Flood susceptibility mapping by best-worst and logistic regression methods in Mersin, Turkey.

Flood disasters resulting from excessive water in stream beds inflict extensive damage. Floods are caused by the expansion of cities, the erosion of riverbeds, inadequate infrastructure, and increasing precipitation due to climate change. Floods cause great damage to agricultural areas and settlements. Regions that may be affected by floods should be identified, and precautions should be taken in these areas to prevent these damages. Flood susceptibility maps are produced for this reason. The purpose of this study was to construct a flood susceptibility map so that susceptible locations in Mersin may be identified. Firstly, 429 flood events were identified for the flood inventory map. Twelve conditioning factors, namely elevation, slope, distance to river, distance to drainage, drainage density, soil permeability, precipitation, land cover/land use, stream power index (SPI), topographic wetness index (TWI), aspect, and curvature were used to create flood susceptibility maps, applying logistic regression and best-worst methods. The flood inventory data were used to prepare susceptibility maps and test their consistency. The receiver operating characteristic (ROC) curve was used for consistency analysis. In logistic regression, 86% of floods were located within 20% of the study area that was categorized as high and very high susceptibility. According to the value of the area under the ROC curve (AUC), logistic regression had a 0.901 value. Land use, soil permeability, and elevation were the most important factors in the logistic regression method. In the best-worst method, 85% of floods were located within the 14% of the study area categorized as high and very high susceptibility. According to the AUC value, the best-worst method had a 0.898 value. Elevation, distance to river, and precipitation factors had the highest coefficient value in the best-worst method. Based on the AUC values, the flood susceptibility maps had a high prediction capacity.

A GIS-based multi-criteria decision-making method for the selection of potential municipal solid waste disposal sites in Mersin, Turkey.

Due to rapid urbanization and the resulting rapid population increases, an important problem for cities today is the elimination of solid waste or finding suitable places for waste storage. Municipal solid waste disposal (MSWD) site selection is one of the most important steps in urban waste management. Many criteria political, economic, social, and technological should be considered in this process. Geographic information systems (GIS) and multi-criteria decision-making (MCDM) are tools that are superior to traditional methods in the planning phase of site selection studies. In this study, suitable MSWD sites were determined in Mersin (a Turkish province) based on GIS and the analytic hierarchy process, an MCDM method. Unsuitable areas in the study were removed at the beginning of the analysis. Eleven evaluation criteria were selected: elevation, slope, permeability, distance from lineaments, groundwater level, distance from rivers and water surfaces, distance from roads, distance from settlements, distance from protected areas, and land cover. Considering the evaluation and exclusion criteria, 19.12% of the study area was deemed suitable, and 80.88% was determined unsuitable for an MSWD site. An MSWD suitability map was created as a result of the study. The outcomes indicate that 80,377 ha and 83,022 ha of the study area were classified as high and very high suitability, respectively. Based on these results, we evaluate whether the locations of existing solid waste landfills are appropriate and propose alternative solid waste landfills for each district.

Monitoring of land subsidence due to excessive groundwater extraction using small baseline subset technique in Konya, Turkey.

Konya, which is located within the Konya Closed Basin, is the most important agricultural production region in Turkey. The future of agriculture is threatened in this region due to the decline in groundwater levels and the intensive agricultural activities that require high water consumption and are not suitable to the climate conditions of the region. In addition to these parameters, the geological structure of Konya also poses various environmental problems such as land subsidence and sinkhole formation. This study aimed to investigate the causes of the land subsidence problem in Konya and its surroundings with the help of the interferometric synthetic aperture radar (InSAR) technique and auxiliary data, namely optic, Coordination of Information on the Environment (CORINE), and groundwater monitoring station data. In order to investigate the land subsidence in the study area, 58 Sentinel-1A images acquired between 2014 and 2018 were processed by using the small baseline subset (SBAS) technique. In addition, the time series derived from the SAR data was validated by a global navigation satellite system (GNSS) station located in the study area. The results revealed that severe land subsidence, some of which reached 75 mm/year, occurred in certain areas of the study area over a period of three and a half years. High consistency was found between the land subsidence and the groundwater level change observed in the region, with a cross-correlation of over 95%. Moreover, the temporal and spatial patterns of the cultivated area and urbanization, which are the main reasons for the consumption of groundwater in the region, were revealed using the optic data.

Land Subsidence and Its Relations with Sinkhole Activity in Karapinar Region, Turkey: A Multi-Sensor InSAR Time Series Study.

The Karapinar basin, located in the Central Anatolian part of Turkey, is subjected to land subsidence and sinkhole activity due to extensive groundwater withdrawal that began in the early 2000s. In this study, we use Interferometric Synthetic Aperture Radar (InSAR), Global Navigation Satellite System (GNSS), and groundwater level data to monitor and better understand the relations between groundwater extraction, land subsidence, and sinkhole formation in the Karapinar basin. The main observations used in the study are InSAR-derived subsidence velocity maps calculated from both Sentinel-1 (2014-2018) and COSMO-SkyMed (2016-2017) SAR data. Our analysis reveals broad areas of subsidence with rates exceeding 70 mm/yr. The InSAR-derived subsidence was compared with GNSS data acquired by a continuously operating GNSS station located in the study area, which show a similar rate of subsidence. The temporal characteristic of both InSAR and GNSS time series indicate a long-term subsidence signal superimposed by seasonal variability, which follows the overall groundwater level changes, with over 80% cross-correlation consistency. Our results also indicate that sinkhole activity is limited to slow subsidence areas, reflecting strong cohesion of near-surface rock layers that resist subsidence but yield to collapse in response to aquifer system deformation induced by groundwater extraction.

Use of Landsat land surface temperature and vegetation indices for monitoring drought in the Salt Lake Basin Area, Turkey.

The main purpose of this paper is to investigate multitemporal land surface temperature (LST) changes by using satellite remote sensing data. The study included a real-time field work performed during the overpass of Landsat-5 satellite on 21/08/2011 over Salt Lake, Turkey. Normalized vegetation index (NDVI), vegetation condition index (VCI), and temperature vegetation index (TVX) were used for evaluating drought impact over the region between 1984 and 2011. In the image processing step, geometric and radiometric correction procedures were conducted to make satellite remote sensing data comparable with in situ measurements carried out using thermal infrared thermometer supported by hand-held GPS. The results showed that real-time ground and satellite remote sensing data were in good agreement with correlation coefficient (R2) values of 0.90. The remotely sensed and treated satellite images and resulting thematic indices maps showed that dramatic land surface temperature changes occurred (about 2°C) in the Salt Lake Basin area during the 28-year period (1984-2011). Analysis of air temperature data also showed increases at a rate of 1.5-2°C during the same period. Intensification of irrigated agriculture particularly in the southern basin was also detected. The use of water supplies, especially groundwater, should be controlled considering particularly summer drought impacts on the basin.

Is there any correlation between the preoperative parameters and correction loss in patients operated for hyperkyphosis?

OBJECTIVES: Preoperative, postoperative, and latest follow-up data of sagittal balance and spinopelvic parameters of our patients treated surgically for hyperkyphosis were evaluated retrospectively, to determine whether there is any correlation between the preoperative pelvic incidence and postoperative correction loss. METHODS: Totally 33 patients (18 females) who were operated for hyperkyphosis and, were reached at the latest follow-up were included in the study. Age at operation, gender, date of operation, etiology and level of the deformities, instrumentation, and graft types were noted in detail. The kyphosis angles were measured by the Cobb method. The preoperative and postoperative spinopelvic parameters (pelvic incidence, sacral slope, and pelvic tilt) were recorded. RESULTS: The average follow-up was 4 years (range 3-8 years). The mean age at operation was 21 years (range 14-40 years). Scheuermann kyphosis was diagnosed as the etiological factor in 18 patients (53%). The mean preoperative kyphosis angle was 76° (range 55-98°), which decreased postoperatively to 38° (range 20-55°) (p<0.05). The mean kyphosis angle two years postoperatively was 41° (p>0.05). Preoperative and latest follow-up spinopelvic parameters were also not significantly different. Furthermore, no correlation could be found between the age at operation, instrumentation level, spinopelvic parameters, and correction loss. CONCLUSION: There is no correlation between the preoperative pelvic incidence and postoperative correction loss in patients treated surgically for hyperkyphosis. Further studies with larger sample size and longer follow-up should be conducted.