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Among natural disasters, floods have the highest human toll. The economic impacts of floods are greater in developing countries, including Iran, and are particularly severe in the colder months of the year in the west of the country. The purpose of the present study is to analyze the most severe historical synoptic floods that occurred in Karkheh Basin  (1 April, 2019). Descriptive - analytical research method and its environmental approach into circulation. Analysis of synoptic systems of large floods such as the April 12, 2019 floods show that Western Europe's high-pressure systems, Black sea, East of the Caspian and low pressure north of the Red Sea, Eastern Mediterranean in harmony with the high-rise systems of Western Europe, Low Mediterranean East with a temperature drop of about 50 degrees Celsius(The temperature at sea level In the eastern Mediterranean and Red Sea about 25 degrees Celsius and in the middle of the atmosphere -25 degrees Celsius) also the climb Humidity from the Arabian Sea, North Indian Ocean, Red Sea, Oman Sea and Persian Gulf and Along with Mid-width cold air loss On the area and the establishment of the Polar jet stream) Core up to 70 m(And the establishment of the front jet stream And positive rotation area On the area shows the structure of the synoptic systems causing the flood in the area.

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Today, human settlements around the world are exposed to natural hazards for a variety of reasons. These risks, which bring with them a lot of human and financial losses, require preventive measures. The purpose of this study is to investigate the development of urban space in order to deal with environmental hazards in Noor city. The method of this research is also descriptive. Data collection is using library and documentary studies and questionnaires. In order to analyze the questionnaires using ANP method and fuzzy logic method, evaluate each of the criteria and determine their importance coefficients. Based on the results, spatial assessment was performed using ArcGis software and hazard zones were identified. According to the results of risk potential zoning, the northern and southern areas of the city have the highest risk potential. To predict the development of residential areas, the combined Markov chain model and cellular automation were used. The results showed that the continuous expansion of built areas in recent decades has caused rapid changes in land use and the built areas of the city has increased from 2.43% of the total area in 2010 to 3.68% in 2019. The results also showed that regardless of the natural hazards, the built-up areas will increase and as a result of urbanization, the built-up areas will be more prone to high-risk lands. However, if sustainable development policies are fully implemented, cities and built-up areas will be able to maintain their development spaces from high-risk areas for the benefit of the city and its residents.

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The morphology of river is one of the issues in geomorphology, engineering and river management. The marginal sections of the rivers have always been subject to the riverbed due to the special social and economic conditions. The Dare Ourt River is one of the permanent rivers in Ardabil province. In recent years, there have always been floods and changes in the morphology of the duct. In this study, the Dare Ourt river was analyzed using Rosegen model at levels one and two. The main data required for this study include: 1: 2000 river topographic maps, hydrometric data and boundary conditions (Ardabil Regional Water Authority). The HEC-RAS hydrodynamic model was also used to more accurately extract the main indices of the Rosegen model. The results showed that most parts of the river have a C6c type with alluvial substrate and other dominant types observed in the four studied ranges include B6c-E6b-F6-D types. Also, the results of field visits indicate a change in the type of river type D range 4 from type C to type F, which is difficult due to the fact that reconstruction and restoration of the river in type F is difficult. Recommended restrictions on the type F is prevented from turning the river.