Sand dunes monitoring using remote sensing and GIS techniques for some sites in Iraq

This study is aimed at monitoring, mapping and assessing the sand dune encroachment in the northern central part of Iraq. The study area includes six districts suffering from the increasing prevalence of sand dunes, particularly in the recent years, which are characterized by dry weather and a reduction in rainfall averages. Remote sensing "RS" and in particular, Earth observation satellites besides Geographical Information Systems "GIS" provide significant contributions to monitoring sand dunes encroachment. Two Landsat TM images acquired on July of 1988, and July of 2009 were assembled and used to extract the research indices. Satellite image based indices; the Normalized Difference Vegetation Index "NDVI", the Tasseled Cap Wetness Indicator "TCW", the Land Surface Temperature "LST", and the Normalized Difference Sand Index "NDSI" (a new index which has been proposed in this study) with RS and GIS techniques were used for monitoring the sand dune encroachment at two sites in the northern central part of Iraq. The results showed an increase in the sand dunes accumulations by 2,020.6 km(2) and 291.1 km(2) throughout the 21 years from 1988 to 2009 in Baiji and Al-Aith sites in the region, respectively. Sand dunes movement rates for the same period were 1,155.9 m year(-1) and 494.2 m year(-1) in the two mentioned sites, respectively. The results showed that the study area in general is exposed to a high risk of sand dune encroachment. The means of soil conditioners and windbreaks has been proposed to mitigate the impacts of sand dune encroachment.