An ınvestigation of hydrological drought characteristics in Kızılırmak basin, Türkiye: Impacts and trends

Abstract

Drought is a natural disaster generally defined as precipitations significantly below the precipitation recorded in actual times. Many researchers classified drought as meteorological, hydrological, agricultural, and socio-economic. Hydrological drought occurs when deficiencies in the surface and ground waters occur due to 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 in Türkiye, using the Streamflow Drought Index (SDI) and Innovative Trend Analysis (ITA) for the time scales of 1, 3, 6, 9, 12-month. Monthly mean streamflow records for 7 stations are obtained from the General Directorate of State Hydraulic Works (known as DSI. Drought severity and duration, which are two important drought characteristics, have been calculated for each time scale with their occurrence terms. Results show 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-year, the basin is exposed to the highest occurrence of droughts. The results of the ITA analysis show that in most of the SDI series of any time scale, a trend is existent and these trends are mostly decreasing trends. Therefore, these results have shown that the basin needs to be kept from the potential effects of droughts with an effective water resources management plan