Empirical methods for predicting suspended sediment load in Gediz River

It is essential to predict suspended sediment load for understanding river morphology, design of dams, water supply problems, management of reservoirs and determination of pollution levels in rivers. The suspended sediment load can be determined by means of several methods such as direct measurements at the sediment gauging stations, sediment rating curve, son modeling methods, and empirical methods which are based on experimental works. The objective of this study is first to determine the best empirical method for Gediz river and then to improve the determined method by genetic algorithm (GA). It is seen that the GA improved Brooks method can be used for Gediz River Basin. In addition, this method was compared with other soft computing (ANN, ANFIS) methods and its performance is found to be as good as them.Akarsu morfolojisinin anlaşılmasında, barajların projelendirilmesinde, içme ve kullanma suyu temin problemlerinde, havza yönetimi çalışmalarında, akarsudaki kirlilik seviyelerinin belirlenmesinde askıda katı madde yükünün doğru tahmini oldukça büyük önem taşır. Akarsulardaki askıda katı madde miktarı, sediment gözlem istasyonlarında yapılan doğrudan ölçümler, sediment anahtar eğrisi, esnek modelleme yöntemleri, deneysel çalışmalara dayanan yaklaşımlar gibi farklı yöntemlerle belirlenebilmektedir. Bu calışmada, Gediz Nehri için en uygun ampirik bağıntının belirlenmesi ve Ege Bölgesi Gediz Havzası için bulunan bu bağıntının genetik algoritma ile iyileştirilmesi amaçlanmıştır. Çalışma sonucunda, genetik algoritma ile iyileştirilmiş Brooks yönteminin Gediz Havzasında uygulanabileceği belirlenmiştir. Ayrıca, bu metod diğer esnek (ANN, ANFIS) metodlar ile karşılaştırılmış ve onlar kadar iyi performans göstermiştir

İklim değişikliği altında su yönetimi ve büyük barajların rezervuarına ve dolusavak tasarımına etkileri

İklim değişikliği, esas olarak su kaynaklarınıetkileyen endişe verici bir konudur. Afganistan, iklim değişikliğine karşı ensavunmasız ülkelerden biridir. Ülke, on yıllardır süren savaş ve çatışmalardankaynaklanan veri eksikliği de dahil olmak üzere birçok zorlukla karşı karşıyakalmıştır. Bu araştırma, iklim değişikliğinin Afganistan'ın farklıbölgelerindeki iki havza üzerindeki etkilerini araştırmayı amaçlamaktadır.Kokcha ve Shakardara havzaları birbirinden farklı özelliklere sahiptir. Çalışma2050-2069 ve 2080-2099 dönemlerinde Representative Concentration Pathways (RCP4.5ve RCP8.5) senaryoları dikkate alınarak yapılmıştır. Gelecekteki iklimverilerini hazırlamak için, Çift Modelli Karşılaştırma Projesi Aşama 5'ten(CMIP5) İklim Üzerine Disiplinlerarası Araştırma Modeli (MIROC5) kullanılmıştır.Her iki havzada da hidrolojik modelleme için SWAT modeli kullanılmıştır.2050-2069 ve 2080-2099 dönemlerinde RCP4.5 senaryosu dikkate alındığında Kokchahavzasında yıllık su kapasitesinde sırasıyla yüzde 36,14 ve yüzde 32 azalmabeklenmektedir. Ancak aynı dönemlerde RCP8.5 senaryosuna göre bu azalma yüzde32,34 ve yüzde 20,25 olarak tahminlenmektedir. Bir barajın bulunduğu Shakardarahavzasında, su mevcudiyeti RCP4.5 senaryosuna göre yüzde 71,47 ve yüzde 67,88düşüş göstermekte ve buna göre söz konusu dönemlerde RCP8.5 senaryosu altındaise &nbsp;yüzde 63,03 ve yüzde 65,2 oranında birazalma beklenmektedir. Havzadaki barajın (SWAD) 31,74 milyon metreküp sutedarik edecek şekilde tasarlanan rezervuarı, her iki senaryoda da gelecekte sukıtlığı ile karşı karşıya kalacaktır. Bu çalışmanın sonucu, her iki havzada daiklim değişikliği dikkate alınarak su yönetimi planlaması için kullanılabilir.Climate change is a concerning issue that mainlyaffects water resources. Afghanistan is one of the most vulnerable countries toclimate change. The country has many challenges including data deficiency dueto decades of war and conflicts. This research aimed to investigate the impactsof climate on Kokcha and Shakardara watersheds, which have variouscharacteristics. The study was performed considering RepresentativeConcentration Pathways (RCP4.5 and RCP8.5) scenarios in the periods of2050-2069 and 2080-2099. The Model for Interdisciplinary Research on Climate(MIROC5) from Coupled Model Intercomparison Project Phase 5 (CMIP5) was used toprepare future climate data. Soil and Water Assessment Tool (SWAT) model wasemployed for hydrological modeling in both watersheds. In the Kokcha basin, theannual water capacity indicated 36.14 percent and 32 percent decreaseconsidering the RCP4.5 scenario in the periods of 2050-2069 and 2080-2099respectively. However, it decrease by 32.34 percent and 20.25 percent usingRCP8.5 at the same periods. In the Shakardara basin with an existing reservoir,water availability indicates 71.47 percent and 67.88 percent declineconsidering RCP4.5 scenario and will decrease by 63.03 percent and 65.2 percentunder the impacts of the RCP8.5 scenario in the mentioned periods accordingly.The existing Shah wa Arus Dam (SWAD), which was designed to supply 31.74 x 106cubic meters, will face water scarcity in the future under both scenarios. Theresult of this study can be used for water management planning consideringclimate change in both watersheds.</p

Evaluation of satellite-based precipitation data sets in hydrological modeling using Soil & Water Assessment Tool (SWAT)

In the case of changing climate and water crises, the design of every hydraulic structure requires hydrological modeling to investigate the effects of climate change in the region. For this purpose, climate data are the key factor in making a model. However, data scarcity is an issue in developing countries and remote areas. Satellite-based and remote sensing data are an alternative option to be used instead of ground-based meteorological data. Various satellite-based data sets are available to be employed in modeling; nevertheless, the researchers face the challenge of choosing the most precise and reliable data set that should be well suited to the targeted area. In this study, three satellite-based precipitation datasets were investigated using Soil &amp; Water Assessment Tool (SWAT) to analyze their accuracy in the hydrological modeling of the Shakardara watershed, located in the Northwest of Kabul city in Afghanistan. In this research, hydrological modeling was performed using precipitation data from Tropical Rainfall Measurement Mission (TRMM_3B42), Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS_v2), and NASA Prediction of Worldwide Energy Resource (NASA POWER) datasets separately. The models were calibrated and validated based on observed river discharge. The acquired result shows the TRMM_3B42 as the most precise and compatible with the region than CHIRPS_v2 and NASA POWER data sets. This research can be used as a reference for hydrologists and water infrastructure designers in the area and other data-scarce regions.</p

Assessment of climate change effects in Aegean river basins: the case of Gediz and Buyuk Menderes Basins

IPCC Fourth Assessment Report (AR4) discloses that the global climate system is undoubtedly warming. Observations have shown that many natural systems, including hydrologic systems and water resources, are being affected by regional climate changes, particularly temperature increases. Eventually, these effects will have to be considered in water resources planning and management. Accordingly, need is indicated to evaluate the impact of expected climate change on hydrology and water resources at regional and local levels. The presented paper summarizes the results of the sub-project studies under the United Nations Development Program-Global Environment Facility (UNDP-GEF) Project. The studies cover the generation of climate change scenarios, modeling of basin hydrology, and testing the sensitivity of runoff to changes in precipitation and temperature. Simulation results of the water budget model have shown that nearly 20% of the surface waters in the studied basins will be reduced by the year of 2030. By the years 2050 and 2100, this percentage will increase up to 35% and more than 50%, respectively. The decreasing surface water potential of the basins will cause serious water stress problems among water users, mainly being agricultural, domestic and industrial water users