This study investigates the stability of hydrological drought trends in the Euphrates Basin from 1960 to 2020 using three-dimensional (3D) graphical representations based on innovative trend analysis (ITA) and triple Wilcoxon test (WT) methods. Unlike traditional ITA and WT, which are widely used for trend identification but do not inherently provide trend stability information, this study employs a novel approach to assess and visualize trend stability. The Triple WT method divides the data into three equal segments, examining differences without altering the time series. Drought indices are calculated for 3-month, 6-month, and 12-month time scales using historical streamflow data from five stations. The research identifies trends and their stabilities across three distinct periods: 1967–1984, 1985–2002, and 2003–2020. Results show that as the time scale increases, trend differences between extreme drought conditions diminish. One station consistently exhibits significantly decreasing trends, while three stations show unstable trends with notable variations in the standardized streamflow index (SSFI). The use of 3D-ITA and Triple WT effectively captures the dynamics and stability of drought trends, offering a deeper understanding of hydrological drought in the Euphrates Basin. These findings provide a reference for future studies on drought trend mechanisms in various climatic regions.

Bu çalışmada, 2001 yılından itibaren Türkiye’nin elektrik piyasasının kurumsal yapısı ve bu yapıdaki reformlar detaylı bir şekilde ele alınmaktadır. Çalışmanın hedefi, liberalleşen piyasa yapısının yenilenebilir enerjiye olan etkilerini ve bu alandaki düzenlemeleri analiz ederek enerji üretimi ve tüketiminin piyasa fiyatlarına nasıl yansıdığını ortaya koymaktır. Literatüre katkı sağlamak amacıyla, elektrik piyasasındaki fiyatlandırma mekanizmaları, piyasa dinamikleri ve yenilenebilir enerjiye yönelik desteklerin etkileri kapsamlı bir şekilde incelenmiştir. Analizler sonucunda, piyasa fiyatlarının istihdam oluşturma, dışa bağımlılığın azaltılması, teknoloji ve ürün ihracatı perspektifleri doğrultusunda belirlenmesi gerektiği vurgulanmaktadır. Ayrıca, uzun vadeli enerji politikası hedefleri, talep beklentileri ve sistem maliyet gelişimi bağlamında farklı teknolojiler ve ağlar için üretim kapasitesinin entegre senaryo planlamasının önemi üzerinde durulmaktadır.

Aeration is the process by which the area of contact between water and air is increased, either by natural methods or by mechanical devices. This study investigated the most suitable design to provide a maximum air-demand ratio in the case of free surface flow in gated circular conduits. In the experiments performed for this purpose, as the parameters affecting the air demand ratio, the air inlet of each air vent was measured by opening air vents at regular intervals downstream for different conduit openings and different lengths of conduits for air-demand ratio depending on flow rates. In the study, it was observed that the air-demand ratios increased with the increase of the Froude number in all air vents. Although the Qa/Qw value was found to be 0.28 in.the 6 m conduits for the best air demand rate of 2.5% gate opening, the location of the air vent did not have a significant effect on the air-demand ratio. As a result, it has been understood that the suction downstream of the gated conduit flows does not show a local change. It is thought that the air sucked from the air vents is formed by the drag effect of the water.

This study evaluates the propagation of hydrological drought impacts on energy production using the multi-scalar Standardized Streamflow Index (SSFI) and Energy Drought Index (EDI) in a basin-scale hydropower context. The research focuses on analyzing short-term (SSFI3), medium-term (SSFI6), and long-term (SSFI12) indices through Innovative Trend Analysis (ITA) to identify temporal propagation patterns affecting normalized energy production. Hydrological and energy data from 1989 to 2024 were utilized to provide a comprehensive assessment of the relationship between drought conditions and hydropower generation. The results reveal strong correlations between short- and medium-term indices (SSFI3 and SSFI6) and energy production, with correlation coefficients of 0.65 and 0.63, respectively. This underscores the critical influence of short- and medium-term flow variability on hydropower systems. Long-term indices (SSFI12), while exhibiting a weaker correlation (0.52), offer valuable insights into the broader hydrological trends and their implications for climate-driven drought management. EDI analysis further highlights significant periods of drought and surplus, demonstrating the vulnerability of hydropower systems to prolonged drought conditions. Notably, post-2000 trends indicate an increase in the frequency and severity of drought events, emphasizing the pressing need for adaptive management strategies.This study underscores the importance of integrating hydrological and energy data to develop robust water-energy management strategies. It highlights the necessity of continuous monitoring, early warning systems, and the diversification of renewable energy portfolios to mitigate the risks posed by evolving climate scenarios. These findings provide a critical framework for enhancing the resilience and sustainability of hydropower systems in the face of increasing drought propagation under climate change.Questions of interest include:How do short-, medium-, and long-term hydrological conditions affect hydropower generation? How can Energy Drought Index (EDI) and SSFI metrics enhance the understanding of hydropower vulnerabilities? What strategies can mitigate the increasing risks of drought propagation under evolving climate scenarios? How can integrated water-energy management improve resilience and sustainability in hydropower systems?

In this study, the seasonal structure of the flow regime in the Zap Basin (Türkiye) was evaluated using flow data obtained from the E26A021 and D26A037 streamflow gauging stations representing the Upper and Lower basin sections. The timing of the annual flow regime was analyzed using the Centroid Timing (Ct) indicator, while the seasonal concentration of flow was evaluated using the Seasonality Index (SI). In addition, drought conditions affecting the basin were examined using the Standardized Precipitation Index (SPI) to provide a hydroclimatic context for interpreting possible changes in the flow regime. Temporal changes in the Upper basin were evaluated by comparing pre-dam (2000–2011) and post-dam (2013–2023) periods using the Mann–Whitney U test, while spatial differences between the Upper and Lower basin sections were analyzed using the Wilcoxon signed-rank test. The SPI results revealed an increase in the frequency and persistence of drought conditions in the basin, particularly after 2000. Despite these hydroclimatic changes, the Ct and SI values in the Upper basin section did not show a statistically significant temporal change. However, significant spatial differences were observed between the Upper and Lower basin sections in terms of SI values, indicating a stronger seasonal concentration of flow in the Lower basin. These findings suggest that changes in the flow regime in the Zap Basin are manifested primarily through spatial differences in seasonal intensity rather than shifts in timing. The combined use of Ct, SI, and SPI indicators provides a useful framework for understanding the relationship between drought conditions and seasonal flow regime characteristics in data-limited basins.