Türkiye, situated in the Mediterranean Basin, is highly susceptible to drought due to its predominantly semi-arid climate. This study aims to evaluate the temporal and seasonal dynamics of drought across Türkiye by employing three distinct drought indices: the Standardized Precipitation Index (SPI), the Standardized Precipitation Evapotranspiration Index (SPEI), and the Percent of Normal Index (PNI). Long-term spanning the period 1972–2023, monthly areal average precipitation data derived through Kriging interpolation and monthly average temperature data from 255 meteorological stations were used. Drought assessments were conducted on both monthly and seasonal scales, with SPI and SPEI calculated at 3-, 6-, 9-, 12-, and 24-month timescales to capture meteorological, agricultural, and hydrological drought characteristics. The results revealed that the most severe drought occurred during 2007–2009 with nationwide SPI values dropping below − 2.0. Severe droughts (SPI < − 1.5) were observed in approximately 18% of the study period, with summer droughts being 30–35% more frequent than winter droughts. During 2020–2023, more than 70% of stations simultaneously experienced drought conditions, highlighting the increasing influence of temperature-driven evapotranspiration. Notably, SPEI values were consistently lower than SPI during summer and autumn, reflecting the intensifying role of rising temperatures and Potential Evapotranspiration (PET), while PNI corroborated these findings and emphasized Türkiye’s heightened drought sensitivity during the summer season. This study demonstrates the added value of temperature-based indices in drought monitoring and provides essential insights for, drought early warning systems, and water resource management in drought-prone regions. The Mann–Kendall analysis indicates an overall increase in drought severity after 2000, marked by temperature-driven summer drying and a slight winter wetting tendency.

Türkiye için küresel ısınma etkisi ile yağışların azalacağı, buharlaşma ve sıcaklık değerlerinin artacağı tahmin edilmektedir. Bu etkenler göz önüne alındığında göl, rezervuar gibi su kütlelerinde ciddi seviye ve hacim düşüşleri meydana gelebilecektir. Bu çalışmada, Burdur Gölü ele alınarak iklim değişikliği etkisi altında göl su seviyesindeki değişimler incelenmiştir. İlk olarak, 1975-2020 yılları arasındaki göl parametreleri ile iklim parametreleri arasındaki ilişki korelasyon yöntemi ile irdelenmiştir. Daha sonra, 2021-2050 yılları arasındaki göl seviye ve hacim değişim tahminlerine iklim projeksiyonu tahminleri eklenmiştir. İklim projeksiyonlarına göre sıcaklığın referans döneme göre %11,38 arttığı, yağışların %4,5 azaldığı ve buharlaşmanın ise %15 arttığı görülmüştür. Yapılan analizler sonucunda Burdur Gölü su seviyesinin 1975-2020 periyodunda düşüş trendinde olduğu ve bu durumun 2021-2050 periyodunda devam edeceği gözlenmiştir. Ayrıca, yapılan korelasyon analizleri sonucunda göl seviyesi ile buharlaşma arasında (-0,6452) negatif yönlü orta derecede anlamlı ilişki, göl seviyesi ile yağış arasında ise (-0,1066) negatif yönlü çok zayıf derecede ilişki olduğu belirlenmiştir.

Water scarcity is becoming a common problem due to urbanization, industrialization, rapid population growth, and climate change. The situation is exacerbated in semi-arid and arid regions due to low or no rainfall and the resulting pronounced seasonality of river flows. Accurate assessment of reservoir operational performance plays a critical role in water resource sustainability and utilization. In this study, Water Evaluation and Planning (WEAP) models were developed to evaluate the operational performance of five reservoirs in the Yesilirmak Basin in Turkey. Since each reservoir is a single reservoir system, calibration of the WEAP model involved adjusting the approximate rule curves derived by the sequent peak algorithm and the allocation coefficient during hedging until the simulated reservoir storage states matched the observed ones as closely as possible. The agreement of the simulated storage capacities of the WEAP model with the measured volumes was evaluated using the coefficient of determination (R ²) and the Nash-Sutcliffe model efficiency coefficient (NSE). The results demonstrate that the WEAP model can be used to design and plan the operational strategies for the reservoirs in the Yesilirmak Basin. The performance of the reservoirs operated with the designed rule curves was evaluated using the reliability, resilience, vulnerability, and sustainability indices. For Cakmak, Corum and Yenihayat reservoirs, it is shown that these reservoirs are sufficient to meet the demand. The vulnerability of Alaca reservoir is only 1%, which is negligible. The vulnerability for Yedikir is 24% and the failure cannot be ignored.

En tr Geosynthetics; Geotextile, geomembrane, geonet, geocomposite and similar products are materials that provide the functions of natural building materials (sand, gravel, clay, etc.). Developments in the production network have increased the use of geosynthetics in the construction sector. Geosynthetics are widely used in deep excavation and road projects. In geotechnical engineering, geosynthetics are used especially in solving slope stability problems. The high stresses and deformations resulting from the stability losses of the slopes have led the engineers to develop slope reinforcement systems. In this study, geotextile was used in order to affect long term behavior of slope stability and to counter the underground water level. Samples both with and without geotextiles with the same slope angle were resolved by limit equilibrium method in the study. In each analyzes, the ground deformation and factor of safety were compared. The contribution of geotextiles to increasing bearing capacity of soil is emphasized. Geosentetik; geotekstil, geomembran, geonet, geokompozit ve buna benzer ürünler, doğal yapı malzemelerinin (kum, çakıl, kil vb…) gördüğü işlevleri sağlayan malzemelerdir. Üretim ağındaki gelişmeler, inşaat sektöründe geosentetik kullanım alanlarını arttırmıştır. Geosentetiklerin, derin kazı ve yol projelerinde kullanım alanları oldukça yaygındır. Geoteknik mühendisliğinde geosentetikler özellikle şev stabilitesi problemlerinin çözülmesinde kullanılmaktadır. Şevlerin stabilite kayıpları sonucunda oluşan yüksek gerilme ve deformasyonlar mühendisleri şev güçlendirme sistemleri geliştirmeye yönlendirmiştir. Şev stabilitesinin uzun dönemdeki davranışını etkilemek ve yer altı su seviyesine karşı koymak amacıyla bu çalışmada geotekstil kullanılmıştır. Çalışmada, aynı şev açılarına sahip geotekstil kullanılan ve kullanılmayan örnekler limit denge yöntemi ile çözümlenmiştir. Her iki analizde meydana gelen zemin deformasyonları ve güvenlik katsayıları karşılaştırılmıştır. Geotekstillerin zemin taşıma gücünün artırılmasına olan katkısı vurgulanmıştır.

Understanding long-term variations in temperature and precipitation is essential for interpreting regional hydroclimatic behavior and detecting potential shifts in water availability. This study analyzes annual and seasonal temperature–precipitation trends in the Yeşilırmak Basin, Türkiye, using data from seven meteorological stations over a 38-year period (1975–2012). The Randomness Test, Mann–Kendall (MK), and Innovative Trend Analysis (ITA) were applied to detect trends. In addition, a climograph was constructed to characterize seasonal climatic patterns. The climograph for Tokat and Dökmetepe stations shows May precipitation to be 40–50% higher than in winter, while August precipitation is nearly 89% lower than in May. Temperatures rise by approximately 20 °C from January to July, reflecting continental climatic characteristics influenced by the semi-arid transition between northern and central Türkiye. Results indicate statistically significant warming trends at confidence levels above 90%, particularly during summer and autumn, with autumn temperatures increasing by approximately 0.03–0.05 °C per year (Z = 2.3–2.5) at most stations. Precipitation exhibited moderate increases at certain stations, while overall patterns remained steady. While MK and ITA yielded largely consistent results, ITA proved advantageous in weak or borderline cases by detecting structural patterns across value zones. Across all seasonal and annual analyses, ITA identified additional trends in approximately 83% of the cases where MK detected no significant change, corresponding to 25 out of 30 seasonal comparisons. Moreover, in over 92% of statistically significant MK results, ITA outcomes were fully consistent, reinforcing its robustness.

En tr The economic life of the dams is determined by the sediment load from their own basin. The most important factor terminating the life of the dam is filling of dead volume of the reservoir by solid materials (sediment, sedimentation, deposit material) carried by the river. In this study, sediment deposition in Çakmak Dam built on Abdal stream of Yeşilırmak Basin was investigated. Using the bathymetric maps of the dam reservoir belonging to 1988 and 2014 years, the bottom profiles and cross-sections at regular intervals were drawn by using NetCad 7.6 program. The elevation differences occurred by sediment loads were determined from drawing bottom profiles. In addition, using the elevation-area-volume method, the volumetric and areal losses of water in reservoir dead, active and total volume for 26 years were calculated. As a result, the volume of the dam was filled with the sediment. From the results, it has been observed that up to 10 meters of elevation occurs on the bottom of the reservoir due to sediment deposition. Approximately 30% of the dead volume determining the useful life of the dam was filled with sediment. Barajların ekonomik ömrü, havzasından gelen sediment yüküne göre belirlenmektedir. Baraj ömrünü sonlandıran en büyük faktör, akarsu tarafından taşınan katı maddelerin (sediment, rüsubat, çökelti maddesi) baraj rezervuarının ölü hacmini doldurmasıdır. Bu çalışmada, Yeşilırmak Havzası Abdal akarsuyu üzerine inşa edilmiş Çakmak Barajındaki sediment birikimi incelenmiştir. Baraj rezervuarının 1988 ve 2014 yıllarına ait batimetrik haritalarından yararlanılarak NetCad 7.6 programı ile belirli aralıklarla boykesitler alınmış ve taban profilleri çizilmiştir. Çizilen rezervuar taban profillerinden sediment etkisiyle oluşan kot farkları tespit edilmiştir. Ayrıca, kot-alan-hacim yöntemi kullanılarak, 26 yıllık süreçte rezervuar ölü, aktif ve toplam hacminde yer alan suyun hacimsel ve alansal oluşan kaybı hesaplanmıştır. Sonuç olarak, baraj hacminin sediment ile dolan hacmi elde edilmiştir. Elde edilen bulgulardan, sediment birikimi nedeniyle rezervuar tabanında 10 metreye kadar yükselmeler meydana geldiği görülmüştür. Barajın faydalı ömrünü belirleyen ölü hacminin yaklaşık olarak %30’unun sediment ile dolduğu belirlenmiştir.