Oznur Karaca

Classification of residential areas according to physical vulnerability to natural hazards: A case study of Çanakkale, Turkey

The selection of new settlement areas and the construction of safe buildings, as well as rendering built-up areas safe, are of great importance in mitigating the damage caused by natural disasters. Most cities in Turkey are unprepared for natural hazards. In this paper, Çanakkale, located in a first-degree seismic zone and sprawled around the Sartçay Delta, is examined in terms of its physical vulnerability to natural hazards. Residential areas are analysed using GIS (geographic information system) and remote-sensing technologies in relation to selected indicators. Residential areas of the city are divided into zones according to an evaluation of geological characteristics, the built-up areas features, and urban infrastructure, and four risk zones are determined. The results of the analysis show that the areas of the city suitable for housing are very limited. In addition, the historical centre and the housing areas near Sartçay stream are shown to be most problematic in terms of natural disasters and sustainability.

Mine tailing disposal sites: contamination problems, remedial options and phytocaps for sustainable remediation

Mining practices and the absence of proper mine land reclamation has led to heavy metal contaminated sites with serious impact on the ecosystems and risk for human health. The origin of the contamination is often associated to mine tailing deposits because they are a source of the acid mine drainage (AMD). These areas are devoid of vegetation due to the harsh soil conditions that prevent the rooting of plant species. The remediation of these areas followed by revegetation is necessary to suppress the generation of the AMD and its negative effects on the ecosystems. Conventional remediation technologies for heavy metal contaminated sites are usually not applicable because of the high cost associated with chemicals and energy requirements, as well as the long treatment time to remediate large areas. In this study, the use of phytocapping for the remediation of mine tailing deposits and abandoned mine areas is reviewed. Phytocapping is cost effective, environmentally friendly and has multifunctional role against various problems of mine tailings: it provides erosion control, landscape rehabilitation, enhances the soil properties for further colonization of other more demanding vegetal species, reduces the leachability of metals downwards the groundwater, and favors the immobilization of metals forming less bioavailable species. The most critical step in phytocapping is the developing of the first vegetative cover because of the biotoxicity of the mine soil and mine tailings. Several amendment materials can be used to ameliorate soil conditions creating a favorable environment for the rooting of plants, as well as serving as a source of nutrients. Local plant species with fast growing are preferable because their adaptation to the soil and climate conditions favors their self-propagation.

Flood susceptibility mapping using GIS and multicriteria decision analysis: Saricay-Çanakkale (Turkey)

Floods are natural disasters that are among the most damaging natural events for humans and the environment. Globally and in Turkey, a variety of engineering studies are performed to solve problems that may form before and after flood events. In this situation, the preparation of flood susceptibility maps is beneficial to observe areas with tendency to flood and to make plans in accordance with this. This study focuses on previous and current floods on the Saricay River passing through the settlement area of Çanakkale. Within this scope, multi-criteria decision analysis (MCDA) was used with the help geographical information systems (GIS) that was used to determine possible flood areas. In the first stage, the most important factors affecting flooding were determined. These include slope, aspect, elevation, geology, land use and proximity to the river. Subcriteria were developed to ensure more accurate evaluation of each criteria. For each criteria, an appropriate weight value was assigned, and for each subcriteria, an effect value was assigned. All criteria were included in the weighted overlay method, and sensitivity analysis was performed to create a flood susceptibility map for the study area. According to this map, the study area was divided into five classes from very low susceptibility to very high susceptibility. According to these results, 13.9% of the study area has high susceptibility, while 14.2% has very high susceptibility. Furthermore, paleoflood analysis studies of Saricay included identification of fluvial deposits using geological and geomorphological data and determination of soil profiles. Fluvial sediments were dated with the optically stimulated luminescence (OSL) method, and it was determined that the Saricay river changed its course about 30–40 thousand years before present. The ancient bed had NW-SE orientation, while the current bed flows in an E-W orientation within the city.