Tiruneh et al. (2026) Spatio-temporal analysis of drought frequency and severity in the Bilate Watershed, Ethiopia: A multi-scalar SPI Approach

Identification

• Journal: H2Open Journal
• Year: 2026
• Date: 2026-09-05
• Authors: Tilahun Alehegn Tiruneh, Teka Tadesse Dada, Kassaw Beshaw Tessema, Nigatu Toma Sana
• DOI: 10.1016/j.htopen.2026.100078

Research Groups

• Department of Hydraulic and Water Resources Engineering, Institute of Technology, Wolaita Sodo University, Wolaita Sodo, Ethiopia

Short Summary

This study examines meteorological drought in the Bilate Watershed, southern Ethiopia, using a multi-scalar SPI approach. The results show that drought characteristics vary considerably across time scales and locations.

Objective

• Characterize drought variability across short-, medium-, and long-term accumulation periods using SPI-3, SPI-6, and SPI-12.
• Compare drought frequency and severity among the eight meteorological stations and identify locations with contrasting drought characteristics.
• Assess the spatial and temporal distribution of drought and identify periods of widespread drought occurrence across the Bilate Watershed.

Study Configuration

• Spatial Scale: The study area covers approximately 5353.29 km² in the Rift Valley basin, southern Ethiopia.
• Temporal Scale: The analysis spans a 43-year period (1980–2022) with monthly rainfall data from eight meteorological stations.

Methodology and Data

• Models used: Standardized Precipitation Index (SPI)
• Data sources: Monthly rainfall data from eight meteorological stations covering 1980–2022

Main Results

• The analysis reveals that mild droughts were the most common, while severe and extreme droughts occurred less frequently but were associated with substantial rainfall deficits.
• Shorter SPI periods captured frequent short-term moisture fluctuations, whereas longer periods revealed more persistent deficits with greater implications for water-resource availability.
• Spatial analysis showed that the northern and northwestern highlands often experienced relatively severe drought conditions.

Contributions

• This study provides a clearer understanding of drought dynamics in the Bilate Watershed and supports improved drought monitoring, targeted water-resource planning, catchment management, and climate adaptation in southern Ethiopia.

Funding

• The research was funded by [project/program name] with reference code [reference code].

Citation

@article{Tiruneh2026Spatiotemporal,
  author = {Tiruneh, Tilahun Alehegn and Dada, Teka Tadesse and Tessema, Kassaw Beshaw and Sana, Nigatu Toma},
  title = {Spatio-temporal analysis of drought frequency and severity in the Bilate Watershed, Ethiopia: A multi-scalar SPI Approach},
  journal = {H2Open Journal},
  year = {2026},
  doi = {10.1016/j.htopen.2026.100078},
  url = {https://doi.org/10.1016/j.htopen.2026.100078}
}