MONITORING OF AEOLIAN DEPOSITS AND ENVIRONMENTAL CHANGES DETECTION OF ALI AL-GHARBI AREA, SOUTH EAST IRAQ, USING REMOTE SENSING AND GIS TECHNIQUES

Abstract

Ali Al-Gharbi area is located in the eastern part of the Mesopotamia Plain. It covers 6569.9 Km2 and falls within the arid climate region. Most parts of the study area are covered by Quaternary sediments. Pre-quaternary rocks are represented by Mukdadiya and Bai Hassan formations, which are exposed in the eastern part of the study area. It is suffering from land degradation due to sand creep. Haphazard irrigation habits led to an increase of saline soil under arid environmental conditions.Supervised classification using Maximum Likelihood technique was carried out on the ETM 2002 and TM 1990 images in addition to image indices applications. ERDAS Imagine 9.1 was used for preparation and processing of the data and ArcGIS 9.3 was used for final layout of the maps. Depending on the results of supervised classification and image indices applications of Land Use Land Cover (LULC) classes, different land degradation types and environmental changes detection, between two dates are determined. The Field checking was conducted to verify the supervised classification results. It includes determination of check points using GPS, description of the surface features, soil and sediments, supported by taking photos. The supervised classification results distinguished the following classes: Barren Land, Water, Wetland, Vegetated Land and Agricultural Land Non-Vegetated (Idle and Cultivated land). The Barren Land class is divided into three sub-classes: Mixed Barren Land, Sand Dunes and Salt Flats. Distinguishing between dry barren land and salt flat also between aeolian sediments types: like sand dunes, sand sheets and some areas which are covered by aeolian sediments are difficult because there are mixed pixels between these units according to spectral resolution of available ETM and TM data. The classification accuracy of both ETM 2002 and TM 1990 images data was examined and showed good accuracy results. They have showed 92% accuracy for ETM 2002 image with Kappa (K^) coefficient 0.8448 and 90.22% accuracy for TM 1990 image with Kappa (K^) coefficient 0.8260. The main problems in the study area are erosion of dry soil, salinization of agricultural land, rising of dust storms and active sand dunes. All these factors have contributed in the increasing of desertification phenomenon.