جستجوی مقالات مرتبط با کلیدواژه « قم » در نشریات گروه « محیط زیست »

Waste management is a global issue whose importance is increasing day by day. Neglecting proper waste management has caused special problems that can be solved through the coordination of science and experience within the framework of proper management, and in this way pollution caused by landfills, including air pollution, can be minimized. In addition, optimal use of the gases produced in the landfill can be made; therefore, estimating the amount of gases that can be extracted from landfills can help in proper waste management. The purpose of this research was to estimate the amount of extractable gases in the Alborz landfill site in Qom Province. For this purpose, the amount of waste in the landfill, the composition of the waste, and the environmental and climatic conditions of the region were entered into the LandGem software, and an estimate of the amount of extractable gases at this site was made. Considering the number of remaining cells from the Alborz site and the amount of waste production, the useful life of the Alborz site is considered to be 15 years. After estimating the production waste, the necessary inputs for the software to estimate the recoverable gas in the period of 5 and 15 years from 2021 to 2035 have been prepared. According to the calculations made with LandGem software, the maximum amount of gas that can be extracted from the Alborz site per year for a period of 5 years is 11 million cubic meters for rapidly decomposing waste and 0.5 million cubic meters for slowly decomposing waste. Also, the maximum amount of gas that can be extracted from the landfill per year for a period of 15 years for rapidly decomposing waste is calculated at 31 million cubic meters and for slowly decomposing waste at 1.6 million cubic meters, which can be managed and used optimally with proper planning.

Landscape as a whole is the reflection of the structure and function and their interaction. Although, metrics of landscape ecology provide an appropriate tool to analysis the structure and function of landscape, but deep understanding need to enquiry the generality and evolution of the landscape as a whole. This is especially important to urban landscape interpretation. In particular, when urban development is the result of spatial development which mainly influenced by socio-economic processes. As results, the environmental context is less considering. Disturbance in the natural and ecological structures is the consequences of such process that lead to the ecological rupture of the landscape. Accordingly, structural changes affect the functioning of the city's natural ecosystems that making cities more and more unsustainable. Hence, it seems that the first step in improving the current situation is to explain the pattern of landscape changes appropriately and provide a truthful understanding of the effects of urban development patterns of the ecosystem.Accordingly, the purpose of this study is to evaluate the overall landscape changes of Qom over 30 years. Therefore, an attempt has been made to: first, compute the structural and functional changes of the landscape by using landscape metrics. Therefore, the natural and artificial structures that make up the city's landscape were extracted from the US Geological Survey (USGS) using satellite images. Images were taken in 1989 from the Landsat Satellite 5 (TM), in 1999 and 2009 from the Landsat .7 (ETM), and the 2019 from Landsat 8 (OLI). Then, it was classified by Supervised Classification method and Maximum Likelihood using the ENVI software. The natural and artificial structure was classified into four categories: vegetation, building, communication and bare lands. Then, ten appropriate metrics was calculated to quantify the changes in these four aforementioned categories. The essential calculations have been done by the Fragstats software.The results of the study show the uninvited and accelerated changes in the ecosystem of the Qom bese on application of landscape metrics. Qom has experienced serious structural and functional changes over thirty years. The man-made landscape is developing at the expense of devastating natural structures. Natural patches are disappearing. While, the introduced patches are increasing progressively. Of course, introduced patches has not a significant effect on the overall trend of landscape change. Examining the trend of LPI, AREA-MN, SHAPE-AM, SHAPE-MN indicators provides information about changes in the visual form of the landscape. The increase in artificial patches, along with the lessening of the largest desert patches to one-third, indicates the emerging of the progressive fragmentation in the desert landscape of Qom. Meanwhile, the shape of the city is changing into the simple geometric pattern, which means the loss of natural ecosystems. The status of the indicators during different years expresses the simplification of the urban landscape. The result is multiple effects on the urban environment, such as changes in microclimate and its consequences on the fragile desert ecosystem. Therefore, it is necessary to revise the development model and consider serious attention to natural oriented approaches while responding to human needs in such areas. It seems that the present a model of ecological planning along with strategic proposals is obligatory to practice the ecological-based projects for future developments to enhance the quality of Qom ecological landscape.

In a natural watershed, most of the surface is impervious and covered with vegetation, so a large amount of precipitation is lost through plant interception, infiltration into soil and evapotranspiration. However, in an urban watershed due to urbanization, impervious surface of the watershed increases, which tends to increase the volume of runoff and peak discharge, the erosion of the bed and the edges in the downward of canals, and decrease in water level as well as degradation of water quality. The purpose of this research is to apply SWMM simulation for estimating runoff and runoff hydrograph and the effects of land cover changes and low impact development tools on hydrologic response of urban watersheds.

In this research, implementation of SWMM model in one of the urban areas of Qom was considered. The study area is 256 hectares in northwestern part of Qom.

In this study, it was concluded that in sub watershed of 2 and 6, the increase of 70% and 40% in impervious surfaces resulted in 30% increase in runoff volume. Also, 10% increase in impervious area of upstream and downstream of watershed tends to 6/51% and 6/87% increase in peak discharge volume, respectively. The use of storage devices has also had a significant impact on reducing urban runoff.

The results of SWMM model in urban runoff estimation indicate that in order to properly manage runoff in arid areas, the status and location effects of land use on urban runoff rate as well as the use of rain storage tools in these areas should be considered.

Old trees, as one of the most important genetic reservoirs, have high value for all countries. During their long life (sometimes up to several thousand years), these trees have witnessed numerous natural changes and environmental stresses and can be studied as a living history. In this research, in the framework of the national project for identifying and introducing Iranian old trees, a database of old trees of Qom province was prepared. After gathering the necessary information about the old trees from provincial colleagues and local sources during several field visits, a total of 21 tree species over 200 years old were identified that met the criteria for entry into the country's old trees database. In terms of geographical distribution, these trees were in the range of Kahak (9), Qom (3) and Dastgerd (9). Plane-tree with 10 trees was the most abundant species, followed by Berry with eight trees, and Caucasian hackberry, Willow and Cypress each with one tree. The trunk perimeter of trees recorded ranged between 3.1 to 12.5 m and their height ranged between 5.5 to 21.2 m.The oldest tree in the province was Aphine juniper with approximately 810 to 860 years old. According to the description made for each tree, the process of recording the selected trees was carried out by the supervisor of national project, and consultation with the Cultural Heritage and Tourism Organization was undertaken to register the selected trees in the form of national natural heritage.

The habitats are the most basis of plants diversity and the study of habitats are the most important studies in the ecosystem. Qom province Due to ecotonical conditions (the connection between Zagros mountain ecosystem in west and south of province and central desert ecosystem in east of province, ecosystems and habitats diversity is high. this research has been carried out on the natural habitats and effected by human. The former Nature habiatats includes desertic, alpine and wetland zones and the later are includes the marginal of agricultural lands and Ruderal habitats. Moreover in the present survey diversity of plant habitats has been investigated in order to height, temperature and perception gradient. the different habitats by accessed With quadratic sampling in different habitat of province based on Braun-Blanquet. The highest diversity is includes Palang-darreh Valley (south west of province) and the lowest diversity is in relevant to Massileh plain (East of province).