Coulibaly et al. (2025) Estimation of Current Agricultural Drought in the District des Savanes (Northern Côte d’Ivoire)

Identification

• Journal: Open Journal of Modern Hydrology
• Year: 2025
• Date: 2025-11-28
• Authors: Léréyaha Coulibaly, Kouadio Assemien François Yao, Ismaïla Ouattara, Moussa Ouedraogo, Seydou Diallo, Amidou Dao, Emile Gneneyougo Soro, Bamory Kamagate
• DOI: 10.4236/ojmh.2026.161002

Research Groups

• Department of Mines and Reservoirs, Training and Research Unit in Geological and Mining Sciences, University of Man, Man, Côte d’Ivoire
• Geosciences and Environment Laboratory, Training and Research Unit in Environmental Sciences and Management, Nangui Abrogoua University, Abidjan, Côte d’Ivoire

Short Summary

This study investigated the spatio-temporal variability of soil moisture to estimate agricultural drought in the District des Savanes, Côte d’Ivoire, from 1981 to 2022, revealing a predominant intensification of agricultural drought since 1991, despite intermittent recoveries.

Objective

• To analyze, based on soil moisture data, the recent dynamics of agricultural drought in the District des Savanes (Northern Côte d’Ivoire).

Study Configuration

• Spatial Scale: District des Savanes, northern Côte d’Ivoire, covering 40,323 km².
• Temporal Scale: 1981-2022 (42 years).

Methodology and Data

• Models used:
  • Standardised Soil Water Index (SSWI) at a six-month cumulative time scale (SSWI-6).
  • Pettitt test for breakpoint detection.
  • Mann-Kendall test for monotonic trend detection.
  • Sen’s Slope for trend magnitude quantification.
  • Inverse Distance Weighting (IDW) interpolation for spatial analysis.
  • RStudio with SPEI 1.8.1 and Trend 1.1.5 packages.
  • QGIS 3.4.12 and ArcGIS for spatial processing and mapping.
• Data sources:
  • Hydro-climatic data (soil moisture) derived from satellite observations.
  • NASA POWER Climate Data Access database, providing monthly global water balance and climate information.
  • Data spatial resolution: 0.5° × 0.625°.

Main Results

• The SSWI-6 time series revealed predominantly negative trends, indicating an intensification of agricultural drought across the District des Savanes since 1991.
• A significant drought episode emerged in 1994 and became widespread across the district by 2010, with the exception of the Korhogo region.
• The duration of the most frequent agricultural droughts exceeded five months, particularly affecting Boundiali, Ferkessédougou, and Kong.
• A slight recovery in soil moisture was observed between 1995 and 2001, but this improvement was temporary.
• Key breakpoints in the SSWI-6 series were detected in 1991, 1992, and 2009, reflecting significant climatic disturbances.
• Stations M’Bengué (S7), Ouangolodougou (S8), and Tingrela (S10) showed the most pronounced drought progression with absolute Sen’s slopes of 9.35 × 10⁻⁴, 8.63 × 10⁻⁴, and 9.88 × 10⁻⁴, respectively.
• Before the identified breakpoint (e.g., pre-1991), most localities exhibited significant negative trends in soil moisture, while after the breakpoint, negative trends weakened, and some areas showed reversals towards positive trends, suggesting relative soil moisture recovery.
• Total drought proportions ranged from 49% to 51% across stations, with mild droughts being the dominant category (32% to 35%). Severe (3% to 5%) and extreme (2%) droughts were less frequent but occurred across all stations.

Contributions

• Provides a comprehensive spatio-temporal assessment of agricultural drought dynamics in the District des Savanes, a strategically important agricultural region in northern Côte d’Ivoire, using the Standardized Soil Water Index (SSWI-6).
• Identifies specific breakpoints and long-term trends in soil moisture, confirming a general drying process since 1991, interspersed with periods of temporary recovery.
• Maps the spatial heterogeneity of drought intensity and duration, highlighting areas of greater vulnerability and localized resilience within the district.
• Offers critical insights for developing targeted and sustainable water resource management and agricultural planning strategies to enhance resilience against future drought impacts in the region.

Funding

Not explicitly stated in the paper.

Citation

@article{Coulibaly2025Estimation,
  author = {Coulibaly, Léréyaha and Yao, Kouadio Assemien François and Ouattara, Ismaïla and Ouedraogo, Moussa and Diallo, Seydou and Dao, Amidou and Soro, Emile Gneneyougo and Kamagate, Bamory},
  title = {Estimation of Current Agricultural Drought in the District des Savanes (Northern Côte d’Ivoire)},
  journal = {Open Journal of Modern Hydrology},
  year = {2025},
  doi = {10.4236/ojmh.2026.161002},
  url = {https://doi.org/10.4236/ojmh.2026.161002}
}

Generated by BiblioAssistant using gemini-2.5-flash (Google API)