Rahim Kazemi; Samad Shadfar; Reza Bayat
Abstract
Information on the hierarchical importance of the factors influencing on the spatial distribution of springs in a watershed are required for the development of the water quality and quantity management plan. In this regard, we address the integration of GIS and decision support tools, for zoning prone ...
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Information on the hierarchical importance of the factors influencing on the spatial distribution of springs in a watershed are required for the development of the water quality and quantity management plan. In this regard, we address the integration of GIS and decision support tools, for zoning prone areas. In this research to determine hierarchical importance of the elements on the water resources development in Karst regions, first with literature review and field studies, the effective parameters in occurrence of spring were selected. Then thematic layers of these parameters in GIS environment were prepared. Each layer separately crossed with the spatial distribution of spring's layer and priorities of each sub layer with respect to each other in terms of frequency of spring's occurrence were determined. Finally, using the analytic hierarchy process, factors affecting the occurrence of this phenomenon and the weight of each factor was calculated by Expert Choice software. Results showed that the weight of the top layer assigned to the lithology and carbonate substrate alone formed 54% of the weight of this layer. The next layers in order of importance were including the layer of the slope and elevation classes, structural elements, lineaments, limestone contact and drainage layer. Potential map prepared by this method, match 76 percent with the spatial distribution of springs.
Somayeh Jafari; Reza Bayat; Amirhossein Charkhabi; Nader Jalali; Fazel Iranmasnesh
Abstract
Sand dunes developed in 15 provinces with an area of 4.4 million hectares and 56 Citadel, are one of the most important geomorphological features in Iran. Sand and desert stabilization technical office studies, according to project results identify focal and present four regions including Ahvaz, Dasht-e-Azadegan, ...
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Sand dunes developed in 15 provinces with an area of 4.4 million hectares and 56 Citadel, are one of the most important geomorphological features in Iran. Sand and desert stabilization technical office studies, according to project results identify focal and present four regions including Ahvaz, Dasht-e-Azadegan, Susa and the Omidiyeh in Khuzestan province. The mentioned area includes 279,505 hectares of land in Khuzestan. This study has used remote sensing technology, GIS techniques and analyzed effective recorded winds data. Toward were reviewed and analyzed the wind regime of the area for direction of source area using Windrose Diagrams. In this study, based on utilizing and composing of image processing techniques such as image enhancement, threshold, false color composition, filtering and analysis and results of wind data analysis, with other investigations is useful to find the source of sand dunes. The results from direction of source area confirm that source of sand dune located in NW to W, notice Windrose in Khuzestan. The source area are flood alluvial fan plain, alluvial fan, agriculture land, meandering rivers and sensitive formation to erosion including Aghajari formation and Bakhtiari formation that located in the in NW to W section.
Reza Bayat; Amir Sarreshtedari; Ali Jafari Ardekani; Reza Sokuti Oskuee
Abstract
Due to vegetation cover importance in protecting soil and its important role in controlling erosion, this study was conducted to determine the effect of land use managementon the Orumiyehlake watershed erosion rate, using GIS and RS technologies and EPM model. Using ETM+ 2002 satellite imagery, field ...
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Due to vegetation cover importance in protecting soil and its important role in controlling erosion, this study was conducted to determine the effect of land use managementon the Orumiyehlake watershed erosion rate, using GIS and RS technologies and EPM model. Using ETM+ 2002 satellite imagery, field work and existing map, required layer of model prepared and soil erosion was estimated in the current situation. Management scenarios, with good and bad actions through changes hypothetically in land use rank (decreased and increased in steps of five to 50 percent), the rate of soil erosion and changes in estimates were calculated. Results showed that maximum of erosion rates is belong to 3015 and 3054 sub-watershed with values of 768 and 749, minimum is belong to 3072 and 3056 sub-watershed with values of and 287 respectively and the mean for the watershed 485.9 . Trend of erosion rate change due to land use change was linearly and positive, meanwhile ultimate condition with 50% addition or reduction to land use rank, respectively caused 83.7 and -64.6 percent change in soil erosion.
Reza Bayat; Bagher Ghermez Cheshmeh; Hoseingholi Refahi
Abstract
The rate of soil erosion and sediment yield depends on different factors. Vegetation cover is more variable factor effecting occurrence of soil erosion in comparison to the other factors in a given watershed. The main purpose of this study was to investigate the role of canopy cover resulting from land ...
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The rate of soil erosion and sediment yield depends on different factors. Vegetation cover is more variable factor effecting occurrence of soil erosion in comparison to the other factors in a given watershed. The main purpose of this study was to investigate the role of canopy cover resulting from land management on sediment yield. Taleghan watershed was selected as a study area due to the availability of sufficient data. Necessary information was provided for MPSIAC model and was made in GIS environment and all needed calculations were done for preparing sediment yield map. The result of the comparison of the calculated and the estimated sediment yield indicated similarity of them (i.e. 98.3% similarity). For impact assessment of vegetation cover effect on sediment control, canopy cover was changed in a range of ±5 to 25% percent with 5% interval in both good and bad conditions. The effect of these changes was applied to bare soil percentage as well. The related thematic maps were prepared and sediment yield was determined. The result showed that sediment yield varied because of changing canopy cover. The increase and decrease of canopy cover by 25%, affected the sediment yield to change by -29.6% and 26.8% respectively.
