Tuğçe Anılan’s research while affiliated with Karadeniz Technical University and other places

The aim of this study was to employ flood frequency analysis integrated with GIS and HEC-RAS models to provide hazard maps for various return periods of flood discharge in the Değirmendere Basin, Trabzon, Türkiye. Point and regional flood frequency analyses were performed to estimate the flow rates for varying return periods. The L-moments method was used to calculate the distribution parameters of the annual maximum flow data from the regional stations. Based on the results of the regional flood frequency analysis, the HEC-RAS computational fluid dynamics software was employed to simulate the water surface profiles of Değirmendere using the mass conservation/momentum equations under steady flow conditions. Flood hazard maps were developed for flow rates with varying return periods. The results of the model provide a good representation of the flood risk region based on the detailed analysis of flood quantiles. The findings of this study can be used to inform flood management strategies and to enhance the resilience of urban regions to flood events.

Marine outfall systems are often used for the safe disposal of brine, which is the byproduct of desalination processes, consisting of high concentrations of salt. It is of vital importance to obtain a sufficient dilution to avoid negative impacts that brine might cause on marine ecosystems, such as abrupt changes in salinity, temperature, and densities of ambient waters. Hydraulic design of the diffusers is highly important for a sufficient dilution efficiency, while it is very crucial to understand the behavior of dense jets to make a proper diffuser design. For this reason, analysis of brine jet geometries, their behavior, and mixing and dilution processes within the near-field region is of utmost importance. In this paper, the effects of different diffuser designs under certain discharge conditions on brine jet geometry, behavior, and dilution were investigated using three-dimensional Computational Fluid Dynamics models. First, a reference model was created and calibrated using the results of an experiment that had been previously conducted. Then, based on this calibrated model, different models were created, and, in each model, only one discharge parameter was changed, and the rest were kept the same as the previous model to see the effects of the differing parameters on brine jet geometry, behavior, and dilution. Results revealed that discharge angle, number of ports, port spacing and diameters, and jet velocity significantly affect brine jets’ shape, behavior, and mixing and dilution processes. The configuration where there is only one port with 60° inclination yielded the best dilution value of 99.68%.

The time for bacterial concentration to decrease by 90% (T90 values) can dramatically vary from a few hours to a few days, depending on environmental conditions. However, the diffuser design of outfall projects is typically calculated based on a constant T90 value. This study was designed to determine the initial dilution necessary to ensure low levels of coliform bacteria when using diffusers that are not designed to adapt to varying T90 values. Dilution rates are calculated using several T90 values. The results showed a strong inverse correlation between dilution rate and T90 value. To maximize the dilution rate and decrease T90 values, efficient diffuser design is essential. Various diffuser configurations were investigated to meet the dilution criteria. Suggested diffuser scenarios increased the near-field dilution and therefore the desired value of total dilution. The results presented may contribute to an improved understanding and selection of T90 values for the management of marine outfalls.

Appropriate design of marine outfalls is of utmost importance for the safe disposal of brine, which is the byproduct of the desalination process. A thorough analysis of brine jet behavior and mixing and dilution in ambient environments is required for the optimum design. For these analyses, Computational Fluid Dynamics (CFD) models have been increasingly used in recent years. In this paper, studies carried out on dense discharges using different CFD software and turbulence models are systematically reviewed. It was aimed to investigate the effects of differing discharge parameters on brine jet behavior and dilution and to evaluate and compare the performances of different CFD software and turbulence models. Results revealed that differing discharge parameters affect brine jet behavior and dilution significantly; different models performed differently under altering discharge and ambient water conditions, and the use of the most suitable model for optimum discharge is important.

Hidrolik yapıların projelendirilmesinde doğru taşkın debisi tahmini, ekonomik ve güvenli yapı tasarımı için kritik öneme sahiptir. Bu çalışmada Doğu Karadeniz Havzası Trabzon ilinde bulunan akım gözlem istasyonlarına ait taşkın değerlerine dayanarak maksimum debiyi tahmin eden çeşitli modeller geliştirilmiştir. Analizlerde, bu istasyonların alan ve kot bilgileri kullanılmıştır. Trabzon ilinde bulunan ve 9 ile 42 yıl arasında değişen akım gözlem yıllıklarına sahip toplam 16 adet istasyona ait veriler yapılan analizlerde kullanılmıştır. Debi tahmini için klasik regresyonun (KRA) yanı sıra yapay arı kolonisi (YAK) ve öğretme-öğrenme tabanlı optimizasyon (ÖÖTO) algoritmaları da kullanılmıştır. Bu algoritmalarda çoklu lineer regresyon, hiperbolik ve eksponansiyel regresyon fonksiyonları optimize edilmiştir. Gelecekteki maksimum debi tahminlerine yönelik modellemede, ÖÖTO ile optimize edilen hiperbolik regresyon fonksiyonunun hata değerlerinin daha düşük olduğu görülmüştür. Bu durum, ÖÖTO'nun KRA ve YAK yöntemlerine göre daha iyi performans gösterdiğini ortaya koymaktadır. Dolayısıyla, Trabzon ili için ölçüm olmayan yerlerde maksimum debi tahminlerinde ÖÖTO ile optimize edilmiş hiperbolik regresyon modelinin kullanılması tavsiye edilmektedir.

It is very essential in terms of flood risk management to consider social expectations such as risk perception, flood awareness, preparedness, and socio-economic dynamics together with engineering designs. Understanding the way people perceive flood risk can enhance our capability of improving existing flood risk management methods, thus helps us creating disaster resilient societies. In this study, results of a questionnaire which was used for a previous study and had been administered to participants from Eastern Black Sea Region of Turkey were further investigated using statistical methods. The main aim was to understand how demographic factors such as age, gender and education level affect people’s flood risk perception. It was also desired to see that whether they were aware of the parties responsible for taking mitigation measures, or whether they know about possible flood mitigation measures or not. Using the same data with the previous study, but in addition using SPSS software to do statistical analysis, questionnaire results were investigated using convenient statistical tests for each parameter, analysis results were interpreted, and conclusions were drawn. Same tests were conducted using weight coefficients adopted using a certain methodology which is explained in the paper, in order to make a better investigation. Also, results were compared with the results of the previous study. It was seen that there were some consistencies and contradictions between the results of the previous study and this study’s results.

Son yıllarda, taşkın risk algısının ve vatandaşların koruyucu önlemlere ilişkin bilgi düzeylerinin ve farkındalıklarının değerlendirilmesi, yenilikçi entegre taşkın yönetim stratejilerinin oluşturulmasında odak noktası haline gelmektedir. Bu kapsamda, risk algısı, taşkın farkındalığı, hazırlıklı olma durumu ve sosyo-ekonomik dinamikler gibi sosyal bileşenlerin de mühendislik planlamalarıyla birlikte ele alınması taşkın risk yönetimi açısından oldukça önemlidir. Bu çalışma öncelikle, taşkın riski altındaki bölgelerde vatandaşların risk algısı, farkındalığı ve hazırlıklı olma durumları hakkında literatürde yapılmış çalışmalar hakkında bir değerlendirme sağlamayı amaçlamaktadır. Ardından taşkınlara sıklıkla maruz kalan Doğu Karadeniz Havzası için taşkın farkındalığı oluşturma yönetim planı önerilmiştir.

When settlements are located close to a dam, it is important to accurately predict the breach peak flow and the time to reach the peak. Therefore, the prediction of dam breach properties is essential in dam break studies. Dam breach parameters such as the breach side slope, final bottom width, final bottom elevation, weir coefficient, breach formation time, and initial elevation of reservoirs are the key variables for estimating the peak discharge during a dam break scenario. In this study, these six breach parameters were analyzed to investigate the impact of breach parameters on breach peak flow and the time to reach the peak. Thus, several scenarios were calculated and compared for Atasu Dam. The results revealed that the role of the initial water elevation, final bottom elevation, and breach development time had more of an impact on the breach peak flow and the time to reach the peak. In addition, the study indicated that the final bottom width and breach weir coefficient were less sensitive to both the peak discharge and peak discharge time. Furthermore, the analysis indicated that the breach side slope parameter had no major influence on the time to peak while also having an insignificant impact on the peak discharge. Understanding this breach mechanism provides a basis for relevant research in designating key parameters for dam break analysis. Thus, the results can contribute to decision making toward the design of flood mitigation and dam emergency action planning.

Driftwood is one of the important physical components in mountainous rivers which causes severe hazards due to the clogging of bridges, culverts, and narrow sections during floods. Therefore, the understanding of driftwood dynamics and mitigation measures are crucial for managing wood in rivers. Open check dams are the most commonly used engineering measure for preventing driftwood from reaching downstream areas. Nevertheless, these open check dams frequently lose their sediment transport function when they are blocked by sediment and driftwood, especially during major flood events. This paper proposes a new type of open check dam for preventing from clogging. Thus, flume experiments were conducted to examine the influence of different types of open check dams on the characteristics of driftwood deposition. For the model with wood length (LWD)=16.5 cm, wood diameter (D) =15 mm, and wood number (N)=172, the highest trapping efficiency was observed with 90.1% and 87.2% retention rates for the classical debris flow breaker and curved footed open check dams, respectively. Laboratory tests showed that through this proposed design, woody debris blockage in a very short time was prevented from the accumulation of woods beside the dam. In addition to this, most of the sediment passed through the check dam and most of the driftwood got trapped. It can be briefly stated that the geometrical design of the structure plays an important role and can be chosen carefully to optimize trapping efficiency. By designing this type of open check dams in mountain river basins, it may provide a better understanding of the driftwood accumulation and basis for the optimal design of these structures. Further development of the solution proposed in this work can pave the way for designing different types of open check dams for effective flood management.