Assessment of changes in ground water table with use GIS

Ground water is an essential piece in the hydrologic cycle that moves the earth’s water from large water bodies to storm clouds, through rivers and streams and back again. Ground water is water below the ground surface that occupies cracks and pore spaces in bedrock or the pore spaces between sediment particles. Ground water plays a crucial role in maintaining wildlife habitat by contributing water for river base flows, playas, and wetlands. . Accurate prediction of ground water level is therefore crucial to ground water exploitation. The water table is the surface of the saturated zone in an unconfined aquifer. It is identified as the level below which pore spaces and cracks in the subsurface material are saturated. Considering that the study area is located in an arid and semi-arid region and in terms of rainfall is limited therefore groundwater plays an important role in various activities. Because of the shortage of surface water resources in the region is limited and only a few seasonal river were flowing. Evaluation of groundwater levels in the area over a period of several years is necessary. The dominant role of groundwater resources is clear and their use and protection is therefore of fundamental importance to human life and economic activity. Some activities are effective in changing groundwater levels such as: excessive exploitation, major change of land use, climate change, population pressure, agriculture and etc. IMDPA1 model have been used to classify different classes in this assessment. The GIS2 is used to specify the range. The results show that in the 2007 to 2010 there are not in very high class. The most very high class in 2005, all region(7864.5 hectare) is low class in 2007, the most medium class was be in 2010 as well as the most class of high class was be in 2006.

کلیدواژه ها:

assessment ، ground water ، IMDPA ، GIS ، arid regio