پژوهشی
RS
Abstract
Changes in land cover and land use due to human activities have left adverse effects on the environment. The eastern regions of Ardabil province are a clear example of this phenomenon. The purpose of this research is to analyze spatial and temporal changes in land cover and land use and its effects on ...
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Changes in land cover and land use due to human activities have left adverse effects on the environment. The eastern regions of Ardabil province are a clear example of this phenomenon. The purpose of this research is to analyze spatial and temporal changes in land cover and land use and its effects on the temperature of the surface of the earth in Lake Neor. To estimate land use and land cover, random forest models (RTC), maximum likelihood model (MLC) and support vector machine (SVM) were used and the efficiency of each was estimated by the Kappa coefficient and it was observed that the SVM model has the highest Kappa coefficient (0.87) Bands 6, 5 and 10 of Landsat 8 were also used to extract the LST index, and it was observed that the western part of the lake faced an increase in the temperature of the earth's surface. During the time period of 2002, 2013 and 2022, significant changes were observed in the water area of Neor Lake and its nearby vegetation. Barren lands had the largest extent in all studied periods. Vegetation has increased by 1.04 square kilometers based on SVM model. The surface area of the lake was estimated as 3.19 square kilometers based on the MLC model in 2002. The area of the water zone in the MLC model has decreased by 1.56 square kilometers between 2002 and 2022, and this decrease is 0.67 and 0.69 square kilometers for the RTC and SVM models, respectively.
پژوهشی
RS
Abstract
Extraction of the water zone in the western parts of Afghanistan through remote sensing images is an efficient way to investigate and monitor water resources and its impact on the water resources of eastern Iran, especially the wells of Sistan and Baluchestan. In this research, from OLI sensor of Landsat ...
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Extraction of the water zone in the western parts of Afghanistan through remote sensing images is an efficient way to investigate and monitor water resources and its impact on the water resources of eastern Iran, especially the wells of Sistan and Baluchestan. In this research, from OLI sensor of Landsat 8 satellite and TM sensor of Landsat 5 satellite, Normalized Difference Water Index (NDWI), modified Normalized Difference Water Index (MNDWI), normalized difference moisture index (NDMI), automated water extracted index (AWEI), new water index (NWI), and water ratio index (WRI) have been used to extract water areas. In the worst case, the area of the Arghandab dam has decreased by only 2.44 km upstream and the NDMI index has shown an increase of 0.65 square km in the moisture resources of this dam. However, the surface of the well in the southern half of Zabul has decreased from 55.94 square kilometers to 17.82 square kilometers, which shows a decrease of 38.12 square kilometers. This shows a sharp decrease in the level of the semi-well. This has caused more heat to be emitted in the dry areas. But the minimum temperature has decreased from 17.47 degrees to 11.87 degrees Celsius, which has experienced a decrease of 1.95 degrees Celsius. The LST index has a negative correlation with all the indices and the highest correlation with the NWI index was -0.941 in 1994. The lowest correlation was also obtained at the rate of -0.65 related to the NDMI index.
پژوهشی
RS
mehdi feyzolahpour
Abstract
Drought is the most expensive weather event in the world after hurricanes. Early detection of drought and prediction of its occurrence will reduce costs and save human lives. In this research, in order to evaluate the best index in estimating moisture stress and drought, 8 indices NDVI, NDWI, VCI, SR, ...
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Drought is the most expensive weather event in the world after hurricanes. Early detection of drought and prediction of its occurrence will reduce costs and save human lives. In this research, in order to evaluate the best index in estimating moisture stress and drought, 8 indices NDVI, NDWI, VCI, SR, MSI, SIWSI, NDII and NMI were used and Shadgan Wetland was investigated in the period of 2018 to 2023. LST index was also used to check temperature changes. In order to determine the most suitable index, the Pearson correlation coefficient was estimated between the indices and the effectiveness of each index was shown on the Chadwick scale. Based on this, NDWI, MSI, NMI and LST indices have the highest correlation and based on Chadwick's scale in 5 cases, NDWI and MSI indices have a strong and very strong correlation and there is a strong correlation between these two indices at around 0.99 - It has been established. The correlation between LST and NDWI indices was also negative and was estimated at -0.73. Due to the dominance of semi-arid conditions in the region, vegetation-based indices have a very weak capability in drought estimation, and the correlation between NDVI and NDWI was around 0.05. Therefore, based on this, it can be concluded that in Shadgan wetland, indicators based on humidity and temperature stress have better capabilities in drought estimation than vegetation indicators.
پژوهشی
Hydrogeomorphology
Mohammad Hossein Rezaei Moghaddam; Davoud Mokhtari; Tohid Rahimpour; Vahideh Taghizadeh Teimourloei
Abstract
Azarshahrchai catchment area, located on the western slope of the Sahand mountain range, is formed by the connection of numerous tributaries flowing in deep valleys, and every year in the spring season, with the onset of rains, floods occur in these valleys. The purpose of this research is to evaluate ...
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Azarshahrchai catchment area, located on the western slope of the Sahand mountain range, is formed by the connection of numerous tributaries flowing in deep valleys, and every year in the spring season, with the onset of rains, floods occur in these valleys. The purpose of this research is to evaluate the performance of the weighted evidence (woe) function for preparing the flood susceptibility map of the Azarshahr Chai catchment area. In order to reach the mentioned goal, first, the location of 82 flood catch points using Landsat8.c2.l2 satellite images based on the flood of April 2016 was randomly divided into two groups of 70% (57 flood catch points) for training data and 30 percent (25 points) flood) was used for validation data. Then 14 effective factors in flood occurrence elevation, slope, Aspect, slope curvature, distance to river, distance to road, river density, TWI (topographic moisture index), lithology, soil type, rainfall, and NDVI in Arc software environment and land use in ENVI5.3 software environment, analysis, and location of flood catch points in all 14 factors were investigated. The ROC operating characteristic curve was used to validate and correct the results obtained. The results of the research indicate that 19.56% of the basin is in the very high sensitivity class, 19.18% in the high sensitivity class, 24.61% in the moderate class, 21.94% in the low class and 14.68% in the shallow class in terms of flood vulnerability.
پژوهشی
RS
mehdi feyzolahpour
Abstract
Spatial and temporal changes of surface water affect the structure and functioning of the ecosystems of the Teham Dam region as well as the agricultural, economic and social development in this region. In this research, MNDWI, AWEI and NDWI indices and SVM support vector machine model was used to detect ...
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Spatial and temporal changes of surface water affect the structure and functioning of the ecosystems of the Teham Dam region as well as the agricultural, economic and social development in this region. In this research, MNDWI, AWEI and NDWI indices and SVM support vector machine model was used to detect the long-term changes of Teham Dam in the period from 2002 to 2023. The results of the AWEI index showed that the area of the dam was about 2.4 square kilometers in 2007, which decreased to 1.15 square kilometers in 2023. In the MNDWI index, in 2007 and 2023, the area of water was equal to 2.6 and 1.17 square kilometers, respectively. The NDWI map shows a 46.38% decrease in the area of the water zone from 2007 to 2023. But in the AWEI index, this decrease was equal to 47.9. AWEI index with kappa values equal to 0.94 has correctly recognized the boundaries of water areas. According to the SVM model, in this period of time, the amount of vegetation has decreased from 0.8 square kilometers in 2002 to 0.07 square kilometers in 2023. The amount of barren land has decreased almost in this period of time and was equal to 4.57 square kilometers in 2023. The maximum temperature of the earth's surface in July 2002 was equal to 38.3 degrees Celsius and in July 2023 it reached 28.4 degrees Celsius.
پژوهشی
Geomorphology
maryam bayatikhatibi; maryam bayati khatibi; imad ali; sadra kharimzadeh
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
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
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 ...
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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 assessment was done using radar interferometric technique, and then, prone areas were zoned with 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.
پژوهشی
Geomorphology
Arezou Cheraghi; Shahram Bahrami; Somayeh Khaleghi; Kazem Nosrati
Abstract
Dolines are one of the most important karst landforms and 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 were evaluated. Chemical and physical characteristics of 36 soil samples ...
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Dolines are one of the most important karst landforms and 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 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 cell size) obtaining from UAV images, was used to measure the morphometric parameters of dolines. The 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 large area, slope, depth, roundness and clay soils, and 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 large area, slope, depth, roundness and clay soils, as well as more 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 high-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, plunge and steep slopes. In general, vegetation, elevation, slope and type of precipitation play an important role in morphometric differences and soils in dolines.
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
Hydrogeomorphology
Gholamreza Khosravi; Mehdi Teimouri
Abstract
It is necessary to examine all the components at different spatial and temporal scales to describe and evaluate all the complexities to develop river ecosystem management plans. In this regard, a key step is hydromorphological characterization, looking at rivers from a perspective that discloses the ...
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It is necessary to examine all the components at different spatial and temporal scales to describe and evaluate all the complexities to develop river ecosystem management plans. In this regard, a key step 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 MQI and MQIm indices. In the first step, using remote sensing and GIS, the main characteristics studied at the geographical scale and 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. Both the MQI and MQIm morphological evaluation indices are used in different time scales, so they can be considered as complements and not substitutes for hydromorphological condition assessment. By integrating the MQI and MQIm indices, a more comprehensive view of the hydromorphological condition can be gained,
پژوهشی
Groundwater
Shokoofeh Esmaeili; Firouz Mojarrad
Abstract
A major part of the fresh water demand in the world is provided through groundwater. 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 SPI and GRI ...
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A major part of the fresh water demand in the world is provided through groundwater. 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 SPI and GRI indexes in the Eslamabad-e Gharb plain (Kermanshah Province) in a 20-year period and predict the future state of the groundwater level. The values of both indexes were calculated in different time scales. 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. 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 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
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.
علمی
Geomorphology
sayyad Asghari Saraskanroud; Aghil Madadi; nazfar aghazadeh; Raoof Mostafazadeh
Abstract
Soil erosion is one of the significant environmental challenges that leads to the degradation and decline of soil quality. This study examines the impact of land use changes on soil erosion in the Givi Chai region. The use of satellite images (ETM+7 2010 and OLI 2022) as the primary tool for analyzing ...
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Soil erosion is one of the significant environmental challenges that leads to the degradation and decline of soil quality. This study examines the impact of land use changes on soil erosion in the Givi Chai region. The use of satellite images (ETM+7 2010 and OLI 2022) as the primary tool for analyzing land use changes and assessing soil erosion has been a crucial step in this research. The images were classified using an object-based method, identifying various land uses. These uses included residential areas, agricultural lands, barren lands, orchards, dense, medium, and sparse vegetation, and water bodies. The factors influencing the G2 model included R (rainfall), S (soil erodibility) , V (vegetation cover), T (topography) , and I (slope adjustment factor). An erosion map was created and analyzed. Results indicated an increase in residential areas and sparse vegetation while showing a decrease in orchards and medium vegetation cover. These changes directly impacted soil erosion. The amount of erosion in 2022 increased compared to 2010, with the highest erosion occurring in agricultural and barren land uses. The final erosion map indicated areas with very high and high erosion associated with agricultural land use, weak pastures, and residential areas. The increase in agricultural and barren lands and the decrease in vegetation cover were identified as the main factors contributing to soil erosion. The study shows that changes in land use, particularly the increase in residential and agricultural areas, have a negative impact on soil erosion.
پژوهشی
Hydrology
zohreh khorsandi Kouhanestani; Fatemeh Taatpour
Abstract
Rainfall-runoff processes are among the most complex and nonlinear phenomena in hydrology. In water resources management, runoff forecasting faces challenges in ungauged watersheds.In this study, the efficiency of lumped models and machine learning methods was investigated in the Kabkian watershed, that ...
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Rainfall-runoff processes are among the most complex and nonlinear phenomena in hydrology. In water resources management, runoff forecasting faces challenges in ungauged watersheds.In this study, the efficiency of lumped models and machine learning methods was investigated in the Kabkian watershed, that is one of the principal branches of the Karun River. AWBM, Sacramento, SIMHYD, TANK, and SMAR Also, some algorithms in decision trees, artificial neural networks, and support vector regression were applied to simulate daily and monthly runoff in the Kabkian watershed. Monthly and daily discharge, precipitation, and potential evapotranspiration for the period between 1972 and 2022 were used,. The accuracy and efficiency of the methods were examined using R², the Nash-Sutcliffe coefficient, and RMSE. Results showed that SMAR and AWBM, in comparison to other lumped models, have the best efficiency in the simulation of daily discharge in the Kabkian watershed. The Nash-Sutcliffe coefficients for them in the test stage are 0.79 and 0.78, respectively, showing that these models have good efficiency in daily discharge simulation. Also, the SMAR and AWBM models' Nash-Sutcliffe coefficients are 0.71 and 0.72, respectively, and the R2 for the two models is 0.79 in the monthly time series. These values show that these models have good efficiency. In machine learning methods, in the daily series, the random forest algorithm's R2 is 0.61 and has the best efficiency in comparison to other methods. Also, in the monthly series, the random forest's R2 is 0.93, which illustrates good discharge simulation efficiency.
پژوهشی
watershed
Mahnaz Saber; Bromand Salahi; Roghayeh Maleki Meresht
Abstract
The SWAT model was used in this research to simulate the hydrological conditions of the Aras River basin in the future period. The model was calibrated based on the data of 1987-2006 and its validation was done in 2007-2014 with the SUFI2 algorithm and the SWAT model was calibrated based on the monthly ...
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The SWAT model was used in this research to simulate the hydrological conditions of the Aras River basin in the future period. The model was calibrated based on the data of 1987-2006 and its validation was done in 2007-2014 with the SUFI2 algorithm and the SWAT model was calibrated based on the monthly flow rate of the selected hydrometric station. After selecting the optimal parameters and running the simulation in 350 simulator rounds, the values of the evaluation criteria were obtained in the calibration period and in the validation phase. To evaluate the water balance changes of the basin under the conditions of climate change from the downscaled data of the CNRM-CM6 climate model in the historical period (1985-2014) and the future period (2025-2100) under the SSP5-8.5 scenario were used as input data to the SWAT model. The findings showed that evapotranspiration of the Aras basin has wasted a large share of the precipitation of 272mm in the historical period and 351 mm in the future period of the basin, and the amount of infiltration and lateral flow, which are necessary to feeding underground and surface resources, is very low. Also in terms of land use, the minimum ET of the basin was calculated in the use of good pastures. Also, the findings showed that although in the future period the annual rainfall will be 79 mm more than the historical period, but a major part of it will be spent on evapotranspiration in the months of May to July.
پژوهشی
Hydrology
Leyla Babaie; Hirad Abghari; Raoof Mostafazadeh
Abstract
The occurrence of low flow and high flow periods in watersheds is a part of a river's regime. In recent years, changes in river flow and its intensification have impacted the production and utilization of river flows as well as water management, making it an important area of study. Evaluating various ...
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The occurrence of low flow and high flow periods in watersheds is a part of a river's regime. In recent years, changes in river flow and its intensification have impacted the production and utilization of river flows as well as water management, making it an important area of study. Evaluating various characteristics of the flow regime of natural rivers can help understand how river discharge changes due to climatic. In this study, changes in high flow and low flow indices at the Bitas watershed, Mahabad-chai, which monitors a naturally flowing river upstream of Mahabad Dam, were assessed for the period from 1963 to 2020. The results indicated that the Number Spell index was 144 during high flow periods and 253 during low flow periods. The Single Longest index was 1,635 for low flow periods and 163 for high flow periods. The average peak flow and average duration of peak flow indices for high flow periods were 22.6, and for low flow periods, they were 0.33. Additionally, the mean duration was 29.6 for high flow and 54.82 for low flow. According to the results, the total duration index for high flow periods fluctuated between 3 and 163, while the total duration index for low flow was 241. The findings of this study can be used to better understand changes in the natural flow regime, variations in the timing and frequency of low and high flow events, and ultimately to optimize the management of inflow to Mahabad Dam.
پژوهشی
Hydrogeomorphology
Sayyed Hojjat Mousavi
Abstract
Problems of watersheds and their water resources require comprehensive planning and integrated management in this natural open system, which is necessary to be prioritized in national and regional plans to achieve the sustainable development goals, flood risk and crisis management, and solving water ...
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Problems of watersheds and their water resources require comprehensive planning and integrated management in this natural open system, which is necessary to be prioritized in national and regional plans to achieve the sustainable development goals, flood risk and crisis management, and solving water shortage issues. Purpose of this research is the evaluating and analyses of hydrogeomorphometric components in Bastam watershed systematically to understand environmental, flood and erosion issues. In this regard, parameters of the height distribution, average height, altimetry and hypsometry curves, slope, aspect, watercourse rating, branching ratio, drainage density, watercourse boundary, main watercourse length, concentration time, perimeter, area, basin shape, Gravilius coefficient and equivalent rectangle was evaluated. Results showed that study basin with an average height of 2085.341 meters and an average slope of 21.788% is a mature and relatively smooth basin, and its upstream slopes at altitudes of more than 2100 meters are exposed to exploration due to the roughness youth. Maximum extent of the basin with 24.53% belongs to the southeast aspect. Shape of the basin is like a rectangle with a length of 91.842 km and a width of 19.175 km, which has a medium to small flood capacity. Components of branching ratio 3.528, drainage density 0.2985 and compression coefficient 0.09352 indicate the low to moderate flooding of this basin. Its concentration time in the main waterway with a length of 62.675 km is equal to 6.066 hours, which has the maximum flood with 6-hour rains.
پژوهشی
Hydrology
Raoof Mostafazadeh; Javanshir Azizi Mobaser; Shahnaz Mirzaei
Abstract
The river flow regime can be influenced by various climatic and anthropogenic factors, including land use changes, dam construction, flow diversion, and water abstraction, leading to changes in available water and environmental flow allocation patterns. This study compares the changes in flow regime ...
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The river flow regime can be influenced by various climatic and anthropogenic factors, including land use changes, dam construction, flow diversion, and water abstraction, leading to changes in available water and environmental flow allocation patterns. This study compares the changes in flow regime components between two rivers, one natural and one regulated by a dam, in Ardabil Province. Using R programming, various charts, change point analysis, and significant temporal trends were derived for flow statistics, including high flow, low flow, and baseflow. The results indicate change points in all three flow components (annual maximum, Q10, Q25, low flow, and baseflow) in both natural and regulated rivers, with more pronounced changes occurring in the regulated river after dam construction. In the natural Khiavchai River, high flow and peak discharge showed no significant trends, whereas in the regulated Balikhlochai River, all flow components exhibited significant decreasing trends. Comparison of flow duration curves and violin plots revealed substantial reductions in minimum flows and baseflows in the regulated river, with monthly discharge distributions strongly influenced by dam regulation. Comprehensive evaluation of river regime changes and flow components enables prediction of trends and effective water management for environmental flow allocation.
پژوهشی
watershed
Hirad Abghari; Ali Parvish
Abstract
Watershed management, regardless of the role of local and state operators, will derail water and soil conservation policies and have many negative impacts and consequences in the long term. One of the water supply sources of Lake Urmia is the Baranduzchay River basin. Due to the increasing consumption ...
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Watershed management, regardless of the role of local and state operators, will derail water and soil conservation policies and have many negative impacts and consequences in the long term. One of the water supply sources of Lake Urmia is the Baranduzchay River basin. Due to the increasing consumption behavior of the population, sand mining and exploitation of this river is increasing day by day. Due to the need and importance of flood management and flood control to prevent social and economic problems, this research was carried out with the aim of studying the effects of non-standard sand mining on the hydraulic discharge of the river. The study area is located in the Baranduzchay River in West Azerbaijan Province, Urmia County. In this research, a section of the river from the geographic coordinates 490675 UTM and 4121955 UTM (upstream) to the geographic coordinates 490995 UTM and 4125550 UTM (downstream) is examined. In this research, topographic information is used before harvesting the riverbed and riverbank materials and the triangular irregular network (TIN) is extracted to verify the elevation features using the HEC-GeoRAS plugin, which is a bridge between the hydraulic model of HEC- RAS and ArcGIS: The effects of excessive sand mining on the hydraulic and hydrological properties of the river were studied. According to the research objective, the effects of extracting 1 to 2 meters of hydraulic runoff were simulated. This research showed that when the depth of the river bed increases by one to two meters, the cross section
