## 1 Introduction  
The marshes in the southern part of Iraq are among the most prominent phenomena in the region that formed within the sedimentary plain forming a natural balance between the Tigris, Euphrates rivers and Shatt al-Arab leading to the Arabian Gulf. The marshes represent an integrated ecosystem that dates back more than 5000 years and occupied a large area of southern Iraq [1]. The marshes and the surrounding areas in southern Iraq were characterized by the availability of water and the climatic viability of growing economic crops and raising buffalo. However, it has been severely damaged by the drought. Fish are one of the most important elements of livestock in the marshes and are characterized by their abundance. The marshes are also a source of income for many fishermen living in the area. The areas of the marshes are the most important environments for breeding; it is also the habitat of many birds, many of which have migrated from different regions of the world, such as Siberia and northern Europe, especially in winter and spring. The marshes contain needs and papyrus, which are used for the manufacture of various stocks, some of which are animal feed [2]. The draining of the marshes in the second half of the 20 th Century, and particularly in the 1990s, severely disrupted the hydrological regime of the marshes. Large dams in the upper reaches of the Euphrates and Tigris started to change the water distribution throughout the basin since the mid-20 th Century, strongly impacting downstream water use [3]. Turkey first launched its Southeast Anatolia development project, including 22l dams and 19 hydropower plants, in 1977, and rebalanced it in 1989. Iran started large-scale water management projects on the Karun and Karkheh rivers (the important tributaries of Hawiza marsh), in the mid-1990s [4]. Since 2003, local inhabitants began to reflood some of the marshes, often in an uncontrolled and haphazard fashion [5]. Because of the breaching of levees and dams and coincidental plentiful rain in the following two years, the marshes superficially recovered and regained about 55% of their former extent [6]. This recovery was transient, however. Following a drought in 2008-2009, marsh extent declined again and only slightly recovered in the winter of 2009/2010 [7]. The drying up of the marshes has had a significant impact on climate change, in the southern region of Iraq at the very least if the impact is not wider. This means that the area the marshes and its adjacent areas have clear differences in the elements of the climate, resulting from the destruction of the environment and natural resources in the region [8]. Climate change caused by the increase in greenhouse gases in the atmosphere has significantly influenced the water balance by causing changes in evapotranspiration rates, temperature, and precipitation. These changes have had a negative impact on water resource availability [9]. As an important part of the Earth's water cycle, land surface water bodies, such as rivers, lakes, and reservoirs, are irreplaceable for the global ecosystem and climate system. Surveying land surface water bodies and delineating their spatial distribution has a great significance in understanding hydrology processes and managing water resources [10]. At present, remote sensing has become a routine approach for many fields, including geography, land surveying, and most Earth Science disciplines (for example, hydrology, ecology, meteorology, oceanography, glaciology, geology); it is also used for land surface and water body monitoring, because the acquired data can provide macroscopic, real-time, dynamic and cost-effective information, which is substantially different from conventional in situ measurements [11]. Landsat has recently been used to undertake long term monitoring of surface water bodies at global and regional scales [12]. Landsat-8 acquires global moderate-resolution measurements of the Earth's surface in the visible (VIS), near-infrared (NIR), short wave infrared (SWIR) and thermal infrared (IR) [13].