جستجوی مقالات مرتبط با کلیدواژه « geographic information system (gis) » در نشریات گروه « آب و خاک »

Water supply for mines is an important concern in areas affected by high water stress such as Sangan iron ore mine. In such a situation, one of the methods to control and store water in wet periods for use in dry periods is the construction of underground dams. Due to the multitude of influencing parameters and difficulty of making a decision about suitable locations for the construction of underground, applying Geographic Information System and analytical hierarchy process methods have been proposed. For this purpose, factors such as lithology, slope, land use, aquifer and city boundary, and distance from the village, fault, roads, and stream were used. Thematic map of each parameter was prepared using GIS data. Measuring the rate and weight of the maps was performed using the crisp method on a scale from 0 to 9 and analytical hierarchical process (AHP), respectively. After preparing the initial map, the final map was prepared by applying surface water geometric, and environmental considerations. Alarge area of the study area is in the category of medium potential for the construction of an underground dam, and the areas with high potential are located at the confluence of tributary to mainstem of streams, and in the southern half of the study area. The stream located in Nashtifan district, which is located in the southwest of the external border of the Khaf aquifer and serves as the output drainage of Kal Fadak in the northern part of the study area was confirmed as the optimal point.

Proper management of groundwater resources, as the main source of fresh water, is very important. Groundwater vulnerability assessment has been applied as a management tool for prioritizing the use of resources, controling the contaminant transfer and adopting cost-effective ways for aquifer management. This study has adopted a novel approach based on DRASTIC method, analytic hierarchy process (AHP), and genetic algorithm (GA) optimization method to assess the vulnerability of Shiraz aquifer. AHP was utilized to modify the rank of DRASTIC model’s parameters and GA optimization model was used to optimize the weights of DRASTIC parameters based on hydro-geological characteristics and nitrate concentrations of the Shiraz aquifer. The main aim of the GA-AHP model was to maximize the DRASTIC index correlation with nitrate concentration. The vulnerability map of Shiraz plain was provided using geographic information system (GIS). The results suggested that the southern and southeastern areas of Shiraz plain were faced with very high and high classes of vulnerability, respectively. The Pearson correlation coefficient between the developed vulnerability index and the nitrate concentrations was estimated as 80%, which confirmed the accuracy of the vulnerability map of Shiraz plain.

Due to climate change and growth of urban communities, the need for groundwater and exploration of these resources are increasing. Therefore, the purpose of this study was to provide a groundwater potential mapping using the geographic information system (GIS) in a region located in Booshehr plain using an ensemble of certainty factor (CF) method with Bagging data mining method. For this purpose, in the first step, 339 well locations were identified in the study area, of which 238 wells (70%) were randomly selected as training points and 101 wells (30%) were selected as validation points. In the next step, 15 factors affecting groundwater such as altitude, slope angle, slope direction, slope length, plan curvature, profile curvature, topographic wetness index, distance from fault, fault density, distance from river, drainage density, rainfall, lithology, Soil and land cover were prepared in ArcGIS 10.3 and Saga GIS software. The spatial relationship between the effective parameters and the location of the wells was determined using a CF model. These weights were used to implement the Bagging model. In order to validate the accuracy of the ensemble model, the RMSE and MAE indices were used. Also, in order to validate the accuracy of the maps, ROC and AUC were used. The results of this study showed that the values of RMSE and MAE indices for training and validation are equal to 0.247, 0.162, 0.256 and 0.169 respectively. The evaluation results of the ROC curve indicated that the AUC was 86.2 and 94.8%, respectively, for CF models and the ensemble of CF model with the Bagging model.

In order to simulate surface runoff and depth of flow on surface area of watershed and outflow rate, a new hydrological model with numerical structure has been designed and presented. In this model, surface flow governing Saint- Venant equations in one- dimensional and two- dimensional forms along with the Parlang infiltration model parameters, have been solved using a finite difference numerical method, for the kinematic wave approximation using an implicit scheme. In order to solve the system of nonlinear equations resulting from discretization of the flow and infiltration equations, the Newton Raphson method was used. An algorithm and program of this model in one- and two-dimensional modes have been developed by using MATLAB software and their results have been analyzed. For checking the accuracy of the presented numerical model in estimation of the height and volume of the surface flow, the model was implemented for the Maroon valley watershed in Fars province. Topographic condition and slope of the basin surface used in the surface flow equations and the parameters required in infiltration equation have been prepared using the GIS maps and elevation models for feeding the numerical model. Comparison of the model computational hydrographs with the observed results at the hydrometric station in the basin outlet and also investigation of the statistical coefficients calculated from the results showed similarities and good accuracy in simulation of the flood hydrographs by the numerical model. Also, the kinematic wave had a good approximation in predicting the amount and occurrence time of the selected floods peak discharges. The average accuracies of the one- and two- dimensional models in predicting the amount and occurrence time of the selected floods peak discharge were c 97.3 and 97.2 percent and 95.45 and 98.47 percent, respectively.

The accessible water resources would not be able to meet the different needs erelong. Inevitably this would cause to search for newer lands for irrigation. According to the water resources’ limitation and the necessity of using the pressurized irrigation systems to gain the optimum use of the available water resources, it would be necessary to determine suitable lands for agriculture and pressurized irrigation. The land suitability (LS) classification is defined as the determination and classification of specific land areas according to their suitability for the desire use. The parametric evaluation system (PES) makes it possible to have the best decision by ranking different effective factors on the goal parameter. By considering that the underlying management and proper planning and optimum use of resources requires accurate and detailed information of the area of interest, in this context, Geographical information system with the ability of spatial analysis capabilities, analyzing and integrating the map information, tables and reports, can play a great role in achieving the set goals.
At the current study the zonation of priority of applying drip irrigation systems (DIS) within Babol and Babolsar counties is done by parametric evaluation of some of soil physicochemical characteristics and water chemical characteristics by geographic information system (GIS). The soil characteristics were Texture (T), Depth (D), Slope (S), Acidity (pH), and Electrical Conductivity of soil saturation extract (ECe). The water characteristics were Chloride (Cl), Boron (B), Electrical Conductivity (EC), Sodium Adsorption Ratio (SAR) and Residual Sodium Carbonate (RSC). These data were obtain from Jahad e Keshavarzi (agriculture) organization of Mazandaran.
The evaluation of the soil parametric index (SPI) indicated that the most area (approximately 90% of the total studied area (TSA)) is “suitable”. The most area for water parametric index (WPI) (approximately 75% of the total studied area) was “currently not suitable”. The evaluation of WPI’s sub-indexes indicated that the most limitation levels (severe and very severe levels) were related to residual sodium carbonate (RSC) index (approximately 90% of TSA). It was 9.4%, 8.5%, 0% and 0% for chlorine (Cl), electrical conductivity (EC), boron (B) and sodium adsorption ratio (SAR) sub-indexes respectively.
According to the results to apply DIS at the studied area, the prevention considerations (to prevent emitters from clogging due to high levels of RSC), like pickling would be necessary. In addition using drippers which have less sensibility to clogging is suggested, in order to preventing drippers clogging at very severe damage possibility locations.

The analysis of the urban pathway inundation via modeling is an effective step towards the enhanced management of urban transportation and the reduction of the hazards caused by the infrastructure damages. Given the complexity associated with data and the information related to the pathway inundation (such as topography, hydrology, buildings and so on) the rational, SCS and SWMM models can be utilized as reliable and efficient estimation methods in small urban areas with relatively small basins. The present paper is adhering to the Digital Elevation Model (DEM) and employing data such as elevation spots, the intensity-duration curves of precipitation, segmented plans, urban usage, and with execution of the mentioned models determines the surface outlet runoff as well as the dimensions of each drainage canal. In this regard, our research aims at re-evaluating the proper dimensions and flow of each drainage canal through the comparison of the obtained results with the current status of the drainage. The results obtained from the implementation and execution of the models demonstrated 7 percent reduction in the dimension of the drainage canals according to the current status of the region.

Nowadays one of the solutions to protect aquifers in developed countries is to prevent contamination of aquifers. In this study Salafchegan-Neyzar Aquifer vulnerability against agricultural pollution was evaluated, by Drastic and GIS models. In this method, seven hydrogeological factors that were effective in groundwater pollution were combined. The seven factors are: watertable depth, the net recharge aquifer, aquifer media, soil media, topography and the unsaturated hydraulic conductivity. Vulnerability zoning maps were drawn from the results obtained. Zones vulnerable to nitrate pollution were determined. Using GIS techniques and by single-parameter sensitivity analysis, the influence of parameters used were investigated. Results showed that depth to water table aquifer of Salafchegan was the most important factor influencing vulnerability in Salafchegan-Neyzar aquifer. The results of different qualitative zones was shown in four categories of very low, low, medium, high which were 550, 853, 150 and 498 square kilometers before the correction of model were converted to 351, 486, 401 and 425 after the model correction. In general, sensitivity analysis showed that effective and theoretical weight of using parameters, aren’t fully coincide and in some cases have considerable differences.

In modern agriculture، the preparation of soil fertility map seems to be necessary to plan for appropriate using of fertilizers for crops. This study was conducted to prepare a distinct map for evaluating soil fertility according to soil chemical properties in 136 soil samples of Ardabil plain in Ardabil province. To achieve this purpose، the available K and P، total N، EC، pH and organic matter of soil were mapped using geostatistical Kriging estimator into Geographic Information System (GIS) by ArcGIS9. 3 software. The Analytical Hierarchy Process (AHP) was used for weighting soil fertility factors as the input data. Then a membership functions was defined for each factor by factorial scoring and the map of soil fertility was prepared and classified for wheat and potato by using AHP technique into GIS program. The results showed that 74. 84، 3. 59، 19. 3 and 2. 32 percentage of lands for wheat cropping were classified based on soil fertility into groups of weak، moderate and suitable، respectively while for potato it was 24. 88، 27. 57، 7. 19 and 40. 34 percentage، respectively. As a final result، this type of distinct soil fertility map for different crops could assist us to manage the appropriate using of lands and fertilizers.