AN INTEGRATED APPROACH FOR THE ASSESSMENT AND MONITORING OF LAND DEFORMATION IN THE RIYADH CITY AND ITS SURROUNDINGS AND FOR IDENTIFYING THE CONTROLLING FACTORS
Abstract
An integrated approach (remote sensing, field, geodesy, geology, and hydrogeology) was conducted to assess and monitor land deformation at Riyadh city and its surroundings. Two settings were investigated. The first, Jinadriyah area (1.5 km2), an urban area located east of Riyadh city, was selected to assess deformation associated with urbanization over desert lands. The second location was Al Kharj area (19,790 km2) to the south of Riyadh city, a reclaimed desert land that was selected to assess the deformation associated with agricultural groundwater extraction from fossil aquifers. My investigations revealed high subsidence rates (up to -30 mm/yr) over Jinadriyah that could be related to mining of aggregate and other construction materials, development of dump sites and fill areas, and construction of roads and buildings or collapse of underlying sinkholes. Subsidences over Al Kharj area reach up to -14 mm/yr that is caused by excessive groundwater extraction from the fossil aquifers and the presence of compressible clays.