A. Rastegarnia; mehdi karami; M. Ghafoori
Abstract
Introduction: Water resources quality assessment of the dam sites is one of the primary studies in the designing of these structures. The main challenges in Iran are the reduction of water resources and the limitation of groundwater exploitation. Much of these resources are formed in karst water resources ...
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Introduction: Water resources quality assessment of the dam sites is one of the primary studies in the designing of these structures. The main challenges in Iran are the reduction of water resources and the limitation of groundwater exploitation. Much of these resources are formed in karst water resources in the karstic susceptible formations such as the Asmari carbonate formation in Zagros Mountain, Iran. In this study using laboratory and field studies, various parameters and indices were assessed to investigate the water resources quality of Bazoft dam site for different purposes. Bazoft dam is a double-curvature arch dam with a height of 211 meters which is located in Chaharmahal and Bakhtiari Province of Iran. The bedrock of the dam site consists of limestone and dolomite rocks of the Asmari and the Jahrom formations. The Jahrum formation formed the right abutment, the riverbed and the lower parts of the left abutment. The Asmari formation formed the rocks in the middle and upper part of the left abutment.
Materials and Methods: After field studies, chemical analyses have been performed on the collected water samples from the water resources such as springs, river and the exploratory boreholes in the dam site. PH and electrical conductivity (EC) were measured by pH meter and electrical conductivity apparatus was measured at 25 ° C. Concentration of ions such as calcium, magnesium, bicarbonate was measured by titration method. The concentration of ions such as sodium and potassium, sulfate and nitrate were measured using the Flame-Photometry, and Spectrophotometry methods, respectively.. The test error in all cases was low and the results were confirmed. The indices such as Langelier saturation index and Ryznar stability index, sodium adsorption ratio (SAR), soluble sodium percentage, residual sodium carbonate, permeability index, Kelly ratio, were calculated based on related equations. Principal factor analysis (PCA) is used to determine the most influential variables when the number of variables is investigated and the relationship between them is unknown. In this method the variables are set on the elements so that the first factor is reduced to the next factor of the variance, hence the variables that are based on the first factors are the most influential. PCA reduces the dimensions of the initial data by turning the main components around the vertical and horizontal axes of coordinates. This rotation actually increases the variance between the main components and therefore it is called Variance Maximize Varimax or orthogonal rotation. The Varimax command is one of the most common methods of orthogonal rotation that preserves the independence between the extracted agents. This method reduces the number of the larger factor loadings to the lowest number. In this method, the scree plot chart determined the number of factors extracted. Parameters of R2 and RMSE in order to investigate the performance of relations have been used. As R2 is closer to the one and the RMSE is closer to the zero, the proposed relationship will yield better performance.
Results and Discussion: Anions such as HCO3, Cl, SO4, CO3 and NO3 and cations such as Ca, Na, Mg, and K are the most, respectively. From the viewpoint of hardness, all waters are placed in the hard category. According to the percentage of Na, the spring’s water is excellent, the water of the borehole is good and the river is acceptable. The results of factor analysis showed that 87.13 percent of the water quality variations are controlled by four factors. The most important factors affecting the water quality of the dam site include EC, TDS, Na %, SAR, Cl, SO4, alkalinity, Na, and CO3 with 50.91 %. The second factor include calcium, magnesium, potassium ions with 15.82 %, the third factor include nitrate, bicarbonate, and hardness with 11.61 % and pH and carbonate with 7.17 % are fall into the fourth factor. The correlation matrix of the parameters was investigated and the accuracy of some relationships was examined on the basis of different statistical criteria. The relationships of LSI with RSI and EC with TDS in the dam site and their comparison with previously suggested equations indicated that there is a high correlation and each relationship is applicable for a particular area. Also, the trend of points obtained from each equation has the appropriate consistency but the RMSE of the assessed equations is high. EC plot against TDS to determine the relationship between the two parameters in the Bazoft dam site is TDS=0.70Ec-31.24.
Conclusion: The concentration of all assessed cations and anions is lower than the WHO permissible limit. The water resources are corrosive and all indices indicated the appropriate quality of water resources for farming and drinking.
J. Dowlati; Gh. Lashkaripour; N. Hafezi Moghadas
Abstract
Zahedan aquifer is located in the northernof Zahedanwatedshed. It is essential to evaluate the quality of groundwater resources due to proving some part of drinking water, agricultural and industrial waters of this city. In order to carry out ground water quality monitoring, and assess the controlling ...
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Zahedan aquifer is located in the northernof Zahedanwatedshed. It is essential to evaluate the quality of groundwater resources due to proving some part of drinking water, agricultural and industrial waters of this city. In order to carry out ground water quality monitoring, and assess the controlling possesses and determine cations and anions sources of the groundwater, 26 wells were sampled and water quality parameters were measured.The results of the analysis showed that almost all of the samples proved very saline and electrical conductivity varied from 1,359 to 12,620μS cm−1. In the Zahedan aquifer, sodium, chloride and sulfate were predominant Cation and Anions respectively, and sodium-chloride Na-Cl( and sodium - sulfate)Na-So4) were dominant types of the groundwater. The factor analysis of samples results indicates that the two natural and human factors controlled about the 83/30% and 74/37% of the quality variations of the groundwater respectively in October and February. The first and major factor related to the natural processes of ion exchange and dissolution had a correlation with positive loadings of EC, Ca2+, Mg2+, Na+, Cl-, K+ and So42- and controls the 65.25% of the quality variations of the ground water in October and the 58.82% in February. The second factor related toCa2+, No3- constituted the18.05% of the quality variations in October and 15.56% in February, and given the urban development and less agricultural development in the aquifer, is dependent on human activities. For the samples collected in October, the saturation indices of calcite, gypsum and dolomite minerals showed saturated condition and calcite and dolomite in February showed saturated condition for more than 60% and 90% of samples and gypsum index revealed under-saturated condition for almost all samples.The unsaturated condition of Zahedan groundwater aquifer is resulted from the insufficient time for retaining water in the aquifer to dissolve the minerals. So42- and No3- Ions in more than 70 percent samples showed unnatural sources (the sewer infiltration).
M. Akbarzadeh; B. Ghahraman
Abstract
In geo-statistics, prediction of an unknown value of random field has been performed in specified time and position, using spatio-temporal Kriging. In some circumstances, a suitable covariate increase the estimation prediction. Geo-statistical methods of Universal Kriging (UK) and Kriging with External ...
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In geo-statistics, prediction of an unknown value of random field has been performed in specified time and position, using spatio-temporal Kriging. In some circumstances, a suitable covariate increase the estimation prediction. Geo-statistical methods of Universal Kriging (UK) and Kriging with External Trend (KwET) were applied to Mashhad plain water quality data sets. The optimal network to monitor groundwater quality was presented, using Entropy. All wells ranked based on the criterion of Entropy and mutual information. Then, the optimal network was determined based on the percentages of acquired information and relying on the spatio-temporal Kriging. Based on UK and KwET, electrical conductivity (EC) was the best covariate. KwET with EC as a covariate was the superior Kriging method. A network covering 111 wells showed to be as informative as the existing monitoring network with a total of 237 wells.
