Sadat Feiznia; Soheila Youneszadeh Jalili; Hasan Ahmadi
Abstract
Due to difficulties in the application of traditional methods for identifying sediment sources, fingerprinting techniques, based on physical, chemical and organic properties of sediment and source materials, are increasingly being used as a valuable and effective alternative approach to obtain such information. ...
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Due to difficulties in the application of traditional methods for identifying sediment sources, fingerprinting techniques, based on physical, chemical and organic properties of sediment and source materials, are increasingly being used as a valuable and effective alternative approach to obtain such information. The first step in this method is using an appropriate combination of diagnostic properties that is able to differentiate sediment sources. In this study a combination of properties was used in different subbasins of Khur-Sefidarak Basin, located in Savojbolagh Township, Alborz Province and the share of each lithological unit on production of suspened load was estimated. By preparing lithological map, lithological units are considered as sediment sources and sediment behind the small dams are considered as deposittional areas. Aboat 43 samples were taken from lithological units and trap sediments of small dams in outlet of different sub basins. Then particle sizes finer than 62.5 µ were seprated and concentration of nine geochemical elements in the samples were obtained. After being certain about absence of outliers data and after using analysis of variance and Kolmogorov-Smirnov Tests, discriminant analysis is used for finding the final proper combination. Among different elements, Ca is the most important element for differentiating geological units in different subbasins of Khor-Sefidarak Basin. Finally, relative importance of each geological unit in producing suspended load was calculated. Results have shown that Zagun and Shemshak Formations have the highest share in sediment production of the area.
shima nikoo; Hossein Azarnivand; Gholam Reza Zehtabiyan; Hasan Ahmadi; Mohammad Ali Zare Chahouki
Abstract
Combating desertification which is a serious threat for the environment and human welfare requires understanding complex issues of this phenomenon using evaluation, awareness of severity of it's processes and determination of it's factors. So here, after recognizing the characteristics of the region ...
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Combating desertification which is a serious threat for the environment and human welfare requires understanding complex issues of this phenomenon using evaluation, awareness of severity of it's processes and determination of it's factors. So here, after recognizing the characteristics of the region showing existence desertification, we assess its current status with emphasis on climate, water, geology-geomorphology, soil and wind erosion as the most criteria of desertification. According to more consensus on regional model or flexible model to modify, Iranian Model for Desertification Potential Assessment (IMDPA) ,which is calibrated to use in arid area of Iran, was chosen. At first the rainfall seasonality indicator was added to the model as a special climate character. Then primary assessment of desertification was done. At last according to the result of primary assessment, the area environmental conditions and revealed issues during assessment the model was modified, final assessment and mapping of desertification were done. At last according to the result of primary assessment, the area environmental conditions and revealed issues during assessment the model was modified, final assessment and mapping of desertification were done. Based on the results desertification intensity in 33/94% and 66/06% of the area are severe and moderate respectively. Also the major factors affecting desertification across Damghan region are climate, salinization of water and soil resources, improper land use, over exploitation of underground water, over grazing and improper irrigation method.
Mahsa Ghazimoradi; Mostafa Tarkesh; Hossein Bashari; Mohammad Reza Vahabi
Abstract
In this study, the ability of Generalized Additive Model (GAM) for mapping potential distribution of Ferula ovina Boiss, and the description of species response curves to environmental variables were examined in Fereidonshar region with area of 1000 square kilometers located in West of Isfahan province. ...
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In this study, the ability of Generalized Additive Model (GAM) for mapping potential distribution of Ferula ovina Boiss, and the description of species response curves to environmental variables were examined in Fereidonshar region with area of 1000 square kilometers located in West of Isfahan province. The presence and absence data of the species were collected from 278 sites (including 138 presence sites and 140 absence sites) by random systematic method, and 9 soil variables, 22 climate variables and 3 physiographic variables were mapped with pixel size of 72*72 square meters by using interpolation techniques (krigging, Inverse Distance Weighting) for the entire studied area. Then, the relationships between presence and absence of the species with the environmental variables were examined by GAM method. According to the results, the presence of Ferula ovina was inversely correlated with some environmental variables including soil silt and clay contents and also its distribution was directly correlated with slope, distance from sea level, organic matter content, soil saturation percentage and average annual temperature. The model evaluation conducted by the separate data gave Kappa coefficient equal to 0.64 and ROC area under curve equal to 0.86. According to the produced potential habitat map and the response curves of the species, the presence of Ferula ovina is more likely in the habitats with mean annual temperature: 9-11 degree centigrade, slop: 25-50%, elevation: 1950-3000 meter (Above sea level), CaCO3 content of soil: 10-30%, organic matter: 4-6%, silt: 10-30% and soil saturation percentage: 45-60%. The GAM enables managers to identify appropriate areas for rangelands rehabilitation and protection programs. The produced model has a suitable performance in identifying regions with high growth potential and rangelands rehabilitation and protection programs.
REZA SHAHBAZI; Sadat Feiznia; Razieh Lak; Hasan Ahmadi
Abstract
Study of surface sediments of southern Khuzestan plain in Shadegan marshes surroundings was made to understand the nature of the sediments, their classification and determining the most effective physical and chemical characteristics of sediments change. Samples were taken from 27 points inside the work ...
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Study of surface sediments of southern Khuzestan plain in Shadegan marshes surroundings was made to understand the nature of the sediments, their classification and determining the most effective physical and chemical characteristics of sediments change. Samples were taken from 27 points inside the work units. The chemical characteristics of sediment samples containing calcium carbonate, calcium sulfate, sodium chloride, sodium, magnesium, calcium, electrical conductivity, pH and sodium absorption ratio, was measured. After removal all carbonates and evaporates materials, the portion of carbonates-evaporates and terrigenous parts, was specified. Granulometry for terrigenous part was done for terrigenous materials. The new method of classification was performed for these fine sediments containing solutes, which considers the portion of the chemical and terrigenous parts, was performed. In order to specify the most effective factors and variables in the sediment variability, factor analysis and cluster analysis were used consequently. Classification results showed that the sediments are marl, with similar components with Iran tertiary marls. Two main factors, the components of the new classification and the chemical characteristics were controlled sediments variability, while the chemical characteristics had more effective roles. According to the results of cluster analysis, Sodium was the most effective variable which its value varies up to more than 20 in different work units. The results of this study show that the use of the new method of classification together with statistical analysis led to extract more details from flat and broad playa and sabkha environments.
Dariush Ghorbanian; Ehsan Zandi esfahan; Heydar Sharafieh; Alireza Eftekhari
Abstract
The use of saline and lands low-yield lands for forage production is an important step towards optimal utilization of low quality soil and water resources and supplying livestock forage as well as conservation of soil and water resources. Therefore, this research was aimed to investigate the establishment ...
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The use of saline and lands low-yield lands for forage production is an important step towards optimal utilization of low quality soil and water resources and supplying livestock forage as well as conservation of soil and water resources. Therefore, this research was aimed to investigate the establishment potential, canopy cover percentage, height growth and yield. Garmasar Desert Research Station with a soil salinity of 30-35 ds/m and Atriplex canescens, Atriplex leucoclada, Atriplex verrocifera, Aeluropus lagopoides and Aeluropus littoralis were selected and the species were cultivated in three replications. In each replication, 15 individuals of the study species were cultivated on each row. According to the results, the establishment percentage of At. ca, At. le, At. ve, Ae. la and Ae. li was recorded to be 95.5%, 95.5%, 100%, 97.7%, and 100%, respectively, indicating high establishment potential. The results of analysis of variance for annual yield showed that all the study species were able to produce forage in saline lands with a soil salinity of 35 ds/m.Among the study species, At. ca and At. le had the highest canopy cover and height. The highest forage production (more than 2 kg ha-1) was recorded for At. le, compared with other study species.Our results clearly showed that yield and canopy cover superior to other traits in showing the differences among the study species.
Esmaeil Sheidai Karkaj; isa jafari; roghayeh jahdi
Abstract
Fires are one of the most important factors affecting natural ecosystems. This study was done in order to investigate the effects of fire on soil chemical properties, soil seed bank and vegetation cover in Yeke Bermagh, Highland ranegelands in the southern part of Golestan National Park. After determination ...
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Fires are one of the most important factors affecting natural ecosystems. This study was done in order to investigate the effects of fire on soil chemical properties, soil seed bank and vegetation cover in Yeke Bermagh, Highland ranegelands in the southern part of Golestan National Park. After determination of control and burned area, sampling was done with 5 transects and 5 plots. Vegetation cover, density and production were recorded in each site. One plot was chosen for analysis of soil chemical properties and soil seed bank along transects. Sampling for seed soil bank determination was accomplished in two depths, 0-5 cm and 5-10 cm. In order to distinguish the differences between the two depths in each site, the independent t-test, and pair t-test were used. Comparison of soil properties in the two control and burned areas showed that pH, potassium, nitrogen, phosphors, carbon, EC and CEC in the burned area was more than control area. According to the results the amount of richness and diversity of seed bank in the control area was higher than the burned area. Furthermore, richness and diversity in the first depth was more than the second depth, in both areas.
Mohammad Jankju; Fariba Noedoost; Fahimeh Rafiei
Abstract
This research was conducted to compare plant functional types (PFT) and traits in an old-field (abandoned for 28 years) and a control site, in the Baharkish rangelands, Quchan, Iran. In the both sites, 40 randomized quadrates were established. Floristic list, frequency, canopy cover and 20 vegetative, ...
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This research was conducted to compare plant functional types (PFT) and traits in an old-field (abandoned for 28 years) and a control site, in the Baharkish rangelands, Quchan, Iran. In the both sites, 40 randomized quadrates were established. Floristic list, frequency, canopy cover and 20 vegetative, phenological and morphological plant traits were measured for all plant species, within each quadrate. According to the Pearson correlation analysis, and by using R software, 9 plant traits including life form, plant canopy, reproduction mode, reserve organ, root type, leaf phenology, growth form, life cycle, and regeneration mode, were known as the major plant functional traits. Data classification and ordination were applied on a matrix of 9 traits ×112 species, by using CANOCO and TWINSPAN softwares. It led to identification of 5 plant functional types. Total canopy cover of two PFT was significantly (70%) reduced and that of three PFT’s were relatively (10-20%) increased in the abandoned field. In conclusions, plants being annual, therophyte, geophytes, and rhizomatus are tolerant, whereas those being perennial (phaneropyte, chemaphyte, hemicryptophyte), having tap root system, and wide canopy cover are known as sensitive to ploughing disturbance.
esmaeil sheida karkaj; javad motamedi; fateme alilu; hamid sirusi
Abstract
Grazing management is one of the basic elements in managing rangeland ecosystems. Proper use of grazing lands in order to achieve optimal efficiency and maintain the sustainability of rangeland ecosystems is the purpose of grazing management. In order to evaluate the response of vegetation to grazing ...
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Grazing management is one of the basic elements in managing rangeland ecosystems. Proper use of grazing lands in order to achieve optimal efficiency and maintain the sustainability of rangeland ecosystems is the purpose of grazing management. In order to evaluate the response of vegetation to grazing in summer rangelands of Chahar Bagh region of Golestan province, vegetation density, vegetation cover and functional properties were measured at five different grazing sites. Thus, using the statistics method of samples and regarding the size of the dominant plants canopy, 20 plots 1*1 meter by using a systematic- random method was considered in order to do sampling in each site and the density, and vegetation cover were recorded within each plot. Finally, parameters were analyzed using Duncan test and analysis of variance and the vegetation compositions of sites were compared using cluster analysis and Jaccard's coefficient of similarity. Results showed that the grazing intensity have significant effect on the vegetation. As grazing intensity increased, the density of desirable species decreased and density of undesirable species increased. So, the enclosure site had the highest desirable species density. Moreover, some functional types such as perennials, Hemicryptophytes, Chamephytes, grasses and decreaser plants significantly reduce with increasing grazing intensity. The greatest increase belongs to grasses with density of 9.8 and class I of palatability with density of 22.8 in enclosure site. Between functional groups, grass life form had the greatest increases in enclosure site with the cover of 19.65 percent. According to results of clustering and similarity index, pen surrounding and watering sites had similar vegetation composition. Enclosure and key area also had similar composition. In general, it can be concluded that increase in grazing intensity has caused negative changes in vegetation in study sites and the changes in watering area, village vicinity and pen area clearly observed. So, using of the management methods in order to improve vegetation indices and pushing it toward balance is recommended.
sedigeh mohamadi; Ali Salajegheh; Hassan Ahmadi; Jamal Ghoddousi; Ali Kianirad
Abstract
Suspended sediment load is the biggest non-point pollution source and a major factor of degradation of surface water quality. Because of hydraulic models of sediment transport can not predict the suspended sediment load, sediment rating curves as usual hydrological methods are utilized spread for this ...
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Suspended sediment load is the biggest non-point pollution source and a major factor of degradation of surface water quality. Because of hydraulic models of sediment transport can not predict the suspended sediment load, sediment rating curves as usual hydrological methods are utilized spread for this goal. Cause of regression equations of rating curve have a lot of bias due to logarithmic convert, correction factors in optimization of sediment rating curve were used for eliminating of logarithmic conversion effect and bias of extrapolation in 20 hydrometric stations in up streams and major rivers of Sefidrood watershed. Comparing of 9 rating curve methods as one-linear, one-linear with correction factors as CF1, CF2, FAO, two-linear, mean loads within discharge classes, mean loads within discharge classes with correction factors as CF1, CF2 and FAO was conducted by RMSE and NASH criteria. Results showed that mean loads within discharge classes, mean loads within discharge classes with CF1 and CF2 correction factors have the most fitting to Sefidrood watershed stations. Our findings illustrated that CF1 and CF2 correction factors in majority of stations have compensated underestimation of rating curves and increased efficiency of models. Power of equation between sediment load and area was more than of one. According to results 30 million ton suspended sediment load enter to reservior of Sefidrood dam annually. Key words: sediment rating curve, Sefidrood, model efficiency, logarithmic conversion, NASH criteria.
Azam Tabarzadi; Meghdad Jourgholami; Alireza Moghaddam Nia; Baris Majnounian Garagiz; Pedram Attarod
Abstract
Many environmental challenges such as stormwater runoff and flood risk, chemical and particulate pollution of urban air, soil and water, the urban heat island, and summer heat waves are exacerbated in urban environments. Runoff from heavy rainfall in many parts of the world lead to erosion, sedimentation ...
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Many environmental challenges such as stormwater runoff and flood risk, chemical and particulate pollution of urban air, soil and water, the urban heat island, and summer heat waves are exacerbated in urban environments. Runoff from heavy rainfall in many parts of the world lead to erosion, sedimentation and transportation of elements that forest covers is the most important factor in controlling it. In this research, the qualitative and quantitative characteristics of runoff in Chitgar forest park have been investigated. For this purpose, runoff discharge, physicochemical parameters including total suspended solids, total dissolved solids, pH, and chemical parameters including calcium, magnesium, sodium, potassium, nitrate and phosphate were measured and analyzed during three storm events. The results of the present study indicated that the average values of the measured parameters were 1988.3 l / h, 40.64 mg/l, 2064.8 mg/l, 7.75, 2.95 mg/l, 2.23 mg/l, 584.4 mg/l, 5.71 mg/l, 1.36 mg/l, and 0.71 mg / l. Also, the correlation between parameters showed that there was a strong relationship between measured parameters, with the highest correlations between calcium with discharge (0.66) and total dissolved solids (0.69) and sodium with pH (0.7) and total dissolved solids (0.65). Comparison of the results obtained from this study and with those of other studies on water quality status of different rivers indicates that the qualitative pattern of urban runoff and also the relationships among the qualitative parameters of urban runoff are very different from surface runoff of rivers.
mansoure kargar; zahra yousefi; ALI Taheri
Abstract
According to the important role of rangeland on the exploiters of its and rangeland ecological changes in the economic and social systems, planning and decision-making to assess the current situation is the most important. In this regard, this study intends to determine the difference between experts ...
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According to the important role of rangeland on the exploiters of its and rangeland ecological changes in the economic and social systems, planning and decision-making to assess the current situation is the most important. In this regard, this study intends to determine the difference between experts and exploiters to examine and compare the affecting factors on the utilization of rangelands according to four priority measures including strengths, weaknesses, and opportunities and threats. For this purpose, the SWOT analysis was used to analyze the affecting factors on the exploitation of rangelands. Identified factors using the questionnaire set based on Likert spectrum items and AHP analysis were prioritized and compared by the pastorals and experts. The results of the comparison indicate that prioritize of the strengths, weaknesses, opportunities and threats is different between experts and stakeholders, and in some cases there is a considerable distance between experts and pastorals. The factors related to the strengths, weaknesses, opportunities and the threats had priority the adaptation of animal species and plant cover-weight with weight 0.117, weighing experienced pastorals resignation with weight 0.026, increase scientific studies on rangeland in research centers, the Department of Natural Resources with weight 0.185 and weighting fluctuations in livestock markets with weight 0.076 respectively.
Ataollah Kavian; Atta Safari; Aidin Parsakhoo
Abstract
In this study, the sediment yield of forest roads of Darabkola watershed was investigated andestimated using WARSEM and SEDMODEL. Rainfall simulator was applied to measure thesediment of abovementioned roads directly. In order to apply WARSEM and SEDMODEL models,field operations for measurement of different ...
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In this study, the sediment yield of forest roads of Darabkola watershed was investigated andestimated using WARSEM and SEDMODEL. Rainfall simulator was applied to measure thesediment of abovementioned roads directly. In order to apply WARSEM and SEDMODEL models,field operations for measurement of different parameters including road length and width, heightand coverage of road cut-slope, road longitudinal slope, shape and configuration of the road, roadsurface, and etc. were carried out in 63 different segments of the path of forest roads in the studyarea as 11979 meters long. Then sediment yield of roads was measured by rainfall simulator withnozzle of 3 meters high and plot of 2 square meters. Results of the WARSEM and SEDMODLmodels and rainfall simulation showed that sediment yield of forest roads are equal to 9.918, 5.109,and 4.141 kg/m2/year, respectively. Results also showed that there was no significant differencebetween sediment yield of rainfall simulation and SEDMODEL at significance level of %95. It wasalso revealed that SEDMODL is more suitable for estimating sediment yield of forest road withvalues of RD, MD, BIAS, RE and RMSE equal to 21.42, 4.54, 0.04, 17.59 and 0.71, respectively.
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.
Roya Vazirian; Hamid Reza Asgari; Majid Ownegh; Chooghi Bairam Komaki
Abstract
Understanding the relationship between soil and plant is essential for reclamation of degraded lands. In order to investigate the relationship between Atriplex halimus density with carbon sequestration the rangeland of Incheborun was studied. Soil samples were collected randomly by Auger in the depth ...
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Understanding the relationship between soil and plant is essential for reclamation of degraded lands. In order to investigate the relationship between Atriplex halimus density with carbon sequestration the rangeland of Incheborun was studied. Soil samples were collected randomly by Auger in the depth of 0-30 cm of the soil profile in three different plant densities (<200, 200-400 and >400 stand per hectare) with 30 replications. The data were subjected to ANOVA using statistical software SPSS 21.0. Means were separated by T-test at P≤0.5. The results of this research showed that the soil organic carbon have ranging from 0.48 to 0.64 (with an average of 0.56%) in Atriplex plantation areas, while the organic carbon have ranging from 0.03 to 0.12 (with an average of 0.078%) in the control region.Therefore, plantation measures caused significant difference in soil organic carbon contents per unit area in Atriplex plantation areas as compared to that observed in the control area. Sequestered carbon in per unit is 26.27, 27.85 and 30.66 ton/ha respectively for low, medium and high Atriplex density areas. The results indicated that the rate of organic carbon as well as soil carbon sequestration increased with plant density. There were no significant difference among sequestered carbon and soil organic carbon values under those three different levels of densities, while significant difference were observed between three plantation areas and control area.
javad zahiri; hadis shahrokhi; Ahmad Jafari
Abstract
Suspended sediment load estimation is one of the most important and complicated debates on sediment transport and river engineering. Therefore, the variety of methods developed to estimate suspended sediment load in rivers. According to the empirical nature of these methods, the results have low accuracy ...
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Suspended sediment load estimation is one of the most important and complicated debates on sediment transport and river engineering. Therefore, the variety of methods developed to estimate suspended sediment load in rivers. According to the empirical nature of these methods, the results have low accuracy and vary so widely from one method to another. Recently, with advances in computer science, various algorithms such as tree based methods have been developed. In this study, sediment rating curve method along with new algorithms such as M5 and Genetic Programing (GP) are used for estimating suspended sediment load in rivers. Flow and sediment discharge data at five hydrometric stations, Behbahan and Cham Nezam on Maroon River, Jow Kanak on Allah River and Moshrageh and Shadegan on Jarahi River are used in present study. The efficiency of tree models, in all stations, was greater than sediment rating curve method, and the RMSE performance of M5 method is 7 to 41 percent superior to sediment rating curve method. The results of this study indicate the close proximity of both M5 and GP efficiency, which according to the simple and conceptual structure of M5, this method is proposed to estimate suspended sediment load in river streams.
Meisam Alizadeh; Behrouz Malekpour; Hamid Arya; Samaneh Verdian
Abstract
In near future, earth's temperature fluctuation will be considerable. This phenomenon is the result of concentration of greenhouse gases in the earth's atmosphere. Therefore, it seems necessary to prevent of its happening. The biological methods including plant biomass and phytomass and soil are proposed ...
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In near future, earth's temperature fluctuation will be considerable. This phenomenon is the result of concentration of greenhouse gases in the earth's atmosphere. Therefore, it seems necessary to prevent of its happening. The biological methods including plant biomass and phytomass and soil are proposed as the best and practical ways. Watersheds are the greatest physical and geomorphologic units which are contain two important factors soils and plants. So that the current trend of climate change is a double challenge and threat to the sustainability of watersheds. Soil and plant carbon sequestration are economic feasibility act and adaptable to their environment which they can be provided with land management ways by kind of scientific method. Therefore by scientific method of landuse planning, this research has been carried by aims of study of kind landuse on soil carbon sequestration and determines best of landuse in Vaz watershed of Nour city. Soil sampling was carried at the selected different landuse area at two depths of 0-15 and 15-30 centimeters and after analyzing soil organic matters were calculated. Results showed that forests are rich at both depths. But on the farms and orchards, rangelands and rural areas have had least amounts of organic material. Therefore Vaz watershed has 741666 tons of reserve of carbon.
Kourosh Kamali; Gholamreza Zehtabian; TAYYEBEH MESBAHZADEH; Hosein Shahab Arkhazloo; Mahmood Arabkhedri; Alireza Moghaddam Nia
Abstract
The sustainability of soil, especially in fragile ecosystems, is an indispensable indicator of sustainable land management that depends on the physical, chemical and biological properties of the soil. In order to study the soil sustainability in Semnan desert region of farms, gardens and rangelands as ...
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The sustainability of soil, especially in fragile ecosystems, is an indispensable indicator of sustainable land management that depends on the physical, chemical and biological properties of the soil. In order to study the soil sustainability in Semnan desert region of farms, gardens and rangelands as arenas located on an educational farm with different irrigation administrations, the Sustainability Index (SI) and the Cumulative Ranting (CR9 &CR11) were used. Exploring the crust and sampling of surface and subsurface horizons of selected areas and measuring 12 important and effective characteristics of soil physical properties, the indices were calculated in each area and the effects of different types of land use on soil stability were investigated. The results showed that the SI in the surface layer of arable land due to the impact of cultivation and the positive role of organic matter was above one, and in the rest of the land was less than one which indicating the instability of the soil. According to the CR results, surface and subsurface layers of soil were not found in very stable and stable classes in the studied lands. The CR results also showed that the stability soil in the multi cultivates farm is a better condition, it may be due to its positive role in increasing soil correction factors compared to other lands. Correlation analysis of the indices showed that soil organic carbon, structural index, electrical conductivity, sodium adsorption ratio and mean weight diameter have a direct and more effective impact on soil sustainability.
mostafa nahid; mohammadreza zandmoghadam; zeynab Karkehabadi
Abstract
With rapid growth of urban construction and urbanism as well as creation and development of infrastructure, flooding in urban areas has become more controversial. Occurrence of urban flood hazards in human settlements causes irreparable damages to the citizens. Therefore, in order to decrease the psychological ...
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With rapid growth of urban construction and urbanism as well as creation and development of infrastructure, flooding in urban areas has become more controversial. Occurrence of urban flood hazards in human settlements causes irreparable damages to the citizens. Therefore, in order to decrease the psychological and social impacts of urban flooding, attention to resilience approach of urban flood is discussed. The study of literature shows that enhanced resiliency against natural disasters is affected by social, economic, physical and managerial factors. Accordingly, the main objective of this study is to investigate the mentioned structures on resiliency of Tehran metropolitan area against urban flood. The methodology of this study is practical and in terms of survey and descriptive - analytical. The results of the study showed that in terms of socio - cultural index, the most favorable areas were identified. In terms of economic index, according to the components of the relevant component, the study area is the most desirable areas in terms of economic resilience. Also, managerial - institutional resiliency has been the most suitable areas in terms of managerial - institutional resiliency. In the physical resilience, according to the structure of the region and using wlc and ahp methods, it was found that the strengths and weaknesses of the region have a good physical resilience.
Mohammad Nohtani; Sadat Feiznia; Hasan Ahmadi; Hamidreza Peirovan
Abstract
Loess Deposit is one of the most important Quaternary Deposits of northeastern parts of Iran which have high erosion rate. This study was performed with field- Rainfall- Simulator which has a plot area of 1 m2 in Gorganrood Drainage Basin to determine the effective factors on sediment yield. Landuse, ...
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Loess Deposit is one of the most important Quaternary Deposits of northeastern parts of Iran which have high erosion rate. This study was performed with field- Rainfall- Simulator which has a plot area of 1 m2 in Gorganrood Drainage Basin to determine the effective factors on sediment yield. Landuse, slope and erosion feature maps were overlaid in GIS to obtain land unit map. Then on work units, rainfall simulator analyses were performed. The produced runoff and sediment in 69 points on work units were collected and were measured. Adjacent to each rainfall simulator plot, samples of surface material were collected in the field to analyze for physical and chemical characteristics. In the field, descriptive tables were prepared for different work units in which locality, slope percentage, elevation, depth of A horizon of the soil and other necessary informations were recorded. In order to determine logical relationship between different variables, regression and correlation analyses were performed. In statistical analyses, it was found that slope percentage has the highest correlation coefficient and has the highest direct relationship with sediment yield and sediment production and silt amount is the second factor. The investigation of multiple regression analyses generated a model which shows %80 of sediment production variations. In this model slope percentage, cation exchange capacity and silt have possitive relationship and Calcium cation has negetive relationship with sediment yield.
Abbas Alipour; Jaber Rahimi; Ali Azarnivand
Abstract
Groundwater resources play central role in meeting domestic and agricultural demands of residents in arid regions. Owing to rapid urbanization, water use and land use has changed considerably. Overexploitation of wells posed a huge burden on available water resources. Degradation of water resources along ...
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Groundwater resources play central role in meeting domestic and agricultural demands of residents in arid regions. Owing to rapid urbanization, water use and land use has changed considerably. Overexploitation of wells posed a huge burden on available water resources. Degradation of water resources along with an increase of salinity has adversely affected water resources. Hence, current paper focuses on determination of water quality of the wells of nine provinces of Iran which are influenced by water shortage. In this regard, WQI is a suitable index for analyisis and classification of data. To provide a holistic influence from individual water quality parameters on total water quality, water quality index (WQI) is employed. In other words, WQI is average weight of multiple parameters. Apart from WQI which has been used for drinking purposes, Wilcox has been used for agricultural water quality analysis. After identification of water quality conditions, sustainable settlement of population should be considered. Environmental planning and management, policy making, obtaining conclusive strategies and land use planning should be taken into account after providing water quality maps. Generation of water quality maps is an effective step for optimal operation of groundwater resources as well as for decision making. In present study, most of aquifers have been identified of low water quality (WQI=200-300).
saeedmohammad sabouri; hossein hajialibegi; morteza talebian; morteza fattahi
Abstract
Tectonic activities by the occurrence of earthquakes and the creation of driving force, tectonic uplifts, fissures and fractures caused by faults, creating and seam and cracks in rocks and accelerating the process of mechanical and chemical weathering, creating fault gouges and fault shear as the materials ...
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Tectonic activities by the occurrence of earthquakes and the creation of driving force, tectonic uplifts, fissures and fractures caused by faults, creating and seam and cracks in rocks and accelerating the process of mechanical and chemical weathering, creating fault gouges and fault shear as the materials prone to landslides, increasing the penetration of rocks, changes in the direction and slope of geological layers, etc. cause landslides. The study area is located in the structural zone of Central Alborz and Central Iran between the coordinates of 49.22 to 51.15 east longitude and 35.81 and 36.9 north latitude. In this study, after library surveys and field observations, the location of 280 landslides with fault zones of faults in the region was compared with the relevant software and it was found that 34% of the total landslides identified in Fault zone. Due to the 5% area of fault zones, the high percentage of landslide occurrence indicates the relationship between tectonic activity and landslide occurrence. Therefore, it can be said that tectonic activities have caused landslides in the study area and due to the large number of landslides in the study area, the area can be assessed tectonically with high activity. Vulnerability of residential areas is also high in areas near active and Quaternary faults, because in addition to seismic waves and surface rupture during an earthquake, they threat by another hazard called landslides.
