Journal of RS and GIS for Natural Resources
Year:2012 | Volume:3 | Issue:4|Papers Count:10

Geographic information system (GIS) and artificial neural network (ANN) modeling were used to investigate the effects of land cover change on groundwater quality and to predict their condition for future. Input parameters for running ANN model included seven maps: distance from roads and built-up areas, density of population and cultivated land in the years 1995, 2002 and 2008, digital elevation model (DEM), soil and geology. The output parameter was the observed groundwater quality in the sampled wells that included pH, SO4, NO3- and Fe. For NO3- and Fe the model was run with data from 2002, 2008 and their condition was predicted for 6 years of the future. About pH and SO4, the model was run with 1995 and 2008 data, and their condition was forecasted for 14 years of the future. This study reveals that the significant changes in the land cover due to the rapid growth of population have resulted in an extensive downgrading of groundwater quality in Ghara-su basin. Due to the intensive agricultural activities within the study area, ground water quality in the aquifer has been continuously degrading. Spatial distribution maps of various pollution parameters were prepared that demarcate the geographic distribution of water pollutants in a comprehensive manner and help in suggesting groundwater pollution control and remedial measures in a holistic way.

Since the water resources in grazing management and optimum use of rangelands have considerable importance. This study is a model for quantitative, qualitative and spatial distance assessment of water source’s propriety for sheep and cow grazing based on Geographic Information Systems (GIS). Integration data were carried out based on FAO (1991) methodically. Land evaluation done in rangelands of Piranshahr located in West Azarbaijan province. In this research from combining three factors quantity, quality and water resource’s distances the final model of degree of propriety of water resources for Sheep and cow grazing characterized. Results showed that accesses to water resources which the slope factor was the cause this limitation, where the limiting factor of propriety of water resources. So in terms of accesses to water resources 11367.32 ha (83.27%), 2308.37 ha (16.7%) and 31.77 ha (0.03%) from the area rangelands respectively located in S1, S2 and N suitability classes and about cow grazing, 75.7% (10343.43 ha) located in S1 classes, 13% (1785.65 ha) in S2 classes, 4.4% (600.46ha) and 6.8% (934.12 ha) located in S3 and N classes, respectively. According to the study area that is mountainous and have cold semi arid climate and the rainfall is relatively large, water quantity and quality sub models results showed that there is no limitation factors in this regard, and all of the samman units locate d in S1 classes.

Application of land use planning to optimize human activities is seen as an efficient tool to manage his activities on the environment. Managers and users take advantage of various methods to manage human activities across the lands. Obviously, the application of those methods which consider land realities in more details may result in most feasible plans for land use planning. The objective of this study is land use planning using Analytical Hierarchy Process (AHP) for irrigation farming purpose in parcel A of Gheshlagh dam watershed in Kurdistan province, western Iran. Geographical Information System (GIS) was used to map the collected data for each criterion considered in AHP method for the study area. Then, the produced maps were weighted using expertise’ opinion on each of the criteria. The weighted maps were applied to AHP for zoning the study area from suitability point of view for irrigation farming. The results showed that less than ten percent to the study area showed a suitable capability for irrigation farming, which was mostly concentrated in the eastern part within the study area.

The goal of this paper is reviewing and comparing of Shadegan international wetland changes during last two decades. To achieve this goal, the trend of changes in Shadegan international wetland and the relative consequences were examined by supervised classification of LandSat satellite images. For this purpose, maximum likelihood algorithm, in ENVI®4.8 software was utilized during 20 years period (1990-2011). WRASTIC index, one of the existing methods for evaluating risk and vulnerability of the surface water, was used for finding inflow water quality to the wetland. Results of this study show six percent decrease in area of Shadegan wetland during these years, about 1796.61 Km2 (25.71%) declination in water and soil areas, and by 1796.76 (9%) increase in the total area of vegetation cover. Growing vegetation cover denotes water pollution, eutrophication, and early devastation of this international wetland. A result of calculation WRASTIC index showed that wetland basin components have the great impact on pollution of inflow water to wetland. Continuing of this trend, make irreparable effects on this existence and integrity of this wetland.

In this study, the effect of urban reforestation on carbon sequestration in arid soils was evaluated, using the Quick Bird satellite image. Soil samples were collected (0-15, 15-30 cm) from the field visits and soil organic carbon content of the samples was measured.  Correlation coefficients between the satellite bands and vegetation indices with the results obtained from the analysis of geospatial data and data analysis using regression method, the best fit model for preparation the soil carbon sequestration maps were obtained.  The results of verified analysis showed the accuracy of the produced maps and corresponded well with the ground sampling points. The survey maps prepared to show that the reforestation on barren land area in Isfahan is caused of increased carbon sequestration in the dry land soil. Furthermore, a higher rate of carbon sequestration in the surface soil layers and decreases with increasing depth. Depending on the species planted in soil, the rate of carbon sequestration is varying. Soil carbon sequestration in areas that have been cultivated conifers species is greater than the hardwoods species.

Unplanned development of industries can be harmful to sustainable development. Some of the harms include destruction of farmlands and natural ecosystems and emission of environmental pollutants. Furthermore, establishment of industries in unsuitable and risky sites can cause heavy damages. Thus, unplanned development of industrial plants should be stopped and suitable lands for industrial purposes should be studied and identified. The aim of this research is land suitability assessment for industry’s establishment in Malard county using AHP-Fuzzy Logic method. Various qualitative and quantitative criteria effective in land suitability assessment were identified and selected. Then, using AHP method, qualitative criteria were quantified and weighed. In modeling process, fuzzy logic was used to convert discrete variables to continuous variables and change data layers to raster format and combines them in Arc®GIS software. Finally, the land suitability map for industrial development was developed.

Today, desertification is one of the major challenges for this century. For evaluation and mapping of desertification, many researchers have been conducted leading to regional and local models. The first step for implementing the model working unit is prepared. The purpose of this study was comparing the effect of map scale in preparation geomorphological units for desertification hazard mapping. For this purpose, in three scales traditional executive of Iran (1:250000, 1:100000 and 1:50000) was prepared classes of height, slop, aspect and lithology maps. And then work unit map based on geomorphology obtained from them. With get bigger scale range from 1:250000 to 1:50000 map polygon’s number for all maps increased with a linear trend. And also, study range was smaller and increased in polygon diversity. For stochastic analysis between diversity of an abundance of work units in three scales, used chip-square test. A result showed that significant are at 99% confidence level. A comparison of scale changes, showed that by 2.5 times of a scale of 1:250000 to 1:100000, five times of a scale of 1:250000 to 1:50000 and two times of a scale of 1:100000 to 1:50000, the number, frequency and percentage of area in work units almost have changed with the same proportion. More detailed study on three unites: mountains, pediment and playa showed that the geometric and spatial disciplines increased in the mountains toward the playa. Finally, scale of 1:100000 scale was introduced as an optimal scale in the study.