Urban geological mapping: Geotechnical data analysis for rational development planning

Urban geology provides information on urban geologic environments as a scientific basis for planners and engineers for rational land use planning and urban development. Such mapping can be classified in terms of purpose, content and scale. In this study, procedure for preparation of engineering geological mapping in Tunis City (Tunisia) is given, as a case study. The main restricting factors for urban development: such as lithology; topography; slope; seismotectonic; water table depth; flooding susceptibility and seismic-induced effects were considered in the preparation of maps. All these information layers were manipulated using the Geographic Information System (GIS), and they were then combined to produce uniform engineering geological maps. Results are illustrated as a suitability map for construction in the study area. Consequently, the study area was categorized into four different zones as: (1) a high region with potential risk of superficial perturbation; (2) a low and flat zone with flooding risk; (3) a low zone with flooding and probability of sliding risk; (4) a region with mud levels and settlement risk.