Mehdi Teimouri; Omid Asadi Nalivan
Volume 6, Issue 21 , March 2020, , Pages 155-179
Abstract
1-IntroductionThe main objective of this research is to prioritize the factors affecting the occurrence of landslide and its susceptibility zoning in Lorestan province using the maximum entropy and MaxEnt models. To do this research, 11 factors affecting the occurrence of landslide including height, ...
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1-IntroductionThe main objective of this research is to prioritize the factors affecting the occurrence of landslide and its susceptibility zoning in Lorestan province using the maximum entropy and MaxEnt models. To do this research, 11 factors affecting the occurrence of landslide including height, slope, aspect, surface curvature, distance from the stream, fault and road, lithology, land use, rainfall, and topographic humidity index have been used. In this research, 30, 40, 50, 60 and 70 percent of landslides were evaluated for validation to determine the sensitivity and accuracy of the model. For evaluation of the model, the relative recognition function curve (ROC) was used. From the total of 176 landslides, 70% of the data was used as the test data and 30% as the validation data using Mahalanobis distance method and the accuracy of the model in the testing and validation stages based on the curve level was reduced. The results showed that 35.5% of the province of Lorestan has a landslide sensitivity. Based on jackknife diagram, rainfall, distance from road, lithology and land use layers were the most important factors influencing the sensitivity of landslide. The AUC level based on the relative function recognition curve indicated a 90% accuracy (excellent) of the maximum entropy method at the training stage and 83% (very good) at the validation stage to determine the landslide susceptibility. The results of this study will be suitable for provincial administrators and managers in order to land planning and reduce the damage caused by landslide occurrence.Mass movements, including landslide, is one of the most important issues in natural hazards, because its occurrence can cause many human and economic losses, especially in mountainous areas (Symeonakis et al., 2016). Regarding the destructive effects of landslides on natural resources, as well as human habitats and erosion of significant volumes of valuable soils, the identification of susceptible areas and zoning of potential occurrence or landslide susceptibility is vital and very important (Zhang et al., 2019). In recent years, the use of GIS and remote sensing along with machine learning methods has created a new step in the zoning of landslide occurrences. Lorestan province is a vulnerable area to landslide hazard due to the mountainous and wetness conditions. Therefore, the main objective of this research was to prioritize the factors affecting the occurrence of landslide and its susceptibility zoning in Lorestan province using the maximum entropy and MaxEnt model.2-MethodologyLorestan province with an area of 2829612 hectares is one of the major provinces in the west of the country. To do this research, 11 factors affecting the occurrence of landslide including altitude, slope, aspect, surface curvature, distance from the stream, fault, and road, lithology, land use, rainfall, and topographic humidity index have been used. The required maps were prepared using GIS and RS techniques. In this research, 30, 40, 50, 60 and 70 percent of landslides` division were evaluated for validation to determine the sensitivity and accuracy of the model. For evaluation of the model, the relative recognition function curve (ROC) was used. Using Mahalanobis distance method, from the total of 176 landslides, 70% of the data was used as the test data and 30% were utilized as the validation data for having the best classification. The difference of the current research with other similar studies was that in this study, use was made of Mahalanobis distance method for classification of validation data and training instead of random classification. The Mahalanobis distance helps to classify data richness and prevents random selection of points for validation. Maximum entropy method (MaxEnt model) is one of the methods of machine learning and one of the main advantages of MaxEnt model is the ability of this model to identify the most important variables and sensitivity analysis of variables using Jackknife method, which has been investigated in the current study.3-ResultsThe results showed that 35.5% of the province of Lorestan had landslide susceptibility. Based on Jackknife diagram, rainfall, distance from road, lithology and land use were, respectively, the most important factors influencing the susceptibility of landslide. The AUC level, based on the relative function recognition curve, indicated 90% accuracy (excellent) of the maximum entropy method at the training stage and 83% (very good) at the validation stage to determine the susceptibility of landslide occurrence.4-Discussion and conclusionLandslide is considered as one of the most dangerous natural disasters in the world. In this study, taking into account the affective environmental and human factors, and using the maximum entropy method, the map of landslide susceptibility of Lorestan province was prepared. The results showed that factors such as rainfall, distance from the road, lithology, land use, distance from the fault and slope were the most important factors influencing landslide susceptibility with the participation of over 60%, regarding which, land use management and road construction principles need human activity interventions. The drawn ROC curve showed that the accuracy of the model in the estimation of landslide susceptibility regions both in the stage of the test and in the validation stage was excellent and very good, which meant the excellent performance of the model. According to the obtained results, it can be said that MaxEnt model had a high ability to determine areas with landslide susceptibility and due to the speed and accuracy of the model,it is suggested that in similar researches, especially in developing countries, due to the lack of facilities and financial resources, as well as the time consuming of identifying areas with landslide susceptibility, it can be used. In addition to natural factors, some human factors such as road construction, play an important role in the occurrence of landslide, which requires avoiding ecosystem change as a disaster risk factor to reduce relative risks. The results of this research can be applicable to the decision making and management of provincial lands as well as urban planning, and they can have a significant role in preventing and reducing the damage caused by landslide.
reza dehghani; hassan torabi; hojatolah younesi; babak shahinejad
Abstract
River flow prediction is one of the most important key issues in the management and planning of water resources, in particular the adoption of proper decisions in the event of floods and the occurrence of droughts. In order to predict the flow rate of rivers, various approaches have been introduced in ...
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River flow prediction is one of the most important key issues in the management and planning of water resources, in particular the adoption of proper decisions in the event of floods and the occurrence of droughts. In order to predict the flow rate of rivers, various approaches have been introduced in hydrology, in which intelligent models are the most important ones. In this study the application of hybrid wavelet vector hybrid model to estimate the discharge of Kharkhe basin rivers on daily discharge statistics of hydrometric stations located upstream of dam during the statistical period (2008-2018) has been evaluated and its performance with vector machine model The backup was compared. The correlation coefficients, root mean square error, mean absolute error was used for evaluation and also comparison of the performance of models in this research. The results showed that the hybrid structures presented acceptable results in the modeling of river discharge. Comparison of models also showed that the hybrid model of support-wavelet vector machine has better performance in flow forecasting. .Overall, the results showed that using a hybrid backup vector machine model can be useful in predicting daily discharge.
Mehdi Bashiri; Seyedeh-Maedeh Kavousi Davoudi; Ali Afzali
Volume 5, Issue 14 , June 2018, , Pages 157-178
Abstract
Introduction
The mass movement of materials on steep slopes under the influence of gravity and motivation factors such as earthquakes, floods and torrential rains called landslide. Landslide similar the other natural phenomena is an important natural disaster that occur every year in the mountainous ...
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Introduction
The mass movement of materials on steep slopes under the influence of gravity and motivation factors such as earthquakes, floods and torrential rains called landslide. Landslide similar the other natural phenomena is an important natural disaster that occur every year in the mountainous and highland areas of our country. By risk assessment of landslide occurrence, the sensitive areas with a high potential risk can be identified. Also the effect of different environmental factors on the pattern of high-risk areas can be used in risk management, practically.
Methodology
One of the basic measures for achieving methods for mass movements control and management is identifying the effective factors in occurrence of this phenomenon. Also, in countries involved in the landslide, there is an increasing tendency for risk and damage assessment of this phenomenon. Therefore, at the present study, using fractal geometry, the effects of land use, geology and geomorphology on the landslide patterns were evaluated in the Tooye-Darvar watershed, Semnan province. Because the fractal theory studies and recent reviews in the earth science indicate that some geological processes such as mineralization, sedimentation, deposition, volcano, morphology and etc have self-similar characteristics. First, using aerial photo interpretation, field surveying and recording the position of landslides using GPS, the landslide distribution map prepared. Then, information layers for each slope, aspect, elevation, geology, geomorphic units, soil erosion class, distance from fault, distance from road, distance from stream and land-use factors prepared.in the ArcGIS software environment using digital elevation model (DEM) of the region with a pixel accuracy of 20 meters. Also the landslides information layer prepared according to the field studies and rasterized. Then, different layers overlapped and table of combined properties for merged layer includes the information of each pixel, extracted and entered into the Excel environment. In Excel, the relative importance (or frequency ratio) calculated for each different class of information layers.
Statistical analysis
After collecting and recording data and creating the database, the SPSS v.23 used for data analysis. In the first stage, the normalization checked using Kolmogorov-Smirnov test at the 5% confidence level. Then, the effect and significance of each measured variable investigated in landslide occurrence.
Calculating the fractal dimension
The landslide areas available in each unit extracted as a polygon and the resulting image transmitted to the Fractalyse software and its fractal dimension calculated using box-counting method. Then, the fractal dimension of landslides placed in work units transferred to the SPSS environment and statistical comparison performed with the aim of investigating the geometric or morphologic differences of sliding zones in different land uses and geologic and geomorphic units. Then to compare the different landslide hazard classes, the density or compression ratio of landslide used in each hazard class. The density ratio calculated by dividing the landslide density in a particular hazard class to the average density of landslides based on the area density or the number of landslides.
landslide susceptibility zonation
In order to zonate the landslide susceptibilityusing bivariate statistical methods, the information value and the area density, each of the factors affecting landslide occurrence include slope and elevation maps, slope aspect, soil erosion class, geomorphic type, geological unit, land use, distance from the stream, distance from the road and distance from fault in GIS environment digitized and classified. Then, based on the two above mentioned methods, the weight of each factor and its related classes determined. The weighted maps of effective factors combined and using natural breaks method, the obtained maps classified in very low, low, moderate, high and very high hazard classes. In order to evaluate the implemented model in the region , 2/3 of landslide points and 2/3 of landslide areas used for modelling and the remaining 1/3 of each one used to evaluate the model.
Discussion
The results of fractal dimensions study in 146 landslide areas using box counting method showed an average of 1.987. Study of the spatial features in landslide areas include landuse, slope aspect, soil erosion class, geological unit, geomorphic type, height and slope class, distance from road, distance from fault and distance from stream showed that only the effect of geomorphic types on geometric dimension of landslide areas is significant and this significance is caused by high difference (sig=0/000)between mountains and plateaus and upperterraces types. Finally, the density ratio for landslide areas and points in each class of spatial characteristics for landslide occurrence, calculated and the effects of these variables on landslide occurrence severity, presented and analyzed. Also, in the landslide susceptibility zonation about 1/2 of landslides located in the high and very high risk classes that indicates the high potential for landslide in this region.
Conclusion
The results showed that the surface erosion has no significant effect on occurrence of large landslides but it has affected the landslide points. Also, the presence of marl and lime in study area that is a geological unit susceptible to dissolution can be effective in landslide occurrence. Geomorphologically, the mountain and hill types have been effective, which could be due to the high slope of these types. In the case of landslides occurrence in the vicinity of roads, faults and streams, it can be concluded that the small landslides has been affected by road, but it has no significant effect on the occurrence of large landslides. But the existence of fault in the area and proximity to the fault led to the occurrence of extensive landslides. Finally, the presence of stream in the area has also been effective in occurrence of large landslides, but the landslide points, has not been affected by existence of stream in their buffers. Also, high potential for landslide in the study area represents the being endangered for regional installations, agricultural lands, engineering structures and buildings.
Ata Ghafari Gilandeh; Behrooz Sobhani; Elnaz Ostadi Babakandi
Volume 3, Issue 9 , March 2017, , Pages 159-175
Abstract
Flooding is a major natural disaster. This phenomenon becomes more important when it is occurring especially in the city. Therefore, prevention of the communities from the impacts is inevitable. The high level of awareness of potential runoff area for flood management is important. Given this importance, ...
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Flooding is a major natural disaster. This phenomenon becomes more important when it is occurring especially in the city. Therefore, prevention of the communities from the impacts is inevitable. The high level of awareness of potential runoff area for flood management is important. Given this importance, this paper deals with the calculation of runoff with SCS method in Meshkinshahr city and its surrounding area, For this purpose, we used GIS software and the accession of the ARC-HYDRO, especially Arc-CN-RUNOFF software. Finally, the layers of soil hydrologic group, the integration of land use and rainfall averages were compared with the index table, then the resulting map was obtained. Curve number Map (CN), which was proportional to the permeability of the 20 classes. Curve No (32) for areas with high permeability and low runoff and curve number is high (98) for areas with low permeability and high runoff. Dimensional map of the height map is runoff from zero to areas with very high permeability and high runoff starts 99/0, including the use of low permeability to continue. Check the map showed that both CN and RUN-OFF lot to do with the type of the user, so that the use of man-made and synthetic runoff curve number and height are more.
Ahmad Nohegar; Majid Khazaei; Rasoul Mahdavi Najafabadi; Abdolrasoul Telvari
Volume 3, Issue 8 , December 2016, , Pages 161-181
Abstract
Received: 2015.03.15 Accepted: 2016.10.15 Ahmad Nohegar[1]* Majid Khazaei[2] Rasoul Mahdavi Najafabadi[3] Abdolrasoul Telvari[4] Abstract River bank erosion is one of the major sources of sediment for many rivers around the world. The aim of this study was to identify erodible riches in Bashar river ...
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Received: 2015.03.15 Accepted: 2016.10.15 Ahmad Nohegar[1]* Majid Khazaei[2] Rasoul Mahdavi Najafabadi[3] Abdolrasoul Telvari[4] Abstract River bank erosion is one of the major sources of sediment for many rivers around the world. The aim of this study was to identify erodible riches in Bashar river because the role of this river's in development of Kohgiluyeh and Boyerahmad province. In this study, using Satellite imagery, aerial photos and field survey from 1975 to 2015, the riverbank migration patterns for period of 40 years were investigated. After creating database of recorded data Bashar river, bank lines in different years digitized. Then, by comparing successive changes in bank line position, patterns of erosion and accretion was determined. Due to dischargr and Geological factores effectes on river pattern, these factors were evaluated. The Result of for identify erodible riches in Bashar river using GPS and field surveys, verified. The area of bank erosion and accretion by comparing sequential changes in banklines position determined. For short-term analysis, the migration rate from one any image to the next image is estimated. For long-term analysis, the migration rates are based on the difference between the 1975 image as the reference, and subsequent images. The results indicate that the erosion– accretion patterns in the sub aerial and subaqueous areas of the beshar river have changed significantly since 1994. For the short-term analysis, the highest erosion and accretion amounts are 4.7 and 7 ha from 1975-1984 and 1984-1990, respectively. the lowest erosion and accretion amounts are 2.6 and 2.3 ha from 2008-2011, respectively. The highest rate of bank erosion in different reaches equal to 9.6 and 4.6 ha/y in reachs of fifth and second bserverd. Also rate of bank accretion in fifth and second reachs equal to 9.6 and 4.6 ha/y observerd. the lowest erosion and accretion rate in reach of seven equaled 11.7 and 6.4 ha/y accounted, respectively. The correlation coefficient the between erosion and discharge and annual discharge averagelly for the short-term analysis observed 0.54 and 0.44, respectively. [1]- Professor, Faculty of Environment, University of Tehran (Corresponding Autor), Emial:nohegar@ut.ac.ir. [2]- Ph.D Student Watershed Management Engineering, Hormozgan University. [3]- Assistant Professor, Department of Rangeland & Watershed Management, Hormozgan University. [4]- Science and Research Branch Islamic Azad University (Ahwaz Branch).
Abstract
Abstract
In recent years geomorphological instantaneous unit hydrograph approach has gained wide acceptability in estimating the runoff from a watershed due to different storm patterns and watersheds with scanty data. Using geomorphologic features is a suitable criterion for derivation of hydrograph ...
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Abstract
In recent years geomorphological instantaneous unit hydrograph approach has gained wide acceptability in estimating the runoff from a watershed due to different storm patterns and watersheds with scanty data. Using geomorphologic features is a suitable criterion for derivation of hydrograph and watershed management in ungagged watersheds. In this study, using morphometric characteristics of Daryan Chay basin, such as bifurcation ratio and longest flow path, geomorphological instantaneous unit hydrographs which were derived for 5 events and by using criterion such as determination coefficient, percentage error in peak discharge and time to peak discharge, Nash-Sutcliffe efficiency and percentage error in runoff volume were compared with observed hydrographs. The findings showed that the most important components of the hydrograph were time to peak and peak discharge. A slight difference was observed between simulated time to peak using geomorphological instantaneous unit hydrograph and observed hydrograph. In other words, geomorphologic instantaneous unit hydrograph predicted the geomorphological instantaneous unit hydrograph accordingly.
Hafez Mirzapour; Ali Haghizadeh; Rezvan Alijani; Zahedeh Heydarizadi
Volume 5, Issue 15 , October 2018, , Pages 153-169
Abstract
Abstract
Introduction
The importance of planning and managing water resources, as well as an increasing population growth and the limitation of surface water resources in the country, has made the accurate prediction of rivers' flow by using modern tools and methods of modeling, as an inevitable necessity. ...
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Abstract
Introduction
The importance of planning and managing water resources, as well as an increasing population growth and the limitation of surface water resources in the country, has made the accurate prediction of rivers' flow by using modern tools and methods of modeling, as an inevitable necessity. In addition, proper river flow prediction in river management, flood warning systems, and especially planning for optimal operation is required. In order to predict the flow of a river, several methods have been developed over the past years. In general, these methods can be classified into two categories of conceptual models and models based on statistics or data. The basis of the most of the predictive methods is the simulation type of the current status of the system which is called "modeling". Considering that in most cases the conceptual models require accurate data and knowledge of processes affecting the phenomenon, and this has so far been accompanied by many problems, researchers have turned to the statistical models. Over the past four decades, time-series models have been widely used in predictive river flow as a statistical model. In each science, the collected statistics corresponding to the variable which is going to be predicted and which is available in the past periods are called time series. Indeed, a time series is a set of statistical data collected at equal and regular intervals. Statistical methods that use such statistical data are called analytical methods of time series. The basis of many decisions in hydrological processes and decisions on exploitation of water resources is according to the prediction and analysis of time series. Assessment of the temporal changes of base flow in watersheds, particularly in low flow seasons is very important.
Methodology
Time series models are represented in three main forms: self-correlated models (AR), moving average (MA) models, and self-correlated and moving average (ARMA) models. The condition of using these models is the static nature of the used data. If the data is not static, the data series must be static with the existing methods. The existence of "I" in ARIMA indicates the non-static nature of the original data and the change in the data for modeling. If the data series has a cyclic and rotational state, the type of model is seasonal or SARIMA. Time series models have two components of (p, d, q) and s (P, D, Q). S (P, D, Q) is a seasonal component. P and q are respectively autoregressive parameters and non-seasonal moving average. P and Q are autoregressive parameters and seasonal moving average. The other parameters, D and d, are differential parameters for making the time series static.
Result
The statistical and probabilistic models have been presented and developed. This study aimed to analyze and compare the performance of series 30 and 56 years and monthly average discharge related to the Kakareza River in the Selsele city and the Kashkan Afrineh River in the Poldokhtar city in Lorestan province. To this end, the first climate in this region was determined. Next, the autocorrelation function and partial autocorrelation real data draws in XLSTAT software was done. Subsequently, the data was normalized using the Box-Cox and logarithmic. Then, the data trend that indicated non-stationary was determined. After that by using the different operator in MINITAB software, the data trend was removed and the suitable model with the lowest Akaike was selected. Then both periods 12 and 24 months for the two regions were simulated. Results showed that the selected models in 12 and 24 months periods had respectively a correlation coefficient of .92 and .86 for the kakareza river and .94, .88 for the Kashkan Afrineh river.
Discussion and conclusion
The most significant difference between the observed and the simulated values is in two months of Esfand and Farvardin. In addition, due to high precipitation, there was a significant increase in the amount of discharge in Farvardin. According to the climatic conditions in the study areas, the model showed a better performance in semi-arid areas.
Zohreh Maryanaji; Moslem Darvishi
Volume 5, Issue 16 , December 2018, , Pages 159-175
Abstract
Abstract
Introduction
Global warming has profoundly changed the climatic regions of the earth and the time and the place of snowfall, which has caused a lot of damage to humans, especially in recent decades. Indeed, depending on the nature of the climatic regions, these changes are diverse and varied. ...
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Abstract
Introduction
Global warming has profoundly changed the climatic regions of the earth and the time and the place of snowfall, which has caused a lot of damage to humans, especially in recent decades. Indeed, depending on the nature of the climatic regions, these changes are diverse and varied. Mountains and valleys play different roles in the uneven distribution of the temperature and snow. The effects of different directions can be very important in snow coverage on the northern and southern slopes. In this research, using statistical models and satellite images in the Alvand, the role of the elevation, the direction of the slope, and the effect of temperature changes on snow cover in the recent decade (2015-2006) have been investigated.
Materials & Methods
In this research, based on Landsat satellite 5, 7, and 8 imagery, the data from the visible and infrared bands were used to extract snow data based on the NDSI index. The NDSI index was applied using relationship (1) to produce snow maps on images. Indeed, the use of relative indices such as NDSI reduces the effect of the topography on the result.
(1)
To investigate the role of the Alvand in snowfall in both of its northern and southern slopes and the snowfall regime changes in its windward slope and windsurf, the harmonic analysis was used. For this purpose, to analyze the snowfall co-ordinates and periodic behaviors and time variations, the monthly mean snowfall per cm with harmonic analysis was used. This analysis is given as a substring using a time series.
(2)
ResultsandDiscussion
According to the findings of the NDSI index, Tuyserkan area receives less snow (62%) than Hamadan (69%). The moist air mass ascending the western slopes of the Alvand's heights causes more rainfall than its eastern slopes. However, the temperature of Hamadan station is lower than that of Tuyserkan due to its northern slopes in the Alvand and the less energy it receives from the sun, which has made the snowfall on the northern slopes be more visible than it is on the southern slopes. The minimum and maximum temperatures have increased in the winter. This steep trend of increase in the winter temperatures along with lower snowfall indicates the effects of climate change and global warming on Hamadan and Tuyserkan regions. The value of the variance in the second harmonic reflects the effect of elevations on the region's climate. The value of the second harmonic variance in the northern slope which is 28% and significant shows the impact of topography on snowfall in the area. Indeed, the snowfall up to 28 % is related to the height and topography of the northern slopes of the Alvand.
While at Tuyserkan Station, this amount is reduced to 20%, meaning that the northern altitude of the Alvand is more effective in the snowfall.
Conclusion
The Alvand is a branch of the Zagros mountain range that passes through Hamedan province and has high peaks. The climatic phenomena of this mountain range are abundantly observed in the province. Severe winds and snowfall of the Alvand altitudes are among these phenomena. The mountainous cities of the province, including Hamadan and Tuyserkan, are among the most affected by the Alvand. This study by examining the hidden features of the climatic data by harmonic analysis and satellite images showed that the northern slope shared more than the southern slope in snowfall which was a significant amount in the second harmonic and a relative decrease in the temperature and snowfall. The northern slope was colder in the northern hemisphere and the sunrise of southern slope got more heat than those that were not exposed to the direct sunlight. The percentage of snow in the NDSI index on both sides of the Alvand confirmed this geographic reality. In general, the results showed a hidden feature of the rise in temperature and snow loss in the data and satellite imagery also recognized this fact. Considering the fact that the Alvand is a climatic region of the country's cold and mountainous regions and the sustainability of the natural environment depends on the relative stability of the climate, in order to achieve sustainable development and land use in the region, it seems that regional climate change should be considered in the context of climate change and the reduction of snowfall in the long time.
Morteza Samadian; Behzad Hessari; MirAli Mohammadi; Mohammad Taghi Alami
Volume 6, Issue 18 , June 2019, , Pages 161-180
Abstract
IntroductionRiver training, flood control projects, and every change of river geometry will change the morphological conditions of a river and the hydraulic characteristics and flow. In fact, the goal of river training plans can be found on the basis of the initial energy equilibrium of the river. In ...
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IntroductionRiver training, flood control projects, and every change of river geometry will change the morphological conditions of a river and the hydraulic characteristics and flow. In fact, the goal of river training plans can be found on the basis of the initial energy equilibrium of the river. In this study, the impact of river training on the hydrodynamic conditions of the Zarrineh River in conjunction with Shahindezh city in different scenarios were investigated. The Zarrineh River training project modeling, as a general objective, is the use of hydraulic simulations to create a river water surface based on new physical, civil, and hydrological properties of a given reach. The motivations for conducting such simulations are flood plain extent mapping based on current and new scenarios and the determination of water level along the study river reach. The purpose of this project was to create maps before and after a new river training plan, all within the GIS and Autocad environment with a georefrenced origin. Study of the Zarrineh River project requires a thorough evaluation of the possible impacts that it may have on the Zarineh River, both upstream and downstream from the Vahdat Bridge. The prediction of the operation, maintenance, and repair or replacement of the bridge, requirements of existing and proposed projects are other roles that river hydraulics simulations play in the planning and design processes. The Zarineh River is a very wild river and every civil project is needed to be evaluated from different aspects, especially from new geomorphological conditions. New liberalized areas beside the river for each scenario should be determined and evaluated for new land use utilizing particularly for Eco-Tourism usagesand repair or replacement of the bridge, requirements of existing and proposed projects are other roles that river hydraulics simulations play in the planning and design processes. The Zarineh River is a very wild river and every civil project is needed to be evaluated from different aspects, especially from new geomorphological conditions. New liberalized areas beside the river for each scenario should be determined and evaluated for new land use utilizing particularly for Eco-Tourism usages. Material and methodMIKE11 was selected to simulate current and selected new river training scenarios that iteratively solve a one-dimensional energy balance to produce water elevations based on river geometry, channel roughness, flow rate, and boundary conditions. MIKE11, developed by DHI, is a software package for simulating flows in rivers. The river geometry is provided in the form of channel cross-sections at regular intervals along the direction of flow. The number of cross sections that are taken varies with study requirements and stream characteristics. About 1 km reach of the upstream and downstream includes Vahdat bridge with 14 cross sections under current situation (without bridges and without training), the bridge with 120 meters without training, the bridge with 120 m, 200 m and 300 m with bed and banks training. For the current scenarios, it is needed to predict stage, discharge, and velocity as functions of time anywhere on a river in different return periods such as 25 yr. To measure cross-sectional coordinates, previous topographic maps generated from field surveys performed with land surveying instruments were used. All information to set up the Mike model, including input data files, simulation period, time step and the name of result files and also initial and boundary conditions were determined and defined. Flow hydrographs for the project at the bridge location for all scenarios were extracted from hydraulical simulations Mike11. For Hydrograph prediction, the Saint-Venant approach with Finite Element method and Six-Point Algorithm of Abbott were used to discretize temporal and spatial elements.Results and DiscussionThe Zarrineh River project consists of Vahdat Bridge that should be modelled and it should be checked for the reliability of new area liberalization without any impact on users of Shahindezh such as municipality, regional water authority, environmental protection agency and ministry of roads and city affairs. In river training scenarios with widening bridge to 300 m, in addition to the liberalization of 90 ha areas on both sides of river banks, the water level increased about 65 cm and the maximum flow capacity increased to 115000 m3. The calibration results indicated that the estimated error rate of flow volume (REV) and the relative error in the peak (REQP) for training scenario were respectively 0.197 and 1.792%, corresponding to the current condition which were about 0.068 and 2.82 percent. The figures showed a good agreement between modeled and observed values. Vahdat Bridge with 120 lengths and 1200 m3/sec (25 yr return flow) will overflow to adjacent areas. The modelling results showed the high potential of the river training for the flood transmission and flood routing. Also, the accuracy of the simulation of unsteady flow is one dimensional for the desired range by the MIKE11 mathematical model.ConclusionThe rivertraining projects should be modelled, controlled, and evaluated for overflow problem from sidewalls. In addition, river bed and banks should be controlled so that they are not affected by water score problem. For secure hydrograph transmission in the reach of the Zarineh River and Shahindezh city conjunction, the 300 m bridge widening scenario was selected and the executive maps and detailed plans for the river training, bridge with a width of 300 meters, sidewalls and end sill structure (river bed stabilizing structure for preventing score) were provided.
Reza esmaili; Maryam Ghorayashvandi; Esa Jokar Sarhangi
Volume 5, Issue 17 , March 2019, , Pages 163-183
Abstract
Extended Abstract
Introduction
Flood is one of the most important hazards in the alluvial fans and its analysis is associated with many complications. The term alluvial fan flooding refers to only a specific type of flood hazards that occurs only on alluvial fans (NRC, 1996). These floods in alluvial ...
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Extended Abstract
Introduction
Flood is one of the most important hazards in the alluvial fans and its analysis is associated with many complications. The term alluvial fan flooding refers to only a specific type of flood hazards that occurs only on alluvial fans (NRC, 1996). These floods in alluvial fans are characterized as high flow velocity, different flow paths, very active erosion, transport, and deposition processes. Many of the rural and urban areas of Iran which are located in areas of alluvial fans are potentially at risk of flood. Therefore, the identification of high risk areas of flood at different scales can be useful in managing them. This research was conducted with the aims of estimating the flash flooding in the northern alluvial fan of the city of Izeh, identifying potentially hazardous areas in terms of flooding, and prioritizing them for management purposes. The study area with an area of 75 km2 is located in the north of the city of Izeh and the Lake Miangaran. The mean elevation is 1470 m. According to the Izeh meteorological station, the average rainfall in the region is 637 mm and the average annual temperature is 23 ° C.
Methodology
The boundaries of the watersheds and alluvial fans were separated and mapped using Google Earth Images of 2016. The potential of flood hazards was studied in three main steps: (1) Identifying active and passive zones of alluvial fans; the geomorphic indices including intersect point of alluvial fan, braided drainage pattern, and alluvial fan topography profile were used to identify the active and passive zones of alluvial fans. (2) The estimation of runoff and discharge with SCS method; the Ghahreman and Abkhezr method (2004) was used to calculate the amount of rainfall during different return periods. The information layers of the soil, land use, and vegetation cover were prepared from maps of the Natural Resources Administration of Khuzestan province. By combining the information layers, the curve number (CN) values for different basins and weighted average were calculated. Using the data such as catchment area, rainfall and its duration, number of the curve, length of stream and its slope, peak of flood discharge and time to peak were calculated. (3) Ranking of the risk areas by TOPSIS method; in the TOPSIS method, the n×m matrix is evaluated for a decision that has m option and n criterion. The basis of this technique is based on the notion that a selective choice should have the least distance with the positive ideal solution (best possible) and the greatest distance with the negative ideal solution (the worst possible condition).
Result
In the study area, twelve catchment- alluvial fan systems were identified. The active areas of the alluvial fans were 5 to 100% of their total areas. Based on soil characteristics and surface coverage, the average relative weight of CN varied from 78 to 90. The rainfall was calculated at 30, 60, 120, 180, and 360 minutes at the return periods of 2, 5, 10, 20, 50, and 100 years. Due to the small size of the basins and the short duration of concentration, the rainfall of 120 minutes with a return period of 10 years, which was 36.77 mm, was considered as the peak estimation criterion. To assess the ranking areas in the TOPSIS method, four criterion including flood peak due to precipitation of 120 minutes with a 10-year return period, time to peak of discharge, active alluvial fan area, and area of villages located in active alluvial fan were used. Twelve studied alluvial fans also appeared as options in the matrix. The results of the flood hazards ranking in the alluvial fans of the study area showed that fans of 2 and 5 were the villages of Perchestan Gurii with a population of 1168 people and the village of Pershestan Ali Hossein Mola with a population of 317 which had respectively had proximity coefficients of 1 and 0.4481 in rankings 1 and 2.
Discussion and conclusion
Within the studied area, the active areas of the alluvial fans are considered to be a major contributor to the flood hazard ranking so that the variables of the alluvial fans area and the area of villages based on them account for 77% of the weight of the ranking. Hence, the determination of the active regions of the alluvial fans can be used on a regional scale using Google Earth satellite 3D images. Using multi-criteria decision-making methods such as TOPSIS can rank the flood hazards in the alluvial fans of north Izeh with regard to the influential variables. This regional-level ranking can show areas at risk and, if necessary, detailed geomorphological studies and field studies will be needed.
Behrooz Sari sarraf; Tahereh Jalali Ansaroodi
Volume 6, Issue 19 , September 2019, , Pages 163-185
Abstract
Introduction In the recent decades, the growth of the industrial activities and the increase in greenhouse gases have imbalanced the Earth's climate which is called the phenomenon of the climate change. This phenomenon directly affects the hydrological parameters. While climate change directly affects ...
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Introduction In the recent decades, the growth of the industrial activities and the increase in greenhouse gases have imbalanced the Earth's climate which is called the phenomenon of the climate change. This phenomenon directly affects the hydrological parameters. While climate change directly affects surface water resources through changes in the major long-term climate variables such as air temperature, precipitation, and evapotranspiration, the relationship between the changing climate variables and groundwater is more complicated and difficult to quantify. The large amount of water is needed in different parts of arid and semi-arid regions provided through groundwater resources. In recent decades, the quantity and quality of water resources have been reduced by unprotected exploitation. In addition, climate change and global warming increase the severity of the problem. Therefore, the predicted effects of climate change on groundwater recharge play an important role in the management of these resources in the future. In this study, Global circulation models, HadCM3 under A2 and B2 scenarios, were used for investigating the impact of climate change on groundwater recharge rates between 2017 and 2030, in the Tasouj aquifer. Methodology In this study, to investigate the climate change in Tasouj basin, the required data were obtained from two sources including Global model output AOGCM which was based on the HadCM3 model and the observed data of the precipitation and temperature of Tabriz synoptic station with the statistical length of 1961 to 2016. To downscale the general circulation modal, the statistical method of SDSM was used. The Hydrologic Evaluation of Landfill Performance model (HELP) simulates all of the important processes in the hydrological cycle including surface runoff, evapotranspiration, vegetative growth, soil moisture storage, and vertical unsaturated drainage for each discrete layered soil column. In general, the modeled hydrologic processes by the program can be divided into two categories of surface and subsurface processes. The modeled surface processes are snowmelt, interception of rainfall by vegetation, surface runoff, and evaporation of water. The modeled subsurface processes are evaporation of water from the soil, plant transpiration, vertical unsaturated drainage. Vegetative growth and frozen soil models were also included in the program to aid modeling of the water routing processes. The required general data included growing season, average annual wind speed, average quarterly relative humidity, monthly normal mean temperatures, maximum leaf area index, evaporative zone depth and latitude. Result According to the simulation of Hadcm3 model, during the period of 2017-2030, the average monthly temperature in all months of the year will increase in the studied area. The highest amount of heating in the average temperature will happen in July about 2 degree Celsius. The highest decrease in precipitation will occur in April and May about 9 mm than the base period. The highest percentage of precipitation in Tasouj basin is used for evaporation. During 14 years of the prediction, the year 2020 has the highest and the year 2029 has the lowest amount of evaporation. In terms of runoff caused by precipitation, the year 2023 with 9.69 percent of precipitation will have the highest runoff. The lowest and highest amount of recharge will respectively happen in 2021 and 2027. The depth of water precipitation is significantly affected by soil moisture and with increasing soil moisture; the depth of water percolation to soil will decrease. The soil moisture content is negative in 2027. Consequently, the highest amount of recharge due to precipitation will happen in Tasouj basin. In the base period, the year 1990 had lowest precipitation and the year 1963 had the highest precipitation. Due to having a negative soil moisture storage in 1990, of 148 mm of annual precipitation, about 76.28 mm was spent for recharge. The amount of runoff is almost zero in this year and the rest of precipitation is evaporated. Despite the high annual precipitation in 1963, due to the high moisture content of the soil, the amount of recharge is only 4 percent of precipitation and most of the precipitation changes to runoff and evaporation. The status of evaporation, runoff and recharge in 2022, as the forecasted most precipitation year, is similar to 1963. Discussion and conclusion In recent years, the climate change has led to significant changes in the weather and the condition of surface and underground water resources in different locations. The response of the groundwater resources to drought and climate change is not as rapid as that of the surface water, but considering that the renewability of these resources takes much longer than that of the surface water, the impact of long-term drought on groundwater resources is much more serious than that of the surface water resources. Therefore, the monitoring of the condition and maintenance of the sustainability of these resources is important. In this way, by using a step by step approach, the impact of climate change on recharge, evaporate, and runoff for the 2017-2030 period was investigated and the simulation result showed that with increasing temperature and decreasing precipitation, of three parameters of evaporation, recharge, and runoff, the evaporation dominated the other parameters. But the high consumption of basin and the increase of temperature and precipitation decrease prevented Tasouj aquifer from returning to its balance. Therefore, a principle planning to control the harvest and treatment of aquifer by underground dam and artificial nourishment is necessary
Robabeh Farzinkia; Mohmmadali Zanganehasadi; Abolghasem Amirahmadi; Rahman Zandi
Volume 6, Issue 20 , December 2019, , Pages 165-185
Abstract
1- IntroductionToday, the phenomenon of land subsidence is one of the most important geomorphologic hazards on a global scale, causing a great deal of damage to urban and rural construction. According to the UNESCO definition, "subsidence is the collapse or land leveling that occurs due to different ...
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1- IntroductionToday, the phenomenon of land subsidence is one of the most important geomorphologic hazards on a global scale, causing a great deal of damage to urban and rural construction. According to the UNESCO definition, "subsidence is the collapse or land leveling that occurs due to different large and small scale causes" (Amir Ahmadi et al., 2013: 2). Pourkhosravani et al, (2012) Only with radar interferometer technique studied the geometry of duality, The results of this study showed that, firstly, citing excessive productivity of underground waters is not the main reason for the subsidence phenomenon; secondly, the phenomenon of subsidence in Iran's plains is the result of a duality in the crustal motions between the plains and adjacent mountains. In this research, the tectonic indexes and radar interferometry technique have been used with regard to the data and information available to detect the tectonic activity of the area.2-MethodologyIn order to investigate the state of activity of the newly tectonic area, topographic maps of 1: 50000 and 1: 10000 map of geology and radar images are used in the earthquake discussion from USGS US from 1923 to 2018. Also, to study the subsidence of the Joveyn area, the satellite Sentinel-1A satellite radar data for 2017 and 2018 was used in Canada and processed by SNAP software. The resources used in this research were based on library studies and surveys, topographic maps and radar images and field surveys.3-Discussion and results and findingsThe results of the used Indicators, earthquake zoning and radar interference are defined in the research as follows:River Gradient Index) SL): This index was first presented by Hack (1973), in the study of the role of rock resistance on water flow in the Appalachian Mountains in the southeast of America as numerical values of the river gradient index Table1).Table(1): River Gradient Index)SL)HighΔH(m)ΔL(m)Lsc(m)SlCondition1200-13001001476932050217low1100-12001001581467170424medium1000-110010029798122931412medium-Asymmetric index(AF):In this calculation, the obtained numbers (33.7) of the basin showed that the value of the index is less than 50. Therefore, we have the tectonic activity on the left side of the main stream and we face the subsidence phenomenon on the right.-Reverse topographic symmetry index: (T)to calculate this index in the Joveyn basin, a section has been created in each sub-area and its value has been calculated. According to (table 2), the index value in all three sub-basins is less than 1, indicating the asymmetry and active tectonics in the whole basin. Table (2): Reverse topographic symmetry indexRouteDa(km)Dd(km)TCondition118/4321/330/86active215/3816/910/9active314/5316/780/86active-Hypsometric and Hypsometric Integral CurvesIn the hypsometry integral, the numerical value has a value of 0.5 in the range of young to adult topography.Mountain Sinocity Index: (Smf)Table (3): Mountain Sinocity Index shapeLMFLSSCondition126/9412/342/18Semi active241/8611/853/5Semi active333/0518/721/76active446/0223/041/99active-Sinocity index of the river: (S)According to the calculations, the index of the main bend and bend of the main river is less than 1. Which represents the new activities in the region.-Valley Depth Wide Index (VF):In passive regions, the average value of this indicator is usually higher than 7 in terms of over-rupture (Ranjbar Manesh, 2013).Table(4): Valley Depth Wide IndexConditionVfVfwEldErdEscnumberactive1.3629205721101604Figure 1active0.8127140814981307Figure 2active0.873135414241301Figure 3active1.6220153416841475Figure 4active2148150514811421Figure 5active1.2127154515271437Figure 6active0/287232421151877Figure 7-Radar interferometric resultsAccording to this map, the maximum subsidence rate in the study area in 2017 and 2018 will be 6.4 and 5.6 respectively. Regarding the maps drawn on this plain with radar interferometry, both indicate the subsidence of the plain. The analysis of plain radar data shows that the highest elevation in the joghatay heights, and the highest subsidence level, occurred on the joveyn Plain floor.4-ConclusionAlthough most scholars consider untreated groundwater to be an important factor in groundwater depletion and the plains of Iran, the role of tectonic factors in exacerbating this phenomenon should not be overlooked. In a study conducted by Purkhosrovani et al. On the causes of the subsidence, only Duval's discussion of radar interferometry was discussed without examining tectonic indices. In this study, in addition to radar interferometry, the tectonic status of the basin was also investigated. For this purpose, geomorphic indices such as watershed shape, drainage basin asymmetry index, inverse topographic symmetry index, mountain front sinusoidal index, hipsometry integral, valley floor height to its height, river sine index, river gradient index, gradient index They offer some of the activities of the area's baby boomers. Among the morphotectonic indices that all indicate tectonic activity in the region, the VF index in the region was less than 2, which by standards is below 6 in this index indicating rising areas. Subsidence caused by tectonic movements occurs when there are two faults, graben and upwelling, and relative movement of parts causes subsidence. The fault status of the area in the southern and northern parts of the region has placed the plain in the graben position. Statistical analysis also showed that the earthquake of 1923 occurred with a magnitude of 6.4 MS. The future activity of these faults may affect the area. The active morphotectonic conditions of the basin, also showed the results of radar interferometry, in the southern part with higher elevation, parallel to subsidence in the plain. The existence of this scouring and its appearance on the radar interferometer map indicates the tectonic activity in the southern rangesof the study area. These results indicate a significant relationship between the subsidence and its lateral elevations, suggesting that these two movements are dual. Based on the above arguments, it can be concluded that one of the factors affecting the subsidence of the Earth in the juvenile plain is due to its soft crustal motions even in equilibrium. Due to the geomorphic hazards of the basin, it is necessary to prepare a zoning map of the area for development activities and land preparation based on which control, protection, prevention or warning measures will be taken.
Ebrahim Asgari; abazar esmali; Raoof Mostafazadeh; Gholamreza Ahmadzadeh
Abstract
1- Introduction The comparison of different geological formations in term of sediment yield is one of the most important issues in many soil and water conservation studies. Moreover, the measurement of runoff production rate and sediment production is the prerequisite of watershed management. The potential ...
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1- Introduction The comparison of different geological formations in term of sediment yield is one of the most important issues in many soil and water conservation studies. Moreover, the measurement of runoff production rate and sediment production is the prerequisite of watershed management. The potential of a watershed toward erosion is the result of erosivity, erodibility of geological formations, slope gradient and land use types in the watershed. Accordingly, runoff is one of the important factors in the water erosion issues. Different geological formations depending on the rock composition, erosion and slope gradient, have a potential to produce sediment and play an important role in the amount of soil losses. The behavior of rocks and quaternary deposits against weathering and erosion depend on the nature of the rock and environmental affecting factors. Therefore, the main aim of the present study was investigating and comparing the geological formations regarding the runoff and sediment yield along with runoff threshold in Gharehshiran watershed of Ardabil province using a rainfall simulator measurement. 2- MethodologyBased on the geologic map of the studied area, the boundaries of different geological formations were defined and then according to the objectives of the present study, a field rainfall simulator (100 × 100 cm) with a height of one meter was used for field experiments. Theoretically, the use of rainfall simulator systems saves time and cost, which can be used for monitoring the amount of runoff and sediment along with all processes involved in erosion and sediment production. However, it should be noted that the use of rainfall simulators is also subject to limitations that can never fully create natural conditions. The plot scale measurements have been conducted through 45 samples in predefined geological formations of the studied area. The runoff threshold initiation time and the amount of runoff and sediment were recorded through field experiments. The runoff and sediment samples were collected in individually stored containers and were then, transferred to the laboratory. The values of runoff were measured and the samples were oven-dried for 24 hours at 105 °C and then the deposited amount of sediments were obtained. The amount of sediment in each sample was determined using a producer of precise weighting. Then, the normality of the data was analyzed using Kolmogorov-Smirnov test. The comparison of the geological formations was examined with respect to sediment amount, runoff, and initiation time threshold using One-way ANOVA method through SPSS software. Furthermore, the significant different in mean values of studied variables between geological formations were compared with Duncan's test. Then, the correlation between the studied variables in various geological formations was evaluated using Pearson correlation analysis in SPSS software. 3- Results and Discussion The results of one-way ANOVA test showed that there was no significant differences between different geological formations considering runoff and sediment yield (p < 0.05). While, there was a significant difference between geological formations with respect to the runoff threshold initiation time (p < 0.05). Comparison of the mean values of runoff threshold time using Duncan test indicated that the highest and lowest thresholds time of runoff production were observed in Qt2 (alluvial terraces) and Qb (basaltic lava) formations with the values of 8.28 and 2.28 minute, respectively. According to the results, there was an inverse relationship between runoff and sediment variables in different formations. Also, the correlation between the runoff threshold time and the amount of runoff was negative with -0.318 correlation coefficient (p < 0.05), while, correlation between the runoff threshold time and sediment yield values was positive (r=0.327) at 5% confidence level. 4- Conclusion Many of the geological formations in this area were related to Quaternary and Tertiary periods. Young alluvial terraces and upland terraces, along with marl, sand, conglomerate, and clay formations were related to the Quaternary period, which were the results of erosion from rock units of past periods. It is suggested that the effects of other effective factors on erosion and sediment production processes should be considered in future researches to make a better and comprehensive conclusion. In conclusion, it can be said that studied geological formations were assigned to the Quaternary era and had a similar behavior in term of runoff and sediment production, while the difference in composition and mineralogy of different formations led to differences in runoff threshold.
hassan torabipodeh; Babak Shahinejad; Reza Dehghani
Volume 5, Issue 14 , June 2018, , Pages 179-197
Abstract
Background and Objective
Drought is one of the phenomena of climate that occurs in all climatic conditions and in all parts of the planet. Drought prediction has an important role in designing and managing natural resources, water resource systems, and determining the plant's water requirement. For ...
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Background and Objective
Drought is one of the phenomena of climate that occurs in all climatic conditions and in all parts of the planet. Drought prediction has an important role in designing and managing natural resources, water resource systems, and determining the plant's water requirement. For estimating drought, various approaches have been introduced in hydrology that artificial models are the most important ones. In this study for evaluating the accuracy of the models in estimating the 12-month standard rainfall index, monthly data from four weather stations in Boroujerd, Dorood, Selseleh and Dolphan in Lorestan province have been used. For modeling of drought in these stations utilized wavelet neural network and artificial neural network models and the results were compared to each other for the accuracy of the studied models. In a few studies, each of the models presented in the drought estimation has been studied. But the purpose of this research is simultaneous analysis of these models at four stations for estimating the standard rainfall index.
Methods
In this study, Boroujerd, Dorood, Selseleh and Dolphan that located in Lorestan province have been selected as the study area During the statistical period, the precipitation parameter was used at monthly time scale (1962-1372) for input and standard rainfall index as the output parameter of the models. For this purpose, at first 80% of the data (1372-1382) were selected for calibration of the models and 20% of the data (2012-2013) were used to validate the models. The wavelet neural network, which has a very good fit with the sinusoidal equations by separating the signal into high and low frequencies, can greatly increase the accuracy of the model and reduce noise. Artificial neural networks are inspired by the brain information processing system that ability to approximate patterns of a model has increased the scope of these networks. Correlation coefficient, root mean square error and mean absolute error value were used for evaluation and performance of the models.
Results
The results showed that both models have good performance in estimating the standard rainfall index in the four stations studied. Also, according to the evaluation criteria, the wavelet neural network model was found to have the highest accuracy and low error rate compared to the artificial neural network model.
Conclusions
In total, the results showed that the use of wavelet neural network model can be effective in estimating the standard rainfall index. also It can be useful in facilitating the development and implementation of management strategies to prevent drought and is a step in making managerial decisions to improve water resources.
behrouz sobhani; Leyla Jafarzadehaliabad; Vahid Safarianzengir
Volume 6, Issue 21 , March 2020, , Pages 181-202
Abstract
1-Introduction Drought is one of the most important natural disasters affecting agriculture and water resources, and its abundance is extremely high in arid and semi-arid regions (Shamsenya et ...
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1-Introduction Drought is one of the most important natural disasters affecting agriculture and water resources, and its abundance is extremely high in arid and semi-arid regions (Shamsenya et al., 2008: 165). Drought is a natural phenomenon that has a complex process due to the interactions of various meteorological factors and occurs in all climatic conditions and in all regions of the planet (Samandianfard & Asadi, 2017). According to the domestic and foreign studies, many researchers have conducted research on drought monitoring and prediction, but the research that can show the drought phenomenon more accurately with the future vision is not takenhas not been conducted if both do not cover the issue adequately. According to the researchers, this study was conducted to model, monitor and predict drought with the new method in Iran in this study.2-MethodologyIn this study, drought modelling in Iran was carried out using climatic data of rainfall, temperature, sunshine, relative humidity and wind speed monthly (for 6 and 12 months scale) for the period of 29 years (1990-2018). At 30 stations using the new TIBI architecture model, a fuzzy set of four indicators (SET, SPI, SEB, and MCZI) valid in the World Meteorological Organization was used. For modelling the new TIBI index, the climatic data were first normalized, then four indices (SET, SPI, SEB, and MCZI) were calculated separately and the fuzzy modelling of the four indices was performed in the Matlab software and eventually to prioritize the drought-affected areas, the multivariate decision-making model, TOPSIS was used.3-ResultsIn order to investigate the effect of drought fluctuations in drought conditions of stations, it is possible to determine the changes in the indicators (SET, SPI, SEB, and MCZI) in the TIBI index analysis. Considering the large number of stations studied, For better understanding, only the drought series diagrams were presented at Bojnourd station on two 6 and 12 month scales (Figures 7 and 8),, (in the mentioned figures, the red arrow shows the drought margin at a 6-month scale with a value of 0.44 and greater, and a value of 0.76 and greater within the 12-month scale. The analysis of these forms shows that at the 6-year and 12-month scale at Bojnourd station, the amount of evapotranspiration was similar in drought conditions, which decreased from April 1994 to February 1999, and after this month an increase was observed if the impact of rainfall on a 6-month scale is weaker than the 12-month scale. It means that from May 1993 to November 1997, an increasing trend followed by the same pattern, and the indicators (SET, SPI, SEB, and MCZI) affect the TIBI index and show some trends, indicating that the new TIBI fuzzy index reflects the four indicators well. The T.I.B.I index at the 6-month scale shows a sharper shape than the scale 12.Prioritization of the stations involved in drought in Iran was analyzed using the TOPSIS model. The results of the TOPSIS model implementation using the degree of importance of the criteria derived from the entropy method indicate that, in terms of drought, more and fewer places are involved with drought by combining the two 6 and 12-month scale. According to the TOPSIS multivariate decision-making model, it was determined that the three stations most affected by drought based on the TOPSIS model were Bandar Abbas, Ahvaz and Bushehr, respectively, in the south and southwest regions of Iran with priority points of score (1, 0.78, and 0.62 respectively), and the three stations of Gorgan, Shahrekord and Orumieh in the northern and western parts of Iran with the scores of 0.026, 0.033 and 0.035 had lower priorities for drought response, respectively (Table 6) and (Figure 11).4-Discussion and conclusionDrought is a natural disaster that is gradually evolving under the influence of climatic anomalies over a long period of time. In recent years, various parts of the Middle East have faced drought, including those regions of Iran in Southwest Asia. In this study, drought phenomenon was assessed at 6 and 12 months using the new fuzzy index T.I.B.I. The results of the research showed that the total frequency of droughts in the 12-month scale was more than 6 months but the severity of a 6-month-old drought is more than 12 months old. On a 12-month scale, the number of drought repetitions is more than 6 months. Drought persistence was higher at 12-month scale, droughts were shorter at short-term and affected by temperature parameter. However, the intensity of drought over a long period of time had a slower response to rainfall changes. The highest percentage of drought incidence in scale of 6 months; Bandar Abbas, Bushehr, Ahvaz and Zahedan stations in the southern half of the study area respectively with the of drought (16.62, 11.24, 14.13 and 62.6 and the lowest in the 6-month scale were Urmia and Ardebil stations, with the percentages of 1.10 and 1.88, Ilam and Yasuj with the drought frequency of 1.61 and 2.01, Rasht and Gorgan, with a high percentage of drought frequency (1.26 and 0.87) in the northern and western part of Iran. The highest percentage of drought occurrence in scale 12; Bandar Abbas and Bushehr stations respectively with drought frequency of 24.30 and 14.83, Ahvaz with drought severity of 18.47, Kerman with 6.74 percent of drought frequencies in the south and southwest of Iran and the lowest in the 6-month scale; stations of Birjand (1.70), Bojnurd (66.6), Urmia (1.17), and Tabriz (66.2) in the northwest of Iran, Rasht (0.58), Sari (0.78) in the northern part of Iran.
Sayed Meysam Davoudi; Reza Ghazavi
Abstract
1- Introduction The strategic management and planning is the highest level of management that has a long-term attitude in resource allocation and decision making. Relying on a combination of perspectives, policies, structures, and effective systems in this field, the strategic approach in water resources ...
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1- Introduction The strategic management and planning is the highest level of management that has a long-term attitude in resource allocation and decision making. Relying on a combination of perspectives, policies, structures, and effective systems in this field, the strategic approach in water resources management prevents sudden future events and crises that will lead to the sustainable development of water resources (Pour Fallah et al., 2009). Determination and development of water resources are one of the important steps in sustainable use of water resources. There are several methods and models for this purpose, each of which contains its own concept and insight and follows specific techniques and instructions. Among the various models, the SWOT matrix, which assesses the system strengths, weaknesses, opportunities, and threats, is more common and well-known (Hill and Vetbrook, 1997). Extraction of a strategy based on the strengths and weaknesses of the internal environment and the opportunities and threats outside the management field provides realistic solutions to the decision maker, and the closeness or distance of the solutions from the sustainable development model - planning (Azarnivand et al., 2013). Although the common use of this model is mainly related to the strategic planning of production and service organizations, its unique features make it possible to use it in the analysis of various issues such as watershed management at extra- organizational levels. More recently, the use of SWOT analysis for water resources management has been proposed in previous research (Petusi et al., 2017; Negar, 2015). 2 -Methodology This study was performed in four main stages, namely identification of internal and external factors, weighting of factors, creation of matrix for the evaluation of internal and external factors, and finally selection of appropriate strategies (Ghazavi, 2019). The formation of SWAT matrix leads to the presentation of four management strategies as follows. • Competitive/Aggressive Strategy (SO): By implementing this strategy, an effort is made to take advantage of external opportunities. • Review/Conservative Strategy (WO): The goal is to take advantage of opportunities in the external environment to improve internal weaknesses. • Diversity Strategy (ST): Reduce the impact of external threats using strengths. • Defensive Strategy (WT): Defensive mode that aims to reduce internal weaknesses and avoid external threats (Sarai and Shamshiri, 2013) 3- Results and discussionAccording to the results of the present study, the total final score of internal factors was 2.98 in the evaluation matrix, which can mean the strength of internal factors. The total final score of external factors was 2.89 in the evaluation matrix, which means that Natanz city has been able to take advantage of the factors that create opportunities or situations, or avoid some of the factors that threaten the city. Based on the results, the best strategic position for Natanz urban watershed is in the offensive range, which focuses on internal strengths and external opportunities. Besides the existing capabilities and potentials in Natanz should be used in managing runoff management. 4- Conclusion In order to provide appropriate strategies and strategies for strategic management of Natanz urban watershed, strengths, weaknesses, opportunities, and threats were studied using the SWOT method. The findings show that Natanz city, despite a low level of the urban basin for various reasons, was not able to make optimal and desirable use of this natural facilities for its development and progress. The existence of impenetrable levels, digging numerous wells to supply water to factories and industries, and the lack of municipal wastewater treatment plants are some of the threats to the region. According to the results, aggressive strategy is the best structural strategy for the Natanz urban watershed.
Kazem Nosrati; Ali Rajabi Eslami; Mojtaba Sayadi
Volume 5, Issue 15 , October 2018, , Pages 171-190
Abstract
Abstract
Introduction
Groundwater is the most important source of drinking water in most communities. Water quality assessment and hydrogeochemical agents that effect water quality due to its direct impact on consumers' health is essential. Before 1970s, the focus of most studies was on physical properties ...
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Abstract
Introduction
Groundwater is the most important source of drinking water in most communities. Water quality assessment and hydrogeochemical agents that effect water quality due to its direct impact on consumers' health is essential. Before 1970s, the focus of most studies was on physical properties of water, but in the recent century developments in sciences (i.e., chemistry and geology) researches on groundwater quality has improved. Approaches to estimate the effects of time and place on the quality and quantity of groundwater are univariate and multivariate statistical techniques. Water resource is getting more and more important in drought and interior regions such as Iran which is located in a desert belt. Therefore, the classification and analysis of groundwater quality in Mallard city in the margin of an interior basin by using multivariate statistical analysis were the aims of this study.
Methodology
The City of Mallard is located in the border of three provinces consisting of Markazi, Tehran, and Alborz. The study area has geographical coordinate with 50° 20´ to 51° eastern longitude and 35° 28´ to 35° 43´ northern latitude. The data used in this study was prepared by rural water and wastewater of Mallard. Thirteen quantitative parameters in thirty-one water wells during 2010-2015 were selected. The data was divided into three qualitative classes on the basis of a hierarchical cluster analysis. Furthermore, to identify the most important water quality parameters in each homogeneous region, a factor analysis on the basis of main component analysis method was used. In order to recognize the suitability or merit of the data, before performing factor analysis, KMO and Bartlett's spit test were done. Hence, the number of factors and main components of groundwater quality were determined. Furthermore, to a better recognition of sample's number on the basis of connection between the factors and their values a graph was depicted that breaks in the axis of the graph defined the number of the main components. In this study, to show the results of the cluster analysis, factor analysis, and one-way variance analysis, SPSS software was applied. After performing a statistical analysis on the basis of the interpolation method and by applying Arc GIS software, the study area was mapped. After registration of the location of any well by GPS, the estimation of use land and geological states was done.
Results and discussion
Based on the quality of water wells in Mallard city, all wells were divided into three qualitative clusters. Accordingly, ten wells were settled in the first cluster, twelve wells in the second cluster, and nine wells in the third cluster. The qualitative zoning showed Mallard's wells in terms of the cluster analysis. The distance between the wells is due to solidarity and self- solidarity between qualitative characteristics of the water wells. The cluster analysis on Mallard groundwater quantitative data resulted in three quantitative classes for water wells in this city. Therefore, each cluster was analyzed by the measurement of a meaningful data and accordingly quantitative status of the clusters were determined. From first toward third clusters, the concentration of all quantitative parameters except PH increased in a meaningful way.
Conclusion
The results revealed that the water quality in the third cluster was low. In each cluster, three factors, as the main parameters that effect and change the water quality, had respectively total variance of 92.85, 83.58, and 88.93. In addition, evaporate formations, using chemical fertilize, household wastewaters, and non-principle repulsed of poultry farm garbage were the effective parameters on water quality changes in the study area.
Ebrahim Beheshti Javid; Fariba Esfandiyari Darabad; Shahram Rostei
Volume 5, Issue 16 , December 2018, , Pages 177-197
Abstract
Abstract
Introduction
Geomorphometry is the science of quantitative land-surface analysis (Pike, 1995, 2000a; Raseman et al., 2004). It is an interdisciplinary field that has evolved from mathematics, the Earth sciences, and most recently computer sciences (Pike et al, 2008, 3). It is ...
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Abstract
Introduction
Geomorphometry is the science of quantitative land-surface analysis (Pike, 1995, 2000a; Raseman et al., 2004). It is an interdisciplinary field that has evolved from mathematics, the Earth sciences, and most recently computer sciences (Pike et al, 2008, 3). It is well to keep in mind the two overarching modes of geomorphometric analysis first distinguished by Evans (1972) as specific, addressing discrete surface features (i.e. Landforms), and general, treating the continuous land surface. The morphometry of landforms per se, with or without the use of digital data, is more correctly considered part of the quantitative geomorphology (Thorn, 1988; Scheidegger, 1991; Leopold et al., 1995; Rhoads &Thorn, 1996). The shape of terrain, i.e. landforms, influences flow of surface water, transport of sediments, and soil production, and determines climate on local and regional scales. Furthermore, natural phenomena like vegetation are directly influenced by landform patterns and their relative position across the landscape (Blaszczynski 1997; Blaschke & Strobl, 2003).
The Earth’s surface is structured into landforms as a result of the cumulative influence of geomorphic, geological, hydrological, ecological, and soil forming processes that have acted on over time. Landforms define boundary conditions for processes operative in the fields of geomorphology, hydrology, ecology, pedology and others (Dikau, 1989; Dikau et al., 1995; Pike, 1995, 2000a; Dehn et al., 2001). In this study, using MRS algorithms and Ecognition software, landforms in the northern slopes of Mount Sabalan have been extracted and the effects of Landform morphometry on its hydrology have been investigated
Methodology
The semi-automated methods refer to the automatic procedures of extracting a landform based-process. This is mainly relying on unsupervised isodata classification, pixel-based classification (supervised /subpixel classifier based on training material), the analysis of digital elevation models (DEM), algorithms, hydrological modelling, and object oriented analysis (Nabil and Moawad, 2014:42).
In this study object-oriented methods and Ecognition software were used for the classification and the extraction of landforms. The object-oriented classification was used as an alternative to traditional pixel-based classifications, to cluster grid cells into homogeneous objects, which can be classified as geomorphological features (Seijmonsbergen, 2012). In addition, the DEM and its derivation (Slope, Profile and plan curvatures, maximum and minimum curvatures), were used in order to extract landforms. Then, using fuzzy logic method, the landform, land use, NDVI index , precipitation, density of river, and lithology layers were Overlaid and the potential flooding area was obtained.
Results and Discussion
In the object-oriented method, determining the scale parameter is a very important factor in the separation of different objects in an image. Scale parameter is a crucial threshold that determines the maximum allowed heterogeneity for segmentation and has a direct influence on the size of the objects to be obtained. The scale parameter, after a trial and error process, is recognized to be within a particular range (Gerçek, 2010:115). A novel method that was introduced by Dragut et al. (2010) and the ‘Estimation of Scale Parameter (ESP) that built on the idea of ‘Local Variance’ (LV) were employed to obtain the optimum scale out of a range of scales. By interpreting thresholds and prominent peaks in the ROC-LV graph, characteristic scales relative to data properties at the scene level could be found. This curve in 100 scale level was produced for the study area by using the ESP software and with respect to curve, the scale of 25 was selected for the segmentation. After segmentation, using the morphometric differences between the landforms, the landforms were extracted. After this stage, the landforms along with three layers of NDVI index, land use, and lithology was fuzzy. Finally, using gamma 0.8, they were combined and the zoning map of the potential flooding was estimated. Flood zoning map was classified into 5 classes and the percentage of each zone risk was calculated in each landform.
Conclusion
In this research, using an object-oriented model, landforms were extracted as plain, peak, pit, ridge, channel, nose, shoulder slope, hollow shoulder, spur, planar slope, hollow, spur foot slope, and hollow foot. An assessment of the effect of landforms on the hydrology of the area revealed that three landforms of hollow, shoulder and planar slope which were respectively 67.3%, 62.9%, and 53.2% had the greatest impact on flooding and their area were zoned as high and very high flooding. On the other hand, plain and pit landforms were zoned in the form of low and very low flooding areas.
Ardashir Yousefzadeh; Battol Zeynali; Khalil Valizadeh Kamran; Saayad Asghari Sar Eskanrood
Volume 6, Issue 18 , June 2019, , Pages 181-205
Abstract
Introduction According to Cornelsen (2015), soil moisture is one of the most important variables in the hydrological cycle. In Manson's studies (2010), soil moisture was identified as one of the major climatic variables by the World Meteorological Organization, the Global Climate Observing System, and ...
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Introduction According to Cornelsen (2015), soil moisture is one of the most important variables in the hydrological cycle. In Manson's studies (2010), soil moisture was identified as one of the major climatic variables by the World Meteorological Organization, the Global Climate Observing System, and the Observational Satellite Observatory. Remote sensing provides a powerful tool for detecting and monitoring soil moisture near the Earth's surface (0 to 5 cm). Also, according to Babaeian research (2015), optical reflection of the soil and thermal emission to Eliit (1979) and Microwave backed by Das researches (2008) is related on soil moisture. Remote sensing techniques based on microwave waves are effective techniques for estimating soil moisture. Surface water levels can be extracted using the NDVI index in Landsat images (Maryam Khosravian et al., 2012, p. 115), and user variations in time series can also be identified. (Malian et al., 1395, p. 49). Due to the limitation of access to radar information, the focus of the study is on the near-visible infrared range and the amount of heat from the surface of the earth is measured from 3.5 to 14 micrometers (Curran, 1985). Soil moisture content with this method requires the estimation of soil surface temperature and vegetation index (Wang & Co, 2009). Vegetation and surface temperature have a complex dependence on soil moisture (Carlson, 1994). According to Gillies et al. (1997), the combination of these two indicators can be used to estimate soil moisture with an acceptable accuracy.In 2017, a model for estimating soil moisture using a visual distance assay was proposed based on the linear physical relationship between soil moisture and the short-range infrared reflection (STR), which is based on the distribution of pixels inside the surface temperature space and the normalized vegetation index (STR-VI) (Sadegi et al., 2017). A trapezoid or triangle model is one of the models used in remote sensing to estimate soil moisture. The study area is the Simineh River basin which is one of the sub basins of Lake Urmia Basin, with an of 3279 km2. Methodology The main data in this study are Landsat 8 satellite imagery. After applying atmospheric and radiometric corrections, the processing of images, between 2016-2017, was done according to the process of view of Figure 1. Figure (1) Research process (Source: Writers) -Thermal-Optical Trapezoid Model (TOTRAM) This model is based on the distribution of pixels in the surface temperature and vegetation cover space that is fitted to estimate soil moisture using a linear equation in space (LST-VI) (Sadegi et al., 2017). Equation (1) -Optical Trapezoid Model (OPTRAM) The base of this model is the insertion of surface temperature to estimate the soil moisture in the visible wavelength range. In this physical model, the linear relationship between soil moisture and infrared reflection is expressed. Equation (2) Result According to the results of this study, the lowest average temperatures of satellite images were respectively -3.23 and 2.12 C in 2015 and 2016, indicating an increase in temperature. In 2017, the highest amount of vegetation density was 0.66. The correlation between the OPTRAM model in 2015 and the STR and NDVI variables, were positive and the correlation indices were respectively 0.709 and 1. These figures for STR and NDVI in 2016 were respectively -0.648 and 1, which indicated a negative correlation between STR and soil moisture; soil moisture decreased with increasing STR and increased with increasing NDVI. And the positive correlation between OPTRAM model and NDVI confirmed it. In 2017, the positive correlation between STR and NDVI with soil moisture were respectively 0.672 and 1. The TOTRAM model in 2015 had a negative correlation with the LST and NDVI indices and they were respectively -0.574 and -1. It indicated low accuracy of this model compared to the OPTRAM model in estimating soil moisture. In 2016, the correlation between LST and NDVI with soil moisture were respectively -0.974 and 0.409. They respectively reached -0.940 -0.787 in 2017. Discussion and Conclusion In this research, due to the limitations of the field information, soil moisture was extracted without the use of ground control points. The comparison of the accuracy of the two models in the region was investigated. The results indicated that soil moisture can be extracted from the STR index with high accuracy, compared to LST index, based on NDVI Triangular space. Due to the low cost and the availability of visible images, radar images were accurately obtained and the correlation between OPTRAM model and soil moisture estimation was confirmed. According to the extraction results, the OPTRAM model can estimate the soil moisture better than the TOTRAM model, due to the fact that it is not influenced by environmental factors and global parameters. According to research results, TOTRAM has two main constraints. First, it cannot be used for a satellite without thermal bonding. Secondly, in addition to soil moisture, the LST depends on environmental factors to be calibrated for each image. To overcome the limitations of the TOTRAM model as well as the empirical visibility of indicators, a new physical trapezoidal model, called OPTRAM, is proposed. It is based on the physical relationship developed between soil moisture and the "reflected infrared reflection" (Sadegi et al., 2015).
Shirin Mohammad Khan; Fatemeh Moradi Pour; Anvar Moradi
Volume 5, Issue 17 , March 2019, , Pages 185-203
Abstract
Introduction
Lake Urmia in the northwest of Iran has faced a steady decline over recent decades. This has led to an increase in the level of dry lands and, consequently, has caused many environmental and social problems.There are many ecological effects on the biodiversity and growth of Artemia, the ...
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Introduction
Lake Urmia in the northwest of Iran has faced a steady decline over recent decades. This has led to an increase in the level of dry lands and, consequently, has caused many environmental and social problems.There are many ecological effects on the biodiversity and growth of Artemia, the Zooplankton, a native of Lake Urmia and major source of food for large birds. Consequently, the monitoring of coastal areas and the extract of changes in these areas in different time intervals have great importance because the nature of the coastline is dynamic. For this purpose, the remote sensing technology has a unique application in the acquisition of information about these phenomena because multi-spectral satellite images have advantages including their availability and digital interpretation.The purpose of this research was to investigate the development of the North West salt land in Lake Urmia using field data, satellite imagery, and geomorphic faces of the region.
Methodology
This research was an applied type and the data was collected through library, laboratory, and field studies. The statistical population was the water Retreat Zone of Lake Urmia Which suffered from wind erosion. This research was carried out using satellite imagery and multiple observations. Also, test sediments were obtained from this area using standard methods. Using remote sensing technology, when combined with land surveys and ground-based results, can provide better and more reliable results. For this purpose, in the present research, along with the use of remote sensing methods, field studies were also used. To carry out this research, samples of lake sediment were taken in different transects from a specific area in the northwest of the lake. The saturated extract of each sample was measured by EC meter. In the next step, using satellite imagery and field survey, the salinity, the expansion of salty and geomorphic faces were extracted. Finally, the results of the field and laboratory data, satellite imagery and geomorphic faces were compared and validated.
Results
The results showed that the surface area of the lake water was very low and spread to vast amounts of salt. Accordingly, the area of the salt land has significantly increased since 2000, especially over the past decade. According to the results of the field studies, areas with higher salt density matched the salt lines obtained from satellite imagery and geomorphic faces. The study area had 12 faces. The harvest area with a total area of 2,641 ha in the central part of the range and sandy areas with a total area of 14 ha in the northwestern part of the area had respectively the highest and lowest extent of outcrops in the studied area. Consequently, there was a close correlation between the field data and satellite imagery and salt land areas in satellite imagery and results of field studies. Due to the increase of the salinity levels in the area around the lake, local winds, and time lapse, the Agrarian lands of Azerbaijan general zone moved towards salinization and desertification. If this trend continues at the same speed, undoubtedly, in the long run, we have to wait for the enormous environmental crisis in the region.
Discussion and conclusion
The strongest indicator to extract the salt is the SI2 indicator with an accuracy of 97% and the weakest indicator is NDSI indicator with a precision of 52%. The EC value in 22 soil samples ranging from 0.9 to 78.37 indicates the high salinity variability in the region. There is the highest correlation with visible bands and infrared bands 1, 2, 3, and 4, which indicates that the saline soils in the visible and infrared areas have a higher reflection. Between 2006-2015, the range of salt land has been expanded. Altogether, with the decreasing trend of the size of Lake Urmia, in 1976 regular domain faces, in 1985 sediment removal, in 1990 harvested area, in 2000 wet area, harvested area, and salt deposits, in 2006 bar salt and salt zone, and between 2011 and 2015 salt zone were formed and expanded.
Saeed Negahban; Diyana Dortaj
Volume 6, Issue 19 , September 2019, , Pages 187-209
Abstract
Introduction Rivers are sensitive to tectonic movements and there is a close relationship between river formations and tectonic movements. The term morphotectonic states the relationship between geomorphology and tectonics, and in many cases morphotectonic, is considered to be geometric tectonics. In ...
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Introduction Rivers are sensitive to tectonic movements and there is a close relationship between river formations and tectonic movements. The term morphotectonic states the relationship between geomorphology and tectonics, and in many cases morphotectonic, is considered to be geometric tectonics. In recent years, geomorphic tectonics has been a significant tool for identifying active tectonic forms and providing seismic hazard maps and understanding the history of current land surveys. There are several methods to study the tectonic condition of a region or basin. In the meantime, geomorphic indicators in the evaluation of the tectonic activities are useful and reliable tools because they can be used for areas that have experienced a tectonic activity. They are easily identified. These indicators allow geomorphologists to quantitatively measure and reasonably compare different landforms and compute morphological indices. The studied area is considered to be an active area in terms of its location (folded Zagros) and the tectonic is considered as an active region. Accordingly, the evaluation and the study of tectonic activity and its effects in regional planning and land use planning and environmental management are of great importance. In this study, the morphotectonic status of the Sirvan basin was evaluated. Materials and Methods In this research, in order to investigate the effect of tectonics on the studied sub-basins, the sources and findings of the research in the field of research were collected through library studies. In addition, to evaluate the studied sub-basins, geomorphologic indices and evidence were used. The research data included 30m DEM, STRM, the topographic map of 1: 50000 and the geological map of 1: 100000of the studied basin. The ARCGIS software was used to evaluate the indicators and final output mapping. According to the objectives, in order to investigate the effect of tectonics on the studied sub-basins, eight indicators including mountain front (SF) index, drainage basin asymmetry index (AF), longitudinal gradient of the river (SL), reverse topographic symmetry index (T), surface congestion index (P), hypersonic integral index (Hi), sinusoidal river index (S), and basin shape index (BS) were used. After assessing the basin based on the existing indicators, the studied sub-basins for each of the indicators and the final results were obtained. Results and Discussion In this study, to evaluate the tectonic condition of the studied sub-basins, each of the indicators was considered. The results of the SL (Sudden Slope) evaluation indicated that the Sirvan sub-basin with SL of 3133 was the most active sub-basin for this indicator. The evaluation of the T index (inverse topographic symmetry index) indicated that the Shevishe River basin with a coefficient of 4 had the highest degree of asymmetry. The P (Surface Water Condensation) evaluation indicated that the highest density was achieved by 397. It was related to the Gheshagh sub-basin, and according to this indicator, the sub-basin was considered to be the most active sub-basin. Based on the HI index (hipsometric integral) Shoeisheh sub basin with a coefficient of / 420 was considered to be the most active sub-basin. In terms of S (sinusoidal river), the sub-basin of Gheshlagh with a coefficient of 1.31 had the lowest coefficient and, therefore, the most active sub-basin for this index. It was also considered as the longest and most active sub- basin for BS (basin shape) of Gheshlagh basin with a coefficient of 2.14. Conclusion In this research, the geomorphic indices were used to study the tectonic conditions of the studied sub-basins. The results of the assessments were different in different sub-basins. Consequently, according to the Smf index (indicating the extent of tectonic congestion and erosion in the region), of the studied sub-basins, Shevishe basin with a Smf level of 11.1 was the most active sub basin. In terms of the AF index (detection of tilt in the drainage basins due to tectonic activity), of the studied sub-basins, the Gheshlagh basin with a factor of 4.70 had the highest stroke. After assessing the basins based on the existing indicators, in order to classify the basins in terms of tectonic activity, the tectonic activity (Lat) partial evaluation index was used. The results of this indicator indicated that, of studied Sub-basins, Shevisheh sub basin with Class 2 average, had a more active status than the other sub-basins. Accordingly, it is necessary to pay attention to the status of tectonic activity of the sub-area in carrying out any planning, land use planning and management, avoid any risky actions, optimize the use of natural resources, and reduce the harmful effects of any planning.
Mohammad Hossein Rezaei Moghaddam; Mir Asadolah Hejazi; Abdollah Behbuodi
Volume 6, Issue 20 , December 2019, , Pages 187-204
Abstract
1- IntrodutionWatersheds are open systems which, due to its complexity and in order to achieve the desired goals, are modeled. Through modeling, the cost of study for complex systems is reduced because large-scale field trials are very costly or impossible. Also, by analyzing the results of the model, ...
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1- IntrodutionWatersheds are open systems which, due to its complexity and in order to achieve the desired goals, are modeled. Through modeling, the cost of study for complex systems is reduced because large-scale field trials are very costly or impossible. Also, by analyzing the results of the model, we can manage the watersheds well. In this research, the performance of the IHACRES rainfall-runoff model was evaluated in the simulation of runoff in the Lanbarn basin. The monthly data on rainfall and temperature of Varzaghan station as input variables for flow simulation and observation data of runoff at Cassin hydrometric station were used to measure the accuracy of the IHACRES model. Based on available years, data from 2002-2000 were used for warming up the model and data from 2012- 2012 were used for calibration and data from 2016-2013 were used for validation purposes. To evaluate the ability of the IHACRES model in runoff simulation, the Nash-Sutcliff coefficient was used. The results showed that the coefficient was 0.71 and 0.74 for calibration and verification, respectively. Therefore, according to the results of the evaluation of the IHACRES model using different performance criteria and because of easy access, less inputs and a reduction in the time spent, it can be advised to use the model to simulate and predict runoff in a monthly scale in the Lanbarn watershed and to use it in order to study surface runoff and river flow in future periods.1- IntroductionIn order to manage watersheds and prevent inconsistencies in measures taken at the catchment area, a model is needed which, according to the existing information and conditions, has the efficiency of simulating the outflow of the region (Yong et al., 2014:47). Integrated models require less information than distributed and semi-distributed models, and, on the other hand, they run faster than other models (Golshan et al., 2017:966). The IHACRES model is an integrated concept model that includes a nonlinear reduction model and a linear lattice model. Despite the relatively recent development of IHACRES, this model has been widely accepted among hydrological models (Sriwongsitanon & Taesombat, 2011). The number of parameters in this model is low, while simultaneously compared with distributed models, we have tried to provide more details of the internal processes (Croke & Jakeman, 2008, Golshan, et al., 2017:966).2- MethodologyTo do this research, the monthly data on rainfall and temperature of Varzaghan station as input variables for flow simulation and observation data of runoff at Cassin hydrometric station were used to measure the accuracy of the IHACRES model. Based on available years, data from 2002-2000 were used for warming up the model and data from 2012- 2012 were used for calibration and data from 2016-2013 were used for validation purposes. The IHACRES model is an integrated metric conceptual model for rainfall-run simulation. This model was developed by Jackman in 1990. The model needs 5 to 7 variables for calibration and is suitable for implementation in large scale basins. In this study, version 2 of this software has been used, which is applicable for basins with continuous data of rainfall, temperature and runoff. This model consists of two nonlinear and linear interconnected segments that are respectively defined for calculation of losses and effective rainfall conversion to runoff.3- Results Based on the results, Nash-Sutcliff coefficient was 0.71 and 0.74 for calibration and verification, respectively. Therefore, it can be stated that the model of low discharge simulates well, but in simulating the maximum discharge, it has little ability and simulates lesser amounts of observational flow. In general, due to low model deviations and good simulation of minimum discharge values, it can be argued that the performance of the IHACRES model in the Lanbaran catchment area is satisfactory.4- Discussion and ConclusionGiven the diversity of rainfall-runoff models, selecting an appropriate model for watersheds is important for increasing the efficiency of planning and managing water resources. Hence, in this study, IHACRES model performance was evaluated in runoff simulation in the Lanbaran watershed. According to the results of the calibration and verification of the model in runoff simulation based on different performance criteria, the model was found to have a high accuracy in simulating runoff at the station under study. It also simulates the amount of monthly flow, which is consistent with the results of studies of Zarei et al. in the basin of Kasaliyan, Lotfirad et al. in the Nawarud basin and the studies of Croke and Jakkman. Therefore, according to the results of the evaluation of the IHACRES model using different performance criteria and because of easy access, less inputs and a reduction in the time spent, it can be advised to use the model to simulate and predict runoff in a monthly scale in the Lanbarn watershed and to use it in order to study surface runoff and river flow in future periods.
Morad Darabi; Hossin gharehdaghy; Masod Nejabat
Volume 5, Issue 14 , June 2018, , Pages 199-218
Abstract
IntroductionMan's undue interference, livestock overgrazing, soil texture disorganization, and change in the geometry of channels are the main factors which could destroy the hydrologic balance of the watershed in an ecosystem. The systematic imbalance in a watershed could destroy the earth crust and ...
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IntroductionMan's undue interference, livestock overgrazing, soil texture disorganization, and change in the geometry of channels are the main factors which could destroy the hydrologic balance of the watershed in an ecosystem. The systematic imbalance in a watershed could destroy the earth crust and increase flooding. It could also result in the erosion and soil sedimentation behind the reservoir dams and the destruction of the agricultural lands, roads, and villages. In addition, it could reduce the production ability of productive sources. Soil erosion is one of the environmental problems that threatens natural resources, agriculture, and the environment. The objective of the present study was to evaluate the biological, managerial, and constructional watershed projects and their effects on reducing erosion, sedimentation, and parameters of land protective cover. This study was conducted between 2001-2010 in the Khorrambid urban watershed from the Sivand dam in Fars province.Methodology A. Primary Collection MethodThe preliminary data for Khorambid urban watershed from Sivand dam was collected by the executive detailed reports (Natural Resources and Watershed Management Office of Fars Province, 2001).B. Estimating the parameters of land cover layer, erosion, and sedimentation before implementing the watershed projectsBefore implementing the watershed projects, the vegetation parameters, erosion, and sediment yields in the executive and detailed reports were used to evaluate the parameters.C. Estimating the parameters of land cover layer, erosion, and sedimentation after implementing the watershed projectsIn the first step, the vegetation classification mapping was prepared and the vegetation parameters were sampled in the paired plots. It must be mentioned that one of the most effective items in estimating the erosion and sedimentation is to know the land cover parameters. To determine the rates of erosion and sediment exited from the network, it was required to calculate the rate of erosion and sediment on the domain. It was also required to calculate the controlled sediments on the waterway or at the rear of structures. In the first step, the locations of all structures executed in the intended sub-basins were specified by GPS to determine the sediments trapped at the rear of the structures. Meanwhile, their types, structural materials, and location maps were prepared. In the second step, the waterway slope, overflow height, reservoir length, waterway width, reservoir volume, and sediment volume were respectively determined by preparing some special forms via clinometer and meter. In addition, to estimate the erosion and the sedimentation of the domain, the experimental model of MPSIAC, modified by ArcGIS10, was used. When the nine layers of the MPSIAC model were combined and overlapped, the homogeneous units map was prepared. Next, the scores of nine factors were estimated and calculated to extract the sedimentation degree of each homogeneous unit according to the following equation:Qs = /253 e0.036R (Equ.1)When the sedimentation map was prepared, the erosion rate was calculated by the Sedimentation Delivery Rate (SDR) equation in the level of homogeneous unit. Regarding the factor of the basin area ( based on square mile), the following equation was used to determine the percentage of SDR.Log SDR = 1.8768 – 0.14191 log(10A) (Equ.2)To evaluate the differences between sedimentation changes in the sub-basins for the pre and post watershed operations, the normality test and Paired T-test in SPSS software were used.DiscussionThe results indicated that the factors’ score of river erosion and surface erosion which were respectively 30.77 % and 30.51% had the most effects and the land cover factor, with 15.05%, had the least effect on reducing the sedimentations to 21.97%. Also, the area of sediment class of 75-100 was 1375 hectares, which was equivalent to 15.78% of the basin's area. Indeed, in terms of the spatial distribution, it was located in the basin outlet and changed to class 50-75. The sediment class of 50-75 was 7339 hectares, equivalent to 84.22% of the basin's area. It reduced to 28.09 % and changed to the lower class of 25-50. Since there was a significant change in the sedimentation of the sub-basins in 0.05 levels, the results of this study indicated that the watershed projects were efficient in reducing the sediments. To manage the water and soil resources, to raise the effectiveness of watershed operations in reducing erosion and sediments, and to raise the land cover layer in Khorrambid watershed, the combination of both biological and constructional programs and treatments undertaken in the basin should be applied.ConclusionWith regard to the findings of this study, before the watershed operation, the sedimentation degrees in two classes of 75-100 and 50-75 were respectively 15.78% and 84.22%. According to the sedimentation class map, the sedimentation degree of 75-100 was located in the basin outlet. Since the structural watershed operation has been extended more than biological watershed operation, the sediment class with the area of 1375 hectares experienced lower sediment degree and changed to 50-75 class after the watershed operation. The sediment class of 50-75 was 7339 hectares before the watershed operation; however, by implementing biological programs, 2447 hectares of that class changed to the lower class of 25-50. Therefore, 15.78% of class 75-100 before the watershed operation reduced to 0% after the watershed operation. In addition, 84.22% of class 50-75 was reduced to 71.91%. Regarding the equation of SDR based on the area factor, the rate of SDR for the basin was 33.03%. Thus, the sediment rates for pre and post watershed operations were respectively calculated as 23755 and 14390 tons, which indicated 39.42 % drops in the total sediments. The results of this study showed that the watershed operation, which was a combination of protective, managerial, and biological programs, was implemented well in the measures of domain and waterway (structural) in the basin. Consequently, the sedimentation mean in Khorambid watershed decreased to 39.42%. The findings of this study are in line with the findings of researchers such as Roghani (2012), Salmanpour (2013), Azami Rad (2013), and Agharazi (2016).
Meysam Yari; Somayeh Soltani-Gerdefaramarzi; Mohsen Ghasemi; Rouhollah Taghizadeh
Volume 6, Issue 21 , March 2020, , Pages 203-225
Abstract
1-Introduction Given the growing population and the increasing need for food, water and soil conservation are of great value. In the context of conservation of soil and water resources, information on the amount of runoff production and erosion to achieve sustainable development is the basis for planning ...
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1-Introduction Given the growing population and the increasing need for food, water and soil conservation are of great value. In the context of conservation of soil and water resources, information on the amount of runoff production and erosion to achieve sustainable development is the basis for planning and decision making. Therefore, careful investigation of surface runoff and floods is an important and key step in planning and managing optimal water resources. One of the factors affecting the characteristics of surface runoff is land-use changes at different basin levels (Melesse and Shih, 2002). Land use is influenced by two components of human needs and environmental processes. Inaccurate land-use changes will disrupt the water cycle from natural equilibrium, resulting in devastating floods, including economic damage, loss of life, loss of water, and consequently reduced water resources (Jakeman et al., 2005). During the last two decades, the Qhareh-su watershed, particularly its downstream, has been experiencing rapid growth in the construction and expansion of residential structures. Human activities and changes in the basin have affected the natural arrangement of stream processes that transmit water and sediment from upstream to downstream. Human interventions are one of the major hazardous issues in this basin that causes changes in the pattern of surface currents and natural conditions of the catchments and encroachment on rivers and streams. In this regard, the present study aimed to investigate the role of land-use change on runoff in a part of Qhareh-su watershed in Ardebil province over a period of almost 20 years due to the availability of information and access to satellite images of different time periods. 2-Methodology The study area consists of a part of Qhareh-su watershed located in Ardabil province with an area of 2162.6283 km2. The minimum and maximum elevation of the mentioned watershed are 1280 and 3829 m respectively, and its average slope is 11.57%. Land use in this area often includes dry and irrigated agriculture, pasture, forest, and residential areas. The aim of the current research is to study the effect of different land uses and its changes during the years 1992-2012 on the surface runoff in a part of Qhareh-su, Ardabil watershed. At first, the maps of land use and curve number in the mentioned years were gathered and the area of each of the units was extracted. In the following, the process of land-use changes in the cases of the study period and its effect on changing the specific retention (S) and curve number were calculated and the height of runoff was estimated using the SCS method. 3-Results The results showed that during the case of the study period, area of forest, water farming, and wasteland land uses were decreased by 2.54%, 16.69%, and 1.19% respectively and the area of the rangeland, dry farming, and urban land uses were increased by 5.74%, 12.39%, 2.29% respectively. These changes have caused the increase of curve number from 78.57 to 79.77 in the years 1992 and 2012, respectively and following the decrease of the specific retention (S) from 69.28 mm in the year 1992 to 64.42 mm in the year 2012. Also, runoff height has increased from 263.4 mm in the year 1992 to 297.07 mm in the year 2012 (11.33%). Calculation of correlation coefficient between different land uses and curve number and runoff height showed that these variables have a direct relationship with rangeland, dry farming, and urban land uses while they have an inverse relationship with the forest, water farming, and wasteland. 4-Discussion and conclusion In the present study, the results of the study showed that land-use change due to its effect on the curve number of the studied basin causes a change in the surface runoff. During this 20-year period, land use has changed and this land-use change has tended to decrease from 1992 to 2012 land use including residential, pasture and dryland areas increased by 2.29%, 12.39% and 5.74% respectively, as well as forest, water and wastewater land use decreased by 2.54%, 16.69% and 1.19%, respectively. As a result, its curve number has increased, followed by a runoff height of 11.33%. This shows that in a natural ecosystem, land use and environmental changes, especially vegetation and land use affect the hydrological responses such as flooding and erosion and sedimentation rate in the area. Ultimately, it will cause severe economic and social damages. Changes in the total volume of runoff and changes in hydrological balance are the most important effects of land-use change on watershed hydrology.
Hamed Gholamian; Alireza Ildoromi
Abstract
1-IntroductionIn the catchment areas without statistics or incomplete statistics, the extraction of flood characteristics and the provision of water resources and sediment transport analysis are appropriate using empirical methods or models based on the watershed characteristics. One of these methods ...
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1-IntroductionIn the catchment areas without statistics or incomplete statistics, the extraction of flood characteristics and the provision of water resources and sediment transport analysis are appropriate using empirical methods or models based on the watershed characteristics. One of these methods is the use of the capabilities and capabilities of hydrological models in simulating the hydrological processes (Valderz et al., 1979). Rainfall-runoff models, most notably the GIUH hydrograph model and the WinTR-55 hydrologic model, are suitable tools for the study and estimation of maximum hydrograph discharge using geomorphologic parameters of the region (Ghorbani et al., 2015). The purpose of this study was to estimate maximum flood discharge, transfer capacity, and sediment yield of the Kermanshah River using the GIUH and WinTR-55 models. 2-MethodologySanqor basin, with an area of 6317 hectares and minimum and maximum heights of 1500 and 3300 m, respectively, is located in the northeast of Kermanshah province and part of Karkheh watershed. Average values of annual rainfall and temperature are 586.9 mm and 12.9 °C. The WinTR-55 model uses parameters, such as main channel length (flow length), channel gradient (flow gradient), manning roughness coefficient, width of waterway floor, and the slope of margins to determine the effects of flow type and velocity on the discharge peak output and water and sediment transport capacity in the basin. To this end, the area was divided into eight hydrological sub-basins after registration of the basin situation. After estimating the geomorphologic and hydraulic parameters of the canal, the discharge was estimated with different return periods using the WinTR-55 and GIUH models. Geomorphologic proportions include length ratio, branching ratio, area ratio, drainage network, and ranking of riverbeds in the basin (Valderz et al., 1979).3-Results and DiscussionThe estimation results of velocity types in each sub-basin with the WinTR-55 model indicate that the laminar flow in the flood basin were on the surface and not inside the channel, but flow frequency was low with high water content. However, centralized and channelized flows were flooded and concentrated, flowing through the canal or small or large drains. Peak discharge values estimated by the GIUH model were, on average, 6.52% higher than those estimated by the WinTR-55 model. The S3 and S4 sub-basins with low gradients and high roughness coefficients had low flow velocities. In S2, S6, and S8 sub-basins, on the other hand, the discharge and flow rate increased due to a high slope. Estimated peak discharge values by the GIUH model showed increases in all sub-basins other than S1 sub-basin and in the outlet relative to the peaks calculated using the WinTR-55 model. Discharge changes obtained from the GIUH increased on average by 76.1% and 7.1% in the outlet and in the S1 sub-basin, respectively, compared to that calculated by the WinTR-55 model. In the S2, S3, S4, S5, S6, S7, and S8 sub-basins, average increases were 7.31, 5.13, 5.98, 6.3, 6.9, 5.8, and 6.67 percent, respectively. The model calibration d and the sensitivity analysis of the flow parameter were done using the canal slope and the results were investigated at the basin output. The results of the model for a change in the slope of the waterway showed a low effect of the slope on the outlet flow variations. The evaluation results of GIUH and WinTR-55 models in peak discharge estimation with observational data by correlation coefficient (R) and root mean square error (RMSE) indicate good efficiency of both models. R values of 0.90 and 0.97 were obtained between observational and calculated data by the GIUH model by the WinTR-55 model, respectively. The RMSE values were very insignificant in the estimation of observed discharge and those estimated by the WinTR-55 model and the geomorphologic hydrograph unit method.4- ConclusionIn this study, the efficiency of WinTR-55 and GIUH models was investigated in peak discharge estimation. The results showed that there was a high flow rate in S1, S2, S6, and S8 sub-basins due to the high mountainous nature, along increased erosion and sediment transport capacity. In S3, S4, S5, and S7 sub-basins, transfer capacity and sedimentation dropped due to low slope and slower flow rate. The estimated discharge values of S8 and S6 sub-basins by the GIUH method increased by 8.31 and 6.67 percent, respectively, compared to those estimated by the WinTR-55 model, which is due to the increased gradient and its role in discharges calculated by both models. The discharge rate in the area outlet estimated by the GIUH method increased by 1.76% compared to that obtained by the WinTR-55 model, indicating the effect of geomorphologic parameters on the calculation of peak discharge in the basin. Assessments of R2 and RMSE showed that the efficiency of the WinTR-55 model was high at maximum average discharge rate for all return periods, with average RMSE values of 0.66 and 0.32 for the GIUH and WinTR-55 models, respectively. The results showed a high correlation between observational and calculated data obtained from both models. Additionally, the calculated RMSE values showed that the GIUH and WinTR-55 models had high and acceptable performance in peak discharge estimation and could well analyze the erosion and sedimentation conditions.Keywords: Hydrograph, Erosion and Deposition, Flow Velocity, Manning Roughness Coefficient, Sonqor Watershed5-References Ghorbani, M., Asadi, A., Jabari, H., & Farsadizadeh, D. (2015). Extraction of Instantaneous Unit Graph Hydrocopy (IUH) Using Shannon Entropy Theory, Journal of Watershed Management, 5(10).Valders, J.B., Fialloand, Y., & Rodriguez-Iturbe, I. (1979). A rainfall–runoff analysis of the geomorphologic IUH. Water Resources, Res, 15(6), 1421–1434.
