Mohseen Kazemi; Sadat Feiznia; Hassan Khosravi; Sadegh Naji; Hamid Mesbah
Abstract
Monitoring the area and their marginal land uses changes in lakes are one of the strategies to achieve proper management of lakes and wetlands. In the present study to monitor Maharlu Lake area and its marginal land uses changes in Fars Province, the Landsat images of 1987, 2001 and 2013 were selected ...
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Monitoring the area and their marginal land uses changes in lakes are one of the strategies to achieve proper management of lakes and wetlands. In the present study to monitor Maharlu Lake area and its marginal land uses changes in Fars Province, the Landsat images of 1987, 2001 and 2013 were selected in wet and dry periods (March and September). By applying geometric and atmospheric corrections, the maximum probability algorithm was used for providing land use map. The Kappa coefficients for the September of 1987, 2001 and 2013 were 0.85, 0.88 and 0.89, and for April of 1987 and 2013 were 0.86 and 0.88, respectively. After providing land use map and validation, the method of comparing satellite images was used to monitor the changes. The changes were monitored by comparing Landsat images after classification. Results showed that the Maharlu Lake area has decreased by 82% in September 2013 compared to 1987. This reduction was 20% in March, 2013 compared to 1979. By reducing the water level of lake in September, bare soil and saline lands were increased by 39 and 37.5%, respectively. Agricultural and range lands have been decreased by 28 and 3.5% from 1987 to 2013, respectively. In general, the area under cultivation around the Maharlu Lake and the water level has been decreased significantly due to the lack of significant changes in rainfall during the long-term period and significant increase in evapotranspiration of Maharlu area during the last three decades. Due to recent droughts, bare soils and saline lands have been increased during this period. This has different consequences which require the proper management and planning of lakes and wetlands, especially during the drought periods.
Seid Saeid Ghiasi; Faezeh Rajabzadeh; Somayye Najirda; Sadat Feiznia; Aliakbar Nazari Samani
Abstract
Shallow landslide susceptibility assessment by using appropriate methods and determine of effective factors in reduce of its hazards is so effective. The aim of this study is to determine the effective factors on shallow landslide occurrence and investigation of Statistical Index Method (SIM) efficiency ...
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Shallow landslide susceptibility assessment by using appropriate methods and determine of effective factors in reduce of its hazards is so effective. The aim of this study is to determine the effective factors on shallow landslide occurrence and investigation of Statistical Index Method (SIM) efficiency for landslide susceptibility mapping. So, determination of each class of factors’ weights was accomplished by using SIM. That was done by adoption of inventory landslide map and ten initial factors including: slope, aspect, rainfall, altitude, drainage density, plan curvature, land use, geology, geomorphological faces and rock unit sensitivity to erosion in ArcGIS 9.3. Then model efficiency was evaluated by using percentage of area under ROC curve and the results showed high accuracy (0.95) of SIM. Principal Component Analysis (PCA) was used for determination of primary causative factors of shallow landslide occurrence. Results showed that five variables of rainfall, slope, aspect, rock unit sensitivity to erosion and plain curvature are the most effective factors on landslide occurrence, respectively.
Hojatolah Samadi Arghini; Sadat Feiznia; Aliakbar Nazari Samani
Abstract
The purpose of this study is to determine the contribution of each lithological units in sediment generation of watershed. In this study, samples were collected primarily from sediments of small dams and sediments of waterways. Grading was performed for all samples by wet sieving. Then, 600 micron ...
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The purpose of this study is to determine the contribution of each lithological units in sediment generation of watershed. In this study, samples were collected primarily from sediments of small dams and sediments of waterways. Grading was performed for all samples by wet sieving. Then, 600 micron and 4 mm sieves were selected as indicators and by choosing 100 grains of sediment from each sample, mineralogical analysis was performed using a binocular and considering mineral and rock fragments the results were compared and adapted with the lithological units and the share percentage of each stone, each mineral deposits were determined by counting the number of minerals and rock fragments. According to the results, Єz lithological unit has the highest share in erosion and sediment yield with a 44.62 percent. This unit consists of pink to red Micaceous shale. PMl lithological unit with 22.88 percent is in the second place consisting limestone. The third lithological unit that has the largest share in sediment yield is Ev unit, which consists of andesite and andesitic breccia with layers of tuff and tuffite. Pl-Qc, Єl, Qt, Js, Et, Ek1, Pd, Єbt and Ef units with 4.25, 3.22, 2.09, 2.05, 2.01, 1.83, 1.33, 1.32 and 1.23 percent are in the next order and have the highest share in the erosion and sediment yield of watershed.
Soheyla Aghabeigi; Abdol Rasoul Telvari; Sayed Khalagh Mirnia; Sadat Feiznia; Mehdi Vafakhah
Abstract
Sediment concentration in rivers, especially in seasonal ones, is affected by flood situation due to changes of rainfall or snowmelt events. Due to the importance of flooding flows in inundation and the useful age of reservoirs built on seasonal rivers, the study and assessment of this issue seems to ...
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Sediment concentration in rivers, especially in seasonal ones, is affected by flood situation due to changes of rainfall or snowmelt events. Due to the importance of flooding flows in inundation and the useful age of reservoirs built on seasonal rivers, the study and assessment of this issue seems to be essential. In the present research, suspended sediment concentration variation in spring and autumn floods and runoff from snowmelt in spring, have been studied for Abshine River in Ekbatan Dam Watershed. Over the forecast period, three storms in autumn, two storms in spring and five snow melt events were selected and compared. Analyzing 226 suspended load samples showed its variability in the area. Sediment rating curves in different base times showed different trends. The correlation coefficient (r) were 0.79 and 0.50 for storms and snowmelts and 0.81 for all data, respectively. Also, coefficient and power value analysis of sediment rating curve, presented the same erodibility for hill slope in both seasons (spring and autumn). Separating falling and rising limbs of flow hydrograph and assessing their effect on discharge explains a better Q-sediment concentration relationship. The hysteretic shape of discharge and sediment concentration had clockwise and anticlockwise form and compound pattern of both forms that reflected the distribution of probable sediment sources throughout the catchment.
Majid Mohammdi; Hamid Reza Moradi; Sadat Feiznia; Hamid Reza Pourghasemi
Volume 1, Issue 4 , February 2010, , Pages 248-258
Abstract
Landside is a natural disaster with great human and economic losses in Iran. In recent year, landslide occurrence due to change of land use and construction of roads, has been on the increasing trend in northern regions of Iran. This phenomenon is more occurring in developing countries due to high rate ...
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Landside is a natural disaster with great human and economic losses in Iran. In recent year, landslide occurrence due to change of land use and construction of roads, has been on the increasing trend in northern regions of Iran. This phenomenon is more occurring in developing countries due to high rate of population growth and natural resources deterioration. There are several methods for landslide hazard zoning and in this research density area and analytical hierarchy process models were utilized. For landslide susceptibility mapping, field study landslides distribution map and effective factors are required. Prioritization of effective factor was carried out using AHP. Our investigation indicates that lithology, distance from road, slope, distance from drainage network, land use, elevation and aspect are the main land slide controlling factor in the area respectively. Evaluation of these models using QS index showed that density area is a better approach for landslide hazard zonation in the region.
Hamid Reza Moradi; Nayereh Ghazanfarpour; Sadat Feiznia
Volume 1, Issue 2 , July 2009, , Pages 119-127
Abstract
One of the effective factors in soil erosion is geological formations of the drainage basin from the view points of their erodibility and the amount of runoff and sediment yield. In this investigation a part of Segzi- Kuhpayeh subdrainage, located in Zayandeh-Rood Drainage Basin with 67091.7 ha area ...
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One of the effective factors in soil erosion is geological formations of the drainage basin from the view points of their erodibility and the amount of runoff and sediment yield. In this investigation a part of Segzi- Kuhpayeh subdrainage, located in Zayandeh-Rood Drainage Basin with 67091.7 ha area was chosen for studying erodibility and sediment yield of Quaternary Formations. For doing this, the map of Quaternary Formations was prepared. Then in each unit a field rainfall simulator was used and runoff and sediment were collected from the plots and erodibility and sediment yield factors were obtained. Soil samples were taken adjacent to each micro plot for laboratory tests and the data were analyzed statistically. The results of regression analyses have shown that erodibility and sediment yield are significantly different in various Quaternary Formations. The most important physical and chemical parameters in sediment yield in different formations are Silt, Sand, very Fine Sand, Wetness, Caco3 and in erodibility of different formations are Silt+ very Fine Sand, Caco3, Silt, Clay, very Fine Sand and EC.
