Showing 9 results for Watershed
Yadollah Balyani, Mohammad Saligheh, Hossein Asakereh, Mohammad Hossein Nasserzadeh,
Volume 15, Issue 37 (9-2015)
Abstract
Precipitation is one of the most intractable elements. The oscillating behavior of the crucial environmental planning (explicit and tacit knowledge of the behavior), is the key variable. Spectrum analysis techniques to understand the behavior of overt or covert methods suitable for the extraction and analysis of climate oscillations with different wave lengths. The size range of the distribution variance across all wave lengths may provide time series. In this study, data from 37 stations Heleh and Mond watershed (both rain and synoptic) from its inception until 2011, who had over 30 years of data, to analyze the cycle of annual rainfall, interest has been taken. So that the space is 3-2 year cycles in every area of study, the highest annual rainfall events are returned. On this basis, the Story of annual precipitation 95 percent for each of the stations under study and cycle meaningful estimate of the time series of basin data were extracted.
Ahmad Reza Arabameri, Mohammad Hossein Ramesht,
Volume 16, Issue 43 (12-2016)
Abstract
Municipal solid waste (MSW) is the natural result of human activities. If an appropriate management system do not use to this problem, it may lead to environmental pollution and jeopardize the human health. Landfill site selection in urban areas is a critical issue due to its huge impact on the economy, ecology, and the environmental health. Therefore, numerous criteria must be considered and the selection process is a complicated since it has to integrate social, environmental and technical parameters. In this study, the most suitable candidate sites for locating landfill in Shahrood-Bastam watershed, as a case study area are determined by using an integration of the Geographical Information System (GIS) and Multi Criteria Decision Making (MCDM) methods. For this purpose, 12 data layers including Elevation, Stream density, Fault density, Habituate density, distance to road, plan curvature, lithology, slope, Temperature, soil, land use and distance to protected area extracted with Arc GIS 10.1 are prepared and one of MCDM methods which is Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is implemented. For determination of criteria weight, analytic hierarchy process was used. Lithology, land use and slope criteria with the highest score (0.24, 0.18, and 0.14) had the greatest impact on landfilling. The results showed that, zone 2 for the reason of low fault and drainage density, suitable distance of Urban areas, appropriate slope, topography and lithology has obtained the lowest Euclidean distance from ideal positive (0.026), the highest Euclidean distance from ideal negative (0.228), and the lowest relative distance from the ideal solution (0.894), as a result, The greatest weight and highest priority is allocated for landfill. The results of this research will be fruitful in systemic management approach of urban regions
Saman Alimoradi, Asadollah : Khoorani, Yahya Esmaeilpoor,
Volume 17, Issue 44 (6-2017)
Abstract
The aim of this study is to retrieve land surface temperature (LST), air temperature (AT) and precipitation and to study their relationship with vegetation in rang lands of Karun watershed of Khuzestan province. For this purpose, land surface temperature (LST) and NDVI was drived from NOAA-AVHRR for maximum amount of greenness (April) for a period of 27 years. In order to extract LST, Price algorithm was used. Also air temperature and precipitation were interpolated for selected weather stations using IDW method. Spatial correlation outcomes (on 0.05) between NDVI with LST and air temperature show a reversed relation. This spatial relation is stronger for LST, so that this coefficient is often upper than 0.6, while seldom is 0.4 for air temperature and precipitation. Spatial regression models show that 62 percent of NDVI changes is determined by LST (R2=0.62) and air temperature and precipitation determine very limited amount of NDVI dynamics.
Dr. Mohammad Javad Vahidi, Dr. Rasoul Mirabbasi,
Volume 19, Issue 53 (7-2019)
Abstract
In order to protect soil and water resources should be identified erodible areas of watersheds, to be able to prevent land degradation and to control erosion in the form of soil conservation planning or watershed management. Therefore, the present study aimed to classification and delineation of susceptible areas to water erosion in the Hervi watershed using Hjulstrom curve, has been conducted. Increasing of accuracy, speed and facility of spatial achievement, using GIS technology, are advantages of the present study. In this study, were separated 10 sub-watersheds based on the feeding levels of streams. Spatial variability of soil properties in sub-watersheds, such as texture and the mean diameter size of the particles using hydrometer method were measured; also the maximum potential velocity of outlet in sub-watersheds based on the characteristics of each sub-watershed were calculated. Then, status of erosion and sediment in watersheds and sub-watersheds was studied using Hjulstrom curve (based on the mean diameter size of sediment particles and the maximum potential velocity of outlet), and was comparatively classified in term of erodibility. Finally, delineation map of susceptible regions to water erosion in the study area were obtained. The results revealed that the upstream and side areas of the watershed including: Sub-watershed No.4 (8.94% of the land), has very high erodibility, and Sub-watersheds No.1 and No.9 (36.94% of the land) have high erodibility. These areas are steep and often devoid of vegetation or have poor vegetation (such as poor pastures and rain-fed farming); so, it is necessary a proper strategy to prevent further erosion.
Parviz Ziaiian Firouz Abadi, Ayoub Badragh Nejad, Reza Sarli, Mahboub Babaie,
Volume 20, Issue 57 (6-2020)
Abstract
Rivers are the natural flow of surface waters that flow in a certain bed seasonal or permanently. Rivers include a vast range of narrow waterways and with mountainous high steep to low steep and wide beds flowing in plains. However, rivers have had an effective role in urban development and human civilization, therefore, identification of flood prone areas and flood part in the potent lower fields of Birjand watershed would lead to aid feeding the artificial environment of the water shed and would also lead to increase of quality in the environment fields. The purpose of this study is to identify the environment about the river and evaluating the danger in case of occurrence of flood crisis. All of the processes and analyses of data were performed in the GIS atmosphere utilizing the three methods of saw Fuzzy, AHP and Boleyn logic for weighting data such as (gradient, erosion, land application, watershed system, soil, geological fault distribution, quaternary unit, level of underground waters, and satellite imagery) and the potent areas in terms of confronting danger were located. The results of the study showed that the areas that the effort for exploiting floods was made have characteristics such as (existence of alluvium and colluvium sediments in the high steep feet of the slopes and watersheds with major stone occurrences, existence of fan-shaped sediments and alluvial fan in the external aperture of dry rivers and water ways with mountainous watersheds and hills leading to low steep fields, existence of low fields from the manner of altitude in proportionate to fields near). Finally, the best model that could present a better evaluation and conclusion about this matter was the Boleyn logic model in locating the flood part.
Khadijeh Haji, Abazar Esmali-Ouri, Raoof Mostafazadeh, Dr Habib Nazarnejad,
Volume 22, Issue 66 (10-2022)
Abstract
Also, because of human activities and natural phenomena, the face of the earth has always undergone a change. Therefore, for optimal management of natural areas, awareness of the ratio of land cover/land use changes is a necessity. Therefore, extraction of land use maps as the most important goal in the management of the natural resource can be considered. The purpose of the present study was to evaluate land cover/ land use changes at the Rozechai Watershed during the period of 30-years 1985-2015 using Landsat 5 and Landsat 7 satellite imageries such as TM and ETM+ sensors; plus, land use maps were prepared using TerrSet software and object-oriented classification in 1985 and 2000 years. As well as the land use map of procurement by the geographical organization in 2015 has been used. The results show that rangelands level has the highest percentage among all land use types during the period of 30 years, but between 1985 and 2000, and 2000 to 2015, the level of rangelands has a decreasing trend indicating the destruction trend in the region of the replacement of moderate- poor rangelands and good rangeland by dry farming. Also, the tables of obtained from the error matrix indicate that the observed values in the diameter of the error matrix are much larger than the values outside the diameters. Thus, the overall accuracy for the years 1985, 2000, and 2015 were 97, 90 and 96 percent, and The values of Kappa index were 91%, 84% and 94% respectively, indicating a high degree of accuracy in the object-oriented approach to classification.
Asadolah Hejazi, Zahra Heidari,
Volume 23, Issue 68 (4-2023)
Abstract
In recent years, population growth and consequently the shortage of drinking water resources have increased the importance of studying the areas of caries Regarding the importance of the subject, in the present study, the evaluation and monitoring of the developed karstic areas and the potential of contamination of Cartesian resources in the Ravensar basin have been addressed In this study, 7factors were used to evaluate the factors of Karst development in Ravansar basin as well as two methods of OWA and ANP. The method of work is that after the necessary processing, using the OWA method and applying weights obtained through the ANP model, the zoning is done After designing the zoning map, using the satellite imagery of 2007 and2015, the development of human development areas in the developed karstic areas has been evaluated The results of this study indicate that most of the studied basin, especially in northern and western areas of the basin, are highly and relatively developed in the class, The calculation of the area of man-made areas suggests that in2007, about 2.6 km of occupied areas of man-made industrial zones have been occupied which, according to the growing population, increased to 3.8 km in2015, human-made areas have been extracted in developed artisanal areas
Mr Jaefar Derakhshi, Dr Behroz Sobhani, Dr Saeed Jahanbakhsh,
Volume 24, Issue 72 (6-2024)
Abstract
In this study, the prediction of precipitation and temperature values using the general atmospheric circulation models during 1964-2005 is investigated. Climatic data including daily values of total precipitation and mean temperature were obtained from the Iranian Meteorological Organization. Considering the climate change scenarios RCP4.5, RCP2.6 and RCP8.5 for the coming period 2010-2100 were evaluated under the canESM2 climate change model of Aharchai Basin. Due to the low accuracy of the general circulation models, the SDSM4.2 miniaturization model was used and the changes in precipitation and mean temperature parameters were simulated for future time periods. In this study, to calibrate the SDSM model, among the 26 large scale climate parameters (NCEP), on average, 3 parameters have the highest correlation with the mean temperature and 5 parameters have the highest correlation with the average precipitation in the Aharchai Basin. The results of climatic parameters prediction showed that simulation of climatic parameters mean temperature was performed with higher accuracy than mean precipitation values. The reason is that the precipitation data are not normal and unconditional. The results show that the basin temperature averaged more during the period 2070-2099 under the scenario RCP8.5 than the observations period of 1964-2005 and the basin precipitation during the period 2070-2099 under the scenario RCP2.6 showed the highest increase in the entire study period.
Dr Mohammad Ebrahim Afifi,
Volume 24, Issue 75 (2-2025)
Abstract
Among the natural hazards, without a doubt, the flood is known as a natural disaster. In this research, Shannon entropy model was used to prepare a flood sensitivity map. First, 34 flood watersheds were selected from Firoozabad basin, and then these 34 points were classified into two groups. With 22 points, 65 percent of the points for training and modeling, and 12 points, 35 percent of the locations that were not used in modeling were used for validation. First, a map of the status of the floods was developed and Then, 10 factors, slope, tilt, lithology, land use, NDVI, SPI, TWI, altitudes, rainfall and distances from the river were selected as flood factors in Firoozabad basin. Prioritizing the effective factors in the occurrence of flood by Shannon entropy index showed that the NDVI layers (2.03), rainfall (0.00), distance from the river (1.89), SPI (385.1), elevation classes (999 (0/19), gradient with weight (0,932), lithology (478/0), TWI (379/0), and land use (280/0), respectively (0/184) have the highest and the least impact Flood events. Based on the results of the ROC curve, the predicted surface area under the curve with 35% of the validation data is equal (91.42%) and for the success rate with 65% of the equal education data (92.53%).
