Drought Analysis with Two Different Indices in Yeşilırmak Basin

Abstract

Reducing the negative effects of drought disaster, which is one of the most important parameters affecting the planning and management of water resources, has become very important today. Many methods have been proposed in the literature for the calculation of drought, which is used to express the periods when precipitation is significantly less than the average, and two of these methods, "Standardized Precipitation Index" and "Reconnaissance Drought Index" were applied to the Yeşilırmak basin in this study. 12-month standardized precipitation index and reconnaissance drought index analyzes were made and compared by using the monthly precipitation and evapotranspiration totals of 8 stations in the Yeşilırmak Basin for the period 1991-2020. The results show us that standardized precipitation index and reconnaissance drought index methods generally give similar signals for wet periods, but reconnaissance drought index method defines more extreme dry periods than standardized precipitation index method in extreme dry periods. While the reconnaissance drought index method defines more extreme dry periods than the standardized precipitation index method; It was observed that the standardized precipitation index method defined more extreme wet periods than the reconnaissance drought index method. In drought analysis, using an index based on more than one meteorological parameter (such as reconnaissance drought index) will give more reliable results instead of using an index based on a single parameter (i.e, standardized precipitation index). It has shown in this study that the effect of evapotranspiration values in drought calculation is very important by comparing it with reconnaissance drought index analysis and standardized precipitation index analysis.