Omid Kavoosi; Khaled Ahmadaali; Aliakbar Nazari Samani
Abstract
Soil erosion and its consequences, such as soil destruction at the source, silting of rivers and filling of reservoirs of dams, are one of the most important natural hazards in watersheds, which reduce ecosystem durability. To be one of the most important practical solutions to control sedimentation ...
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Soil erosion and its consequences, such as soil destruction at the source, silting of rivers and filling of reservoirs of dams, are one of the most important natural hazards in watersheds, which reduce ecosystem durability. To be one of the most important practical solutions to control sedimentation and reduce peak flow is to build a check dam. Therefore, determining the quantitative variables affecting the volume of the structure is an important factor in determining the construction costs and their effectiveness. The present study was conducted to model checkdam volumes at the level of 100 sub-basins in different provinces of Iran (Alborz, East Azerbaijan, Ilam, Isfahan, Bushehr, Tehran, Qazvin, Fars, Mazandaran, and Hamadan). The database used for modeling includes 27 environmental features extracted in each of 100 sub-basins and the modeling was done using Genetic Expression Algorithm (GEP). The results of modeling showed that the most important characteristics in estimating the volume of checkdam among the 27 characteristics are: precipitation, temperature, TWI index, shape factor, height difference, concentration time, slope, drainage density and NDVI index. The results of estimating the volume of the structures using the nine selected variables showed that the R2, RRMSE and NSE values for the training phase are .088, .035 and 0.92, respectively, and for the test phase, they are 0.91, 0.29 and 0.91, respectively. Also, based on the results, the characteristics of environmental precipitation can be used with great accuracy to estimate the volume of sediment control structures in a short time, and therefore, before their implementation, the related costs were known in order to prioritize the areas.
Roghaye Shad; Mehdi Ghorbani; Khaled Ahmadaali; Aliakbar Nazari Samani; Maryam Yazdanparast
Abstract
Land use changes in countries like Iran, which is facing space limitations, should be thoughtful and in accordance with proper planning, just like water consumption. On the other hand, the inherent dynamism of human beings and their needs has made the way and extent of land use change over time. Therefore, ...
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Land use changes in countries like Iran, which is facing space limitations, should be thoughtful and in accordance with proper planning, just like water consumption. On the other hand, the inherent dynamism of human beings and their needs has made the way and extent of land use change over time. Therefore, the aim of this research is the dynamic modeling of land use changes based on the human-environmental system in Taleghan watershed. For this purpose, land use maps for the years 1994, 1999, 2002, 2009, 2014, 2019 were classified into six classes of pasture, forest, agricultural land, barren land, residential land, and water using Landsat satellite time series images. After the validation of the maps and the detection of changes, under the three scenarios of current economic growth, rapid economic growth and sustainable development, simulation was carried out until 1435 using dynamic system modeling. The results of detecting land use changes during the period show that the trend of changes in agricultural lands, pastures, forests, has been decreasing, and barren lands and residential areas have always had an increasing trend during the survey period. The results of the simulation show that among the three scenarios examined, the sustainable development scenario of coordination between the amount of land utilization and meeting the needs of the community and economic growth has been acceptable. Therefore, it can be concluded that the sustainable development scenario is an important basis for land use planning in the coming years in order to reduce the destruction of natural resources and maintain a stable state in it, and this scenario will bring favorable economic growth in the future.
Marziyeh Haji Mohammadi; Aliakbar Nazari Samani; Arash Zare Garizi; Hamidreza Keshtkar; Mahmood Arabkhedri; Amir Sadoddin
Abstract
The SWAT model is widely used to simulate watersheds and evaluate the impact of conservation watershed management practices. In this model, the simulation of the watershed processes is based on hydrological response units (HRUs) which are created by overlaying land use /land cover, soil and slope maps. ...
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The SWAT model is widely used to simulate watersheds and evaluate the impact of conservation watershed management practices. In this model, the simulation of the watershed processes is based on hydrological response units (HRUs) which are created by overlaying land use /land cover, soil and slope maps. Meanwhile, in the HRUs definition steps, these units become conceptual and lose their spatial location and continuously. This approach is a useful and often inevitable way to simulate large and heterogeneous watersheds in terms of computational efficiency. However, if the aim is spatializing and evaluating the effectiveness of management methods on runoff, sediment and other pollutants in medium to small basins, it is necessary to know the exact location of HRUs. The purpose of conducting this study was present a new approach to defining spatial and independent HRUs and compare the simulation results based on this method with the standard form of the model. In the new approach, independent and spatial HRUs are defined through pre-processing procedures in GIS and uniquely named soil units. The model results of both approaches were very similar and no significant difference was observed in the model outputs in Taleghan watershed. The Nash-Sutcliffe coefficient of the simulated runoff and sediment at the outlet with the standard approach was 0.75 and 0.64, respectively. While, it was obtained 0.74 and 0.61, respectively for the new approach. The definition of spatial HRUs by applying the proposed method provides more tangible and practical outputs, which is more beneficial for identifying the critical areas as well as locating conservation practices compared to the conceptual HRUs approach.
Aliakbar Nazari Samani; Aryan Salvati
Abstract
Having knowledge on the quantitative amount of watershed sediment yield is one of the most basic information to deal with soil erosion and conservation as well as design of dams. In Iran, the estimation of suspended sediment load is often based on measurement curve methods. Since sediment discharge data ...
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Having knowledge on the quantitative amount of watershed sediment yield is one of the most basic information to deal with soil erosion and conservation as well as design of dams. In Iran, the estimation of suspended sediment load is often based on measurement curve methods. Since sediment discharge data are random and discontinuous, in practice, their internalization and extrapolation is associated with many errors. This review is to evaluate the number of data available to estimate daily sediment load with Loadest regression models. Therefore, daily discharge data of Ghazaghli station in Gorganrood forest watershed were used. So that different percentages of available data were accidentally deleted and the amount of sediment load was estimated by 11 methods. According to the evaluation results (Taylor diagram), model number 2 has the best accuracy and in the absence of up to 50% of the daily sediment data, the correlation coefficient of more than 0/5 in the annual sediment estimation and only for the first year And in the rest of the years under study the correlation coefficient is unacceptable. Therefore, the use of sediment measurement curve methods with the data available at the level of Iranian stations, if the number of data available to construct the measurement curve is less than 185 will be associated with very little accuracy. Also, the higher the amount of available data belonging to the periods of low sediment transport (autumn and dry years), the lower the efficiency of the Loadest method will be.
Ali Jafari; Aliakbar Nazari Samani; Fatemeh Tavakolirad
Abstract
Doing the research for monitoring, evaluating and comparing the results with the parameters of projects is essential in the most natural resources and watershed management projects. Also in flood spreading projects the measurement, processing and evaluating the obtained information seems necessary. ...
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Doing the research for monitoring, evaluating and comparing the results with the parameters of projects is essential in the most natural resources and watershed management projects. Also in flood spreading projects the measurement, processing and evaluating the obtained information seems necessary. Entrance the large amount of flood with suspended material and sedimentation, changes the soil properties gradually. In this study influence of flood spreading on soil mineralogy changes was evaluated after 10 years. In order to investigate the changes in flood spreading ditches, three rows between the spreading channels which had received the flood were chosen as the sampling sites. To investigate and identify the clay minerals of flood spreading area and compared with the control area near to flood spreading area, thirteen samples of 0-15cm soil horizon from three flood spreading rows and settling ditches were selected. The results obtained from X-ray diffraction curves showed the presence of palygorskite, Illite, chlorite, smectite and kaolinite in control area, three settling ditches and flood spreading rows. There was no difference between the types of clay minerals in control area with settling ditches and flood spreading rows but the amount of some clay minerals was different in these situations. It seems that the dry climate of region was the serious factor in no change of clay minerals. Flood spreading had little effect on types of clay minerals and just was able to change the amount of clay minerals in flood spreading rows.
vahid chitsaz; Aliakbar Nazari Samani; Saeed Soltani; sadat feiznia
Abstract
Sediment and erosion are two natural phenomena in watersheds. Due to irregular recording and sampling difficulties, daily data are not available for sediment records. Therefore, decision makers and researchers have to apply interpolating methods to estimated sediment yields. In this study, 30 watershed ...
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Sediment and erosion are two natural phenomena in watersheds. Due to irregular recording and sampling difficulties, daily data are not available for sediment records. Therefore, decision makers and researchers have to apply interpolating methods to estimated sediment yields. In this study, 30 watershed characteristics including physiography, geomorphology, vegetation, climate conditions in 69 watersheds located in the Karoon and Karkheh basins were used to statistical analysis. Based on the principle component analysis, eight characteristics including area, perimeter, river length, relief, mean of elevation at 85% upstream and 15% point of longest flow path and the number of landslide events were selected. Then using Cluster Analysis, six homogenous regions were identified and multiple regression models were applied. Due to constriction of large dames on the studied watersheds, access to the reliable data is a challenges for sediment yield analysis. Based on the sediment-precipitation double-mass curves 29 out of 35 stations were influenced by upstream dam. Results indicated that the effects of large reservoir dams can influence the downstream sediment yield along 98 Km of river length. The results show that in each group a particular combination of variables influence the sediment yields of the watersheds. According to the validation indices (NS and R2) the obtained models have the high performance (R2 = 0.71 and NS=0.72). In general, the physiographic characteristics of the watershed such as length, area, main flow path and relief are more important than other climatic, vegetation and geological factors. The total explain variance by the mentioned variables is 87.3%.
Mohsen Farzin; Aliakbar Nazari Samani; saeideh menbari; sadat feiznia; gholamabbas kazemi
Abstract
This research tries to show the role and importance of karst formations in the infiltration of surface flows and recharge of groundwater resources in the region by determining the lineaments of geological formations in watersheds leading to the Persian Gulf and explaining the relative contribution of ...
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This research tries to show the role and importance of karst formations in the infiltration of surface flows and recharge of groundwater resources in the region by determining the lineaments of geological formations in watersheds leading to the Persian Gulf and explaining the relative contribution of each formation. For this purpose, The closest sub-basins to the Persian Gulf from the four basins of the rivers including Mond, Helleh, Kol-Mehran and Zohreh, to extract the lineaments, draw rose diagram and analyze them using ENVI® 5.3 software, PCI Geomatica, GIS10.3.1 and Rock works 2016 was selected. Initially, the frequency, density, intersection, direction, size and intensity of the lineaments in the formations of the region were determined. Then, by explaining and defining the lineament index, the importance and impact of each formation in the potential recharge of groundwater resources were determined. The results show that the highest percentage of frequency, intersection percentage and length of lineament are attributed to Asmari-Jahrom Formation and the highest percentage of Lineament intensity to Ilam-Sarvak Formation; the numerical value of the lineament intensity in the karst formations is three times as non-karstic formations. In general, the investigation of the condition of the lineament shows that the lineaments are basically created in the karst formations, so that the numerical value of the lineament index in the karst formations is 72.7, while the value in the non-karstic formations is 2.3. Furthermore, orientation of lineaments according to their frequency and length, in the whole range of study,
Aliakbar Nazari Samani; mahmoud samadi; arash malekian
Abstract
For developing of water resources a lot of different factors (such as: geological structure, faults, joints and geomorphological metrics) are important. This research tried to assess the effects of geomorphology on karstic water resources in central Elburz region. Geomorphometrics indices were prepared ...
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For developing of water resources a lot of different factors (such as: geological structure, faults, joints and geomorphological metrics) are important. This research tried to assess the effects of geomorphology on karstic water resources in central Elburz region. Geomorphometrics indices were prepared in the form of separate layer in GIS and RS and were overlaid on the springs distribution map. To assess the relationship between springs frequency, discharge and geomorphology statistical analysis such as correlation and factor analysis were done. Results indicate a close relation between spring occurrence and hillslope curvature and TPI. Also the Pearson correlation coefficient of elevation and lineament density and drainage density was significant (P<0.01). According to results the discharge of springs are directly related to drainage density and indirectly related to elevation and lineament density. Moreover the fetor analysis on 17 variables revealed that the first six components had Eigen value of more than 1 and 73.5% of total variance was explained by them. Result indicated that for future developing such a geomorphology characteristics can give suitable information of water resources.
Alireza Sepahvand; Hasan Ahmadi; Aliakbar Nazari Samani; Sebastiano Trevisani
Abstract
The geomorphometric indexes have been widely used for separation of surface landform features in the geomorphology science over the past decades. In this study, Multilayer Perceptron Neural Network (MPNN) was used to provide karstic landform classification. To that regard, initially, geomorphometric ...
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The geomorphometric indexes have been widely used for separation of surface landform features in the geomorphology science over the past decades. In this study, Multilayer Perceptron Neural Network (MPNN) was used to provide karstic landform classification. To that regard, initially, geomorphometric indicators were extracted from Digital Elevation Model (DEM), and then these indexes were used as neurons of input layer in artificial neural network. Furthermore, the box plots were applied to analyze the relationship between karstic landforms (such as dolines, hills, karstic plains, karstic valley and headland) and geomorphometric indexes. The results showed that 34, 6.9, 1.07, 48.5, 9.51 percent of the studying area are spatially covered by valleys, plains, dolines, highlands and hills respectively. It has also been found that the optimal structure of artificial neural networks for classification of landform is model No. 12-9-1 by having the learning rate 0.1 and 87.18 percent of determination coefficient. Also, it should be noted that the accuracy of the innovative method for classification of karstic landform is 90.58 percent. The analysis revealed that variations in geomorphometric indexes are very visible in the landform of hills, highlands and karstic valleys, whereas there are slightly overlapping in the plains and dolines.
Aliakbar Nazari Samani; Behnaz Zarrin; Shahram Khalighi sigaroudi
Abstract
Rainfall erosivity (RE) energy is an important factor on the soil detachment and transition of them implying an important role on the regional potential region erosion. . In this study SPI index was used in order to determine the climate condition and its consequent effects on RE in Fashand watershed, ...
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Rainfall erosivity (RE) energy is an important factor on the soil detachment and transition of them implying an important role on the regional potential region erosion. . In this study SPI index was used in order to determine the climate condition and its consequent effects on RE in Fashand watershed, Elburz province. At first the drought, wet and normal periods were determined for four rain gage station and then, both EI30 and modified Fournier index (MFI) were calculated at each gauge station. The regression analysis was used to investigate the relationship between EI30, MFI and 24-hour rainfall as well as annual rainfall of data-logging rainfall stations. After that through applying the regression equation the EI30 was extrapolated for eleven typical rain gauges over the different climate periods. The best correlation was obtained between EI30 and annual rainfall (R2 = 0.71). The spatial zonation RE maps were extracted through Geostatistical analysis for drought, wet and normal condition . According to the findings the effects of climate variability on the amount of RE are significant. Maximum and minimum RE are related to the wet and dry period respectively. However the RE on the summer season of dry condition is more than the wet condition and such condition together with low vegetation cover related to the drought condition lead to complicated situation. Despite the popular thought that the low RE can be addressed into the drought condition the rainfall pattern affect the erosivity potential and not the amount of precipitation.
ghobad rostamizad; ali salageghe; ali akbar nazari samani; jamal ghodoosi
Abstract
One of the types of water erosion and land degradation which causes imbalance, is the gully erosion phenomenon. Land degradation, a broken ecological balance of the land and landscape and risk of falling at biological resources in these areas, the study of the gully, is inevitable and necessary especially ...
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One of the types of water erosion and land degradation which causes imbalance, is the gully erosion phenomenon. Land degradation, a broken ecological balance of the land and landscape and risk of falling at biological resources in these areas, the study of the gully, is inevitable and necessary especially in the Darrehshahr Township. In this regard, Gully 36 number were selected in Darrehshahr area in the ilam province. To this end, were identified environmental factors, Physical - Chemical Soil properties, cover and hydrological properties of gullies tested using aerial photography, the digital maps and field operations. To determine the extent effect these factors on each of the gully geometry characteristics using fuzzy logic and information theory, the membership function and the weights of the membership function of each of the factors was calculated. Then relationship between the independent and dependent variables was obtained by using multivariate regression. Results of statistical analysis using multiple regression (stepwise method) revealed that length of gully with upstream area of the gully, top and bottom width and cross section of the Gully with basin elongation, deep gully with basin elongation and slope curvature, high of head Gully with local slope of the gully and steep walls of gully with percentage cover have a significant relationship. So could be concluded that characteristics of geometry gully in the study area would be a function of the upstream, basin elongation, curvature slope, Local slope of the gully head and the percentage of canopy cover catchment area of gully.
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Abstract
Stochastic climate generators are used in many studies such as application of hydrologic, environmental management and assessment of agriculture risk. These studies require for assessment of risk to long term series from meteorological data. Considering of climate data limitation at large area in Iran ...
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Stochastic climate generators are used in many studies such as application of hydrologic, environmental management and assessment of agriculture risk. These studies require for assessment of risk to long term series from meteorological data. Considering of climate data limitation at large area in Iran and short term of data, it is necessary using of climate generator and evaluation of precision and accuracy. Therefore in this study have been evaluated the efficiency of three generators namely CLIGEN, ClimGem and LARS-WG in sangeneh and Zidasht station with different climate condition. Statistical test of t (t paired) have been used to compare the differences between observed and production weather data such as yearly and monthly precipitation amount, yearly number of wet day, yearly average of max. and min. temperature. The obtained results show that CLIGEN generator have the better efficiency than two others generator in two stations and five considered variables. ClimGen haven't had the good efficiency in two stations. Also, LARS-WG generator have had the good efficiency in Zidasht station, but it's efficiency have had the less efficiency for product of temperature variables in Snganeh station. Generally, the obtained results show that the efficiency of these generators is better in mild climate than arid and semi-arid climate.
Omid Rahmati; Aliakbar Nazari Samani; Mohammad Mahdavi
Abstract
Determination of groundwater potential in respect to increasing trend of water demand in Iran, is found to be an unavoidable and vital subject. The present research was aimed to assess the efficiency analytical hierarchical process (AHP) to identify potential groundwater zones. Initially, five parameters ...
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Determination of groundwater potential in respect to increasing trend of water demand in Iran, is found to be an unavoidable and vital subject. The present research was aimed to assess the efficiency analytical hierarchical process (AHP) to identify potential groundwater zones. Initially, five parameters (viz., lithology, annual rainfall, drainage density, lineament density and land slope) were used in Ghorveh-Dehgalan plain. Influencing groundwater potential were selected. A questionnaire was prepared to collect ten experts attitudes to paired comparison of such parameters. The normalized weights of criteria/parameters were determined based on Saaty’s 9 point scale and its importance in specifying groundwater potential zones using analytical hierarchy process (AHP) and eigenvector method. To prepare lineament distribution maps, ETM+ Landsat images and PCI Geomatica were applied. Finally, the set of criteria were integrated by weighted linear combination method using ArcGIS 9.3 software to generate groundwater potential prediction map. The pumping test results collected and overlaid with groundwater potential prediction map. The validation of the groundwater potential prediction map was conducted based on frequency ratio and results of pumping 20 wells in study area. Results from comparing predicted potential of groundwater and by the groundwater specific capacity (SPC) showed 85% accuracy. It was established in the study that the AHP technique is promising of make accurate and reliable prediction, specifically in no-data aquifers.
Omid Rahmati; Aliakbar Nazari Samani; Nariman Mahmoodi; bahram choubin
Abstract
One of the techniques to eliminate groundwater resources crisis is to carry out artificial recharge projects, which cause infiltration of water from the surface into the aquifer and balance of the water table. An appropriate site selection for artificial recharge is one of the most important steps in ...
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One of the techniques to eliminate groundwater resources crisis is to carry out artificial recharge projects, which cause infiltration of water from the surface into the aquifer and balance of the water table. An appropriate site selection for artificial recharge is one of the most important steps in implementation of these projects, itself. In this study, capability of gridding technique and AHP method was evaluated for zonation of artificial recharge potential. Accordingly, a grid, with cell size 0.1 km2, was defined for rangelands of Chamshor watershed and geological parameters, slope, thickness of unsaturated layer, electrical conductivity and transmissivity were selected for entry into the model. Finally, potential zonation map of artificial recharge project, using gridding technique, Analytical Hierarchy Process (AHP) and weighting linear combination methods were produced for implementation of artificial recharge. In order to assess the model, the project of artificial recharge in the study area was used which has had a successful performance on balancing the water table level, reducing destructive floods and increasing vegetation. Finally, the accuracy of the gridding technique and AHP method was 87.5 percent. In conclusion, the zonation of artificial recharge potential which was obtained by gridding technique and AHP method was reliable and it is recommended to be used in the site selection of flood spreading systems to be able to carry out artificial recharge projects.
Ali Akbar Nazari Samani; alireza oliaye; sadat feiznia
Abstract
Assessment frequency of springs has become an important issue for land use planning, especially water resource identification and environmental protection.The purpose of this study is to produce a spring occurrence potential map in Bojnourd Basin, based on a logistic regression method using Geographic ...
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Assessment frequency of springs has become an important issue for land use planning, especially water resource identification and environmental protection.The purpose of this study is to produce a spring occurrence potential map in Bojnourd Basin, based on a logistic regression method using Geographic Information System (GIS) and remote sensing (RS). The locations of the springs (359 springs) were determined in the study area. In this study, 14 effective factors including spring were used in the analysis: lineament density, distance to lineament, distance to drainage, drainage density, normalized difference vegetation index (NDVI), profile curvature, tangential curvature, surface rate, vector dispersion, precipitation, elevation, geology, aspect and slope. Binary logistic regression coefficients of the variables by selecting 300 spring randomly. 59 another spring were used for validation that 80.6% of the springs were correctly predicted. The accuracy of the model was measured using ROC curves which showed that accuracy is 86.6 percent which indicates that the model shows high accuracy in the analysis of spring occurrence potential in the study area. The results showed that the distance of lineaments, distance of drainage, drainage density, vegetation index, profile curvature, tangential curvature, vector dispersion, precipitation and slope have the greatest impact on the occurrence of springs. Finally, spring occurrence potential map was divided into four probably classes of very low, low, medium and high. According to the survey results, this method can be used to identify sources of groundwater in karstic zones and has important role in better management of the karstic Basins.
sara Edrisnia; Ahmad Pahlevanroy; Alireza Moghadamnia; Aliakbar Nazarisamani; Abas Miri
Abstract
In Low rainfall, dry areas such as Iran that surface fresh water resources are limited and this water is exposed to pollution risk, finding and preserving underground water supplies is the best way for removing water needs. In addition, in some parts of Iran, climate and tectonic structure have created ...
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In Low rainfall, dry areas such as Iran that surface fresh water resources are limited and this water is exposed to pollution risk, finding and preserving underground water supplies is the best way for removing water needs. In addition, in some parts of Iran, climate and tectonic structure have created good conditions for forming karstic table. Following America, China and Turkey, Iran has the highest percentage of karst and more than eleven percent of Iran’s area is covered by karstic constructors.The purpose of this study is exploring the relationship between lineaments extracted from satellite imageries, tectonic elements, hydrography network and topography factors with Karstic water resources abundance in Maharloo using GIS and remote sensing. Information layers including lineaments, range curvature, elevation classes, slope, vegetation, springs, tectonic elements and hydrography network were provided through field visits, topographic maps, geology, satellite imagery and digital models. Findings were analysed with statistical tests such as Chi square, Pearson correlation coefficient, PCA test, and principal component analysis. It was found out that there is a close tie between formation type, topography (egslope, elevation and range curvature), lineaments and hydrological factors with spring abundance. The significant role of environmental and structural factors drives the necessity of paying attention to them in investigation of the abundance of springs and transmission of groundwater in Karstik areas.
M Zare; Aliakbar Nazari Samani; shahram khalighi; javad bazrafshan; mohsen hasan joury
Abstract
Land use Changes have recently been increasing due to anthropogenic and climatic factors. Natural resources management critically needs land use maps and simulation of its changes for understanding the interaction and relationship between humans and natural phenomena, as well as for making premium decisions. ...
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Land use Changes have recently been increasing due to anthropogenic and climatic factors. Natural resources management critically needs land use maps and simulation of its changes for understanding the interaction and relationship between humans and natural phenomena, as well as for making premium decisions. Accordingly, present study has dealth with simulation of future changes land use of Kessillian watershed. Hence, land-use and land cover maps of the catchment was prepared by using multi-period Landsat images captured in 1986, 2000, and 2011. Then, applying cellular automaton and Markov model, the land-use/land cover condition in 2011 was predicted 0.9 using ROC. Thereafter, this model was run for simulating land-use/land cover changes in 2030. According to the results of detection and simulation of changes, forest land reduction trend will continue but the area of rangelands and inhabited areas will expand. Agricultural lands will not seriously change due to steep slope and low fertility after several consequent plantings. In most cases, maximum changes occurred around the forest and rangeland areas and changes will decrease far from these margins. Markov model can precisely show the land changes in the area via time period and can anticipate the future of them. Therefore, this model can be applied in order to manage the land.
aboalhasan fathabadi; Ali Salajegheh; hamid pezeshk; Aliakbar Nazari Samani; hamed rouhani
Abstract
In order to manage and implement conservational activities in watershed successfully, it is necessary to determine the sediment sources. In recent years, sediment fingerpering techniques have been used for estimating sediment sources contribution. With respect to small source samples, having many answer ...
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In order to manage and implement conservational activities in watershed successfully, it is necessary to determine the sediment sources. In recent years, sediment fingerpering techniques have been used for estimating sediment sources contribution. With respect to small source samples, having many answer as a result of over fitting, there are some uncertainties in estimated sources contribution. In this study, the uncertainty associated with the multivariate mixing model was estimated using Monte Carlo simulation and GLUE approach in Zidasht-Fashandak sub- watershed. The sediment and source samples were taken in the study area and then, 54 geochemistry and three organic characteristics were measured. 17 elements were also selected as optimum tracer composition using Kruskal–Wallis H-test and multivariate discriminate analysis. Meanwhile, sources contribution were estimated using multivariate mixing models. Results showed higher contribution of sub-surface sources than the surface resources. Also, the distance between lower and upper limits for all sources and resolutely uncertainty bands were high.
golaleh ghaffari; Hasan Ahmadi; Omid Bahmani; Ali Akbar Nazari Samani
Abstract
Although more than 45 years has passed since the first time operating watershed projects were run inside the country and considering the increasing budget that is being allocated to such projects, terrible soil erosion, natural resource degradation and the dazzling and painful consequences of such events ...
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Although more than 45 years has passed since the first time operating watershed projects were run inside the country and considering the increasing budget that is being allocated to such projects, terrible soil erosion, natural resource degradation and the dazzling and painful consequences of such events are indicative of low efficiency and failure of natural resource protection projects. Therefore, since watershed projects involve many agents and management needs to be as effective as possible, assessment of how suuccessfully the project objectives have been realized is essential. The sologhan aquifer’s basin with an area of 20571 hectar is one of the basins in which watershed project was carried out in winter 2000. To assess the effectiveness of the above mentioned project, required statics and data was collected and the accuracy of meteorology and hydrology data was examined and the double mass curve, annual hydrograph comparisons, hydrologic analysis, sediment examination in dry and moist periods, sediment graph, studding the amount of sediment in precipitation periods prior and post projects implementation were considered and used. Double mass curve shows the positive effects of this operation on the amount of runoff and sediment. Hydrologic regime curves show as well that watershed operations had positive impacts upon the basins hydrologic reaction to rain so that the amount of runoff as a result of similar amount of precipitation has decreased. Furthermore, the amount of annual suspended load has decreased from 47892.56 to 22365 tons, so did the amount of Debbi and sediment. Above results prove the positive effects of watershed projects.
Gholamreza Zehtabian; Hassan Ahmadi; Aliakbar Nazari Samani; amir houshang ehsani; Mahdi Tazeh
Abstract
Plains are one of the most important geomorphological units and different parameters have been considered for classification of plain areas. One of most common classifications in natural resources studies in Iran entailing different qualitative and quantitative factors is: bare plains, apandazh plain ...
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Plains are one of the most important geomorphological units and different parameters have been considered for classification of plain areas. One of most common classifications in natural resources studies in Iran entailing different qualitative and quantitative factors is: bare plains, apandazh plain and covered plain. Such classifications are used to make plains distinguishable from one another. In this study, the geomorphometrical parameters were considered for plain classification by using artificial neural networks and sensitivity analysis. These parameters were extracted by using mathematical equations and applying the corresponding relations on digital elevation models and they are not widely used in Iran. Geomorphometric parameters that were used in this study included Percent of slope, Plan Curvature, Profile Curvature, Minimum Curvature, the Maximum Curvature, Cross sectional Curvature, Longitudinal Curvature and Gaussian Curvature. These parameters were calculated in an area of 125000 hectare and at 1500 points, and the result was compared and calibrated with ground truth map. Sampling method in this study was Latin Hyper cube that is a kind of stratified random sampling. Results of this study show that the most important geomorphometric parameters to classify desert plains include Plan Curvature and Profile Curvature that have the highest sensitivity among different plain types. The more the topography of the area reduced the more the contribution and importance of these factors for separating plain types decreased so that these parameters were most prominent in bare plains but had the lowest efficiency in covered plains.
Khosro Shahbazi; ali salajagheh; mohammad jafari; hassan ahmadi; ali akbar nazari samani; mohammad khosro shahi
Abstract
Negative impacts of gully erosion in marl areas are severe due to improper landuse practices such as irrigation, tillage, overgrazing and degradation of vegetation cover. The objective of this research was to evaluate hydraulic flow thresholds of gully erosion in the agriculture (AG), fair rangeland ...
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Negative impacts of gully erosion in marl areas are severe due to improper landuse practices such as irrigation, tillage, overgrazing and degradation of vegetation cover. The objective of this research was to evaluate hydraulic flow thresholds of gully erosion in the agriculture (AG), fair rangeland (FR) and poor rangeland (PR) areas in the Qasre-shirin, Kermanshah, Iran. Nine flumes were performed in the field to determine the critical values of hydraulic parameters including flow discharge, velocity, Froude and Reynolds numbers, Darsi resistance coefficient, shear tension, head-cut dimensions as well as vegetation cover. Results showed that respective critical value of discharge as the gulling thresholds for AG,FR and PR was 1.53, 12.0 and 4.49 li/s indicating significantly higher (p<0.05%) in the FR due to higher vegetation cover. In addition, there were no significant differences for flow disturbance based on Froude number, while the respective value of Rinuldze number in the AG, FR and WR were obtained 3113, 26092 and 9525 significantly higher in the FR. Furthermore, the critical level of shear tension for gully formation in the AG, FR and WR were found 12.12, 14.01 and 9.28 Nm-2, respectively showing significant differences among them. Finally, it is concluded that hydraulic flow parameters as the gully triggering are strongly affected by vegetation cover through landue practices so that higher plant cover in the FR was the key factor resulting in significant enhancement of gully.
Omid Asadi Nalivan; Mohsen Mohseni Saravi; Ghavamodidn Zahedi Amiri; Ali Akbar Nazari Samani
Abstract
Sustainability is a concept that emphasizes substantially on investments conservation (natural, social and economic) toward intra-generation equity. When sustainable development is achieved an overlapping is created between ecological, economic and social classes. The goal of this study is to measure ...
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Sustainability is a concept that emphasizes substantially on investments conservation (natural, social and economic) toward intra-generation equity. When sustainable development is achieved an overlapping is created between ecological, economic and social classes. The goal of this study is to measure and evaluate watershed sustainability. In order to evaluate sustainability in Zidasht basin 1, an ecosystem approach has been used to create balance between three categories of economic, social and ecosystem. Selective variables were obtained by common assessment methods. The IUCN method was used to analysis and evaluate the sustainability of the study basin. By and large, two subjects of human welfare and ecosystem sustainability are dealt with within IUCN approach. Two criteria, six indices and 28 variables were measured in human welfare section and also four criteria and 10 indices and 35 variables were evaluated in ecosystem sustainability section. Above mentioned indices measurement using software Wellbeing Score has scored based on intervals 0-100.finall indices and criteria Arithmetic Mean method integration was completed and map was developed in GIS. Final scores for ecosystem and social and economic issues were derived equal to 51 and 49, respectively. Final results of this study based on the Barometer of Sustainability showed that sustainability of Zidasht 1 basin is moderate. This situation can be improved by ecosystem conservation and people life style quality enhancement.
Elham Meshkati; Hassan Ahmadi; Aliakbar Nazari Samani; M.H Davoodi
Abstract
Landslide occurs inevitably and naturally in many slopes due to sensitive formations, moisture, andother factors. Taleghan watershed is prone to landslide due to the presence of huge Miocene marlmasses. After construction of Taleghan reservoir dam, moisture and ecological condition of theregion changed. ...
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Landslide occurs inevitably and naturally in many slopes due to sensitive formations, moisture, andother factors. Taleghan watershed is prone to landslide due to the presence of huge Miocene marlmasses. After construction of Taleghan reservoir dam, moisture and ecological condition of theregion changed. In this paper, factors impacting upon landslide hazard (slope, aspect, hypsometry,geology, land use, distance to road, distance to lake) were studied and their role and importance onthis phenomenon were verified in a large (maximum distance of 1500 meter from lake) and a small(maximum distance of 450 meter from lake) spatial scale. Thus, GIS maps of the above mentionedparameters were provided using satellite and aerial images and field activities. All maps werecrossed with a resolution of 100m*100m. It was found out that the distance to the lake didn’tinfluence upon landslide in a large spatial scale but it falls effective as the distance to the lakereduces. In fact lake has a local effect and mostly influences at maximum 200 meter distance.
Kazem Nosrati; Frouzan Ahmadi; Ali Akbar Nazari Samani; Mohammad Reza Servati
Abstract
Soil erosion is one of the most destructive phenomena which cause significant ecological changes in many areas. Soil conservation and erosion control is essential because of the irreparable damage caused by soil erosion. Soil conservation programs will not achieve until to find adequate methods of combating ...
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Soil erosion is one of the most destructive phenomena which cause significant ecological changes in many areas. Soil conservation and erosion control is essential because of the irreparable damage caused by soil erosion. Soil conservation programs will not achieve until to find adequate methods of combating land degradation and ways to reduce the sediment. Therefore, we need to have enough knowledge of the sediment sources and identify places to be at high risk to soil erosion. In this study we used fingerprinting technique in the Taleghani catchment, Khorram Abad city, Lorestan Province to determine the contributions of sediment sources including agricultural, rangeland, and forest in sediment yield. In view of this, 39 soil were collected from different sources: agriculture, rangeland, forest and channel bank and 19 sediment samples including 11 samples from bed sediment and 8 samples from suspended runoff, respectively. 11 tracers including C, N, P, Na, K, Cu, Zn, Mg, Mn, Fe and Ca were selected as the primary tracers. The results showed that discriminant function analysis were selected Mg, C, Zn and Ca as the optimum set of tracers that can discriminate 3 sediment sources. Mixing model results showed that the contribution of each sediment source is 53.37, 30.37, and 16.26 percent for agriculture, rangeland, and forest, respectively. These results were consistent with the evaluation results of nitrogen and organic carbon stocks. The results of this study can be used in selecting most appropriate erosion control method the study area and generalized to similar areas.
ali azareh; Gholamreza Zehtabian; Aliakbar Nazari Samani; Hassan Khosravi
Abstract
In management, the monitoring means systematic collection and storage of data from activities and strategies that provide assessment and report about the overall condition of the study area. In this research, among different existing methods, IMDPA model was selected for monitoring desertification in ...
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In management, the monitoring means systematic collection and storage of data from activities and strategies that provide assessment and report about the overall condition of the study area. In this research, among different existing methods, IMDPA model was selected for monitoring desertification in Garmsar plain. Based on the study area two criteria including agriculture and water were selected as the main effective criteria on desertification and desertification intensity was evaluated on the basis of seven indices including: groundwater table fluctuation, electrical conductivity, sodium absorption ratio, agricultural mention cropping pattern, agriculture yield according to land suitability, irrigation method and highly inappropriate utilization of machinery, fertilizer and pesticide chemicals. The results showed that the average weights of agriculture criterion were 2.17 and 2.27 in 2002 and 2011 respectively classified in medium class of desertification. Also, the index of irrigation method classified in very high class of desertification was the most effective factor on land degradation among studied indices in during 2002-2011. Studying the average weight of numerical value, it is distinguished that the intensity of desertification for the total area were 1.93 and 2.10 in 2002 and 2011 respectively.
