Ghasem Mortezaii Frizhandi; maryam mirakbari
Abstract
Drought is a natural and repetitive phenomenon. In this study, using SDI and GRI indicators, the hydrological drought condition was evaluated and compared with meteorological drought indicators. In the MATLAB environment, the GRI index was determined. According to the results, the GRI index during the ...
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Drought is a natural and repetitive phenomenon. In this study, using SDI and GRI indicators, the hydrological drought condition was evaluated and compared with meteorological drought indicators. In the MATLAB environment, the GRI index was determined. According to the results, the GRI index during the statistical period (1981-2015), the maximum drought severity was -73.25, and the maximum duration of drought was 79 months. These values are higher than the SDI index in the same time scale and the common statistical period. The Frequency of different groups of GRI indicator in the 35-year statistical period showed that normal drought had the highest percentage of abundance. The SDI index has the highest maximum continuity in the low-level time scales compared to the drought indicators of the meteorology. Frequency of drought groups was calculated based on an SDI index for the statistical period for different time scales. The results of this study showed that SPEI on 24 and 48 months scale with 3 month delay have the highest correlation with GRI which showed the impact of meteorological drought after two years has more effect on groundwater resources. Knowing the time interval between the occurrence of meteorological drought as main cause of coming drought that could help planners and managers to take the necessary management measures to cope with the drought caused by a shortage of water resources including surface and groundwater.
Feridon Ghadimi; Pegah Javadi Sharif
Abstract
The mixing of freshwater and salty water in saline playas, high dissolution of calcareous stones, agricultural activities, industrial effluents and municipal and rural waste landfills are the most important sources of groundwater threats that threat human health. In this study, 46 water samples were ...
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The mixing of freshwater and salty water in saline playas, high dissolution of calcareous stones, agricultural activities, industrial effluents and municipal and rural waste landfills are the most important sources of groundwater threats that threat human health. In this study, 46 water samples were taken from Arak plain and their physical and chemical variables were determined. Multivariate statistical analysis including stage factor analysis on the physical, chemical and chemical variables of groundwater in Arak aquifer have an important role in distinguishing between different pollutants in the region. The stage factor analysis gave five factors in the hydrochemistry variables of Arak aquifer. In the first factor, the EC, TDS, Cl, SO4, Ca, Mg and Na variables have a natural origin, which is the mixing of saline water from Mighan playa and freshwater aquifer. In the second factor, HCO3 is a natural origin due to the dissolution of limestones in southern Arak and HNO3, originating from humans and as a result of the influence of urban absorption wells and agricultural activities. The origin of the elements in factor three and four, mainly Zn, Cu, Fe and Mn, is mainly due to industrial activities and landfill, and F, is also due to agricultural activities, i.e, the use of phosphate fertilizers. This study also showed that stage factor analysis is a suitable method for separating source of contaminants. Therefore, appropriate measures should be taken by organizations and companies to control human pollution from sources such as Arak municipal wastewater, agricultural and industrial wastewater.
Maryam Azarakhshi; Mohammad Mahdavi; Hasan Ahmadi; Hosein Arzani; Jalil Farzadmehr
Abstract
Plants cover composition, condition, trend, production, and grazing capacity of the rangeland change annually. In this research, the role of temporal rainfall distribution on rangeland production was assessed. This research had down in the rangelands of Ilam (with semiarid to semi humid climate) and ...
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Plants cover composition, condition, trend, production, and grazing capacity of the rangeland change annually. In this research, the role of temporal rainfall distribution on rangeland production was assessed. This research had down in the rangelands of Ilam (with semiarid to semi humid climate) and Qom and Markazi (with arid to semiarid climate) provinces. By attention on plant cover maps in each province 10 main types of plant cover in Ilam, 8 types in Qom and 10 types in Markazi were selected. In these sites, relative factor to plant cover and soil contains: canopy cover, density, production, germination and, soil cover were measured along four 400m transects into 60 plots .the production of the graze able species was measured by clipping and weighting method. The regression techniques and correlation coefficient were used to the relation between production and precipitation. to determination the role of the temporal distribution of rainfall of the rangeland production, the relationship between rainfall and production was calculated in seven time steps contains. The results show that only 4% of the total forage production is explained by annual precipitation but in 96% cases there were related with start of growth season (March) and growth season(early March to late July).this result shows the importance of growth season precipitation on the forage yield in rangelands.
Mohammad Rahim Forouzeh; gholam ali heshmati; hosein barani
Abstract
Iran is a country with an ancient culture. During a long time, its inhabitants have created various classifications, nominalizations and technologies on the basis of preference and innovation in different fields in order to adapt with the events happening around. These rich sources of knowledge are being ...
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Iran is a country with an ancient culture. During a long time, its inhabitants have created various classifications, nominalizations and technologies on the basis of preference and innovation in different fields in order to adapt with the events happening around. These rich sources of knowledge are being eroded with an unimaginable speed that is in fact a part of the process of local indigenous culture destruction. Accordingly, their data collection and protection are of importance. This study aimed to record the knowledge of nomads of Boirahmad tribe about time and place recognition, playing an important role in forming their various activities in rangeland. The research was done in Dilegan Rangeland that is the summer quarter residence of nomads and located in cold weather regions of Kohgiloie and Boirahmad province. Participatory observation was used for data collection. Regarding the knowledge of experienced sheepherds about temporal and spatial components, interviews were divided in two parts, interview with sheepherds and others. By applying free interviewing and participatory observation, the required data for local calender and rangeland identification were recorded. Finally the interview notes were analyzed via content analysis method. Results show that nomads had local daily and yearly calendar in their knowledge, regulating their activities in accordance with. Daily calendar consists of 12 parts that different parts of a day are named accordingly. Also in their yearly calendar different times of the year are classified in 13 various time units which nomads' annual activities (such as migration, harvesting edible and medicinal plants,…) are set based on this calendar. As it was previously mentioned, it is recommended that the classification and naming patterns of time and place in rural and tribal traditional system be more investigated by rangeland management authorities and researchers of habitat prediction. Thus, it will give the possibility of more realistic analysis of the following research and also offered more practical solutions to advance the goals.
Fatemeh Maghsoud; Mohammad Reza Yazdani; Mohammad Rahimi; Arash Malekian; ali asghar zolfaghari
Abstract
Overview, drought is effected an unusual dry period which is enough continued and causes imbalance in the hydrologic status, as depletion of surface water and groundwater resources. The purpose of this research is modeling meteorological drought prediction using Neural Network- Multi layer Perceptron, ...
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Overview, drought is effected an unusual dry period which is enough continued and causes imbalance in the hydrologic status, as depletion of surface water and groundwater resources. The purpose of this research is modeling meteorological drought prediction using Neural Network- Multi layer Perceptron, parameters and climatic signals in three time scales include short, middle and long term in a rain-gauge station located at south plain of Qazvin Province. Three different scenarios were tested as inputs model. Optimal combination of variables was determinate by Gamma-Test after identification of input variables using cross-correlation. Results showed, influence of climatic signals increased and against the influence of meteorological parameters decreased when time scale were increased from short-term to long-term. MEI (Multivariate ENSO Index) and rainfall were introduced as the most effective climatic signals and meteorological parameter for each scale, respectively. Neural Network modeling which has hidden layer with enough neurons, Sigmoid Function in middle layer and linear function at output layer was used. The most appropriate of the number neurons was determined in each scenario and wasn’t observed significant correlation between increasing or decreasing the error and number of neurons. Finally, the most appropriate network structure was determined based on evaluation indexes in three scenarios and each time scale.
Hamid Gholami; Mohammad Reza Mehrdadi; Mehdi Najafi; Mehdi Biniaz
Abstract
Quantifying source contribution of aeolian sediments is essential to prioritize sources and mitigate wind erosion. The objective of this research is quantifying uncertainty associated with results of sediment fingerprinting method using Monte-Carlo simulation technique in the Sirjan plain. Six sediment ...
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Quantifying source contribution of aeolian sediments is essential to prioritize sources and mitigate wind erosion. The objective of this research is quantifying uncertainty associated with results of sediment fingerprinting method using Monte-Carlo simulation technique in the Sirjan plain. Six sediment samples were collected from the sand sheets and forty source samples consisting Qt (n=13); Qc (n=17); Qsg (n=5); and Dc (n=5) were collected from geological spatial sources in the surrounding area. Concentration of eight geochemical elements were measured in both sample group. A two-stage statistical method including Kruskal Wallis H test and a stepwise discriminant function analysis applied for discriminating of aeolian sediment sources. Based on two-stage statistical method, four geochemical properties consisting Fe, K, Mg and Cu were selected as optimum fingerprints. The Qc and Dc were recognized as dominant sources for aeolian sediments in the study area and also, full uncertainty or full range (0-100%) calculated for some source contributions. Therefore, management activities for mitigation of wind erosion should establish at the Qc and Dc source regions. This technique has great potential for quantifying source contribution of aeolian sediments at other area with active wind erosion.
Jamshid Nosrati Rad; Ali Akbar Jamali; Hosein Sargazi
Abstract
Identification of the barriers and socio-economic factors of villagers for rural development is evident. To identify this issue, consideration of social capital and socioeconomic variables that affect the satisfaction of watersheds has been considered. The purpose is to assess the level of satisfaction ...
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Identification of the barriers and socio-economic factors of villagers for rural development is evident. To identify this issue, consideration of social capital and socioeconomic variables that affect the satisfaction of watersheds has been considered. The purpose is to assess the level of satisfaction of watershed dwellers from the fifth agricultural development and income generation program (between 2008 to 2013). The study was an applied and descriptive cross-sectional study in 2017. The studied population of the Saravan watersheds included Morti, Kalehgan, and Qaderabad. The data gathering tool was a researcher-made questionnaire. The reliability of the questionnaire was confirmed by Cronbach's alpha test with 0.79 was relatively good. 102 questionnaires were completed and collected for collecting data in the studied basins. A nonparametric analysis was conducted to compare the mean of satisfaction of the three basins by the Kruskal-Wallis statistical method. Results were shown in many cases, the Morti watershed showed significantly more satisfaction. The level of satisfaction from GDP with an average of 3.5 and capital possessions with an average of 3. 3 had good satisfaction among the watersheds. The conclusion shows that the level of satisfaction from the fifth development plan was relatively good, which was not satisfactory with financial resources. Satisfaction rate based on the Morti watershed with 558 dwellers due to the abundant water and production, were more satisfied than Kalehgan and Qaderabad. We propose that to evaluate of fifth develop plans for watersheds of Iran in different provinces.
Alireza Motevali; Ali Talebi; Mehrdad Safaei; Mohammadreza Ekhtesasi
Abstract
Landslide is one of the most important geological phenomena in northern slopes of Iran (Alborz) which causes considerable damages gradually. In the last few years, due to unfavorable changes in land uses and increasing degradation of pastures, forests and farmlands as well as implementation of inappropriate ...
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Landslide is one of the most important geological phenomena in northern slopes of Iran (Alborz) which causes considerable damages gradually. In the last few years, due to unfavorable changes in land uses and increasing degradation of pastures, forests and farmlands as well as implementation of inappropriate development projects in areas prone to landslides, geology formation prone to landsliding, rainfall rate and steep slopes, the occurance of this destructive phenomenon has constantly increased. In this research, landslides which occurred around Sari-Kiasar road were investigated using physically based models i.e. SINMAP and SHALSTAB and the stability map of the region was determined applying these models. First, the physical and mechanical properties of soils in 13 points were measured and evaluated by 56 landslide points. The results of field studies, laboratory samples, running models and data analysis showed that these models (SINMAP and SHALSTAB) have success rate equal to 87.3 % and 69.5%, respectively for predicting the slope instability in ChaharDonge region. This means that the SINMAP model has more efficiency than SHALSTAB model for slope stability analysis.
Amir Reza Keshtkar; Behnaz Asefjah; Yusef Erfanifard; Ali Afzali
Abstract
The development and implementation of practical natural resources and catchment managementpolicies require a comprehensive knowledge of the system processes (biological, physical, andsocio-economic), their complicated interactions, and how they react to different changes. Thecurrent research assessed ...
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The development and implementation of practical natural resources and catchment managementpolicies require a comprehensive knowledge of the system processes (biological, physical, andsocio-economic), their complicated interactions, and how they react to different changes. Thecurrent research assessed the ecological, physical, and socio-economic consequences ofbiologically-based management scenarios targeting runoff and soil erosion problems in theDarenari catchment. The Darenari catchment with an approximate area of 554 ha is located in Farsprovince, Iran. Three biological activities and 8 management scenarios were considered. Ecologicalconsequences were studied using the weighted land cover area index (WLCAI). Physical effectswere investigated applying the runoff curve number (SCS-CN) hydrologic model. Economic andsocial effects were assessed applying the cost/benefit analysis as well as examining the outcomes ofa social survey. Then, a fuzzy AHP approach was applied to weigh the criteria and ultimately, thebest management option was chosen using FTOPSIS model. The results showed that social criteriawith the highest weight and scenario No 8 was the best scenario and had first priority. The resultsidicated that the multi-criteria decision making techniques included capability of expressingdifferent aspects of the problem and are the perfect tool for watershed resources management.
Mohammad Reza Ekhtesasi; mohammad sefid; Ali Morovati Sharif Abadi
Abstract
Zonation of quality of drinking water sources is necessary for Water Management in Arid and Hyper Arid areas. In this research, spatial variations of quality characteristics of water (EC, Na, K, Mg, Ca, NO3, SO4, Alkalinity, Cl, TH and TDS were investigated in one-year period (2015-2016) based on the ...
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Zonation of quality of drinking water sources is necessary for Water Management in Arid and Hyper Arid areas. In this research, spatial variations of quality characteristics of water (EC, Na, K, Mg, Ca, NO3, SO4, Alkalinity, Cl, TH and TDS were investigated in one-year period (2015-2016) based on the data collected from 55 drinking deep wells of Yazd Plain. In order to evaluate and select the best method of interpolation was used Simple kriging, Ordinary kriging and Inverse Distance Weighted and RMSE. Zoning maps showed that groundwater of Charkhab and Yazdgerd respectively are in the Southeast and Northwest of study area, which are affected by flow of the Mehriz and Taft river, that are higher quality than the middle part of study area.The changes in the main indicators of quality such as TDS are from less than 500 to more than 2500 mg/lit and EC from less than 700 to more than 3,500 micromhos/cm that this achievement reflects the need for utilization management and preparation of drinking water with best quality to enter the network. Also the wells in the center of study area such as 16 Silo, 12 Dehno, 13 Dehno and 24 Dehno in terms of quality parameters such as TDS, TH, EC and Cl have more than double the national standard limit, that is recommended to remove them or adjustment operation of wells in drinking water network.
Azam Karimi; Ataollah Ebrahimi; Esmaeil Asadi borojeni; Pejman Tahmasebi; Rahman Tavakoli
Abstract
One of the important factors threatening forests and rangeland is fires that leads to destruction of a large part of forests and rangelands. Study of this phenomenon and providing management strategies plays a major role to deal with and control such crisis. This study aimed to identify the affecting ...
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One of the important factors threatening forests and rangeland is fires that leads to destruction of a large part of forests and rangelands. Study of this phenomenon and providing management strategies plays a major role to deal with and control such crisis. This study aimed to identify the affecting factors of fire occurrence. The identification of major criteria conducted using a questionnaire as well as gathering information from Natural Resources and Watershed Management Organization in addition to calculation some others. To do so, 3 category of variables including 1- Human factors, 2- Biophysical factors and 3- Instrumental and logistic factors that contained altogether 26 variables are studied. In this research, Geographically Weighted Regression (GWR) method was used for mapping and zonation of the burned areas in the province that were occurred from 2007 to 2013. Results showed that amongst the 26 studied variables, monthly income (R=-0.61 and VIF=8.08) and number of rangeland and forest guardian members (R=-.56 and VIF=10.81), number of guard stations (R=-0.54 and VIF=2.2), guardsmen’s’ average age (R=0.53 and VIF=9.71 ), average of slope (R=0.5 and VIF=8.99) and number of voluntary rangeland and forest guards (R=-0.42 and VIF=15.11) are respectively the most affective variables on the occurred fires in range and forestlands. Finally, based on extracted predicted map Vardenjan, Mizdej-olia, Poshtkouh Ardal, and Aarmand are the most vulnerable counties for fire incident. Whilst, Monj and Mougooei encountered the least vulnerability of number of fire occurrence that is significantly in line with occurred fires.
majid kazemzadeh; arash malekian
Abstract
One of the most important dynamic ecosystems is river, awareness of spatio-temporal water quality changes of which is necessary. In this research, we studied the spatiotemporal water quality changes using three techniques of Cluster analysis (CA), Discriminant analysis (DA) and Principal Component analysis ...
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One of the most important dynamic ecosystems is river, awareness of spatio-temporal water quality changes of which is necessary. In this research, we studied the spatiotemporal water quality changes using three techniques of Cluster analysis (CA), Discriminant analysis (DA) and Principal Component analysis (PCA) in the Aji-Chai watershed over 1981-2010. Applying clustering, we identified three homogeneities clusters. Stations which were labeled in the first cluster showed that they are located in the upstream of Aji-Chi River. In comparison with other stations, these stations showed better water quality and the lowest changeability. DA methods significantly determined the three functions which described about 73.50, 20.30 and 3.40% of total variances. In the other word, in general three functions described the 97.20% of the total variances. Also the DA methods revealed the HCO-3, SAR, Na+, SO42- and Ca2+ were the most important parameters affecting upon water quality, based on which it's possible to seperate homogenous clusters. Finally, the results of PCA showed that the first two factors were the most important factors of water quality changes in the Aji-Chai River Watershed. These factors described about 78.75 and 14.71% of the variances, respectively.
Maryam Moradnezhadi; Arash Malekian; Meghdad Jourgholami; Ali Ghasemi
Abstract
24 hour precipitation distribution pattern and its relationship to short-term rainfall is an important issue in hydrology studies such as in flood simulation and in design of hydraulic structures. Accordingly, this study made an attempt to investigate the relationship between daily precipitation and ...
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24 hour precipitation distribution pattern and its relationship to short-term rainfall is an important issue in hydrology studies such as in flood simulation and in design of hydraulic structures. Accordingly, this study made an attempt to investigate the relationship between daily precipitation and hourly and minute precipitation using data from rain gauge station of Nowshahr in a coastal-forest region in north of Iran. The patterns of daily rainfall temporal distribution were examined using Pilgrim and Huff techniques. Finally, the obtained regional pattern using statistics were analyzed to evaluate absolute percent relative error, mean absolute error, root mean squared error and mean square error. Results of the relationship between 24 hour precipitation and 5 and 30 minutes and 1, 2, 3, 6, 9, 12, and 18 h rainfall showed that in all cases an exponential relationship can better explain this relationship than linear regression equations and logarithmic relations. Study of the rainfall temporal distribution pattern showed that in all extracted 24 hour events, the highest rainfall occurred in the lower quartile and in all rainfall events constant decrease in rainfall intensity occurred from the moment it started till it ended so that no fluctuation was observed in precipitation over time signaling that rainfall intensity would increase again. The results indicated that in similar areas, l SCS-type IA model could show reasonably better estimation in comparison with other models.
TAYYEBEH MESBAHZADEH; nahid alipour
Abstract
Dust phenomenon is one the problem that is developed due to human interference and unreasonable utilities from natural resources and their destruction. In this review, the dust phenomenon frequency was done using selected synoptic stations statistical in Alborz and Qazvin provinces during 2000 to 2014 ...
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Dust phenomenon is one the problem that is developed due to human interference and unreasonable utilities from natural resources and their destruction. In this review, the dust phenomenon frequency was done using selected synoptic stations statistical in Alborz and Qazvin provinces during 2000 to 2014 that annual frequency was evaluated by extraction of dust codes from meteorological data statistically. In order to study of velocity and direction of region winds, wind rose and storm rose of Karaj and Qazvin stations were drew and prevalent wind direction was determined that it showed prevalent wind is northwest and southeast at Karaj and Qazvin stations respectively. Study of the effect of drought on dust phenomenon event was done using SPI, PNI, ZSI indicator for annual scale and was evaluated via SPSS software. The drought result show that 2013 was the driest year at Karaj station and the SPI, PNI and ZSI values were obtained -1.64, 58 and -1.39 respectively. Also 2008 was the driest year at Qazvin station and SPI, PNI and ZSI values were calculated -2.34, 50 and -1.99 respectively. With studying of annual dust frequency with regard to 06 and 07 codes detected that totally 169 days was reported as day with dust at Karaj station that 2012 and 2014 had the most event frequency. Furthermore, totally 115 days with dust accrued at Qazvin station that 2011 with 23 days had the most event frequency.
S.Mahdi Taghipour; Shahram Khalighi Sigaroodi; Amir Alambaigi
Abstract
All rural and nomadic communities reside in natural watershed areas and, based on the specific climatic and geological conditions that each catchment area has, they are useful for living. Today, there is a danger to the livelihoods of non-residents as well as climate change caused by human activities, ...
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All rural and nomadic communities reside in natural watershed areas and, based on the specific climatic and geological conditions that each catchment area has, they are useful for living. Today, there is a danger to the livelihoods of non-residents as well as climate change caused by human activities, in other words, global warming due to the burning of fossil fuels. Accordingly, in this study, using the indices defined in the natural, social, physical, human and economic parameters, we examine the amount of five effective capital in the capacity of watershed adaptation to the climate change phenomenon in the three villages of Haji Abad, Gisur and Noodat Pashang In Gonabad city. In this study, due to climate homogeneity, 3 villages in the dry climate of Gonabad city have been selected. In this research, based on the questionnaire, the size of each of the five indicators and the organized interviews with the target groups in the three villages of the desert region were 3.13, 3.39, 3.14, 3.26, 7.2 was calculated. Also, using the Freeman test, it was found that there is a significant difference between different capital, which, respectively, social, human, physical, natural and economic, have the greatest impact on the capacity of aquaculture adaptation, so it is better to solve The watershed problem has used social and human capital to inflate other (physical, natural, and economic) capital
javad Motamedi(torkan); Hassan Solali
Abstract
Investigation of the grazing behavior of grazing animals on the rangeland is one of the basic necessities of grazing management in different climatic regions. The current study with the aim of exploring the grazing behavior of Makuyi sheep breed was conducted in the mountainous rangelands of Kelid Daghi ...
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Investigation of the grazing behavior of grazing animals on the rangeland is one of the basic necessities of grazing management in different climatic regions. The current study with the aim of exploring the grazing behavior of Makuyi sheep breed was conducted in the mountainous rangelands of Kelid Daghi of Jolfa as representative rangelands for Makuyi sheep breed dispersion in East Azerbayjan Province. For this purpose, a herd with 300 sheep including three mature ewes (3 years old) was chosen and tagged. In the next stage, by attaching GPS to each of them, their travelled distance, the movement speed of the sheep while grazing, grazing duration of particular plant species, period of rest and rumination during grazing months were derived. The results indicated that the time spent for grazing, at the final stages of the grazing season is longer than at the earlier stages of the grazing season. Nearing the final stages of the grazing season, distance travelled by the sheep during the day increased. The average speed of the sheep movement at the earlier stages of the grazing season was less than their speed at the final stages of the grazing season, due to the day length change and, consequently, the daily temperature change, and the change in the vegetation composition of the rangeland and, consequently, the change in forage quality and quantity. Based on the obtained results, the movement path of the sheep, the elevation profile of the path for the livestock movement during the grazing season months had the same trend and considerable changes were not observed in it. The small area of the study site, and also livestock lead by shepherd along a specified path during the grazing season are effective factors in this regard. Awareness of the mentioned cases is helpful for determining appropriate areas of livestock movement and proper dispersion of livestock in the rangeland, and that if the current dispersion of livestock by shepherd in the rangeland is properly carried out, and leads to livestock efficiency improvement.
leila kashi zenouzi; shahram banjshafee
Abstract
This study aimed to investigate the relationship between expression of soil salinity factors and vegetation cover in Foojerd watershed. To this end, the vegetation types in the region and the formation of relatively homogeneous in terms of soil and topography, soil and vegetation were sampled by a systematic ...
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This study aimed to investigate the relationship between expression of soil salinity factors and vegetation cover in Foojerd watershed. To this end, the vegetation types in the region and the formation of relatively homogeneous in terms of soil and topography, soil and vegetation were sampled by a systematic random sampling. The samples according to the area consists of homogenous units were determined. In each plot characteristics of range species and percentage of vegetation cover were recorded and soil profiles were dug. Depending on the depth of the soil profile and the depth of the roots of the plants were sampled and conductivity, exchangeable sodium, sodium absorption ratio and absorption of sodium in each of the soil samples were measured. Pearson correlation coefficient of salinity and vegetation type and percentage of vegetation cover were calculated using SPSS18.0 software. The results showed that vegetation has a negative correlation with soil salinity factors. Based on analysis of variance and Duncan were revealed that test the type of plant species were depended on soil electrical conductivity and sodium absorption rate and the percentage of canopy cover was affected by soil electrical conductivity and exchangeable sodium content. So soil sodality is the most important limiting factor to grow vegetation in Foojerd watershed.
TAYYEBEH MESBAHZADEH; Zahra Ayazi; farshad soleimani sardoo
Abstract
By identifying the removal areas the reasons can be identified instead of addressing the causes, And focused on executive activities in the harvesting areas And for this, the identification of sediments is particular importance In this paper, with the aim of better understanding and interpreting sedimentary ...
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By identifying the removal areas the reasons can be identified instead of addressing the causes, And focused on executive activities in the harvesting areas And for this, the identification of sediments is particular importance In this paper, with the aim of better understanding and interpreting sedimentary samples, Investigating and analyzing the distribution of sediments in the facies of the study area has been investigated. For this purpose, after sampling of surface soil and preparation of samples, The drying procedure was performed according to A.S.T.M standard in 8 classes, which was smaller than 64 microns to 4000 microns. By entering the data into Gradistat software, statistical parameters such as mid-diameter, skewness and sample sorting were calculated based on the Fulc's comprehensive drawing method. The results of the study showed that the particle sorting is between 0.8 and 0.3, which confirms the near-average spacing distance from the harvesting area to the sediment accumulation point. The results of the particle tilting index are in the median vein facies, agricultural lands, agriculture, and sandy areas with symmetrical pebble cover. In other facies, the index is tilted towards fine particles. In the facies of the Rigi plain, the puffy lands and the permafrost shells of the wear coefficient classes are between 0-200 and then fully angled and the particles are transported from a distance. In the rest of the facies, the wear coefficients are between 200 to 400, in which case the particles are semi-angled and the particles are transported from a relatively distant distance.
Mehrnoosh Ghadimi
Abstract
Given the time/cost inefficient nature of land mapping for monitoring of the changes in the earth dams’ body across the world, the Radar Interferometry is introduced here as a modern alternative method. In this study, to investigate the changes in the Taleqan dam’s body, we employed the GMTSAR ...
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Given the time/cost inefficient nature of land mapping for monitoring of the changes in the earth dams’ body across the world, the Radar Interferometry is introduced here as a modern alternative method. In this study, to investigate the changes in the Taleqan dam’s body, we employed the GMTSAR software and processed 68 Sentinell- A images taken in the time period of 2014-2018. Additionally, utilizing the radar interferometry in the short range, the time series was determined. The time series results implied that the maximum dam subsidence is 3 mm/y along the line of sight. To justify the changes in the Taleqan dam’s body, some studies were carried out on the rip rap of the dam’s body. The obtained results implied that the changes have been caused by erosion and weathering. Due to undesired diffusion coefficient and low resistance of the stones with external volcanic and reolithic structure, such material collapsed under the influence of atmospheric and temperature factors, leading to displacement in the downstream. The performed investigations implied capability of the radar interferometry in monitoring of the earth dams and critical structures and providing information that can play a vital role in analysis of the dams’ behavior and completion of the precise tools measurements.
sadat Feiz Nia; Mariam Musavian; Zohreh Abdolahian Dehkordi; Khadijeh Ebrahimi Dorche
Abstract
Physical characteristics of drainage basins suchas geological materials, landuse type and vegetation cover, soil type, surfacepermeability, depth of underground water table, topographical conditions anddrainage are important factors in flood occurrence which affect prevailingequations on water movement ...
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Physical characteristics of drainage basins suchas geological materials, landuse type and vegetation cover, soil type, surfacepermeability, depth of underground water table, topographical conditions anddrainage are important factors in flood occurrence which affect prevailingequations on water movement in drainage and determine storage capacity ofdrainage basins. Geology is one of the most important factors affecting floodoccurrence of drainage basin. In this study it is attempted to investigate theeffect of geology factor on flood occurrence in Joneghan drainage basin,Shahr-e – Koord, using a new method. In this respect, after preparing base mapsconsisting of slope amount , geology , landuse , erodibility of geologicalmaterial , soil depth and drainage pattern , studies were performed in twostages as follows: In the first stage, flood occurrence of hill slopes of eachsub- catchment was investigated. For doing so, work unit map was prepared usingslope and infiltration maps. Then in each sub-catchment, land use, erodibilityof geological materials and soil depth were overlaid with work unit map one byone and dually. In the second stage, flood occurrence of drainage wasinvestigated as follows: First, longitudinal profile of main drainage of eachsubcatchment was prepared using GIS. For investigation of flood occurrence ofdrainages, slope and permeability of geological units were used. The results ofthe first stage showed that permeability, slope, erodibility of geologicalmaterials and soil depth have the greatest effect on flood occurrence,respectively. Also based on this four – factor method, subcatchments weredivided into five flood occurrence classes as follow: low, low to medium,medium, relatively high, and high. The results of the second stage showed thatdrainage flood occurrence belongs to two classes of low to medium and medium.By combining slope and drainage flood occurrence, it can be concluded that thethird subcatchment with medium flood occurrence is more susceptible to floodrelative to other subcatchments. With regard to the results of the presentstudy, it can be concluded that geology has high impact on flood occurrence andpermeability of geological materials decrease flood occurrence in the basin.
kazem Nosrati; mohammad mehdi hossein zadeh
Abstract
Growing population and increasing water resources demand have caused to slump groundwater level in many plains. Therefore there is a necessary to improve the quantity and quality of the aquifers. One of the most important methods to increase water table in recent decade is groundwater artificial recharge. ...
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Growing population and increasing water resources demand have caused to slump groundwater level in many plains. Therefore there is a necessary to improve the quantity and quality of the aquifers. One of the most important methods to increase water table in recent decade is groundwater artificial recharge. The main objective of this study is to select sites more suitable for groundwater artificial recharge in Ravansar plain. In view of this, the raster map layers of criteria including geology, slope, alluvial thickness, infiltration rate, permeability, erodibility, land use, percent of silt and clay were prepared. Then each of these criteria was ranked using analytic hierarchy process (AHP) and weighting liner component (WLC) methods for two artificial recharge methods including flood spreading and spreading basin. The results showed that based on the selected indicators and the zonation map in two methods, the best sites located in northern, northeastern and southwestern of the study area and fluvial fans adapted with the best sites for groundwater artificial recharge.
ardavan ghorbani; Farid Dadjoo; null null; Mahmood Bidar lord
Abstract
The purpose of this study is to investigate the relationships between aboveground net primary production (ANPP) and environmental factors (such as elevation above sea level, slope, aspect, compound topographic index, seasonal and annual precipitation, seasonal and annual temperature) which was carried ...
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The purpose of this study is to investigate the relationships between aboveground net primary production (ANPP) and environmental factors (such as elevation above sea level, slope, aspect, compound topographic index, seasonal and annual precipitation, seasonal and annual temperature) which was carried out in the rangelands of Hir and Neur in Ardebil province. Initially, considering the vegetation types and different classes of environmental factors, at the maximum vegetative growth stage, using one square meter plot with clipping and weighing (harvesting) method ANPP was estimated. Using digital elevation model (DEM) map, the maps of slope, aspect, elevation classes and topographic index were extracted. In addition, using gradient equations (calculated from the study areas stations) the seasonal and annual precipitation and temperature maps were extracted. One-way analysis of variance (ANOVA) was used to evaluate the factors between different sites. Then, to determine the most important environmental factors affecting on the ANPP changes, the principal component analysis (PCA) was used. Also, the ANPP map prepared using regression equation in GIS. The results showed that the variables are significantly different in sampling sites (P<0.01). The results of PCA indicated that the components of one (include annual precipitation, annual temperature, elevation) and two (include slope) with 76.10% had the most effect on ANPP. Also, ANPP map prepared using the extracted regression equation and the accuracy of the map was 0.71, which indicates the validity of the model.
zeinab nazari; nematollah khorasani; sadat feiznia; mahmoud karami
Abstract
One of atmospheric phenomena of dry and semi-dry areas and areas adjacent to these areas is the phenomenon of dust and production of particulate matter (PM10) that have many environmental hazards. The purpose of this research is determination of chemical composition and source identification of elements ...
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One of atmospheric phenomena of dry and semi-dry areas and areas adjacent to these areas is the phenomenon of dust and production of particulate matter (PM10) that have many environmental hazards. The purpose of this research is determination of chemical composition and source identification of elements in aerosols in city of Kermanshah. Enrichment factor are used to identify natural and anthropogenic sources of these elements in aerosols. Tracing of sreams is performed using contour line in level of 500hpa . Samples of aerosols is analyzed for 20 elements by ICP-OES. According to this study, The elements such as iron, potassium, calcium, selenium, arsenic, cobalt, phosphorus, magnesium and sodium have low EF- values, this indicates that these elements have originated from the crust. These elements account for 84% of the total concentration of elements. This shows that crustal elements are the main contributor to the elements in PM10 in the Kermanshah atmosphere. The results of this research show that the most frequent pass of streams to west Iran; west to east of Iraq is in the first rank, then, westnorth to eastnorth of Jordan, east to westsouth of Syria and east to west of Mediterranean. Therefore, it can be stated that Iraq and its neighboring regions have important role in production of aerosols.
