Detection of changes over the long term for a series of hydrological variables is an important and critical issue, which is subject to increasing interest. In this study, trend analysis of the streamflow of the Euphrates basin, which is the biggest basin in Turkey, is carried out. The non-parametric trend tests (Mann–Kendall and Spearman's rho) are applied to annual average, minimum and maximum streamflow data of 22 selected stations in the Euphrates basin. All the streamflow records date back over at least 24 years, with lengths in the range 24–44 years. The Mann–Kendal rank correlation test is used to determine the year in which trends begin. The linear slopes of trends are calculated by using Sen's estimator of slope technique. Based on the test's procedures, with respect to annual minimum streamflow, significant decreasing trends are detected for six stations and an upward trend is found for only one station. While no trend appears relating to annual maximum streamflow for any station, a decreasing trend is found with respect to annual mean streamflow for one station. The results are expected to assist water resources managers and policy makers in making better planning decisions in the Euphrates basin.

Abstract:The purpose of this research is to evaluate farmers' risk perception towards climate change in dry farming areas of theŞanlıurfa province in Southeastern Anatolia Project (GAP) Region, Turkey, and their willingness to pay for adaptation practices and explore the potential factors that contribute to the understanding of climate change. The main material of this research comes from a sample of 466 farmers among 32,809 inŞanlıurfa who were chosen via a simple random sampling method. Sampling was conducted in 2014 and participants were interviewed face to face by questionnaires and local interviewers were used in order to maximize the reliability of the results. The logistic regression and fit tests were used for analysis. The results indicate that 53% of farmers have a risk perception about climate change and 62% of farmers accept paying for adaptation practices to reduce its potential effects. Explanatory affecting factors, such as age, agricultural income, amount of land owned, farming experience, agricultural credit usage, household numbers, non-agricultural manpower, education level and water perception, significantly explained the risk perceptions. This study is one of the first of its type in GAP-Şanlıurfa, Turkey. Therefore, the results could be helpful for decision-and policy-makers to develop adaptive strategies.

New investigation techniques for detecting hydro-meteorological data trends are required due to significant changes in precipitation and streamflow affecting the planning and operation of water resources. In this study, the trends analysis is carried out for the observation of climatic and hydrologic parameters such as temperature, humidity, precipitation and streamflow in the Euphrates Basin located in the Southeastern Anatolia Project (referred to as GAP from the Turkish acronym for Güneydoǧu Anadolu Projesi) region, which is the most important integrated water resources project in Turkey. The relationships between different meteorological and hydrological parameters in the basin are evaluated using the overlay mapping technique, popular in various engineering disciplines. The significant trends are indicated on the thematic maps and the visible changes are observed in different parts of the basin. Decreasing trends are detected in minimum streamflow, while the increasing trends in the annual mean and maximum temperature and in the annual mean and maximum humidity parameters are observed for many stations. The study concludes that the overlay mapping technique can be used effectively to observe the climatic changes and trends in hydrometeorological variables. The results are expected to help water resources managers and policy makers in decision-making for better planning in water resources planning and management.

A general approach is presented for risk engineering and identification of the risk benefits analysis, goals and limits for risk evaluation in certain applications by considering the first-degree secondary moment methods. A computer program is developed in the Java language (DAM RISK) with the aim to determine the safety levels of spillways in existing dams (or dams in the planning or construction phase). In consideration of a possible risk, observed overflow values are used, with the purpose of the rehabilitation values that need to be known, thus producing data ready for technical and financial analysis. This program is used to perform risk analysis for the Kürtün and Oymapınar dams in Turkey with the purpose dam rehabilitation at risk. Different spillway dimension and the change in risk for the reservoir damping factors are also presented. The most important conclusion for planners and risk evaluators is the graph that shows the riskless region in spillway dimensions. Various features of the computer program and areas in which it might be further developed are considered in detail. The results of the applications carried out are given in terms of risk evaluations.

Drought is a phenomenon of climate and is one of the catastrophic events that cause much damage on each occurrence. One of the ways of drought adjustment, evaluation and drought monitoring is based on indicators that can be used to determine its extent and continuity in a region. In this study, drought analysis (the duration and severity of drought) in the north Iraq region was studied by using the Standardized Precipitation Index (SPI) for time intervals of 1, 3, 6, 9 and 12 months. That feature of this method helps to compare the drought events in different places and scales. To observe dry and wet periods and the severity and length of drought monthly rainfall data of 15 meteorological stations of the northern Iraq provinces from 1979 to 2013 were used. Calculations were performed on the SPI by using the SPI code in MATLAB computer software. The results of the study showed that the continuity of dry periods in the 6, 9 and 12 month periods was higher than in the 1 and 3 month time intervals. Moreover, according to the calculation, the driest year was observed in 2008. This analysis is essential because it gives full information about the longest dry and wet periods for all stations of the region.