The Eastern Anatolia Region drought analysis

Water, on Earth, is a fundamental element that sustains life and facilitates the cycle of hydrological events, serving as a vital resource for all living organisms. Water is in constant circulation across the Earth's atmosphere, seas, oceans, and land, but it is a finite resource. Water scarcity, known as drought, is a natural disaster resulting from the absence of water in time and space. Drought can manifest in various forms, such as meteorological, hydrological, and agricultural drought. Characterized by a lack of precipitation and inappropriate distribution of rainfall, drought is a climatic abnormality with significant economic, social, and environmental impacts. Due to its profound influence on the Earth's water, atmospheric, and climatic systems, drought has become a subject of great interest among researchers. Moreover, drought can occur anywhere on the planet, under any climatic conditions, at any time, making effective water resource management crucial. The design and development of water resources, distribution and conveyance systems, and various agricultural sectors depend largely on how drought is managed and mitigated. Determining the exact onset and cessation of drought is considerably challenging compared to other natural disasters. Analyzing past periods before experiencing drought and making preparations and accurate planning during drought periods can help mitigate its adverse effects. Consequently, research focusing on the analysis of drought and its future severity has gained importance. Upon reviewing the literature, it is evident that a comprehensive and up-to-date assessment of drought in the eastern regions of Turkey has not been sufficiently explored. Therefore, this study aims to evaluate historical droughts in the region, update the drought status using meteorological data, and identify vulnerable areas. This encompasses necessary updates for more accurate assessment or prediction of potential disasters in the future. In this thesis study, 61 years (1961-2021) of monthly total rainfall data for 14 meteorological stations within the boundaries of the Eastern Anatolia Region were obtained from the Meteorology Regional Directorate. Drought analysis calculations for the region were performed using these data. Two meteorological drought indices based on precipitation were used to identify droughts. These methods are the Standardized Precipitation Index (SPI) and the newly introduced Actual Precipitation Index (API) in the literature. The analyses were conducted for drought severity intervals at 1, 3, 6, 9, and 12-month periods. Since continuous series are required for drought analysis, missing months and years were completed using the normal ratio method. For the Standardized Precipitation Index (SPI), the SPI-SL-6.EXE computer software was used for time scales, while for the Actual Precipitation Index (API), a Matlab code developed by Zekai Şen and colleagues was used. In the research, the results were classified according to the indices, the outcomes of the analyses were visualized using the Excel computer program, and the results were compared with each other. As a result of the study, it was determined that, according to SYİ values, the longest drought periods for all time spans mostly began in the years 1980 and 2000. Furthermore, when looking at API values, it was observed that in almost all examined stations, the number of drought years exceeded the number of rainy years. According to the results obtained, it was concluded that approximately 33% of the region was slightly rainy, 41% was mildly drought-stricken, and 16% was moderately drought-stricken. By examining all SYİ and API values, the lowest and highest values were determined, and the driest and wettest months were identified.