The status of transboundary rivers in Turkey

Turkey, like many countries today, faces challenges in efficiently developing and managing its water resources while working to maintain water quality and protect the environment. This situation causes that the transboundary rivers in Turkey have been the most important. In this study, issues relating the development and management of the transboundary rivers of Turkey are discussed. For this purpose, this paper analyses the general characteristics, climate and water resources, current water usage status, and energy potential of the transboundary rivers, namely Euphrates-Tigris, Çoruh, Orontes, Kura-Arax, and Maritza. In addition, two significance development plans, which are the Southeastern Anatolia Project (GAP) and the Çoruh River Development Plan located in the transboundary rivers, are evaluated. The total feasible hydropower potential of projects reaches 37896 GW h/yr when all planned projects are completed. This value corresponds to 16.5% of the annual electric energy production of the Turkey in 2011. The GAP will also irrigate 1058509 hectare of land area.     

Hierarchical approach to hydrological model calibration

Hydrological models have been widely used for water resources management. Successful application of hydrological models depends on careful calibration and uncertainty analysis. Spatial unit of water balance calculations may differ widely in different models from grids to hydrological response units (HRU). The Soil and Water Assessment Tool (SWAT) software uses HRU as the spatial unit. SWAT simulates hydrological processes at sub-basin level by deriving HRUs by thresholding areas of soil type, land use, and slope combinations. This may ignore some important areas, which may have great impact on hydrological processes in the watershed. In this study, a hierarchical HRU approach was developed in order to increase model performance and reduce computational complexity simultaneously. For hierarchical optimization, HRUs are first divided into two-HRU types and are optimized with respect to some relevant influence parameters. Then, each HRU is further divided into two. Each child HRU inherits the optimum parameter values of the parent HRU as its initial value. This approach decreases the total calibration time while obtaining a better result. The performance of the hierarchical methodology is demonstrated on two basins, namely Sarisu-Eylikler and Namazgah Dam Lake Basins in Turkey. In Sarisu-Eylikler, we obtained good results by a combination of curve number (CN2), soil hydraulic conductivity, and slope for generating HRUs, while in Namazgah use of only CN2 gave better results.     

Anatolian surface wave evaluated at GEOFON Station ISP Isparta, Turkey

We have studied seismic surface waves of 255 shallow regional earthquakes recently recorded at GEOFON station ISP (Isparta, Turkey) and have selected these 52 recordings with high signal-to-noise ratio for further analysis. An attempt was made by the simultaneous use of the Rayleigh and Love surface wave data to interpret the planar crust and uppermost mantle velocity structure beneath the Anatolian plate using a differential least-square inversion technique. The shear-wave velocities near the surface show a gradational change from approximately 2.2 to 3.6 km s^− 1 in the depth range 0–10 km. The mid-crustal depth range indicating a weakly developed low velocity zone has shear-wave velocities around 3.55 km s^− 1. The Moho discontinuity characterizing the crust–mantle velocity transition appears somewhat gradual between the depth range  25–45 km. The surface waves approaching from the northern Anatolia are estimated to travel a crustal thickness of  33 km whilst those from the southwestern Anatolia and part of east Mediterranean Sea indicate a thicker crust at  37 km. The eastern Anatolia events traveled even thicker crust at  41 km. A low sub-Moho velocity is estimated at  4.27 km s^− 1, although consistent with other similar studies in the region. The current velocities are considerably slower than indicated by the Preliminary Reference Earth Model (PREM) in almost all depth ranges.     

Controlling factors of recent clastic coastal sediments (Viransehir,Mersin bay,S Turkey)

The Plio-Quaternary conglomeratic sets within the marine environment of the Viranşehir coast (W Mersin, S Turkey) are responsible for the evolution of sandy and gravely beaches due to their control on various factors such as sea floor irregularity, wave energy, and organic activity. The conglomeratic sets close to the shoreline (50–150 cm) act as wave breakers, creating hard substratum and high energy, well-oxygenated environment for organisms like Patella sp., Phoronida worms and Brachidontes pharaonis (Fischer P. 1870). The boring activities of these organisms have disintegrated the sandy matrix of these sets. Finer-grained matrix sediments have been transported to the interset and open sea, while cobble–pebbles have been carried landwards and have created imbricated gravely beach deposits without matrix. Sandy beach is evolving where the conglomeratic sets away from the shoreline (5.0–10.0 m). In this example, sets form a bar; causing fivefold division as backshore, berm, surf zone, bar and offshore from land to sea. Poorly sorted, cobbles-pebbles cobbles and pebbles are found associated with the high-energy environments of bars, whilst well-sorted sands are observed in low energetic environments on shore. The sets and recent shell fragments are the main sources of coastal sediments in Viranşehir. However, the amount of shell fragments decrease towards the active river mouth. This is due to sediment and fresh water influx from the river causing deteriorated temperature, salinity and light penetration of the marine environment resulting in less organic diversity. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Sulfur-isotope distribution and contamination related to the Balya Pb–Zn Mine in Turkey

Sulfur-isotope (³⁴S) values and weight (%) of acid-volatile sulfur (AVS), chrome-reducible sulfide (CRS), elemental sulfur (ES), and acid-soluble sulfates were determined in Balya Mine ore rock, mine wastes, and Kocacay River and Lake Manyas sediments. Estimation of isotopic fractionation (³⁴S) between product sulfate and initial CRS (pyrite) was used to evaluate the progress of sulfide oxidation in the mine-waste area. Water- and acid-soluble sulfate produced from different mine-waste samples, such as metallurgical waste (MW) and waste rock (WR), in laboratory experiments also shows distinct ³⁴S values and allows identification of the acid-mine-drainage sources in the mine-waste area. Average ³⁴S_SO4values are –1.43 for MW (n=4) and +2.06 for WR (n=8). Short (24 hr) and long (60 days) term leach experiments were considered using alternating wet/dry conditions to simulate sulfate-production capacity and metal-discharge characteristics for MW and WR piles. Release of heavy metals follows the order of Pb²⁺ >Mn²⁺ >Zn²⁺ >Cu²⁺ for these pile samples. Values of ³⁴S_SO4 for river water that was collected after 3–4 h of heavy rainfall are close to values of ³⁴S_SO4 for water-soluble sulfates from mine-waste piles used in laboratory leach experiments.This revised version was published in February 2005 with corrections to the placement of the figures.     

Failures of structures during the January 24, 2020, Sivrice (Elazığ) Earthquake in Turkey

Natural Hazards - On January 24, 2020, a severe earthquake of magnitude Mw 6.8 hit the Sivrice district of Elaz?? province at 20:55 (17:55 GMT) local time. This earthquake caused...