عنوان مقاله [English]
Increased utilization of water and the use of chemicals in agriculture with agricultural development projects reduces the quantity and quality of water entering the lake and its satellite wetlands are. Industrial development has led to an increased release of hazardous waste into the lake. To develop urban land use change is an increase in municipal waste. Indiscriminate use of land for the cultivation of steep slopes, increasing soil erosion and dry land visible impact on the quality and quantity of inflow to the lake and its satellite wetlands will. In this study of water level fluctuation of lakes in order to safeguard them in terms of importance, nature and location of water collection and continue life as a factor for a natural heritage and, at the national level and between countries region has assumed the position of special.
Climate change as a result of reduced rainfall, increased temperature, uncontrolled use of surface and subsurface water resources and watershed areas clearly visible. These changes led to changes in water quality that is the basis of sustainable development, it is. Today discounted quantity and quality of water resources is one of the major challenges facing sustainable development. In this context, monitoring and assessment of coastal areas can, as a matter to be considered in national development and natural resource management.
2- methods and Materials
The data used in this study consisted of ETM and TM images from 1989, 2011, digital topographic map of 1/50000 is the GPS mapping and interpretations. Use of the image sensor, having six bands ranging from the visible and infrared reflectance and pixel size, pointed, R., et al, 1389. It has an average resolution of the sensors.
According to the study aimed to evaluate the changes in time intervals ranging from satellite images was 23 years old, the first attempt to apply the corrections needed in the preprocessing stage, geometric correction, and atmospheric respectively. Therefore, satellite images of geometric and radiometric examined and corrections were made. ERDAS 9.2 software was used to perform this task. Then, to determine changes in surface lake water were analyzed. Accordingly, the first series of satellite images of different spatial resolution of the spectral composition of lake water characteristics was analyzed. Then, try to: First detection of changes in land use and lake water levels is studied in the past two decades. Second, long-term shoreline change map, altitude and area of Lake Urmia in a long-term and annual periods should be introduced. To achieve the main objectives of the study, different types of multi-temporal satellite images of Landsat TM and ETM + Urmia Lake region that were available were selected.
As regards the lake is one of the most overcrowded areas in the North West is therefore the need to revitalize it to twice. One of the undeniable effects on the risk area around the lake is the wind that moved the salt particles into the cities of the country and has had a significant impact on areas outside the border. For reviews of this subject, Due to figures 8 and 9, which represents the amount of salt lakes in different areas, the wind direction is from the area of salt-affected areas, the risk will be added. So cities where the wind direction is south-west of them are located in East Lake (Tabriz, Azar, Sofian, Miandoab, etc.). The area of highest risk are located. And the wind direction in the cities as their Western, such Bonab is at the peak of the danger. At Overall it can be describes that the majority of area of towns around the lake are located in the eastern part. The wind direction is southwest or Western in them at the risk of the impact of relocation of the salt particles. This is widespread of a wide level of the surrounding land and salt storms will threaten neighboring countries.
The evaluation results indicate that the coastline is a significant change in annual and seasonal scales. The maps also show that the change in annual shoreline recession, especially in East and South East study area has been very clear this recession has been measured in some areas up to 8 kilometers. According to studies, various reasons have contributed to the reduction of lake water.
The rate of 65% due to climate change, 25 percent of the dams in the basin of the lake, and 10% reduction in rainfall in the area is. In recent years, the rapid recession increased the concentration of lake water and salt mineral deposits in most surplus coastline have caused. This process in turn has created numerous ecological issues. East and south east region has been studied in a large expanse of saline lands and cultivated lands without added that the ratio of the area of the lake less. The disaster caused by the drying of the Lake heavily impact on economics and ecological and environmental issues. In particular, will be impact on the extent of direct health & the residents of the Lake margin. & And tens of thousands of square kilometers were affected & With regard to the values of gardening - crop area and population, on the one hand, inhabitants of the region due to its adjacency to other empty threat of irreparable environmental issues to be evaluated.