Mohammad Javad Amiri; Hamid Jourkesh; Ahmad Nohegar
Abstract
Introduction: Flood is caused by a sudden increase in the water level of a river due to heavy rainfall, in which excess water flows out of the basin and the riverbed and enters adjacent areas, causing extensive damage to the region's ecosystems and infrastructure. In order to determine and implement ...
Read More
Introduction: Flood is caused by a sudden increase in the water level of a river due to heavy rainfall, in which excess water flows out of the basin and the riverbed and enters adjacent areas, causing extensive damage to the region's ecosystems and infrastructure. In order to determine and implement a strategic plan in the direction of crisis management, understanding the mechanism and development of the flood phenomenon and the amount of runoff created as a result is a priority.Material and methods: In this study, three events of flood on 16 February 2017, 26 March, 2019 and 23 January 2020, when the average rainfall in the Shiraz watershed was 100 mm every three days, were selected and interacted with a synoptic approach. Atmospheric conditions and flood patterns were identified. Next, using by HEC-HMS hydrological model, the amount of rainfall to runoff conversion in each of the sub-basins in the Shiraz watershed was simulated.Results and discussion: The results showed that the maximum precipitation occurs in February and the minimum in July. The maximum annual rainfall is 627 mm in the mountainous areas of Qalat and Golestan and the minimum is 245 mm in Maharloo lake. Synoptic results showed that the establishment of low altitude and cold-water trough at the level of 500 hPa in the eastern Mediterranean along with the establishment of dynamic low pressure system in Iran caused surface air instability in Fars province and by injecting moisture from the Persian Gulf to the massif. The weather has caused floods in Shiraz. The results of rainfall-runoff modeling showed that the highest runoff in Sadra and Qalat sub-basins were 5773 and 5076 thousand m3, respectively, and the maximum peak discharge in Sadra and Qalat was 666 and 389 m3/sec, respectively. It happened at 17:00. The highest volume of rainfall penetration in Qalat and Chenar Rahdar was 5423 and 2546 thousand cubic meters, respectively, and the lowest level of penetration in the Quran Gate was 247 thousand m3, the main reason being the high density of residential-commercial use in this sub-basin.Conclusion: Therefore, it is suggested that in order to manage the flood crisis in Shiraz, controlling runoff produced in northern sub-basins such as Qalat, Golestan and Sadra and increasing the level of permeability can be effective in controlling floods.
samaneh habibi; Mahmoud Behrouzi; ahmad Nohegar
Abstract
Introduction: Emissions of particulate matter from car exhaust, tire wear, engine lubricants and street fence wear contain heavy metals which is dangerous for urban ecosystem; However, most of the particles are deposited on the canopy and soil of plant which absorbed by the plant. Pollution-resistant ...
Read More
Introduction: Emissions of particulate matter from car exhaust, tire wear, engine lubricants and street fence wear contain heavy metals which is dangerous for urban ecosystem; However, most of the particles are deposited on the canopy and soil of plant which absorbed by the plant. Pollution-resistant species with high capacity to absorb suspended particles can be used to remove suspended particles from the urban environment. For this reason, in this study, concentrations of heavy metals in leaves and soil of tree species in Bandar Abbas were measured and evaluated. Also the species with the highest potential for adsorption of heavy metals were identified.Materials and methods: In order to achieve the research approach, at first three tree species including: Azadirachta indica, Conocarpus and Prosopis juliflora were selected as the dominant plants in Bandar Abbas and in 30 points of the fields with 5 points of non-polluted environment outside the city (control), and sampled from the surface soil and leaves of these species, and after preparing and digesting the samples, the concentration of heavy metals (cadmium, manganese, zinc and lead) emitted from urban traffic, were measured using atomic absorption spectrometry in soil and tree leaf samples. Next, the difference in heavy metal concentrations between tree species was analyzed by ANOVA and between soil and leaves and between urban and control environments was analyzed by t-student test. Then, to determine the tree species with high accumulation of heavy metals, two indices of heavy metal accumulation (BCF) and bioaccumulation index (MAI) were used.Results and discussion: The results showed that the pattern of heavy metals in soil and leaves of tree species was Mn> Zn> Pb> Cd. The maximum concentrations of heavy metals in the soil and leaves were Conocarpus, Azadirachta indica and Prosopis juliflora, respectively. Spatially, the highest concentration of heavy metals in the sampling points was related to Imam Hossein street, which has an east-west extension and passes through the north of Bandar Abbas and the north-south streets of the city are connected to it; However, the minimum concentration of heavy metals was observed in the Persian Gulf streets. The concentrations of Mn and Pb in the soil of plant species were different and their differences were significant at 95% level, but concentration of Cd and Zn wasn't different in the soil of tree species. in Pb, Mn and Zn concentrations weren't differences in the shoots of the studied tree species and their differences were not significant at 95% level; However, the concentration of Cd in the shoots of the species was different and the difference between the species was significant at 95% level. There was a significantly difference in the concentration of heavy metals between soil and leaves at 95 and 99%; Also, the concentration of heavy metals in soil and leaves between urban and control field was significantly different at 95%. The pattern of BCF index in all species was Zn> Pb> Mn> Cd and heavy metals had moderate accumulation for tree species. Bioaccumulation index (MAI) showed that Conocarpus has the highest adsorption potential of heavy metals and the lowest adsorption potential was observed in Prosopis juliflora. In the spatial distribution of this index, Imam Hossein street and the streets that originate from it, have the highest index of bioaccumulation of heavy metals.Conclusion: Conocarpus, by absorbing pollutants from urban traffic, purifies the polluted air of Bandar Abbas; but Prosopis juliflora, which is one of the migratory trees in the city of Bandar Abbas, with strong and deep roots, dries up the surface and groundwater of the region. On the other hand, its potential to absorb urban air pollutants is very weak. Therefore, Conocarpus despite their resistance to drought and heat, have a high potential in purifying urban pollution, can replace Prosopis juliflora.
Atousa Soleimani; Ahmad Nohegar
Abstract
Introduction: Place attachment is an emotional connection to a specific location or perspective where usually includes physical and social elements (Devine-Wright, 2013). From Hummon's point of view, the community attachment is defined as an emotional investment in one place (Buta et al., 2014). Today, ...
Read More
Introduction: Place attachment is an emotional connection to a specific location or perspective where usually includes physical and social elements (Devine-Wright, 2013). From Hummon's point of view, the community attachment is defined as an emotional investment in one place (Buta et al., 2014). Today, environmental concepts deeply have social implications, and a large part of the people’s environmental beliefs and behaviors changes under the influence of cultural and social systems (Kalantari et al., 2016). The purpose of this study was to investigate the relationship between community attachment and environmental behaviors considering the role of mediating attachment of the place among residents of Tajrish neighbourhood located in the district One of Tehran. Material and methods: The present research was a descriptive, analytical-correlational survey. A sample of 284 was selected from inhabitants of Tajrish neighbourhood based on random sampling method. The participants were asked to fill out the research questionnaire whose reliability and validity were confirmed. The obtained data were statistically analyzed using the correlation analysis and structural equation modeling in SPSS-21 and AMOS-21. Results and discussion: The results of standard coefficients obtained from structural equation modeling showed that community attachment can directly and positively predict place attachment (p < 0.01, β=0.65) and place attachment also can directly and positively predict pro-environmental civic participation (p < 0.01, β=0.48). Finally, the study findings revealed that community attachment affects pro-environmental civic participation both directly (p < 0.01, β=0.41) and indirectly, through the mediating role of place attachment, (p < 0.01, β=0.31). In order to assess the fitness of the model, in this research, fit indices from eight main indicators were utilized. In this study, the relative Chi-square, (CMIN/Df) was estimated at 1.375, indicating the acceptable condition of the model. The Root Mean Square Error of Approximation (RMSEA) of 0.036 also demonstrated the validity of the model developed in this study. The GFI and AGFI indices, absolute fit indices, should be in the range of zero to one, and values greater than 0.9 for the GFI index and 0.85 for the AGFI index indicate the optimal fit of the model. In the model measured in the present study, the value of 0.990 for the GFI index and 0.965 for the AGFI index showed a highly favorable fit of the model. For the Increasing Fitting Index (IFI), the Tucker-Lewis Index (TLI), and the Comparative Fit Index (CFI), values greater than 0.9 represent the ideal fit of the model. IFI, TLI, and CFI were, respectively, 0.996, 0.990, and 0.996 in this study. The (Bentler-Bonett) Normed Fit Index (NFI) is based on the correlation between the present variables in the model in a way that the coefficients of correlation between them would lead to high values of the adaptive fit index. The acceptable value of this index should be greater than 0.9 which was obtained in the present study and is an indication of the confirmation of the research model. Conclusions: The present study demonstrated that community attachment has a direct and significant effect on the place attachment and the environmental behavior. On the other hand, community attachment indirectly affects the creation of environmental behaviors in citizens through involving the sense of attachment to the .place; hence, place attachment is considered as an intermediary factor in creating environmentalist behaviors
Mohammad Mahdi Hosseinzadeh; Ahmad Nohegar
Volume 9, Issue 1 , October 2011
Abstract
Extraction of water from underground sources is on the increase, especially from basins stored by non-strengthened alluvium, sediments and from shallow areas of the sea. This results in sinking on the surface and leads to ground subsidence. In recent years, the Minab Plain, like many areas of Iran has ...
Read More
Extraction of water from underground sources is on the increase, especially from basins stored by non-strengthened alluvium, sediments and from shallow areas of the sea. This results in sinking on the surface and leads to ground subsidence. In recent years, the Minab Plain, like many areas of Iran has faced drought, which has led to more uptake of subterranean water; this lowers the underground water level and results in sinking which appears on the surface as a sinkhole following subsidence. A field study of this sinking phenomenon involves the following procedure: Firstly, the analysis of the drought occurrences in the area including features of water table, sediment and bedrock. Secondly, the consideration of exploitation of the subsurface water; and finally, identification of the different forms of subsidence in the area from the information acquired above. Statistics from the Sheikh Abad rain-gauge station (covering a period of 27 years) were used for this investigation. Data on precipitation are presented with the decimal method and the standard precipitation index, an index that shows any decrease of climatic rainfall in the area. This data shows that in recent decades there has been less than normal rainfall and that the area has undergone a period of intense drought. In most parts of the plain new alluvium was formed at a depth of 2-3 meters from the surface, the sediment of which often constitutes large grains, which gradually changed to form finer sediment in the form of sand, silt and clay containing salt-water. Therefore, it can be said that with increasing depth, the sediments become tinier (smaller) with an increase in salinity. All of the wells in this area have settled on washed silt sediment and have a high density around the rivers of the Minab area. Because of recent droughts and the drying up of the water supply canals of Minab dam, the digging of wells has increased from 164 in 2002 to a current figure of 607 dug wells. Critical factors related to occurrences of subsidence, are that the existing alluvium covering with the varying thickness up to 150 meters has formed small-grain, silt clay-silt loam soil, which has increased surface subsidence following extraction of underground water over the past two decades.
Mohammad Mahdi Hosseinzadeh; Reza Esmaili; Ahmad Nohegar; Mahdi Saghafi
Volume 7, Issue 1 , October 2009
Abstract
Population increase and the illogical use of the natural resources of special forest cover have led to natural hazards. The study area is located in the northern Alborz in Chalos, Noshar, Noor and Amol cities and in Mazandaran Provice. In this study, we used the digital numbers from the landsat satellite ...
Read More
Population increase and the illogical use of the natural resources of special forest cover have led to natural hazards. The study area is located in the northern Alborz in Chalos, Noshar, Noor and Amol cities and in Mazandaran Provice. In this study, we used the digital numbers from the landsat satellite TM and ETM+ data for two different dates (summer of 1988 and 2000). First of all, remote sensing images and the processing techniques were used in this study. Then, the images were analyzed using the NDVI index and Tasseled Cap transformations and, finally, the change detection process was studied. This research was analyzed using the trend of total land cover changes, thematic changes in each one and the forest cover area. The findings revealed that the forest cover area that, at the two different dates, it comprised 2719 Km² (total 5121 Km²) and the greatest changes in area had taken place between the two periods in the semi-crowded forest region. Local changes occurred in about 32 percent of the distribution of forest area. Investigations also mentioned show that there are vast changes in the spatial distribution of quantity accumulation, estimated on average at about 3.2 percent. .
