پژوهشی
Geomorphology
Arezou Cheraghi; Shahram Bahrami; Somayeh Khaleghi; Kazem Nosrati
Abstract
Dolines as karst landforms play an important role in soil formation. In this study, the morphometry of dolines and their relationship with the physicochemical characteristics of soil in Noakoh Anticline in Kermanshah province were evaluated. Chemical and physical characteristics of 36 soil samples of ...
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Dolines as karst landforms play an important role in soil formation. In this study, the morphometry of dolines and their relationship with the physicochemical characteristics of soil in Noakoh Anticline in Kermanshah province were evaluated. Chemical and physical characteristics of 36 soil samples of dolines were collected and measured in the laboratory. Also, digital elevation model (DEM; 13 cm) obtaining from UAV images, was used to measure the morphometric parameters of dolines. Pearson’s correlation and T-tests were performed on data using SPSS software. Results showed that large dolines have higher slope, depth and roundness, as well as sandy soils, and higher EC, pH, potassium, phosphorus, water holding capacity and soil organic carbon. Also, low- elevation dolines have higher values of area, slope, depth, roundness, and host soils wih higher EC, PH, potassium, water holding capacity, organic carbon, and saturation percentage than high elevation dolines. The dolines located in the plunge of the anticline have higher values of area, slope, depth, roundness and cntain soils with higher values of clay%, EC, PH, potassium, water holding capacity, organic carbon and saturation percentage than the dolines in the central part. The mean of the most morphometric parameters and physicochemical characteristics of the soil in steeper-slope dolines is higher than in low-slope dolines. Therefore, the morphometric and pedological differences of dolines show that their formation and evolution are more at lower altitudes, plunged areas and steeper slopes. In general, vegetation, elevation, slope and type of precipitation play an important role in morphometric differences and soils in dolines.
پژوهشی
Hydrogeomorphology
saeed negahban; mehri marhamat
Abstract
Flood is one of the most destructive natural disasters with social, economic and environmental consequences. Therefore, comprehensive flood management is necessary to reduce the effects of floods on human life and livelihood. The main goal of this study is to investigate the application of the maximum ...
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Flood is one of the most destructive natural disasters with social, economic and environmental consequences. Therefore, comprehensive flood management is necessary to reduce the effects of floods on human life and livelihood. The main goal of this study is to investigate the application of the maximum entropy model (Entropy Maxent) in R software for flood susceptibility mapping in Fars province (Jahrom urban basin). First, by using the information of natural resources of Fars province and field visits, flood-prone points (50 points) were determined. In the next step, environmental variables such as altitude, slope, and distance from the river, drainage density, average annual rainfall, land use, soil type, and geology were selected by performing the multiple collinearity test, and vegetation cover and topographic humidity index were removed. Among the selected environmental variables, the three factors of height distance from the waterway and land use have had the greatest impact in the modeling process. After that, the receiver operating characteristic curve (ROC) was drawn for the flood sensitivity map, and the value of training data (0.943) and test data (0.932) was obtained. In the following, the model was optimized and upgraded using the genetic algorithm. As a result, this flood susceptibility map can be useful for researchers and planners in flood mitigation strategies.
پژوهشی
Hydrogeomorphology
Hamid Amoonia; Mohammadreza Yousefi Roshan; Mohammad Dِaymevar
Abstract
Gorgan Bay, one of the most important wetlands in northern Iran, has experienced significant water level fluctuations with severe environmental consequences for surrounding areas. This study employs a comparative analysis of spectral water indices to monitor water level changes in Gorgan Bay. Previous ...
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Gorgan Bay, one of the most important wetlands in northern Iran, has experienced significant water level fluctuations with severe environmental consequences for surrounding areas. This study employs a comparative analysis of spectral water indices to monitor water level changes in Gorgan Bay. Previous studies have documented substantial water level variations, leading to substantial ecological and economic losses, highlighting the urgent need for effective management strategies. The present research utilizes Landsat 5 and 8 images to investigate water level changes in Gorgan Bay through a comparative assessment of spectral water indices (NDWI, MNDWI, AWEI, and NDPI). The findings reveal that MNDWI outperforms other indices, with an average RMSE of 21/66, for water extraction from Landsat imagery. MNDWI-derived water area estimates indicate an increase of 2384 hectares between 1990 and 2000, a decrease of 1488 hectares between 2000 and 2010, and a further decrease of 11080 hectares between 2010 and 2020. The alarming 11080-hectare decline in water area from 2010 to 2020 underscores the need for intensified efforts in Gorgan Bay's water level monitoring and management. This study emphasizes the potential of satellite imagery and spectral water indices, particularly MNDWI, as valuable tools for effective water level monitoring and management in Gorgan Bay. The results can serve as a scientific guide for managing and planning water level changes in Gorgan Bay.
پژوهشی
Geomorphology
maryam bayatikhatibi; imad ali
Abstract
The Quetta sub-basin is a part of the Pishin River basin, situated in the southwestern region of Pakistan. This study aimed to determine the spatial distribution of annual soil erosion through the utilization of the Revised Universal Soil Loss Equation (RUSLE) model. To accomplish this, numerous data ...
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The Quetta sub-basin is a part of the Pishin River basin, situated in the southwestern region of Pakistan. This study aimed to determine the spatial distribution of annual soil erosion through the utilization of the Revised Universal Soil Loss Equation (RUSLE) model. To accomplish this, numerous data mining techniques were employed, along with machine learning algorithms, to produce thematic layers (K, R, LS, C, and P) that served as input parameters for the RUSLE model. According to the resultant model, soil erosion in the study area ranged from 0.00 to 866 tons per hectare per year. The estimated values for rainfall-runoff erosivity (R), soil. erodibility (K), topography (LS), and cover management (C), factors ranged from 147 to 191 (MJ.mm.ha⁻¹.h⁻¹year⁻¹), 0.0229 to 0.0259 (t.ha.MJ⁻¹mm⁻¹), 0.002 to 360.77, and 0.001 to 1, respectively. The statistics revealed that 58% of the land in the study area experiences a very low degree of soil erosion, at an erosion rate less than 13.58 t/ha/year. About 24% of the study area faces low erosion, with an erosion rate spanning from 13.58-44.16 t/ha/year. 13% of the area is demarcated as moderate soil erosion severity, at an erosion rate ranging from 44.16-81.53.14 t/ha/year. On the other hand, 5% of the study area experienced high to very high soil erosion, with an erosion rate of 81.53-866.34 t/ha/year.
پژوهشی
Roya Ahmadi; Hoda Ghasemieh; Reza Ghazavi
Abstract
Drought is one of the most complex meteorological phenomena that can occur in most parts of the world; however, its impact is more pronounced in arid and semi-arid regions, making its study crucial for water resource management. In this research, the meteorological and hydrological drought status in ...
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Drought is one of the most complex meteorological phenomena that can occur in most parts of the world; however, its impact is more pronounced in arid and semi-arid regions, making its study crucial for water resource management. In this research, the meteorological and hydrological drought status in the Qom-Kahak, Neyzar-Salafchegan, Marvdasht-Kharameh, and Beyza-Zarqan basins located in the Central Plateau basin was investigated using the SPI, SPEI, RDI, and SSI indices on 1-, 6- and 12-months timescales during the statistical period of 2004 to 2023. The results indicated that more than 95% of the study stations have experienced all conditions from very wet to very severe drought. SPI index on 1-month time scale in all study stations and SPEI index on 6-month time scale in 83.3% of stations and on 12-month time scale in 67.7% of stations showed drought more severely than other drought indices. Examination of the occurrence frequency for the SSI hydrological index classes on a 12-month timescale also showed that the highest drought classes were observed in Shadabad and Kharamah stations. The comparative analysis of meteorological and hydrological drought indices in each of the basins showed that showed that the highest cross-correlation between the SPI and SSI on a 12-month timescale was observed in Salafchegan and Qaleh Cham stations with a forward time lag of 12 months equal to 0.574, and the highest pearson correlation coefficient on a 12-month timescale was for Salafchegan-Qaleh Cham stations (r = 0.309 and p-value = 0.001).
پژوهشی
Groundwater
Shokoofeh Esmaeili; Firouz Mojarrad
Abstract
A major part of the fresh water demand in the world is provided through groundwater. Any abnormality in groundwater directly affects human. Droughts and wet periods are among the most important factors that have a significant effect on the fluctuation of the groundwater level. The purpose of this study ...
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A major part of the fresh water demand in the world is provided through groundwater. Any abnormality in groundwater directly affects human. Droughts and wet periods are among the most important factors that have a significant effect on the fluctuation of the groundwater level. The purpose of this study is to investigate the relationship between the Standardized Precipitation Index (SPI) as a meteorological drought index and the Groundwater Resource Index (GRI) as a hydrological drought index in the Eslamabad-e Gharb plain (Kermanshah Province) in a 20-year period and predict the future state of the groundwater level. Both indices were calculated in time scales of 1, 3, 6, 9, 12, 18, 24 and 48 months. To obtain the relationship between two indices, the correlation coefficient was used once in different time scales and again with time delays of 1 to 12 months in the GRI index. Then, the future precipitation data of the plain in a 20-year period were extracted with four CMIP6 models under three scenarios, and then were downscaled with the SDSM model. Finally, the CanSM5-CanOE model was selected and its downscaled data were entered into the regression model of the relationship between precipitation and water level to predict the future state of the groundwater level. The results showed that the highest significant correlation coefficient between 48-month SPI and 48-month GRI values is observed at a time delay of 12 months, which indicates the effect of precipitation on changes in the groundwater level in medium and long-term scales. The forecast results of the groundwater level for the coming period indicate a water level drop of 5.17, 6.02 and 8.08 meters respectively under the three scenarios SSP1-2.6, SSP2-4.5, and SSP5-8.5.
پژوهشی
Geomorphology
sayyad Asghari Saraskanroud; Fariba Esfandyari; Mehdi Faal Naziri; Batool Zeinali
Abstract
Land subsidence refers to the gradual or sudden lowering of the earth's surface as a result of various factors such as tectonic activities, mining, oil and gas fields, and illegal extraction of underground water. In Alborz province, the growing trend of population and migration in recent years has added ...
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Land subsidence refers to the gradual or sudden lowering of the earth's surface as a result of various factors such as tectonic activities, mining, oil and gas fields, and illegal extraction of underground water. In Alborz province, the growing trend of population and migration in recent years has added to the increase in demand and the amount of water withdrawal from the underground water table, so it is subject to subsidence due to the sharp drop in the level of underground water. In this research, subsidence was first evaluated using the radar interferometric technique, and then, prone areas were zoned with a multi-criteria algorithm in the time frame of 2016 and 2023. The results of information extraction with interferometric technique showed that the average amount of subsidence in the urban boundaries of Saujblag, Karaj, Nazarabad, Chaharbagh and Fardis is between 15 and 320 mm. According to observations, the highest amount of subsidence is in the eastern part and then in the southern and southwestern parts. According to the estimated results of subsidence risk zoning; The parameters of water level drop, land use, slope and geology, respectively, with weight coefficients of 0.16127, 0.141875, 0.130145 and 0.128474, are the most important factors in creating the risk of subsidence in the study area, which are 31 and 23%, respectively. From the range, it has a very high and high probability of danger. Finally, it can be said that the most important factor in subsidence in the studied area is excessive use of underground water and the drop in water level. In some urban areas, such as Hew and Goch Hesar, Malekabad-Mehrshahr-Mehrvila-Kamalshahr, and Mohammadshahr, the highest risk of subsidence can be seen.
پژوهشی
Hydrogeomorphology
Gholamreza Khosravi; Mehdi Teimouri
Abstract
To describe and evaluate all the complexities and to develop river ecosystem management plans, it is necessary to examine all the components at different spatial and temporal scales. In this regard, a key step for this is hydromorphological characterization, looking at rivers from a perspective that ...
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To describe and evaluate all the complexities and to develop river ecosystem management plans, it is necessary to examine all the components at different spatial and temporal scales. In this regard, a key step for this is hydromorphological characterization, looking at rivers from a perspective that discloses the relevant processes and forms. The aim of this study is to classify, evaluate, and determine the hydromorphological condition of the Khormarud River in Golestan province, Iran, by employing the integrated application of the Morphological Quality Index (MQI) and the Morphological Quality Index for monitoring (MQIm). In the first step, using remote sensing and GIS, field survey as well as some data and hydromophological information, the river system was divided into spatial units including bio-geographical regions, watersheds, landscapes, river segments, river reaches, and geomorphic units. In the second step, the main characteristics studied from the geographical units to the river segment and reach units were described. The above information is used to determine the hydromorphological status of reaches by MQI and MQIm methods. Based on the analysis of MQI, 15 reaches are placed in very poor and poor classes. In contrast, nine and two reaches are placed in moderate and good classes, respectively. The difference among MQI index values across the reaches is significant at 5% level. In addition, the difference among MQIm index values for the two periods, before and after human interventions, in the investigated reach is significant at 5% level. For most reaches, the lowest scores are related to the indicators of vegetation, functional, morphology, and stream changes, respectively. By integrating the MQI and MQIm indices, a more comprehensive view of the hydromorphological condition can be gained, particularly regarding its temporal changes, trends, and tendencies. The integration of the MQI and MQIm indices for hydromorphological condition assessment can be applied to other river basins in Iran by adapting the methods and approaches presented in the results of this study.
