO3, Ca-Mg-HCO3, Ca-Mg-HCO3-SO4, Na-Ca-HCO3 and Na-Ca-HCO3-SO4. World Health Organization (WHO) and Turkish Standards Institute (TSE 266) standards were used to evaluate the usability of water resources in the study area as drinking water and it has been determined that only the samples H16 and H18 can be unfavorable to use as drinking water. Electrical conductivity, sodium percentage, sodium adsorption rate, residual sodium carbonate, Kelley index, permeability index parameters, Wilcox and US Salinity Laboratory Diagrams were used to evaluate the suitability of water resources as irrigation water. According to the results obtained, it was determined that all waters were suitable for irrigation water, except for samples HG16 and HG18. In addition, in terms of the industrial use properties of the water resources, HG1, HG11 and HG19 samples are in the "bubbling waters when boiling" class, while the HG16 and HG18 samples are in the "highly foaming waters when boiling" class. HG9, HG10, HG11, HG13, HG16, HG18 and HG19 samples in the class of “carbonate precipitations occur” and this type of water can cause rotting and calcification.