maryam etehadi abari; a a; a a; meghdad jur gholami
Abstract
Land cover is also important factor for protecting the soil against erosion. A fully forested watershed experiences relatively little surface erosion, but timber harvest alters the canopy cover, exposing the soil to water and wind. Forests provide the maximum amount of soil protection. Reduction of vegetative ...
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Land cover is also important factor for protecting the soil against erosion. A fully forested watershed experiences relatively little surface erosion, but timber harvest alters the canopy cover, exposing the soil to water and wind. Forests provide the maximum amount of soil protection. Reduction of vegetative cover by forest harvesting generally increases the average surface runoff volume and sediment While, the hydrologic response of forest harvesting has been rarely considered. Towards this attempt, the present study has been conducted to investigate the effect of vegetation cover on hydrological components in plot scale (2m*1m) with four replicates in tow slope scale (0-20%, 20-40%) in Kheyrud Forest of Iran during December 2014 until December 2015. The rain depth was measured by using a rain gauge installed in the study area. The runoff volume and sediment yield were also measured through field data collection and lab analyses by weighting and decantation methods. The results of the study showed significant effects of vegetation cover (P ≤0.01) on runoff volume and sediment yield. Natural forest without harvesting, forest with selective harvesting treatments exhibited the lowest amounts of runoff and sediments, with averages of 372.31, 878.96 cc, and 0.08, 0.17 gr m-2 respectively, in comparison to other treatments. Linear regression among mentioned parameters (precipitation, runoff, and sediment) were determined. The results show that there were significant correlation and linear regression among precipitation, runoff and sediment.
Fazel Amiri; Hossein Arzani
Abstract
Range inventory is the recognition and evaluation of potential and actual production in order of optimal utilization of this valuable natural resource. Determination of range suitability for medical and industrial plants, considering sustainable utilization and creating models for medical and industrial ...
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Range inventory is the recognition and evaluation of potential and actual production in order of optimal utilization of this valuable natural resource. Determination of range suitability for medical and industrial plants, considering sustainable utilization and creating models for medical and industrial plants use in Ghareh Aghach of Semirom watershed by FAO (1991) and GIS, was the main objective of this research. Determination of range suitability for medical and industrial plants use, in Ghareh Aghach of Semirom watershed based on a method suggested by FAO and GIS was the main objective of this research. Two criteria’s of vegetation cover and accessibility to water resources were integrated to determine suitability model of medical and industrial plants on rangeland. In vegetation cover criteria, the samples were randomly collected along 3 two hundred meter transects in each vegetation type. Vegetation cover percentage, composition, abundance, and the presence or absence, diversity, production, application and consumption of medicinal plants and industrial were measured using 1m2 quadrates. Accessibility to road and slope determine and by integrating these two criteria, suitability maps based on FAO method were prepared. The results showed that from 7158.69 hectares of study rangelands, 3.69% ha (0.05%), 1761.1 ha (24.6%), 3217.7 ha (44.95%) and 2176.17 ha (30.4%) of the area were classified to S1, S2, S3 and N suitability classes for medical and industrial plant utilization.
Soheila Pouyan; Mohammad Zare; Mohammad Reza Ekhtesasi
Abstract
Dust event is one of the common and destructive phenomenon in arid and desert regions. This phenomenon has negative impacts on human life and environment. Dust storms, in addition to soil loss, can cause and aggravate health problems, food production reduction, economical damages into the industrial, ...
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Dust event is one of the common and destructive phenomenon in arid and desert regions. This phenomenon has negative impacts on human life and environment. Dust storms, in addition to soil loss, can cause and aggravate health problems, food production reduction, economical damages into the industrial, agricultural and communication sections. Therefore, accurate investigative of this phenomenon is necessary. The aim of this research was regional analysis of dust storm index (DSI) in 44 meteorological stations of Iran. At first stage, the dust storm index for each station was calculated using hourly dust data. Next, monthly averages of dust storm index (DSI) were used for regional analysis using linear moments approach. Based on regional analysis, the study area is divided to six homogeneous dust storm index regions. Pearson Type III (PE3) and Generalized Logistic (GLO) distribution models were the best regional distribution models for 1, 4, 5, 6 homogeneous regions, and 2, 3 homogeneous regions, respectively. Estimation of the dust storm index and its regional analysis can be used in many environmental studies, decision making and management processes in relation to combating desertification and dust storms.
Bahareh Jebalbarezi; Gholamreza Zehtabian; ِAli Tavili; Hassan Khosravi
Abstract
Investigation of the effect of plant community on limited water resources of deserts is an important issue in water resources management. Different species of Haloxylon are compatible with desert condition and can use groundwater resources due to deep roots and proper structural condition. The purpose ...
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Investigation of the effect of plant community on limited water resources of deserts is an important issue in water resources management. Different species of Haloxylon are compatible with desert condition and can use groundwater resources due to deep roots and proper structural condition. The purpose of this study was investigation of the effect of Haloxylon planted forests on groundwater resources in Jafarieh plain. For doing the study, at first the number of Haloxylon plants was determined in these forests using satellite images and JMicroVision software. Then using minimum water requirement of each plant, estimated with lysimeter, the number of surplus plants was determined based on their water requirement and rainfall of the region. Then groundwater level status was determined using GMS 8.3 software and MODFLOW model. The results showed that the number of Haloxylon plants in the study area was equal to 3746291 and the amount of groundwater evacuation by these plants was equal to 56.194 Mm3. The reduction of groundwater table was about 0.46 meter in the first study period (1992-2001) and 0.93 meter in the second study period (2002-2012) so that the reduction of groundwater level in the second study period was about 2 times bigger than the first study. This results showed that severe reduction of groundwater table has happened in recent decade because of planting Haloxylon. However the positive effects of these forests on reducing damages of dust storms should not be ignored.
alam cheraghian; Somayyeh Dehdari; mohammad faraji; Ali Ariapour
Abstract
The present study investigates the effect of restoration actions on Mesquite tree planting, the construction Furrow Contour actions and Eucalyptus tree planting on physical and chemical properties of soil in a Chahshirin in 75 km of Behbahan city. In this study, along with each treatment, a non-operational ...
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The present study investigates the effect of restoration actions on Mesquite tree planting, the construction Furrow Contour actions and Eucalyptus tree planting on physical and chemical properties of soil in a Chahshirin in 75 km of Behbahan city. In this study, along with each treatment, a non-operational correction treatment was selected as a control, two of which were adjacent to each other. Systematic random sampling was carried out during 3 transects of 100 meters in two depths of 30-0 and 60-30 cm soil in each site of correction and control. Soil samples were transferred to the laboratory and nitrogen, phosphorus, potassium, organic matter, organic carbon, lime, clay, silt, sand, electrical conductivity and acidity factors were measured. The results of the independent t-test showed that the factors studied had a significant difference at the level of 1% and 5% compared to the control area. Also, the results of analysis of variance ANOVA between correction treatments in the first and second depths for phosphorus, potassium, organic matter, carbon, lime and Ec showed a significant difference at 1% level. Also, for nitrogen at the first depth and the amount of silt and sand in the second depth, a significant difference was observed at 1% level. In other words, it was observed that the three restoration actions carried out had positive effects on the soil properties; the planting of the tree and the construction of the Farrow Contour had better conditions than the Eucalyptus tree plant site.
Amin Zarratipour; marjan firoozinejad; Khalil Delfan Hasanzadeh
Abstract
Abstract The phenomenon of climate change and global warming and its impact on different ecosystems Needed extensive studies. For this purpose, was done Study of the efficiency of thermal bands and land use changes in determining the surface temperature index using a separate window algorithm in the ...
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Abstract The phenomenon of climate change and global warming and its impact on different ecosystems Needed extensive studies. For this purpose, was done Study of the efficiency of thermal bands and land use changes in determining the surface temperature index using a separate window algorithm in the Bandar-e Emam Khomeyni of Khuzestan province by Landsat 8 satellite imagery. Based on this, was used vegetation index (NDVI) for band ratio between the red and near infrared bands to prepare the LST map and were used four seasonal images in 2016-2017 years. The results of the comparison of the two thermal bands showed that the thermal bond 11 is higher accuracy than the thermal bond 10 (RMSE = 3.6 for the band 11 and RMSE = 4.4 for the band 10) because the wavelength of it is higher. Also, the estimation of the comparison of satellite imagery data with ground truth showed a high accuracy (R2 =0.9). Comparing the temperature of the users was determined that the industrial and urban areas more effective on increasing LST than the vegetation and water areas. Base on bands ratio between near and red infrared bands showed that the vegetation index decreased with increasing temperature. So, the lowest amount of vegetation was estimated in August (-0.42) and the highest was in October (0.35).
Behzad Rayegani; Susan Barati Ghahfarokhi; Ahmad Khoshnava
Abstract
The aim of this study is to develop a comprehensive approach to identifying dust & sand sources and to investigate their changes over a set period of time using remotely sensed data. For this purpose, data OLI data of Landsat 8 during the years 2013 through 2015 were used to make maps of vegetation ...
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The aim of this study is to develop a comprehensive approach to identifying dust & sand sources and to investigate their changes over a set period of time using remotely sensed data. For this purpose, data OLI data of Landsat 8 during the years 2013 through 2015 were used to make maps of vegetation cover, soil moisture and land cover sensibility to wind erosion. These maps were combined with geology and roughness by multi-criteria evaluation method to obtain a map of sand & dust source potential areas. In the second step, information of synoptic stations, meteorological and air pollution measurements was prepared, and using statistical analysis and with the help of Modis data, the history of local events was obtained. These regions were integrated with the map of sand & dust source potential areas using the MCE method (WLC) and based on a stratified random sampling plan, susceptible sites of sand & dust sources were identified. In order to validate the identified areas and investigate the trend of their changes, the time series of satellite data and weather stations data were used and the trend of vegetation, soil moisture and surface temperature at the location of identified areas during a 15-year period were monitored. Validation results show high accuracy of identified areas and significant reduction trend of vegetation, soil moisture and surface temperature in the locations of identified sites during the study period
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.
Khosro Shahbazi; Ali Salagegheh; Mohammad Jaafari; Mohammad Khosroshahi
Abstract
Gully erosion affects land degradation, particularly in the semiarid reigns. Topographic thresholds are strongly affected by landuse change and destroy of vegetation. The objective of this study was to evaluate topographic thresholds of gully erosion in different landuse including agriculture (AG), fair ...
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Gully erosion affects land degradation, particularly in the semiarid reigns. Topographic thresholds are strongly affected by landuse change and destroy of vegetation. The objective of this study was to evaluate topographic thresholds of gully erosion in different landuse including agriculture (AG), fair rangeland (FR) and weak rangeland (WR) which carried out in Ghasreshirin, Kermanshah, Iran. The topographical parameters were measured in the field and relationship between gully catchment area and slope was analyzed for each landuse. The results revealed that some main topographic characteristics mainly cross-section, width, depth and gully branches length in the FR was significantly lower than in the AG and WR (p<0.05). Furthermore, analysis of gully threshold based on catchment area-slope showed that the critical area for gully formation in AG, FR and WR was 1300, 1689 and 1233 m2, respectively which was significantly lower in FR reducing by vegetation cover. The respective slope threshed was 1, 3 and 3 percent in AG, FR and WR. However, the affected area by gully erosion in AG, FR and WR was 12.4, 14.1 and 21%, respectively. The gully in the agricultural land was more dipper compared with other land uses. The volume of gully channels in FR was 3.4 and 2.2 times less than AG and WR, respectively. It is concluded that rangeland degradation and thereby removing vegetation attribute to severe gully erosion and consequently environmental problems such as soil carbon dioxide emission.
Maryam Saffariha; Hossein Azarnivand; Mohammad Ali Zare Chahouki; ِAli Tavili; Samad Nejad Ebrahimi; Daniel Potter
Abstract
Salvia limbata is an herbaceous plant which belongs to Lamiaceae family and is native to Iran. In this study, essential oils and variety of chemical compounds of Salvia limbata in flowering stage in different altitudes in July were studied. In order to study the active ingredients of plant in studied ...
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Salvia limbata is an herbaceous plant which belongs to Lamiaceae family and is native to Iran. In this study, essential oils and variety of chemical compounds of Salvia limbata in flowering stage in different altitudes in July were studied. In order to study the active ingredients of plant in studied sites in flowering stage nine plant samples were examined for phytochemical analysis. Identification of the basic constituents (quantity and quality) with GC / MS and GC-FID (gas chromatography coupled to mass spectrometer) has been done. The yield of essential oils in flowering stage in Paeein Taleghan 0.34% in Mian Taleghan 0.34% and in Bala Taleghan is 0.46%. According to the results, difference in altitudes in three habitats shows a significant difference among the percentages of the obtained compounds. The most important constituents of essential oil include α-Pinene, β-Pinene, allo-aromadendrene and Spathulonol. Also, Salvia is reported as one of the sources for the extraction of α -pinene.
Delaram ziaei jazzi; rafat zare bidaki
Abstract
Soil erosion along environmental problems. The consequences of soil erosion can be examined from a variety of perspectives.the cost of soil erosion is divided into two categories of on-site and off-site costs. Soil erosion affects the production cycle and economics directly and indirectly. The purpose ...
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Soil erosion along environmental problems. The consequences of soil erosion can be examined from a variety of perspectives.the cost of soil erosion is divided into two categories of on-site and off-site costs. Soil erosion affects the production cycle and economics directly and indirectly. The purpose of this study was to estimate and compare direct and indirect economic losses of soil erosion in different land uses in the Beheshtabad Basin.To achive this, first sediment production by each landuse was initially determined by using SWAT model. NS and R² model coefficients for calibration were 0.72,0.73, and 0.66,0.71 for validation. Then direct loss of erosion was calculated based on the method of replacing the main soil organic fertilizer (NPK) by chemical fertilizers and indirect loss of erosion based on the loss caused by sedimentation behind the check dams inside the basin and reservoir dams outside the basin. According to the results, the highest amount of economic loss of soil erosion was related to rainfed farms equivalent to 56 million Rials per hectare Due to the fact that these lands are located on high slopes and also incorrect agricultural operations .The least amount was related to gardens,equal to 4.5 million-rials/hectare that indicated the importance of trees crown covering and observing the proper slope in the construction of gardens in the soil conservation. In this basin,excess grazing and improper utilization of rangelands have led to high erosion rate and sediment production in upstream rangelands and 3.33 million-Rials/hectare economic losses of erosion in this land use.
zahra Abdolalizadeh; Ardavan Ghorbani; Raoof Mostafazadeh; Mehdi Moameri
Abstract
The purpose of this research is to facilitate the quantitative evaluation of various ecological factors in determining the rangeland condition by four-factors method and six-factors method using mainly structural variables of vegetation. In this study, the condition of 28 sites located in the northern ...
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The purpose of this research is to facilitate the quantitative evaluation of various ecological factors in determining the rangeland condition by four-factors method and six-factors method using mainly structural variables of vegetation. In this study, the condition of 28 sites located in the northern part of Ardebil province was determined by 4 and 6 factors methods, separately for grassland and shrubland habitats, and some parameters of vegetation were quantitatively measured. The results of condition determination were compared in the two mentioned methods. Finally, using Pearson correlation test, the relationship between variables of vegetation and the scores of rangeland condition were compared and regression relations were extracted. The results indicated that the average score of the rangeland condition in the modified four-factors in both grasslands and shrublands (69 and 60 scores, respectively) was higher than the six-factors method (64 and 54 respectively), and paired t-test comparison showed a significant difference (P≤ 0.05) between the two methods. Also, the results showed that variables such as canopy cover of decreasing specious canopy cover, forbs canopy cover, annual forbs canopy cover and production had the most significant positive relationship (P≤ 0.05), and the variables of invaders and pebble-gravel cover had the highest negative correlation (P≤ 0.05) with rangeland condition. The results of extraction of multivariate linear regression models by step-by-step method showed strong relationship (R2=68.46-88.41) between evaluated variables with condition score. Also, validation analysis of the models indicated the ability of both methods to predict the rangeland condition score.
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.
Seid Saeid Ghiasi; Sadat Feiznia; Alireza moghadam nia; Ali Najafinejad; Somayye Najirad
Abstract
Landslide susceptibility assessment is a primary tool for understanding the basic characteristics of slopes that are prone to landslides. In this study, a landslide susceptibility assessment was accomplished, by adopting the Statistical Index Method (SIM) and the Analytic Hierarchy Process (AHP). Ten ...
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Landslide susceptibility assessment is a primary tool for understanding the basic characteristics of slopes that are prone to landslides. In this study, a landslide susceptibility assessment was accomplished, by adopting the Statistical Index Method (SIM) and the Analytic Hierarchy Process (AHP). Ten landslide causing factors were considered including: elevation, slope, aspect, lithology, land use, drainage density, plan curvature, precipitation, geomorphologic faces, and rock unit’s sensitivity to erosion. The SIM was used to determine the weighted value (Si) for classes of every landslide causing factor, the AHP was utilized to determine the weighted value (Wi) for every factor. The summation of the product of Si by Wi represent the landslide Susceptibility Index (LSI) value for every pixels. Based on the derived LSI, landslide susceptibility map (LSM) was produced then the study area was grouped into five susceptibility classes. The densities of landslide for five susceptibility classes implying there is a satisfactory agreement between the susceptibility map and the actual landslide data. In the following, the results of the LSM were quantitatively validated using observed landslide dataset and the receiver operating characteristic (ROC) method. The validation results showed that the AUC for prediction rate of model was 95.2%. The landslide susceptibility showed the areas with lithology of old terraces, young terraces, lahar, and porphyritic trachyandesite-trachyte with different degrees of sensitivity to erosion which distribute between 10–40% slope and more than 60% are very prone to slope failure. Therefore, SIM and AHP were found to be effective models for landslide susceptibility mapping.
Mehdi Ghorbani; Jamileh Salimi Kouchi; Payam Ebrahimi; Sareh Rasekhi
Abstract
Today the concept of participatory management is a functional and modern approach in the management of natural areas. This approach is a comprehensive approach to personal and group stakeholder participation to achieve sustainable management and empowerment of local communities. Therefore, identifying ...
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Today the concept of participatory management is a functional and modern approach in the management of natural areas. This approach is a comprehensive approach to personal and group stakeholder participation to achieve sustainable management and empowerment of local communities. Therefore, identifying and realizing the most influential actors in local decisions is important step. The aim of this study was to determine social powers and key stakeholders in the period before and after running a local community project in network of local stakeholders. This study have been carried out through questionnaires and direct interviews with members of split Rural Development Committee, in the Sarayan watershed in South Khorasan province is covered by RFLDL international projects. For this purpose, ties of trust and partnership with local stakeholder network using quantitative indicators were analyzed at the micro level. This article analyzes the position of the local development groups and determines the key actors in terms of authority, influence and intermediation before and after the empowerment project. The results show that the centralisation before and after the run is reduced. It is claim that this project reduces centralization in network structure and strengthens trust and participation between stakeholder that has an important role in establishment of natural resourses participatory management and rural development.
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.
Somayeh Movahedi; aboalhasan fathabadi; null null; Ali Heshmatpour
Abstract
In this study using Frequency Ratio (FR), Statistical Index (SI), Weights Of Evidence(WOF), Logistic Regression (LR), Random Forest (RF) models the probability of gully formation was calculated in Aytamar watershed and susceptibility maps was prepared. First the thematic maps of 13 gully conditioning ...
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In this study using Frequency Ratio (FR), Statistical Index (SI), Weights Of Evidence(WOF), Logistic Regression (LR), Random Forest (RF) models the probability of gully formation was calculated in Aytamar watershed and susceptibility maps was prepared. First the thematic maps of 13 gully conditioning factors including lithological formations, distance to faults, faults density, altitude, slope-length, slope angle, slope aspect, plan curvature, profile curvature, distance to roads, land use, distance to rivers, stream power index and topographic wetness index was prepared. Then landslide inventory map was combined with each gully conditioning factor and all models weights and parameters were calculated. Area under curve for test data was calculated as 0.74, 0.78, 0.75, 0.86 and 0.96 for Frequency Ratio (FR), Statistical Index (SI), Weights Of Evidence(WOF), Logistic Regression (LR), Random Forest (RF) models, respectively. Random forest, Frequency Ratio and Logistic Regression have the least the area of high susceptibility zone, respectively. With respect three validation criteria multivariate methods including Random Forest and Logistic Regression had the best performance among all models.
Sina NabiZadeh; Ataollah Ebrahimi; Masoumeh Aghababaei; Iraj Rahimi
Abstract
The land use of the watersheds is one of the most affected and highly vulnerable due to developmental process which effect on the other variables such as the hydrological function. The purpose of this research is to monitor land use changes in the past and to investigate predictability of its future ...
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The land use of the watersheds is one of the most affected and highly vulnerable due to developmental process which effect on the other variables such as the hydrological function. The purpose of this research is to monitor land use changes in the past and to investigate predictability of its future using Land Change Modeler (LCM) in the watershed of Farsan County of Chaharmahal-va-Bakhtiari province. For this purpose, the Landsat-5 TM images of 1986 and 2009 as well as the Landsat-8 OLI images of 2017 were analyzed. Land covers including residential areas, agricultural land, dryland farming, rangelands, rocks, water bodies, bare-land and snow were classified for the three periods. The prediction of land cover of 2017 was done using the LCM model based on Artificial Neural Network and Markov chain analysis after assessing model’s accuracy based on Kappa index. The land cover of 2027 was also predicted using a change probability table extracted from occurred changes from 1986-2017. The results show that the rangeland decreased by 4379-ha in the years 1986 to 2017, but the agricultural land increased by 1922-ha. This study proved that the LCM could accurately forecast future changes (85% overall accuracy). An increase of 149-ha of residential area and 100-ha decrease of rangelands in the study area was predicted for 2027. Therefore, while emphasizing the conservation of rangelands, it is necessary to study and use this technique to predict changes, its causes, as well as the consequences of land use changes at the broader scales.
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.
Hossein Norouzi; Asghar Asghari Moghaddam
Abstract
the existence of about 6,000 wells in the plain and the extraction of groundwater resources has led to a sharp decrease in the water table and consequently, an increase in the salinity of the aquifer. For this purpose, 27 samples of Malekan water resources were collected and hydrochemical properties ...
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the existence of about 6,000 wells in the plain and the extraction of groundwater resources has led to a sharp decrease in the water table and consequently, an increase in the salinity of the aquifer. For this purpose, 27 samples of Malekan water resources were collected and hydrochemical properties were analyzed. The results of the analysis were compared with the lake water sample with respect to the hydrochemical characteristics of the main elements. Salinity increasing and saltwater intrusion into the aquifer was investigated using geophysical methods, geochemical diagrams, as well as various ion ratios. The results showed that salinity increases in the aquifers around Urmia Lake is related to the low slope at the end of the plains and its ultra-fine grain sediments, which, as a result, when groundwater flow collide with such sediments, their movement slow down and water raised to the surface via capillary action. Finally shallow groundwater cause to intense evaporation and increasing groundwater salinity. Moreover, In addition, the distribution of surface currents in the ends of the plain leads to evaporation and the formation of salt crops, and high exploitation leads to the gradual flow of water to upstream of the aquifer. The presence of the salty sludge from ancient lakes beneath the alluvial and salts formations with high exploitation and decreasing of groundwater levels leads to upconing in the lower layers of clay formations and reaching the saltwater to the wells.
