Hydrogeomorphology
Alireza Ildoromi; Mehdi spehri
Abstract
In this researchlandslide sensitivity was zoned using statistical models intheKurdistan Dam watershed and the most appropriatemodel was introduced.First, the studied area was determined and with field observations, the number of 9 landslides was recorded and a landslide distribution map was prepared. ...
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In this researchlandslide sensitivity was zoned using statistical models intheKurdistan Dam watershed and the most appropriatemodel was introduced.First, the studied area was determined and with field observations, the number of 9 landslides was recorded and a landslide distribution map was prepared. In the next step, the factors affecting the occurrence of landslides including geology, rainfall, land use, distance from the river, distance from the fault, slope and height were identified and then a map of these factors was prepared. To determine the rateof each of the effective factors in the occurrence of landslides, the map of each information layer of the effective factors is integrated with the distribution map of the landslide and using AHP, BWM and FUCOM statistical modelsseparate information layers are weighted and By overlapping different layers, the final landsliderisk zoning mapswere prepared and compared.The results showed that land use in AHP and BWM methods and rainfall lines, in addition to land use inFUCOM method have the greatest effect and the criteria of heightdistance from the fault and slope respectively in the three AHP, BWM and FUCOM methods have the least effect on the occurrence of landslidestheresults showed that the lithological variable has a great role on the occurrenceof landslides in the studied area.In generalthe results showed that in AHP and BWM methods, the numberof required pairwise comparisons increases significantly with the number of compared parameters, and in this case, the uncertaintyof opinions increases, which shows the superiority of the FUCOM method over It showswell in other ways.
Ahmad Najafi Eigdir; shahram roostaei
Abstract
1-Introduction Several factors have contributed to the occurrence of the landslide that could increase the risk of landslide in any area. Identifying these factors and their value can help to appropriate landslide zonation. The aim of the study is to find ways to reduce the damages caused by them, which ...
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1-Introduction Several factors have contributed to the occurrence of the landslide that could increase the risk of landslide in any area. Identifying these factors and their value can help to appropriate landslide zonation. The aim of the study is to find ways to reduce the damages caused by them, which makes it necessary to zoning the susceptible areas that play an undeniable role in watershed management. Therefore, by using statistical models and assessing them, the sensitive areas to the occurrence of landslide are identified. In this research, the landslide hazard zonation was performed based on the data-driven method. Based on this method, the zoning was done based on the use of slope data, aspect, elevation, precipitation, vegetation, geology, land use, distance to fault, distance to river, and distance to road. To validate the model, the ROC curve has been used which is a new and efficient method for verification. The purpose of this research is to investigate various influencing factors that affect the landslide occurrence in the Nazlochai basin. 2-Methodology In the methodology section, the satellite imagery processing (to identify and extract landslides, vegetation extraction, and land use) and logistic regression model have been discussed for landslide hazard zonation. In this study, by reviewing the previous sources (Mir Nazari, et al., 1393, Abedini, et al., 1393, Ayalew, et al., 2004, Ebadinejad, et al., 2007) and by investigating various factors (morphometric, climatic, and human) in Nazlochai basin, ten effective factors (elevation, slope, aspect, distance to river, distance to road, distance to fault, lithology, landuse, precipitation, and vegetation) on the landslide occurrence in the area were considered. The ArcGIS software was used to digitize and provide information layers for landslide hazard zonation, and the ENVI software was used for image processing, vegetation extracting, and land use mapping. Existing landslides were identified and characterized using various tools including aerial photos, satellite imagery (Google Earth), existing information, Global Position System (GPS), and field surveys. 3-Results and Discussion The obtained coefficients indicated that the occurrence of landslide in the studied area had a direct relation with lithology, slope, and aspect factors, and weak relation with landuse, distance to fault, precipitation and distance to river. Lithology investigation of the region indicated that the more landslides have occurred on calcareous and conglomerate stones, which could be due to the development of the slopes and the accumulation of destructive materials on them. Slope is one of the slippery factors due to gravity and decreasing shear strength of soil in slopes of more than 10% to 45% leads to instability which in most researches is considered as an effective factor, too. Also, north slopes are more susceptible to landslide than the southern slopes due to the reduction of normal pressure and shear strength of the soil. By considering the Pseudo R-square index (equal to 0.34), which is greater than the threshold (0.2), this model shows acceptable fit. The area under the ROC curve was equal to 0.958, which shows a strong correlation with predicted landslides by the logistic regression model. Finally, the study area was classified into 5 landslide hazard classes include very low, low, medium, high, and very high. 4-Conclusion In this research, landslide hazard zonation has been done using the logistic regression model in the Nazlochai basin. The coefficients of variables indicated that the occurrence of landslide in the study area had a direct relationship with the lithology, slope, and aspect factors; and weak relationship with landuse and distance to fault. Thus this indicates the probability of landslide occurrence increases by changing in lithology, slope, and aspect
Amirpouya Sarraf; Hojjatollah Ghasemi
Hydrogeomorphology
eisa jokar sarhangi; ghasem lorestani; vahid falah
Abstract
The studied area on the Haraz Road from Poldakhter to Vana is prone to avalanches due to its cold mountain climate. The purpose of this research is to determine the most important factors affecting the occurrence of avalanches and its risk zoning using LNRF and Shannon Entropy models. For this purpose, ...
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The studied area on the Haraz Road from Poldakhter to Vana is prone to avalanches due to its cold mountain climate. The purpose of this research is to determine the most important factors affecting the occurrence of avalanches and its risk zoning using LNRF and Shannon Entropy models. For this purpose, the criteria of snow cover, elevation, slope, aspect, slope curvature, landuse and distance from the road have been used. The results of determining the most important factors affecting the occurrence of avalanches in the studied area using Shannon's Entropy model showed that the aspect, landuse, distance from the road and snow cover with weights of 0.541, 0.143, 0.129 and 0.083 respectively are more important. Avalanche risk zoning maps show that the highest avalanche risk is due to the location of these areas at an altitude of 2100-2700 meters and a slope of 30-60 degrees with the direction of the northeastern and northern slopes. Evaluation of avalanche risk zoning maps using the empirical probability index (P) indicates the appropriateness of Shannon entropy and LNRF models in the region, but the application of Shannon entropy has led to an increase in map accuracy up to 97%.
Mohammad Hossein Rezaei Moghaddam; asadollah hejazi; Khalil Valizadeh kamran; Tohid Rahimpour
Abstract
1- Introduction Floods are one of the major natural hazards that annually cause extensive damage worldwide. There are numerous floods in the northwest of the country with the beginning of spring and the start of spring rains, which in most cases results in heavy damages. Aland chai catchment suffers ...
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1- Introduction Floods are one of the major natural hazards that annually cause extensive damage worldwide. There are numerous floods in the northwest of the country with the beginning of spring and the start of spring rains, which in most cases results in heavy damages. Aland chai catchment suffers from destructive floods every year since the beginning of spring. The purpose of this study was to examine and analyze the role of hydrogeomorphic indices in flood sensitivity in this basin. Hydrogeomorphic parameters of sub-basins were studied from three aspects of drainage network characteristics (including order of stream, number of streams, length of streams, frequency of stream, bifurcation ratio, length of overland flow, drainage density, drainage texture, texture ratio, infiltration number, constant of channel maintenance, and Rho coefficient), shape characteristics (Including basin area, compactness coefficient, circulatory ratio, elongation ratio, form factor, and shape factor) and relief properties (relief, relief ratio, ruggedness number, and gradient). 2- Methodology With an area of 1,147.30 km2, Aland Chai basin is located in the Northwest of Iran and in the Western Azerbaijan province. This basin is located between 38°- 30¢-14² and 38°- 48¢-22² N and between 44°- 15¢- 13² and 45°- 01¢-02² E. The minimum elevation of the area is 1093 meters and the maximum elevation is 3638 meters. This basin is one of the sub-basins of the Aras basin, which flows into the Aras River after joining the grand Qotour River. SWARA multi-criteria decision analysis model was used to weight the parameters. The Step-wise weight assessment ratio analysis (SWARA) model was developed by Keršuliene et al (2010). WASPAS multi-criteria decision-making model was used to prioritize sub-basins in terms of flood sensitivity. The weighted aggregated sum product assessment (WASPAS) method was proposed by Zavadskas et al in 2012. The WASPAS method consists of two aggregated parts, namely (1) The weighted sum model (WSM) and, (2) The weighted product model (WPM). 3- Results and Discussion Hydrogeomorphic analysis is significantly involved in the analysis of hydrological behavior of the basins. In the present study, 22 hydrogeomorphic parameters were analyzed from three aspects of drainage network characteristics, shape parameters and relief properties with the purpose of examining the effect of these parameters on the flood sensitivity of the Aland Chai basin. In the first step, the study area was divided into 15 sub-basins based on topographic and drainage characteristics using a digital elevation model (DEM) with a 12.5m spatial resolution. In the next step, the information of each sub-basin was provided based on 22 hydrogeomorphic parameters using the geomorphological laws of Horton, Schumm, and Strahler in ArcGIS software. According to the comparison among 22 parameters using the SWARA method, drainage texture, texture ratio, and drainage density (weighted as 0.273, 0.273 and 0.156) had the highest impacts on the occurrence of floods in study area respectively. On the contrary, Rho coefficient, constant of channel maintenance, infiltration number, and length of overland flow exhibited the lowest weights respectively. 4-Conclusion The purpose of the current study was to examine and evaluate the role of hydrogeomorphic indices in flood sensitivity of Aland Chai basin, for which SWARA and WASPAS multi-criteria decision-making models were employed. The results of prioritization of sub-basins using WASPAS model indicated that sub-basin 1 with a coefficient of 0.907, sub-basin 3 with a coefficient of 0.858 and sub-basin 2 with a coefficient of 0.818 had respectively the highest sensitivity to flooding. The results also revealed that sub-basins 4, 7, 11 and 15 in are placed in the high level category, sub-basins 8 and 9 are categorized in moderate-level category class, sub-basins 5, 10, 12 and 14 are classified in the low-level class and sub-basins 6 and 13 are situated in the very low level category in terms of flood sensitivity. The total area of sub-basins in the high and very high class of flood sensitivity is 656.72 km2, which comprises 57.24% of the total Aland Chai basin. Therefore, according to the findings of the study, which indicate that the study area has high flooding, it is necessary to adopt protective measures such as watershed planning and dam construction in highly sensitive sub-basins to prevent flooding and mitigate potential damages in cases of severe flooding. Keywords: Flood, Hydrogeomorphic Indices, GIS, WASPAS Model, Aland Chai Basin 5- References Keršuliene, V., Zavadskas, E. K., Turskis, Z. (2010). Selection of rational dispute resolution method by applying new step-wise weight assessment ratio analysis (SWARA), Journal of Business Economics and Management, 11(2), 243–258. https://doi.org/10.3846/jbem.2010.12. Zavadskas, E.K., Turskis, Z., Antucheviciene, J., & Zakarevicius, A. (2012). Optimization of weighted aggregated sum product assessment. Electronics and electrical engineering, 122(6), 3-6. http://dx.doi.org/10.5755/j01.eee.122.6.1810
fatemeh parhizkar; Masume Rajabi; Mojtaba Yamani; Davoud Mokhtari
Abstract
1-Introduction For thousands of years, mangrove forests have played a significant role in the economy and sustainable livelihoods of human societies. Therefore, identifying and measuring changes in the boundaries of mangroves over time can play an important role in planning and conducting effective protection ...
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1-Introduction For thousands of years, mangrove forests have played a significant role in the economy and sustainable livelihoods of human societies. Therefore, identifying and measuring changes in the boundaries of mangroves over time can play an important role in planning and conducting effective protection measures and reducing the vulnerability of mangroves to natural and human hazards. This study aimed to investigate changes in mangrove forests and the relationship between these changes and marine hydrodynamics and coastal morphology in parts of the north and east of the Strait of Hormuz for 47 years. 2-Methodology In this study, Landsat satellite images, MSS, TM, ETM +, OLI sensors from 1972 to 2019 were used to monitoring mangrove forest changes in the west of the Hormuz Strait. In the next step, the necessary preprocesses (radiometric and atmospheric corrections) were applied to the images in ENVI 5.3 software. And the classification of images was done by SVM, MLC, and ANN methods, and considering that to finalize the land use map, all classification accuracy indicators should be adjusted with one or more valid statistical indicators. The kappa index and general accuracy are among the statistical methods used. Post-processing operations also included the integration of classes that were applied to make the land use map more eloquent and eliminate single pixels on different classes. In the next step, the Change Detection method was used to detect changes and tell the results of the classifications. The next step is to convert the classified image to polygon and transfer it to the Arc GIS environment to manage the classes. Of course, the class that is most important to us here is the Mangrove Forest class, which was examined in the period 1972-2019. After the changes in the mangrove forests were identified, with the help of 1: 25000 topographic maps, contours of 2 meters of the range were prepared and the slope map was prepared using DEM images of the area. Also, using the half-hour tide data, the minimum, maximum, and average tide rates of Jask, Shahid Rajaee, Hormoz, and Sirik stations were calculated and finally, these data and maps were prepared to examine the development potential of mangrove forests. 3-Results and Discussion Land use maps were developed using Landsat images using three pixel-based classification algorithms (MLC, SVM, ANN) and the accuracy of the results was assessed using random points. The results showed that the highest overall accuracy and kappa coefficient were 99.44 and 0.99 for region A, and 98.41, 0.97, for region B, for SVM, respectively. Our study showed that SVM could be the most appropriate classification method for this study area. Therefore, SVM land use maps were prepared for the study area for 1972, 1987, 2002, and 2019. After preparing the land-use change map, it was stated that mangrove forests in region A accounted for 55.84% and in region B for 36.18%, tidal areas in region A accounted for 27.63%, and in Area B is 36.58 percent, Water Areas A is 3.04 percent, Area B is 1.78 percent, dry land is 15.37 percent and region B is 99.99. 7% have changed over the past 47 years. To explore the potential for the expansion of mangrove forests, we examined the slope of the region and its relationship with the average tide in the region. Comparing the results of the increasing and decreasing trend of mangrove forests with curves corresponding to the average tidal level and morphological features of the region, we conclude that the study area is about the hydrodynamic characteristics of the sea such as the average tidal area and extent. The catchment area, the height of the waves, and the coastal morphology such as slope and sediments and the water entering the areas from the Hasanlangi River and the Gaz and Hivi rivers have a very high potential for further development of mangrove forests. 4-Conclusion The results show that in the northern part of the Strait of Hormuz, the area of mangrove forests has increased in all the years, but in the eastern part of the study, we have always faced a decreasing and increasing trend and we don't see this part significant development during these 47 years in mangroves. However, according to the study of the geomorphic features of the region such as slope, topography, and the presence of Sabkha and Firth and sediments from the rivers of Hassan Langi, Gaz, and Hivi, as well as the average tide of the region and the vast area it covers, The study has the potential to develop mangrove forests. The results of this study can provide significant information about the progress or regression of mangroves in different coastal areas, can significantly help to implement protection measures and rehabilitate Iranian mangroves.
Reza Aghayari Samian; Ali Mohammad Khorshid Doust; Saeed Jahanbakhsh Asl; Aida Hosseini Baghanam
Abstract
The aim of this study was to predict changes in temperature, precipitation and evaluate the effects of climate change on the status of surface runoff in the Aras catchment. Climatic conditions were simulated in LARS-WG software environment under RCP8.5 scenario. Using the modified Trent White experimental ...
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The aim of this study was to predict changes in temperature, precipitation and evaluate the effects of climate change on the status of surface runoff in the Aras catchment. Climatic conditions were simulated in LARS-WG software environment under RCP8.5 scenario. Using the modified Trent White experimental model, the amount of potential evapotranspiration was estimated for both observation and simulation periods. To ensure the validity of the model, the mean error orthography (RMSE), and the determination coefficient and Nash-Sutcliffe efficiency coefficient (ENS) were used. Also, modeling of surface runoff changes in GIS software environment and SWAT plugin was performed. After forming hydrological units (HRU), the baseline model for surface runoff changes was selected to calibrate and validate the model. The results show that by modeling climatic data during the simulation period, the amount of temperature, evapotranspiration and transpiration will increase, and in contrast, the amount of precipitation has occurred and the flow rate will decrease superficially. The results of validation showed that the accuracy of the model in the selected stations was high and for the precipitation parameter due to its discontinuous nature, the correlation between the data is less than the temperature parameter and different. The results of hydrometric modeling of the basins showed that the Nash-Sutcliffe value is close to 1 and the correlation coefficient between the data is 0.99, which indicates the high efficiency of the model for simulating and estimating climate change and its effects on surface runoff.
Geomorphology
hojatolah younesi; ahmad godarzi; Masoud Shakarami
Abstract
Today, hybrid models of artificial intelligence are considered as a suitable method for simulating hydrological phenomena, including quantitative estimation of river flow. For this purpose, there are various approaches in hydrology to estimate the flow rate of rivers, of which artificial intelligence ...
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Today, hybrid models of artificial intelligence are considered as a suitable method for simulating hydrological phenomena, including quantitative estimation of river flow. For this purpose, there are various approaches in hydrology to estimate the flow rate of rivers, of which artificial intelligence models are the most important. Therefore, in this study, the performance of support vector-wavelet regression, backup vector-gray wolf regression and bat-support vector regression models to simulate the flow of Kashkan river located in Lorestan province during the statistical period of 2010-2011 in the daily time scale were analyzed. The criteria of correlation coefficient, root mean square error and mean absolute value of error and bias were selected for evaluation and performance of the models. The results showed that the hybrid models have acceptable results in simulating the river discharge. Comparison of models also showed that the support-wavelet vector regression model in the validation stage showed values of R2 = 0.960, RMSE = 0.045, MAE = 0.024, NS = 0.968 and BIAS = 0.001 in predicting daily river flow. . Overall, the results showed that the use of hybrid support-wavelet regression model can be useful in predicting daily discharge.
hydrogeology
kamran Razaei Tavabe; azam heydari; mohamad javad sayahpour
Abstract
Quality protection of surface and groundwater as one of the most valuable national resources is vital. For this purpose, Parishan basin was selected as a sample of semi-closed inland Zagros basins and geographical weight regression (GWR) modeling was performed using 25 observation wells of the relationship ...
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Quality protection of surface and groundwater as one of the most valuable national resources is vital. For this purpose, Parishan basin was selected as a sample of semi-closed inland Zagros basins and geographical weight regression (GWR) modeling was performed using 25 observation wells of the relationship between water quality parameters and geological constructs. In this model, water quality parameters such as (EC, TDS, SAR, CL, Na, K, 4 SO) are used as dependent variables and geological formations are used as independent variables. The modeling results showed that the highest correlation based on qualitative parameters such as potassium, chlorine and electrical conductivity is related to the center and east of Parishan basin. Water quality is also effective. Then, by forming the Moran index autocorrelation, the relationship between water quality parameters and geological structures was evaluated. The model with high variability accuracy established a direct relationship between these two parameters and by doing this step, the model validation was confirmed. Finally, based on the prepared maps and the high power of the GWR model, managers and planners can use it to identify sensitive points of changing water resources for spatial modeling.
hydrogeology
Fariba Esfandyari Darabad; Zeinab Pourganji; Raoof Mostafazadeh; Maryam Aghaie
Abstract
Floods as destructive natural hazards need to be predicted in accurate way through evaluation of the hydrological response of watersheds to the effective input rainfall. Due to the variety of rainfall-runoff models, it is very important to choose a suitable model that can simulate the hydrological behavior ...
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Floods as destructive natural hazards need to be predicted in accurate way through evaluation of the hydrological response of watersheds to the effective input rainfall. Due to the variety of rainfall-runoff models, it is very important to choose a suitable model that can simulate the hydrological behavior of the watershed. In this study, various rainfall-runoff transformation methods have been evaluated, including triangular, broken triangular, variable triangular and SCS-curvilinear unit hydrograph methods in Nenekaran watershed, Ardabil province. In this regard, the Wildcat5 hydrological model have been used to this purpose. The precipitation amount at the 25-year return period was calculated using Cumfreq software. After preparing the land use map of the study area using satellite images, the area of each land use in the area has been calculated using ArcGIS software. The precipitation value and the time of concentration were considered constant during the simulation procedure. The results showed that the SCS method had the highest runoff of 44.50 cubic meters per second. The minimum time to the peak was 2.19 hours and the variable triangular method had the lowest peak flow rate. The simple triangular method has a maximum time to peak of 4.51 hours, which shows the great difference between the hydrograph of the SCS method and the other three methods. The difference in the nature of the methods, the watershed condition, and the suitability of estimating tc and CN parameters should be considered in rainfall-runoff transformation methods.
Geomorphology
Reza Abbasian valandar; shahram roostaei; Davoud Mokhtari
Abstract
The Tamtaman area is located between 37◦38/00//-37◦44/00//north and 44◦40/30//-44◦59/30// east in northwestern Iran, approximately 15 km northwest of Urmia. This study aims to identify and zoning the potential development of karst in the area of Tamtaman cave in west Azerbaijan province using ...
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The Tamtaman area is located between 37◦38/00//-37◦44/00//north and 44◦40/30//-44◦59/30// east in northwestern Iran, approximately 15 km northwest of Urmia. This study aims to identify and zoning the potential development of karst in the area of Tamtaman cave in west Azerbaijan province using the AHP method. In this study, the information layers of lithology, tectonics, topography, slope, aspect, hydrology, land use, and climate have been considered as factor maps. The above layers have been called to extract the karst potential model in the GIS environment. Different information layers were classified as Criterion maps by applying expert judgment and assigning the weight of each layer in Expert Choice software and field visits. Finally, according to the obtained weight, the karst development zoning map in the Tamtaman area was obtained. The results obtained in this region exhibited a total area, of 6.68% within the very poorly developed class, 15.64% in the less developed class, 42.50% in the normal developed class, and 35.18% in the developed floor are located. The results show that in the Tamtaman region, the lithological and tectonic factors have the highest weight and are the most important factors controlling potential karst growth, while the land-use factor has the least impact on karst formation.
Geomorphology
elnaz piroozi; Aghil Madadi
Abstract
AbstractSoil erosion is one of the most important problems in the watersheds of Iran, which causes the loss of thousands of tons of arable soil every year. The aim of the present study is to zoning the risk of soil erosion in Givi Chay watershed (northwestern Iran). In this study, first, the effective ...
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AbstractSoil erosion is one of the most important problems in the watersheds of Iran, which causes the loss of thousands of tons of arable soil every year. The aim of the present study is to zoning the risk of soil erosion in Givi Chay watershed (northwestern Iran). In this study, first, the effective factors for erosion in the region were identified and then the information layers of each criterion were prepared in Geographic Information System (GIS). Valuation and standardization of layers was done using fuzzy membership function and criteria weighting, using critic method. Final analysis and modeling was performed using the Multi-Attributive Border Approximation Area Comparison (MABAC) method as one of the Multi-Criteria Decision Making (MCDM) methods. According to the results of the study, slope, land use, soil and lithology had the highest weight coefficient, respectively. Also, the results of the study showed; 283.89 and 414.93 km-square of the area, respectively, has a very high and high risk potential, and very high-risk and high-risk areas in unstable and erodible formations, agricultural uses and gardens and slopes of 25-40 % are located. It can be said that the results of this study indicate the high potential of the study basin in terms of erosion occurrence and it is necessary to control erosion and conservation measures on the agenda of experts and land managers. In addition, the results of validation of the results showed that the use of MABAC method has a high relative accuracy for studying the risk of erosion.
Batool Zeynali; Ehsan Ghale; Shiva Safari
Abstract
1-IntroductionOne of the most important water sources in mountainous areas is snow cover, which significantly affects the amount of runoff on the ground. Moreover, seasonal snow cover influences biotic components and water quality in rivers. Snow cover is one of the most important sources of fresh water ...
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1-IntroductionOne of the most important water sources in mountainous areas is snow cover, which significantly affects the amount of runoff on the ground. Moreover, seasonal snow cover influences biotic components and water quality in rivers. Snow cover is one of the most important sources of fresh water and affects the hydrological system of different altitudes in mountainous areas. Climate change has a major impact on the diversity of snow cover, thereby having adverse effects on snowmelt runoff and glacier mass balance. Remote sensing, due to its advantages, can control large areas with high spatial and temporal resolution. This technology provides the ability to quantitatively measure the physical properties of snow and water in remote and inaccessible areas where ground surveying may be expensive and dangerous. Therefore, it can be said that in basins with no accurate information on snow cover, this technology can be used to extract snow cover.2-MethodologyThe study area is Sabalan Mountain located in Ardabil province and its surroundings. In this study, Landsat 8 satellite images for 2020 and Landsat 5 images for 2000 were used for February due to the presence of sufficient snow to extract the snow-covered area. It was tried to select images with minimal errors. The images were mosaicked after ensuring the absence of common errors and atmospheric correction using the FLAASH model in ENVI5.3 software, then a part of the image was cut based on the research. In the eCognition software, the images were classified into three classes of water, soil, and snow using NDSI and NDSINW, then the classification result was transferred to ArcGIS software and the snow cover area was calculated. The NDSI was proposed based on the normalization of the green band difference and SWIR1 on MODIS images. NDSI and MNDWI are among the most widely used indices for implementing SCG maps. 3-Results and DiscussionIn this research, in order to obtain a snow cover map and its area, an object-oriented classification and NDSI and NDSINW have been used. The snow-covered areas extracted using the object-oriented method for the years 2000 and 2020 were calculated as 2500 and 1954 square kilometers, respectively. The values of 2557 and 1937 square kilometers were extracted as snow-covered area by applying NDSINW and 2610 and 2577 square kilometers were extracted by applying NDSI. The NDSI shows a larger snow and ice cover than it exists because it considers water as snow (Commission Error). Therefore, it is not suitable for distinguishing water from snow or extracting snow-covered area in areas where water exists. In contrast, the NDSINW is able to extract snow cover in areas with aquatic terrains because it uses near-infrared and middle-infrared bands and the difference between them in snow reflection to remove water-covered area. The classification maps were validated using samples taken from the satellite images and for both 2000 and 2020 images, overall accuracy coefficient and the kappa coefficient of the classification were estimated 0.99 and 99%, respectively.4-Conclusions In the present study, the object-oriented classification method was applied for detecting and extracting the snow-covered area based on the combination of optical bands on the Landsat 8 and Landsat 5 images of Sabalan region in Ardabil province. Then, the normalized difference snow index (NDSI) and the normalized difference snow index with no water information (NDSINW) were applied and the results of them were compared to identify the snow cover using the accurate object-oriented classification method. According to the results of the object-oriented classification map and the applied indices, it was found that both indices were able to extract snow cover compared to the object-oriented method in cold and winter area. However, the NDSI index had some error in extracting the snow-covered area due to not limiting aquatic terrains and water-covered areas and considering them same as the snow-covered areas, especially in areas where the presence of water is significant. Therefore, in areas with little or no water, it can be a very good index for extracting the snow-covered area.Keywords: Object Oriented Classification, Snow-covered Area, NDSI and NDSINW Spectral Indicators, Sabalan Mountain. 5-References Custodio, E., Cabrera, M.D.C., Poncela, R., Puga, L.O., Skupien, E., & Del Villar, A. (2016). Groundwater intensive exploitation and mining in Gran Canaria and Tenerife, Canary Islands, Spain. Hydrogeological, environmental, economic and social aspects, Science of the Total Environment, 557, 425–437.Donmez, C., Çiçekli, S.Y., Cilek, A., & Arslan, A. (2020). Mapping snow cover using landsat data: toward a fine-resolution water-resistant snow index. Meteorology and Atmospheric Physics. 10.1007/s00703-020-00749-y.Manickam, S., & Barros, A. (2020). Parsing Synthetic Aperture Radar Measurements of Snow in Complex Terrain: Scaling Behavior and Sensitivity to Snow Wetness and Land cover. Journal remote sensing, 12(483), 1-31.Parajka J., Holko, L., & Kostka, Z. (2001). Distributed modelling of snow water equivalent-Coupling a snow accumulation and melt model and GIS. Institute of Hydrology. Slovak Academy of Sciences, 14, 86-102.Sood, V., Singh, S., Taloor, A., Prashar, SH., & Kaur, R. (2020). Monitoring and mapping of snow cover variability using topographically derived NDSI model over north Indian Himalayas during the period 2008–19.Thomas, A.C., Reager, J.T., Famiglietti, J., & Rodell, M. (2014). A GRACE-based water storage deficit approach for hydrological drought characterization. Geophysical Research Letters, 41(5), 1537–1545.Voss K.A., Famiglietti, J., Lo, M., de Linage, C., Rodell, M., & Swenson, S. (2013). Groundwater depletion in the Middle East from GRACE with implications for transboundary water management in the Tigris-Euphrates-Western Iran region. Water Resource Research, 49: 27-39.Taylor, R.G., Scanlon, B., Doll, P., Rodell, M., van Beek, R., Wada, Y., Longuevergne, L., Leblanc, M., Famiglietti, J., Edmunds, M., Konikow, L., Green, T.R., Chen, J.Y., Taniguchi, M., Bierkens, M.F.B., MacDonald, A., Fan, Y., Maxwell, R.M., Yechieli, Y., Gurdak, J.H., Allen, D., Shamsudduha, M., Hiscock, K., Yeh, P.J.F., Holman, I., & Treidel, H. (2013). Ground water and climate change. Nature Climate Change, 3(4): 322–329.
Geomorphology
Raoof Mostafazadeh; Fariba Esfandyari Darabad; Ahmad Naseri; Ahmad Abyat; Maryam Adhami
Abstract
Fractal dimension is a powerful and important index that reflects the physical and morphological characteristics of rivers and has a close relationship with geometric features of rivers. The fractal pattern was used to investigate the sinuosity of the Gharehsou River in Ardabil Province, using the box-counting ...
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Fractal dimension is a powerful and important index that reflects the physical and morphological characteristics of rivers and has a close relationship with geometric features of rivers. The fractal pattern was used to investigate the sinuosity of the Gharehsou River in Ardabil Province, using the box-counting method. The results show that the fractal dimension of the Gharehsou River varies between 2.068 and 2.186. The minimum fractal dimension is in the first category of meanders with lower areas of tangent circle, and the maximum number of circles falls into the eighth category (having high areas of tangent circle). Based on the correlation between the number and area of tangent circles (0.71 to 0.84), it can be said that the river reaches studied follow a fractal and self-similar pattern. The fractal dimension values in the Anzab village-Taleb Qeshlaqi village reach were calculated to be 2.23, indicating a higher level of self-similarity, which is related with the naturalness of this river reach, which is located within a plain area, and the river has undergone more evolution. On the other hand, in the Taleb Qeshlaqi village-Sabalān Dam reach, the fractal dimension value was found to be 1.85, which may be related to the river traversing steeper paths, limiting its meander development and making the fractal pattern less observable. Human interventions in the river's course, as well as the river's passage through agricultural lands in some cases, have led to changes in the width and depth of the river and restrictions on meander expansion.
Geomorphology
Davoud Mokhtari; Mohammad Hossein Rezaei Moghaddam; diana dortaj
Abstract
Tectono-karst processes play an important role in the formation and change of landforms. Some areas, such as Zagros in Fars province, are affected by tectono-karst activities due to being in a tectonically active area and also having karstic formations. Due to the importance of studying landform changes ...
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Tectono-karst processes play an important role in the formation and change of landforms. Some areas, such as Zagros in Fars province, are affected by tectono-karst activities due to being in a tectonically active area and also having karstic formations. Due to the importance of studying landform changes in different planning, in this research, the analysis of tectono-karst processes in the formation and expansion of the transverse valleys of Zagros, Fars, from the range of Avaz to Karmostaj has been done. In this research, Sentinel 1 radar images, SRTM 12.5m high digital model, 1:100000 geological map of the region and hydroclimatic information of the region are used as the most important research data. The most important tools used in the research were ArcGIS and GMT. This research has been carried out in two stages according to the desired goals, in the first stage, the tectonic status of the region has been evaluated using the SBAS time series method, and in the second stage, using the Fuzzy Logic-AHP integrated model, to the potential The measurement of areas prone to the development of karstic processes has been discussed. The results obtained from the SBAS time series method have shown that some of the transverse valleys of the region are subsiding in comparison to their downstream regions, and this problem has caused a decrease in the height difference, a decrease in the speed of runoff, creating the necessary opportunity for erosion and dissolution, and in The result is the transverse development of these valleys. Also, based on the results, all the transverse valleys are located in the category with high or very high potential for the development of karstic processes, which indicates the role of karstic processes in the formation of transverse valleys in the region. The total results of this research have shown that the formation and development of transverse valleys in the studied area were affected by tectokarst factors.
yaser hoseini
Abstract
1-Introduction Flood is a natural phenomenon, which threatens the life and properties of a large number of people all over the world, yearly. Flood discharge, regarding water resource exploitation, flood control, construction of dams, basin management, and hydrologic studies, is of high importance in ...
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1-Introduction Flood is a natural phenomenon, which threatens the life and properties of a large number of people all over the world, yearly. Flood discharge, regarding water resource exploitation, flood control, construction of dams, basin management, and hydrologic studies, is of high importance in studies. Therefore, the accuracy of these studies and the safety of waterworks and water structures depend on the methods of studies to a large extent. It is impossible to manage water resources in basins without the accurate determination of the peak flood discharge. The advances in flood estimation techniques have made it possible to use rainfall-runoff models to assess the hydrographic properties of the flood in watersheds and decrease the risks of the flood. In studies on water resources, it is of high importance to determine the flood discharge of different basins. Studies of Dile and Srinivasan (2014) and Hoseini et al. (2017) showed that basin level and rainfall can be the most important factor in runoff flow. Consequently, proper simulation and modeling of flood runoff are the important parameters in flood management in the region. However, it is necessary to use new models to determine flood hydrograph parameters. So, this study aimed to determine the peak flood discharge of the Darrehrood basin using regression mode for return periods of 10, 25, 50, and 100 years. 2-Methodology Darrehrood basin is located in Northwest Iran. The basin is surrounded by mountains and is considered the main basin of Ardabil Province. It lies within 47°30' to 48°55' longitude and 37°45' to 39°42' latitude. Its area is approximately 12900 km2. Discharge data were collected from 16 hydrometric stations with a statistical period of 15 years during 2001-2015. Incomplete data related to stations were completed using statistical methods and considering the best statistical distribution of floods in the studied sub-basins, floods with different return periods were calculated then the physiographic characteristics of sub-basins that affect flood rate include: area, slope, shape factor, height average, concentration-time, and curve number achieved using ArcGIS and WMS (watershed modeling system). To evaluate the model, maximum error (ME), root mean square error (RMSE), relative percentage error (ε), mean absolute error (MAE), coefficient of determination (R2), Coefficient of residual mass (CRM), and model efficiency (EF) were used. 3-Results and Discussion The model calibration results showed that the simulated peak discharge and flow volume are in good correspondence with the observed values, so that, the lowest goodness of fit (R2) value in the return periods of 10, 25, 50, and 100 years were estimated to be 97, 96.6, 95.8 and 94.7 %, respectively. The results showed that the linear regression model with very good accuracy can predict the peak discharge in the sub-basins in Darrehrood using the physiographic parameters of the basin and with increasing the return period, the accuracy of the model is slightly reduced. Model evaluation indicators for the return period of 100 years include root mean square error (RMSE), relative percentage error (ε), mean absolute error (MAE), Coefficient of residual mass (CRM), and model efficiency (EF) were calculated 40.75, 52.12, 0.52, 0.92 and 0.62 respectively. Cross-validation diagrams showed that all models were partially underestimated and the scatter of points around the one by one axis was very suitable for the whole return periods. According to the paired t-test of the difference between predicted and actual values in different return periods in the level confidence of 1% are not significant. 4-Conclusions The results of this study show that the model has good accuracy for estimating floods in sub-basins of Ardabil province.
Hydrogeomorphology
Mohammad Mehdi Hosseinzadeh; Ali Reza Salehi Milani; Fateme Rezaian Zarandini
Abstract
Floods, as natural and unexpected events, have occurred frequently in recent decades. To reduce the damages caused by floods and flood management, it is mandatory to assess the possibility of danger and prepare maps of possible danger zones. In recent decades, many destructive floods have occurred in ...
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Floods, as natural and unexpected events, have occurred frequently in recent decades. To reduce the damages caused by floods and flood management, it is mandatory to assess the possibility of danger and prepare maps of possible danger zones. In recent decades, many destructive floods have occurred in the Nakarod catchment. Because of this, to manage floods, reduce damages, and properly use water resources, the flood potential of the sub-basins of the Nakarod catchment has been studied. Neka River is 176 km long, and it is one of the important rivers of Mazandaran province and one of the catchments of the Caspian Sea. In this research, to prepare a map of the sensitivity of the sub-basins to the flood risk of the basin, 11 influencing parameters have been used, which includes elevation, slope, distance from drainage network, drainage density, flow accumulation, rainfall, land-use, geology, stream power index, topographic wetness index and curvature of the topography. The layers were weighted using the Analytical Hierarchy Process (AHP); and eventually, by using the weighted linear combination method in ArcGIS software, the standardized layers were multiplied by the corresponding weight, and then the results of all the variables were added and accumulated together, and the final sensitivity map was divided into five classes. The results of the research indicate that flood sensitivity is different in the sub-basins of the Neka RiverAmong the effective environmental factors in flooding, the elevation and stream density were the most influential factors in the flood risk of the Neka catchment.
Hydrogeomorphology
maryam bayatikhatibi; Negar Zabet
Abstract
In Iran, due to the fact that a large part of the country is located in arid and semi-arid areas, the problem of salinity has become a big problem in agriculture. In Iran, about 14.7% of the total area of the country is made up of saline lands, and nearly 50% of the agricultural lands are faced with ...
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In Iran, due to the fact that a large part of the country is located in arid and semi-arid areas, the problem of salinity has become a big problem in agriculture. In Iran, about 14.7% of the total area of the country is made up of saline lands, and nearly 50% of the agricultural lands are faced with the problem of salinity or alkalinity and waterlogging to varying degrees (Hussaini, 2015). In the Azerbaijan region due to Lake Urmia, and illegal cultivation and extraction of underground water, soil salinity has become a big problem in a large part of the region and it seems that its dimensions will increase in the future. In this article, the most research focus is on the problem of salinity. The soil is within a radius of a few kilometers from Lake Urmia and near Tabriz. Preliminary observations and studies show that the problem of water salinity and then soil salinity has increased in the study area to such an extent that it has caused farmers to complain and abandon agriculture. and in terms of the dangerous dimensions of the problem, it has drawn the attention of researchers to the problem of soil salinity. The main reason for focusing on this area is excessive soil salinity within a 50-kilometer radius of Urmia Lake.
Davoud Mokhtari; Mohammad Hossein Rezaei Moghaddam; Somayyeh Moazzez
Abstract
1-IntroductionDebris flows are mass movements that always threaten human activities and cause a lot of damage. The aim of this study was to zoning the risk of debris flow in the Leilan Chai catchment located in East Azerbaijan province and the impact of this hazard on the Leylan alluvial fan. For this ...
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1-IntroductionDebris flows are mass movements that always threaten human activities and cause a lot of damage. The aim of this study was to zoning the risk of debris flow in the Leilan Chai catchment located in East Azerbaijan province and the impact of this hazard on the Leylan alluvial fan. For this purpose, 10 effective criteria in the occurrence of this hazard, including slope, aspect, elevation classes, land use, lithology, precipitation, distance to fault, river density, distance to river and distance to road were used to prepare a zoning map for debris flow hazard. Identifying areas with high risk sensitivity helps regional managers and planners to manage and control this risk in the basin.2-MethodologyLeilan Chai catchment as one of the tributaries of Zarrineh Rood River is one of the important rivers in the eastern part of Lake Urmia (Movahed danesh, 1999:45). This basin is located in East Azerbaijan province in terms of political divisions. The area of this basin is 723 Km2 and is located in the geographical coordinates of 37° 00′ 31″ to 37° 38′ 20″ north latitude and 46° 14′ 26″ to 46° 38′ 37″ east longitude. The minimum elevation of the basin is 1356 meters and the maximum elevation in the heights of Sahand Mountain is 3554 meters. This basin forms an alluvial fan at the exit of the mountain that called Leilan. In the present study, the SAW decision-making method has been used to weight the criteria. Layer fuzzy was also performed due to their importance in the occurrence of debris flow in ArcGIS and Idrisi software.3-Results and DiscussionMass movements such as debris flows have always been a threat to the development of human activities. The results of weighting the criteria using SAW method showed that lithology, slope and precipitation criteria with a weight of 0.260, 0.211 and 0.190, respectively, are of more importance in the occurrence of this hazard in the study area. After determining the weight of the criteria and sub-criteria, the layers were overlapped in the GIS environment and a potential map of the risk of debris flow in 5 classes was prepared. The results of the final map show that upstream of the basin area due to having high altitude and receiving more rainfall during the year and also having a high slope are highly sensitive to the occurrence of debris flow. The downstream areas of the basin, despite the high density of river and the presence of numerous faults, but due to the very low slope, show low sensitivity to the occurrence of debris flow.4-ConclusionIn this study, an attempt was made to prepare a map of the risk of debris flow occurrence in the Leilan Chai basin using effective criteria in the occurrence of this risk. The final debris flow hazard map was prepared by overlaying and multiplying the final weight of the criteria in fuzzy layers in GIS environment. The results showed that about 117 Km2 (16% of the area) of the study area is in the high and very high risk classes in terms of sensitivity to debris flow. In contrast, 49% of the total area is low and very low sensitivity to this risk. Areas located in high and very high classes mainly include the upper parts of the basin, which have the potential for this risk in terms of slope, precipitation (more than 400 mm) and lithology (presence of volcanic ash). Also, according to the research results, it can be said that this hazard cannot have much effect on the Leilan alluvial fan. Due to the occurrence of this hazard in the upper parts of the basin, the possibility of transferring these materials to the downstream areas and even the surface of the alluvial fan is very low due to the very long distance.
hydrogeology
Mirali Mohammadi; Mahsa Mohtadi
Abstract
The purpose of present research work is to study the hydraulic properties of River Simineh and its process using HEC-RAS model, in a combination with ArcGIS software using HEC-GeoRAS extension to simulate the hydraulic parameters of river having a catchment area of 3726 km2. For that mean, since multi-dimensional ...
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The purpose of present research work is to study the hydraulic properties of River Simineh and its process using HEC-RAS model, in a combination with ArcGIS software using HEC-GeoRAS extension to simulate the hydraulic parameters of river having a catchment area of 3726 km2. For that mean, since multi-dimensional models require long time and high cost in river bends, by using a combination of satellite images and HEC-RAS model a multi-dimensional simulation was prepared. Among those, 58 cross-sections are considered along the river lane that main data required in this research are elevation maps, satellite images, boundary conditions and River Simineh hydrometric stations. The results showed that at the upstream of river, the discharge was 316.3 m3/s and water level was 12.85 m, and at the downstream the flow rate and water level are 313.6 m3/s and 11.52 m, respectively. On the other side of the river bend, the water level variation is around 50 cm and the flow velocity is directly proportion to a distance from the river bank; so that the maximum flow velocity of 2.2 m/s occurred at a distance nearby 1.5 m. To verifying the model, a statistical parameter of NSE coefficient for the water level and flow depth were 0.805 and 0.845, respectively; which shows the accuracy of model. Those results indicate a high accuracy of HEC-RAS model in hydraulic simulation of River Simineh flow. Also, simulations prepared in GIS background have significant impacts on the accuracy of outputs
habibeh Abbasi; Mohammad Taghi Aalami; Mohammad faraji
Abstract
This article aims to analyze the trend of monthly, seasonal and annual changes in the flow and sediment of the Mordaghchai. located in East-Azerbaijan province. In this regard, using non-parametric methods, discharge and sediment data of Gheshlagh-Amir hydrometric station have been analyzed in three ...
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This article aims to analyze the trend of monthly, seasonal and annual changes in the flow and sediment of the Mordaghchai. located in East-Azerbaijan province. In this regard, using non-parametric methods, discharge and sediment data of Gheshlagh-Amir hydrometric station have been analyzed in three time scales: annual, seasonal and monthly. The modified Mann-Kendall test was used to analyze the trend of gradual changes in discharge and sediment data. Also, the Sen's slope estimator was used to estimate the slope of the trend line and the non-parametric Pettitt test was used to investigate the abrupt changes in the discharge and sediment time series. The modified Mann-Kendall test was used to analyze the trend of gradual changes in discharge and sediment, and the Sen' slope estimator test was used to estimate the slope of trend line. Also, Pettit test was used to investigate abrupt changes in the river discharge and sediment time series. The results show that annual, monthly and spring, summer and winter discharges significantly decrease at the level of 5%. The annual and all-season sediment load data significantly decreased by 5%. There is a significant decrease in sediment load in all months except March, April and October. The results of the Pettitt test show that the average annual discharge in the period after the breaking point (1998) has decreased by 45% compared to the period before the breaking point. Also, the average annual sediment load after the breaking point (1996) has decreased by about 52% compared to the previous period.
Morad Darabi; Hossein Malekinezhad; Ali talebi; masoumeh hidari
Abstract
1-Introduction Floods have historically been the most common, deadliest and most expensive hazards among natural hazards. The risk of flooding has increased over time, especially since countries have allowed changes in the land uses and land coves in floodplains and plains. In Iran, like the other ...
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1-Introduction Floods have historically been the most common, deadliest and most expensive hazards among natural hazards. The risk of flooding has increased over time, especially since countries have allowed changes in the land uses and land coves in floodplains and plains. In Iran, like the other flood-prone areas of the world, the severity of floods and the extent of their damages have increased dramatically in recent decades. Land use and vegetation play an important role in the production of runoff due to its effect on infiltration, erosion, evapotranspiration and transpiration. 2-Methodology Khorrambid watershed having an area of 88.7 km is a part of the Sivand Dam watershed. The average rainfall of this basin is 228 mm and it has a semi-arid climate in the view of Domarten. Khorrambid metropolitan basin consists of 12 smaller sub-basins in the study area with three main waterways named A, B and C that cross the city upstream of Khorrambid and pass through the city. In this study, the design, purpose, and efficiency amount of the flood and runoff output amount have been evaluated and finalized from the hydrographic network. The set of Management, Biological and Structural works carried out in the Khorrambid urban basin of the Sivand Dam Branches include: management excavation, piling, seeding, Dry working forage, Dry Stone Structures, rock and PVC mesh, rock and earth dams. Detailed studies and implementation of Khorrambid urban watershed was carried out in 1999 and the implementation of watershed management projects started in 2002 and by the end of 2010 about 33% of the projects were implemented in the study phase. At the same time, the evaluation process regarding the effect of these projects on flood and runoff control took place. This study aimed to evaluate the performance of projects (management, biological and structural) on the runoff and water resources in Khorrambid watershed in Fars province. In this study, first, the height of the dams, the length of the reservoir and the slope of the canals were measured under the basins where structural projects were carried out to determine the route of the new water movement. Then the new concentration time was calculated using the Branse-Williams method. In the next step, soil cover layer data such as the percentage of canopy cover, hydrological groups and vegetation status were obtained to determine the number of curves and maximum holding and infiltration potential in the soil. Then using SCS method and Hyfa software, modeling the flood volume and outflow runoff for sub-basin were estimated. 3- Results and Discussion By analyzing the results of statistical analysis of changes it can be said that there were many changes in all land use and land cover as well as the implementation of structural and biomechanical projects in the studied area. To investigate the effect of land use and structural changes on the hydrological regime of the studied basin, SCS method was utilized. This model was formulated using GIS techniques. The results showed that due to the increase in rangeland land use (from poor to good condition) and the construction of watershed structures, flooding in the area has decreased in case there were 24-hour rainfall. This amount of runoff reduction in the basin A and C was 41% and 72%, respectively. 4- Conclusions It is suggested that by evaluating the projects, if the performance of these projects could be evaluated in appropriate ways and from various technical and engineering aspects, the results would lead to finding the causes of the proposed operation failure and presenting appropriate solutions to address them. On the one hand, this could improve the quality of implementation of watershed management activities, on the other hand, it would increase operational efficiency, and the learnt lessons would enhance future plans. On the other hand, it is recommended that since watersheds are in fact considered as a natural-human system as well as a planning and work unit, comprehensive management of these watersheds is essential for achieving sustainable development goals. Watershed management is a complex process whose practical goals should be in line with the promotion of stakeholders` interests and stakeholders` engagement at all levels of planning and decision making. Integrated Watershed Management requires a flexible process that taking into account the challenges and constraints of the Watershed System, makes good use of its opportunities and potential conditions to ensure the social and economic well-being of its stakeholders while maintaining the security of water, food and environment in order to meet its goals of sustainable development.
Hydrogeomorphology
fatemeh menbari; Amjad Maleki; nayyeri hadi
Abstract
Morphometric analysis of a drainage basins and river network plays an vital role in understanding the hydrogeological behavior of the drainage basin . Therefore, the current research was conducted with the aim of modeling flood and its relationship with morphometric variables using multivariate regression. ...
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Morphometric analysis of a drainage basins and river network plays an vital role in understanding the hydrogeological behavior of the drainage basin . Therefore, the current research was conducted with the aim of modeling flood and its relationship with morphometric variables using multivariate regression. The research method is based on the destruction of morphometric parameters and statistical analysis, including correlation coefficient and linear regression analysis. In this regard, first, the studied basins have been selected using ARC GIS 10.5 software, and the limits of each one has been determined. Then, their morphometric characteristics have been extracted. The Flood discharge has also been reconstructed in return periods of 2 to 500 years using easy-fit software. For modeling, first, the linear relationship between each morphometric variable as an independent variable with flood discharge as a dependent variable was investigated. After ensuring the linear relationship between variables and flood discharge, correlation between each variable and flood discharge was calculated. The variables with the highest correlation were watershed area, basin length, and surface flow length. Using multivariate regression, modeling was used for independent variables and flood discharge. The results show that as the return period increases, the relationship between independent variables and flood discharge increases, So that the correlation of the area with the return period of 25 years is 0.609 and with the return period of 200 years is 0.677.also, the proposed models have more validity for flood prediction using multivariate regression analysis in return periods above 25 to 500 years.
Amin Navidtalab; Ghasem Askari; Farahnaz Ahmadpour; Maryam Tahmasebi
Abstract
1-IntroductionOne of the most important issues, facing the human society and environment, is water resources management. Regarding the drought, this issue turns to a serious challenge for decision makers, and affect the the people more than other natural hazards (Hagman, 1984). Normally, drought occurs ...
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1-IntroductionOne of the most important issues, facing the human society and environment, is water resources management. Regarding the drought, this issue turns to a serious challenge for decision makers, and affect the the people more than other natural hazards (Hagman, 1984). Normally, drought occurs in all climatic conditions (Dai, 2010). Through the current research, we try to investigate drought in Lurestan Province using Percent of Normal precipitation Index (PNI) which evaluates meteorological drought (Hayes, 2006; Zargar et al., 2011). Lurestan Province located in the western Iran, and has an area of about 29,308 Km2. Geographically, it sits between northern latitudes of 32֯ 38' 39" and 34֯ 24' 17" and between eastern longitudes of 46֯ 52' 14" and 50֯ 01' 59". Climatic differences has led to the emergence of three conspicuous climates: (1) mountainous cold climate in the northern and eastern parts, (2) temperate climate in central parts, and (3) warm climate in the south and southeastern parts.2-MethodologyThe meteorological drought intensity is evaluated through different methods including Standardized Precipitation Index (SPI), Percent of Normal Index (PNI), Deciles Index (DI), Effective Drought Index (EDI), China-Z (CZI), Modified China-Z (MCZI), Rainfall Anomaly Index (RAI), Z-Score Index (ZSI), Palmer Drought Severity Index (PDSI), (Willeke et al., 1994; Byun and Wilhite, 1999; Hayes, 2006; Salehnia et al., 2017). To evaluate drought, a period of thirty-year (1988 – 2017) data were adopted from nine synoptic weather stations including Khorramabad, Borujerd, Aligudarz, Aleshtar, Noorabad, Poldokhtar, Kohdasht, Azna, and Dorud. For calculating PNI, the following equation has been applied (equ.1): PNI=P/P ̅ *100 (1)where PNI stands for Percent of Normal precipitation Index, P for annual precipitation (mm), P ̅ for average precipitation of the thirty-year period. PNI (%) ≤110 represents Moderately to Extremely wet climate, 80-110 Normal, 55-80 Moderately dry, 40-55 Very dry, and 40≥ Extremely dry (Morid et al., 2006).3-Resultsand DiscussionConsidering 67 years recorded data for Khorramabad, 32 years for Aligudarz, and 30 years for borujerd, these stations are considered as milestones to reconstruct the data for stations with lack of data for the thirty-year period of study. For other stations, 13 to 17 years of data were reconstructed (Table 1). To find the best reference station for incomplete stations, geographic and climatic resemblance with the stations of complete thirty-year period data was considered. Temperature, precipitation, De Martonne aridity index, and climatic classification by Iran Meteorological Organization (IMO) were evaluated for all stations to find similarities.Table (1): Reconstructed years of data for each station based on geographic and climatic resemblance with the stations of complete thirty-year period data. De Martonne classificat-ionIMO classificationAvail-able yearsReconstr-ucted yearsStation21.3Semi-aridModerately wet, warm summer, moderately cold winter670Khorramabad17.8Semi-aridModerately wet, temperate summer, very cold winter1713Azna18.4Semi-aridModerately wet, temperate summer, very cold winter320Aligudarz7.55Dry or AridModerately wet, warm summer, cold winter1713Dorud18.4Semi-aridModerately wet, warm summer, moderately cold winter300Borujerd18.6Semi-aridModerately wet, temperate summer, cold winter2010Aleshtar19.5Semi-aridModerately wet, temperate summer, very cold winter1713Noorabad14.8Semi-arid to AridModerately wet, warm summer, cold winter2010Kuhdasht10.9Dry or AridModerately wet, very warm summer, moderately cold winter1911Poldokhtar 4-ConclusionNone of stations show Extreme drought. Severe drought is observed in 6 stations with little percentages (3.3-6.6%). Weak droughts has been recorded between 6.6 to 30% in all stations (Table 2). Therefore, dried 80% of springs and rivers in Lurestan could not be solely resulted from meteorological drought in Lurestan. The role of water management in creating this crisis should not be neglected.Table (2): Percentage of different intensities of drought in the studied stationsModerately to Extremely dryNormalModerately dryVery dryExtermely dryStation23.343.3303.30Khorramabad3040236.60Azna26.643.323.36.60Aligudarz2066.36.66.60Dorud30502000Borujerd36.646.616.600Aleshtar36.636.626.600Noorabad33.340206.60Kuhdasht26.65016.66.60Poldokhtar Keywords: Meteorological drought, Drought intensity, drought prediction, Lurestan5- References Byun, H. R., Wilhite, D. A. 1999. Objective quantification of drought severity and duration. Journal of Climate, 12(9): 2747–2756.Dai, A. (2011), Drought under global warming: a review. WIREs Clim Change, 2: 45-65. doi:10.1002/wcc.81De Martonne, E. (1926). Aerisme, et índices d’aridite. Comptesrendus de L’Academie des Sciences, 182: 1395– 1398.Hagman, G. (1984). Prevention Better than Cure: Report on Human and Natural Disasters in the Third World, Stockholm: Swedish Red Cross.Hayes MJ. Drought indices. What Is Drought? Lincoln, Nebraska: National Drought Mitigation Center, 2006. Available at: http://drought.unl.edu/whatis/indices.htm. Salehnia, N., Alizadeh, A., Sanaeinejad, H., Bannayan, M., Zarrin, A., & Hoogenboom, G. (2017). Estimation of meteorological drought indices based on AgMERRA precipitation data and station-observed precipitation data. Journal of Arid Land, 9(6): 797-809.Willeke, G., Hosking, J. R. M., Wallis, J. R. (1994). The national drought atlas. In: Institute for Water Resources Report 94-NDS-4. U.S Army Corp of Engineers, CD-ROM. Norfolk, VA.Zargar, A., Sadiq, R., Naser, B., & Khan, F. I. (2011). A review of drought indices. Environmental Reviews, 19(NA): 333-349.
hydrogeology
maryam baranpour; Bijan Khalili Moghadam; Amin zoratipour
Abstract
Abstract:The climate change is a complex atmospheric-oceanic phenomenon on the global scale. Climate change and global warming is one of the most important factors affecting the degradation of water and soil resources in arid and semi-arid regions; Which increases the occurrence of dust phenomenon. The ...
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Abstract:The climate change is a complex atmospheric-oceanic phenomenon on the global scale. Climate change and global warming is one of the most important factors affecting the degradation of water and soil resources in arid and semi-arid regions; Which increases the occurrence of dust phenomenon. The aim of this study was to evaluate the performance of two statistical downscaling models of SDSM and LARSWG for quantitative screening in predicting climate scenarios and also predicting climate change in the dust center of south and southeast of Ahvaz. In line with this goal, one of the three-dimensional paired oceanic models - AOGCM atmospheric general circulation called HadCM3, The results showed that the simulated data of both models, compared to the observed data, were significant compared to the long-term mean of the base period and had a high correlation with a high coefficient of determination (R2) for all parameters from 0.87 to 0.98. Finally, by confirming the existence of climate change in Khuzestan province , SDSM model due to direct use of HadCM3 models and large scale NCEP data and the type of simulation process and also Combined structure in data mining scale with RMSE, MAE and ME 0.97, 0.18 and 0.021, respectively; It has higher accuracy than LARSWG model in simulating climatic data in the dust center of southern Ahvaz. The SDSM model was also more successful in simulating daily temperature data and wind speed, and the LARSWG model had a better prediction of the daily precipitation parameter.
