Akademik Veri Yönetim Sistemi
ENVIRONMENTAL EARTH SCIENCES, cilt.83, sa.17, 2024 (SCI-Expanded)
Drought indices, such as the Standardized Precipitation Index (SPI) and the Stream Flow Drought Index (SDI), are mathematical indicators that represent an overall decrease in average amounts of rainfall over a specific period of time. The changing values of SPI and SDI can be determined by trend analysis and can help decision makers in estimating and managing the future values of water resources on issues such as dam management and energy production. In this study, in addition to SPI12 and SDI12, trend analyzes of monthly precipitation and stream flow data affecting drought were also conducted. Mann-Kendall Test (MK), Spearman's Rho test, Sen-Innovative Trend Analysis (ITA) were chosen as trend analysis. As a result of the analysis, in precipitation performed with MK, an increasing trend at 95% significance level was detected in January, while no trend was found in the other months. While increasing trends were found in all months using SPI12, no trend was detected in SDI12. In Spearman's Rho test, no trend was detected in SDI12 and precipitation for all months, whereas increasing trend for January, February and April were detected for SPI12 and January for streamflow data. The analysis made with ITA was evaluated in two parts, graphically and statistically. The graphical method was carried out for monthly data. In statistical evaluation of ITA for SPI12 and SDI12, increasing trends were detected for all monthly data, however, in the graphical analysis, different results were obtained for each month, which did not fully support the results of the statistical analysis.