An Investigation of Hydrological Drought Characteristics in Kızılırmak Basin, Türkiye: Impacts and Trends

Abstract

Drought is a natural disaster that is generally defined as precipitations which are significantly below the precipitation recorded in normal times. Drought has been classified as meteorological, hydrological, agricultural, and socio-economic by many researchers. Hydrological drought takes place when deficiencies in the surface and ground waters occur as a result of the long-term lack of precipitation. In this study, a hydrological drought analysis has been performed for Kızılırmak Basin which is the second biggest basin of Turkey by using streamflow drought index (SDI) and innovative trend analysis (ITA) for the time scales of 1, 3, 6, 9, 12-month. Monthly mean streamflow records of 7 stations are obtained from the General Directorate of State Hydraulic Works (DSİ). Drought severity and drought duration which is two important drought characteristics have been calculated for each time scale with their occurrence term. Results have shown that Mild Drought and Wet (SDI≥0) have the highest percentage of occurrences. Using Run Theory, the longest lasted and highest drought has been noted in the SDI-12-time scale of E15A017 station with 149.72 and 103 months as severity and duration, respectively. From the highest severity and longest lasted droughts, it is seen that starting with 2000, the basin is exposed to the highest occurrence of droughts. ITA results have shown that in most of the SDI series of any time scale a trend is existent and these trends are mostly decreasing trends. Therefore, the results of this have shown that the basin needs to be kept from the potential effects of droughts with effective water resources management plan.