Development of an annual drought classification system based on drought severity indexes

Area of Science:

• Hydrology
• Climatology
• Environmental Science

Background:

• Drought characterization is crucial for water resource management in river basins.
• Understanding drought occurrence and intensity aids in developing effective mitigation strategies.
• The Doce River Basin faces significant hydrological variability.

Purpose of the Study:

• To characterize drought occurrence and intensity in the Doce River Basin.
• To develop and evaluate a drought classification system.
• To compare the performance of four different drought indices.

Main Methods:

• Evaluation of four drought indices: Percent of Normal Precipitation (PNP), Deciles Method (DM), Rainfall Anomaly Index (RAI), and Standardized Precipitation Index (SPI).
• Annual index calculation using precipitation data from 89 stations (1985-2015).
• Application of the Thiessen Polygons method to determine average precipitation across nine analysis units (AUs).

Main Results:

• The year 2014/2015 experienced the most severe drought in the Doce River Basin over the 30-year study period.
• Critical drought years identified include 1994/1995, 2000/2001, and 2014/2015.
• The developed annual drought classification system effectively identified drought events.

Conclusions:

• The Doce River Basin experiences severe climatic drought conditions approximately every seven years.
• The proposed drought classification system is efficient for identifying drought events.
• The study provides valuable insights for drought management and planning in the region.