Monitoring Drifting Sand Using Spectral Index and Landsat TM/OLI Datasets in Bahr An-Najaf Area, Iraq

This chapter analyzed the spatial and temporal characteristics of sand dunes, focusing on the rates of creep and movement of both dunes and sand. The study area comprised four types of sand features: Barchan dunes, Longitudinal dunes, Nabkha, and Sand sheets. Hazard analysis of the sand dunes was conducted using a combination of remote sensing techniques and field observations. Four Landsat TM/OLI images (22 Aug. 1988, 18 Aug. 1998, 13 Aug. 2008, and 9 Aug. 2018) have been used to achieve the objectives. The study area utilized the Normalized Difference Sand Dunes Index (NDSDI) to identify and map drifting sand. Notably, the size of the sand dunes underwent significant changes between 1988 and 2008 but remained relatively stable from 1978 to 1988. During these periods, the sand dunes expanded in area, but the valleys in the research region impeded their progress. This expansion and migration of sand dunes substantially threaten human activities in Al-Rahima, Eitha, Khiribah, and Um-Tharawi, with the risk increasing over time. Every decade, the encroachment rate of these sand dunes has been calculated, and it has been found that they approach areas and communities within a distance of 3000 m, indicating the proximity of the hazard. Among the dune fields, the third field demonstrated the fastest creep rate. Overall, the risk posed by these sand dunes has intensified, leading inhabitants in specific regions (southwest of Al-Rahima and Al-Ruhba) to abandon their houses and farmlands. Furthermore, industrial activities, including public services such as utility poles and roadways, are also affected.