Investigation of Increasing Trend of Saline Soils Around Urmia Lake and its Environmental Impact, Using RS and GIS

The Urmia Lake is one of the old and very important water bodies in Iran. Nowadays, for various reasons, this lake has become an environmental crisis. What is happening today to this lake happened to the Aral Sea not long ago and converts it to a salt marsh with huge damaging environmental effects. Drying of the Urmia Lake has many environmental consequences such as degradation and salination of soils. In this study, using Landsat satellite images, Remote sensing (RS) techniques and GIS software, salt marsh around the lake was studied. First, saline areas were detected in satellite data and then the desired color combinations defined in the ENVI software. At last, after extracting the maps from images, area changes were studied and environmental impacts that will occur due to increased saline lands were studied. In a 13-year study period of Landsat satellite images, the trend shows a very rapid increasing of saline lands. In 1998, an area of salt marsh 28.516 km2 has increased to 744.411 km2in 2011.This amount is nearly 26 times since 1998. Increasing of the saline lands, lead to the degradation and loss of soil fertility, and if this trend continues itcan lead to areas of fertile land out of agricultural production.