جستجوی مقالات مرتبط با کلیدواژه « sintacs » در نشریات گروه « آب و خاک »

Population growth, agricultural and industrial development has led to a sharp increase in water use, a decrease in the quantity, quality and pollution of groundwater resources. Appropriate measures to prevent pollution of groundwater resources are the identification of vulnerable aquifers. In this study, combined method (DSM) is the combination of DRASTIC and SINTACS methods, was used to evaluate the vulnerability of Khoy plain aquifer. Both methods use hydrological and hydrogeological parameters of this area to investigate the aquifer vulnerability and zoning of susceptible areas, but each of these methods has inherent characteristics and presents different results. Therefore, in this study due to the similarity of the results of these two. The method has been used simultaneously using combination of their advantages. Validation of each of methods were carried out with measured nitrate values from 26 wells in the study area. The Correlation Index (CI) was calculated between vulnerability maps and nitrate values to validation and compare these methods. The results showed that the CI of combined method is high; therefore, this method is more suitable for assessing the vulnerability of this region. Based on the results of the combined method, 19, 42 and 39 percent of Khoy plain aquifer are located within low, medium and high vulnerable areas.

These days, boom in agricultural section, use of pesticide lavishly, disposal of Industrial and urban wastes result in boosting the probability of aquifer pollution. So, it needs to identify the vulnerable regions for preventing of groundwater pollution and land use management. Thus, we use four methods (AVI، GOD، DRASTIC و SINTACS) for evaluating of ground water contamination in Qazvin- plain. Based on the comparison between indexes and classifications show the majority of vulnerability classification in this region is low to moderate. DRASTIC and SINTACS indexes are the most sensitivities in the central of plain. AVI index is low sensitive and GOD index is classified in moderate. By comparison the following indexes, the vulnerability of SINTACS index region calculated more conservative than other indexes, but AVI index is the lowest vulnerability. Among the above indicators with respect to the groundwater sensitivity in the area, SINTACS index is the better estimation than other indexes. The amount of effective parameters for determining vulnerability in DRASTIC and SINTACS by using the remove of parameters been evaluated, finally the analytical results show that the net nutrition parameters and the type of soil were the most impact on vulnerability of this region.

In recent years that we are faced with water shortage, the entrance of surface pollutants to the groundwater resources has become a serious problem in reducing the quality of groundwater resources. Therefore, identifying vulnerable areas and directing development programs in the areas which have not been vulnerable to pollution is the best way to provide sustainable development programs. In this study, aquifer vulnerability have been assessed using DRASTIC and SINTACS models at the Jarmeh plain, khozestan province. The principle of the DRASTIC model is based on hydrological and hydrogeological pollution transmission conditioning factors. Entering the parameters for both DRASTIC and SINTACS is the same, the main difference between them is that weighing and rating in the SINTACS method is more flexible. Groundwater vulnerability maps have been provided using overlaying of water depth, net recharge, aquifer media, soil media, topography, impact of vadose zone, hydraulic conductivity, the results of the mdels and were validated using nitrate concentration map. Correlation between nitrate and groundwater vulnerability maps provided by DRASTIC and SINTACS was 0.36% and 0.48%, respectively. Sensitivity analysis was investigated to determine the most effective factors using map removal and single parameter methods. The results of both methods show that the unsaturated zone is the most important factor on groundwater vulnerability in the study area.

The protection of the quality of groundwater is very important considering its vast usages in agriculture, industry and as drinking water. Removing groundwater pollution is an expensive process and needs a long time. Therefore, it is necessary to prevent the pollution of groundwater resources using proper methods. One of the usual methods is to investigate areas with high potentials to get polluted. The aim of this study choose a suitable method to identify areas sensitive to pollution in Sarab plain.
Two models DRASTIC and SINTACS were used in “Sarab” plain to evaluate the pollution of groundwater resources. First, the vulnerability maps of the aquifer were provided for each model. To do this, the information layers of “depth of groundwater table”, “net recharge”, “aquifer media”, “soil media”, “topography”, “the effect of vadose zone” and “hydraulic conductivity of the aquifer” were prepared in GIS. As the next step, the land use parameter was combined with the vulnerability maps, to prepare risk assessment maps. Also, to consider hydrogeological condition of the studied area, AHP method was used to correctly evaluate the weights and the ranks of the effective parameters and sub-parameters in DRASTICLU and SINTACSLU modified models. The correlation coefficient between the concentration of the Nitrate in groundwater and the calculated indexes for the studied area was calculated using linear regression.
Based on DRASTIC map, 82.62% of the studied area has medium vulnerability potential. However, 14.43% and 12.94% of the area have low to medium and medium to high vulnerability potential respectively. On the other hand, based on SINTACS maps, the vulnerability potential in 76.48% and 23.52% of the studied area is medium to high and low respectively. Also, according to the results of DRASTICLU index, 24.10%, 48.97% and 24.86% of the studied area are evaluated with low, medium and high risk respectively. However, based on SINTACSLU map, 55.35%, 40.82% of Sarab plain are located in areas with medium and high risk respectively. Besides, according to AHP-DRASTICLU index 7.81%, 50.86%, 37.52% and 3.74% of the studied plain are evaluated as areas with very low, low, medium and high risk respectively. AHP-SINTACSLU index shows similar results to AHP-DRASTICLU index.
To be able to choose the best index to evaluate the potential of vulnerability and risk for Sarab plain, the correlations between Nitrate concentration in groundwater on one hand and the amount of each of the used indexes were investigated. According to the results, DRASTIC index with R2=0.40 has the highest correlation among the investigated indexes. However, regarding risk evaluation, AHP-DRASTICLU index has the highest correlation, with R2=0.56. Therefore, to evaluate pollution vulnerability and risk in Sarab plain, these two indexes are the most accurate and trustable.

Population growth، industrialization and the development of agricultural activities are the causes of increasing municipal and industrial wastewaters and irregular use of fertilizers and pesticides، and consequently the contamination of groundwater resources. Since the main problem with SINTACS models، applies expertise rating parameters to be used in it، in this study، the model using Analytical Hierarchy Process based on local hydrogeological conditions were indeed improvement. To achieve efficient models، the correlation coefficients between nitrate concentrations in the aquifer vulnerability index as an indicator of contamination were determined using Simple Linear Regression Analysis (SLRA). The results showed that the optimal model SINTACS than model the normal SINTACS is correlated with higher nitrate concentrations. Also، in order to assess risk Andimeshk aquifer pollution، land use parameters with the parameters used in the SINTACS model are overlaid، thus in turn specific aquifer vulnerability map was provided. Results from the map showed that the risk of aquifer contamination is not high.