Z. Pashazadeh Laleh; H. Jafari; A.R. Vaezi Hir
Abstract
Introduction: The water is the major key in sustainable development, so it is necessary to be managed and conserved. The quality of surface water resources is mainly controlled by natural or geogenic factors including chemistry of recharge water, soil and geology processes, as well as the man-made contaminant. ...
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Introduction: The water is the major key in sustainable development, so it is necessary to be managed and conserved. The quality of surface water resources is mainly controlled by natural or geogenic factors including chemistry of recharge water, soil and geology processes, as well as the man-made contaminant. Qualitative indicators are used as effective managing tools in decision making programs. Water quality indices (WQI) are the simple and suitable tools to determine the quality statue of the water. In order to calculate the water quality index, many parameters are integrated in mathematical formula to represent the quality condition of the water with a number which classifies the quality in the scales of the weak to excellent. Many water quality indices were introduced by researchers and organizations around the world. Aji-Chay, one of the most important flowing rivers in East-Azerbaijan province, northwest of Iran, is passing through Tabriz plain in its way and finally ends to the Uremia lake. Regarding the focused industrial zones, agricultural field and urban areas in this plain, the river is highly vulnerable to pollution and quality degradation. So, this study was aimed to assess the Aji-chay River based on quality indicators, in order to helps its better management. Materials and Methods: In this research for assessing pollution of the Aji-Chay river using water quality indices, 16 sampling stations were located along the river and water samples were collected during wet (May 2016) and dry (September 2016) seasons. Electrical conductivity (EC), temperature, dissolved oxygen (DO) and pH were measured in the field and total dissolved solids (TDS), turbidity, major ions (Ca, Mg, Na, K, HCO3, Cl, SO4), nitrate (NO3), phosphate (PO4), biological oxygen demand (BOD), chemical oxygen demand (COD) and biological contaminants (fecal coliform) were determined in the laboratory. Quality indicators including the US national sanitary foundation water quality indices in the two forms of multiplicative (NSFWQIm) and additive (NSFWQIa) and Iranian surface water quality index (IRWQIsc) were used to assess the quality of the Aji-Chay river. Results and Discussion: Turbidity and Electrical conductivity (EC) is high at the upstream which is related to movement of the River in upper red formation (Miocene series) which enhances the chloride, sodium, calcium and sulfate. Arsenic concentrations are exceeding the drinking standards (0.01 ppm) across all samples mainly from a geogenic sources as well as discharge of wastewater in some areas. The elements Cd, Mn, Ni, Pb, Mo, Co, Zn, Fe and Al are mainly geogenic, whereas Cu, Ba and Cr are mostly originated from anthropogenic activities. Based on the results, river quality at the wet season is highly controlled by the main branch and Gomnab-Chay, but Mehran-rood plays the major role in downstream water quality at the dry season due to its higher discharge rate. The process was confirmed by Piper and Schoeller diagrams. Most of the parameters are increased in middle parts at the river where the concentrated sources of contaminates and discharge of wastewater increased the organic and biological constituents and nutrients especially in dry season. Assessing the river quality for agricultural uses based on modified Wilcox diagram shows except for Mehran-rood, the other samples are unsuitable for agriculture and the dry season quality is better than the wet season. Based on the results, increase in most parameters and so, pollution and quality degradation of the river are observed to the downstream. Assessing quality of the Aji-Chay river using US national sanitary foundation water quality indices in the two forms of multiplicative (NSFWQIm) and additive (NSFWQIa) and Iranian surface water quality index (IRWQIsc) confirmed the bad to very bad qualitative statue of the river in most stations especially in the middle parts of the Tabriz plain. The results revealed that quality degradation of Aji-Chay river is probably due to discharge of contaminants from municipal and industrial wastewaters (effluents), highlighting the need for managing actions to improve quality of this important river. Comparing the quality indices showed the priority of NSFWQIm (multiplicative form of US national sanitary foundation water quality indices) in quality classification and pollution assessment of the Aji-Chay river. Conclusion: Quality degradation of Aji-Chay river is probably due to discharge of contaminants from municipal and industrial wastewater effluents, indicating the need for managing actions to improve quality of this river. In this study priority of NSFWQIm (multiplicative form of US national sanitary foundation water quality indices) in quality classification and pollution assessment of the Aji-Chay river was confirmed.
A. Vaezihir; mehri tabarmayeh
Abstract
Introduction: Ground water as a dynamic and recyclable natural resource in fractured rock terrains are characterized by single and double fracture porosity models. Due to the heterogeneous nature of the medium hydraulic properties of these rocks are mainly controlled by fracturing and influenced by multivariate ...
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Introduction: Ground water as a dynamic and recyclable natural resource in fractured rock terrains are characterized by single and double fracture porosity models. Due to the heterogeneous nature of the medium hydraulic properties of these rocks are mainly controlled by fracturing and influenced by multivariate parameters. This heterogeneity is due to various compactions , density of fractures and degree of weathering. Therefore, regarding the importance of ground water resources in social and economic development, the study of fractured rock aquifers especially in arid and semi-arid regions is of interest. In this paper zoning of aquifers has been carried out according to their potential using concept of overlaying of drastic parameters on groundwater development.
Materials and Methods: The study area is located in the southwest of Marivan city, Iran. Due to the existence of sandstone and igneous formations and tectonic activities, fractured aquifers, was probably developed. In this paper, Simple Additive Weighted (SAW) and Analytic Hierarchy Process (AHP) using eigenvectors were used to find ground water resources. In order to evaluate the groundwater potential sources, lithology, fracture density, elevation, slope, aspect, drainage density and land use parameters were considered. For this purpose, layers of these information were provided in the IDRISI and GIS medium and then sorted and weighted using the weighted cumulative integrate AHP and SAW methods. The index of ground water potential sources was determined by multiplying each raster layer by its corresponding weighting factor assigned by the AHP and SAW methods. Finally the potential groundwater zoning map was generated by cumulating the seven individual rating and weighting maps.
Results and Discussion: According to the output map of AHP model, 56.8 percent of the total study area had a very high water potential and this includes 94.26 percent with high potential and areas with moderate, low and very low water potential included 22.96, 24.96 and 17.07%, respectively. Regarding to the paired comparison AHP model, despite of direct determination of the weight of the SAW model, weight classes of each criterion were achieved according to the preferred class of all classes to the criteria. It is normal that the results from these two models will be different, so that according to SAW method, 0.73,13.07,30.16,18.65,7.37% of study area included area with very high, high, moderate, low and very low groundwater potential resources, respectively. For validation of two mentioned models (AHP and SAW models), The map of springs location were overlaid on the map of potential sources of groundwater of these two methods and the results showed a good agreement with the model of the position of the spring.
Conclusion: In This study the AHP and SAW models were used to finding underground water sources. The results showed that in both methods, highly potential water resources areas were mainly located in the northwest of the study area and the west and southwest area had higher potential water resources relative to the east part of the study area. This could be due to low slope and elevation or may be related to the alluvial deposits which covered upper parts of the hard rock with low thickness and this plays a main role in recharging of hard rock.
However, comparing the results of the two methods showed that AHP method has better results than the SAW. The result of AHP map showed that the east and center part of the study area had moderate to high groundwater potential which consist of about 50% of area.
M. Tabarmayeh; A. Vaezi Hir
Abstract
It is more expensive to remove pollution from groundwater than to prevent it. Delineation areas that arevulnerable to surface pollutants is one of methods to prevent pollution of groundwater resources. Focusing on this issue, DRASTIC model was used for evaluation of vulnerability of Tabriz-plain aquifer ...
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It is more expensive to remove pollution from groundwater than to prevent it. Delineation areas that arevulnerable to surface pollutants is one of methods to prevent pollution of groundwater resources. Focusing on this issue, DRASTIC model was used for evaluation of vulnerability of Tabriz-plain aquifer to pollution and the aquifer vulnerability map was prepared. The study shows that main zone of the aquifer’s groundwater is low to modrate vulnerability to pollution (DRASTIC Index of 120-40) that consist of about 55.84% and areas with low, moderate to high, and high risk zones comprise 21.81,22.08.% and 0.26% of the studied area, respectively Two tests of sensitivity analyses were carried out: the map removal and the single-parameter sensitivity analyses. Based on the characteristics of the studied area, the results from both map removal and single-parameter sensitivity analyses showed that the depth to water table has the most significant impact on the vulnerability risk zone. By overlaying of the vulnerability and landuse maps the areas where are subjected to potential release of pollutants from the agricultural activities were determined .Nitrate ion concentration and SINTACS model confirms the results of the vulnerability assessment.
