Mulangwa et al. (2026) Lake Victoria to the Sudd Wetland: flood wave timing, connectivity and wetland buffering across the White Nile

Identification

• Journal: Hydrology and earth system sciences
• Year: 2026
• Date: 2026-08-20
• Authors: Douglas Mulangwa, Evet Naturinda, Charles Koboji, Benon Zaake, Emily C. L. Black, Hannah Cloke, Elisabeth Stephens
• DOI: 10.5194/hess-30-5297-2026

Research Groups

• Department of Meteorology, University of Reading
• Department of Geography and Environmental Science, University of Reading
• Department of Water Resources Monitoring and Assessment, Ministry of Water and Environment, Kampala, Uganda
• Directorate of Hydrology and Survey, Ministry of Water Resources and Irrigation, Juba, South Sudan
• Red Cross Red Crescent Climate Centre, The Hague, 2521 CV, the Netherlands

Short Summary

This study quantifies system-scale flood-wave transit time from Lake Victoria to the Sudd Wetland in the White Nile Basin. The results show that flood waves take approximately 17 months to travel through the system, much longer than previously thought.

Objective

• Investigate the timing and propagation of flood waves along the White Nile system.
• Quantify the role of storage-mediated processes and long hydrological memory in shaping flood behavior.
• Provide a physical basis for linking upstream hydroclimatic variability to downstream wetland dynamics and associated greenhouse gas emissions.

Study Configuration

• Spatial Scale: The study focuses on the White Nile Basin from Lake Victoria in Uganda to the Sudd Wetland in South Sudan, encompassing a complex integrated river-lake-wetland system.
• Temporal Scale: The analysis spans 2002-2024, with a focus on the 2019-2024 period of extreme flooding.

Methodology and Data

• Models used: None specified.
• Data sources:
  • CHIRPS rainfall estimates
  • Hydrological data from the Directorate of Water Resources Management (DWRM) in Uganda
  • MODIS-based inundation masks produced by the World Food Programme (WFP)

Main Results

• The study found that flood waves take approximately 17 months to travel through the White Nile system, much longer than previously thought.
• The results show strong attenuation and long hydrological memory within the White Nile-Sudd system.
• The analysis highlights the importance of upstream storage and delayed floodwave propagation in shaping downstream inundation.

Contributions

• This study provides a physical basis for linking upstream hydroclimatic variability to downstream wetland dynamics and associated greenhouse gas emissions.
• The results challenge prevailing assumptions regarding the speed and mechanism of flood propagation in large river systems.
• The study contributes to improving the representation of hydrological connectivity, basin-scale memory, and inland water storage dynamics in both regional and global hydrological and Earth system models.

Funding

• This research was supported by [insert funding agencies or projects].

Citation

@article{Mulangwa2026Lake,
  author = {Mulangwa, Douglas and Naturinda, Evet and Koboji, Charles and Zaake, Benon and Black, Emily C. L. and Cloke, Hannah and Stephens, Elisabeth},
  title = {Lake Victoria to the Sudd Wetland: flood wave timing, connectivity and wetland buffering across the White Nile},
  journal = {Hydrology and earth system sciences},
  year = {2026},
  doi = {10.5194/hess-30-5297-2026},
  url = {https://doi.org/10.5194/hess-30-5297-2026}
}