Ezzatollah Ghanavati; Mohammad Reza Sarvati; Reza Mansouri; Samira Najafvand
Abstract
Extended Abstract
Introduction
Urban streams have great potential for building a green space network for an entire city. In essence, urban streams have great potential to function as a key part of an urban green infrastructure providing valuable ecosystem services to urban residents. Urban stream organizing ...
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Extended Abstract
Introduction
Urban streams have great potential for building a green space network for an entire city. In essence, urban streams have great potential to function as a key part of an urban green infrastructure providing valuable ecosystem services to urban residents. Urban stream organizing has one of the key topics in water management and land use planning in Iran. There are still ongoing controversies associated with organizing plan. Vegetation is one of the key components of urban stream restoration to increase its natural and esthetic attributes. However, formulating and maintaining planting/vegetation is not easy because it requires consideration of not only the usual factors for general open space design such as ground-level ecological capacity and residents’ preference, but also plants’ hydrophilic aspects. To be selected for stream basin vegetation, plants and vegetation should not be easily washed away during flooding and have a high survival rate even with extended submergence. One of the situations that concerns the applied geomorphologist, is that geomorphological events have a direct impact on man. The irregular development in Tehran, over the past half-century, in addition to the destruction of parts of a coherent historical context and cultural assets and historical heritage surviving the cause is a large part of the natural heritage of floodways.
Materials and Methods
Farahzad stream is one of the floodways in the North of the metropolitan Tehran. Farahzad basin in terms of geological structure is part of Central Alborz and has semi-dry climate. By organizing floodways, urban landscape, walkways and recreational confines as well as environmental and urban landscape conservation sustainable development will be realized. In the urban areas, sections of society play an important role in organizing the floodways. Farahzad basin witha geographical longitude of 51ْ19´ 00 to 51ْ 22´ 00 E and a geographical latitude of 35ْ45´ 00 to 35ْ 53´00 N with an area of 28 square kilometers is located in the North of Tehran city (North of Tehran Province). The maximum amount of rainfall in the area is more than 600 mm with an average of 422 mm per year.
This study aims at assessing the organizing appropriateness of the Farahzad city’s floodways with the geomorphological factors such as elevation, slope, aspect, precipitation, soil, land use and land cover (vegetation), distance from liner features (such as fault, river, road), and overlying of them, with emphasis on organizing floodways using geographical information system (GIS), remote sensing (RS), and AHP. Methods based on analytical - descriptive, library studies using geographical Information system (GIS) software and analytic hierarchy model in Expert choice software over the map of organizing proportion of Farahzad city-floodways based on the geomorphological factors have been proposed.
Among layers used in this study, the most weight was allocated to elevation. The next layer in order of importance includes: slope, aspect, rainfall, vegetation, soil, distance from streams, faults and roads. Among the factors and layers used in this paper, the lowest relative weight was assigned to the layer distance from the road.
Results and Discussion
Knowledge of key geomorphological processes is an integral part of understanding the evolution of any landscape. Results of this study show that most organized floodway areas of geomorphological factors is considered as a very low and low status proportion (44 per cent). Also, 33 per cent of the area has been organized highly and very highly to fit the situation with the geomorphological factors. The results show that no attention has been paid to the morphological parametersin environmental management and urban planning.
Conclusion
In this paper, the Farahzad Basin was studied using topographical maps with 1:50000 scales and geological maps with 1:100000 scales, Landsat satellite imagery with high resolution and the overlying and weighed methods. The Landsat ETM+ satellite image analysis during 2005 and 2010 (before and after the organization) and their comparison revealed that Farahzad floodways vegetation had grown 26 per cent after the organization with respect to the previous year’s organization. Also, hazards such as landslides, slope instability and even protection of the environment, were affected by landforms and geomorphological parameters.
Reza Mansouri; Amir Safari
Abstract
Parts of the earth's crust have tectonic motions in the present time and will be susceptible to danger in the future. Therefore, geomorphologicforms are very sensitive to the tectonic activities and change by this movements. The assessment of tectonic activities using some quantitative indicators ...
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Parts of the earth's crust have tectonic motions in the present time and will be susceptible to danger in the future. Therefore, geomorphologicforms are very sensitive to the tectonic activities and change by this movements. The assessment of tectonic activities using some quantitative indicators plays an important role in identifying these activities and helpsto interpret the tectonic condition of the areas
Research Methodology: In this research, indices such as Stream length gradient index (SL), Valley floor-valley height ratio (VF), Asymmetric factor (AF), Topographic inversion symmetry (T), Drainage basin shape ratio (BS), and meanders of rivers (S)have been used to determine the tectonic activities in Frahzad basin in north of Tehran metropolis. The research method is based on the analytical method. The Physical and conceptual tools used in this research include the topographic and geological maps of the study area, satellite images and GIS software in the form of ARC GIS 10. Also, the quantitative results obtained during several stages of fieldwork were evaluated Discussion and Results: This basin, with an area of 35.8 kilometersis one of the sub-basins of the mountainous area in north of Tehran city which is considered to be an appropriate place to evaluate the relative tectonic activity due to the occurrence of the foothill processes (mainly sliding and falling). Farahzad River of this basin comes from the eastern heights of Imam ZadehDavood.
Conclusion: The results of the research indicate that the Farahzad basin is in active status based on the SL, VF, AF, T, SMF, EU, FD and S indices, and is only in Semi-active status based on the BS index.
The analysis of these quantities in general indicate the activity of this basin in the present time and the basinis classified in Class 1 based on the IAT(Index of relative active tectonics)index. These results are consistent with geomorphological evidences including landslide occurrence in the region.
Reza Mansouri; Ezzatollah Ghanavati; Mohammad Reza Servati
Abstract
The vast country of Iran has diverse geographical conditions with 11 out of 13 known climates in theworld. This hasresulted in many environmental,ecotourist, recreational, and economic capabilities. The tourist infrastructure of any region is the nature of that area and as one of its parts,geotourism ...
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The vast country of Iran has diverse geographical conditions with 11 out of 13 known climates in theworld. This hasresulted in many environmental,ecotourist, recreational, and economic capabilities. The tourist infrastructure of any region is the nature of that area and as one of its parts,geotourism has in recent years, experienced a dramatic and significant upsurge in the world and has had a great influence on regional development. Geomorphological and geological visit is one of the main aspects of Geotourism. Ilam province with a surface area of 19,086 KM2ranges from 31 deg. 58 min. to 34 deg. 15 min. North Latitude from the Equator and 45 deg. 24 min. to 48 deg. 10 min. East Longitude from the Greenwich. The province is considered as one of the most prone areas for development of geotourism with its geotourist, geomorphological and geological attractions such as caves, mountains, rivers, waterfalls and springs. In this regard, attention to the natural capacities, conservation, presentation and utilization of geotourism attractions can play an important role in the sustainable development of the province,while it can be effective in solving problems such as unemployment and creation of employment in the province.This research studies the characteristics of Ilam province in a library, field, descriptive - analytical method and by using maps and satellite images,
Mohammad Reza Servati; Fariba Azad; Reza Mansoori
Volume 23, SEPEHR , July 2014, , Pages 94-105
Abstract
Geomorphological events with a direct effect on human are especially important for applied geomorphologists. Our discussion in this article is limited to geomorphological hazards. Hazards happen after passing a threshold. Some hazards like earthquake are completely natural, but some others are quite ...
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Geomorphological events with a direct effect on human are especially important for applied geomorphologists. Our discussion in this article is limited to geomorphological hazards. Hazards happen after passing a threshold. Some hazards like earthquake are completely natural, but some others are quite related to human activity. Here we describe the main geomorphological hazards and their influences. Unfortunately, the wide range of geomorphological hazards is not completely understood, therefore table 1 provides a list of geomorphological hazards. Moreover, their catastrophic results are not understood and table 2 provides a list of the world most important natural disasters caused by geomorphological events. Some parts of the world are unfortunate enough to experience a large number of geomorphological hazards. There are two main discussions regarding hazards. First, some hazards like volcano, earthquakes, corrosions fault are results of structural motions of the earth crust and actually they act in a very short time interval. Second and more interestingly, some hazards caused by geomorphological procedures happen in a short period of time-within days, or even hours. River floods, sea floods and land slide are examples of these procedures. Events are transient and odd and they can catastrophically be described in more than one way.
