Interrelationships Between NDVI, Surface Water, and Regional Hydro-Climatic Variables In the Sudd Wetland

Climate change and its variability impact water availability in wetlands, jeopardizing their ecosystems. This study focuses on the Sudd Wetland, Africa’s most extensive and one of the world’s largest tropical wetland systems. We analyzed historical climate data (temperature, rainfall) in the Sudd and its upstream regions to assess climate impacts on the wetland’s health (NDVI) and water conditions (surface water extent, lake height) using spatial and temporal trends. The study unveils distinct seasonal and long-term variations in vegetation and temporal fluctuations in surface water dynamics within the Sudd Wetland. While central areas experienced declining NDVI (vegetation cover), peripheries showed an increase. The wetland gained open water surface area, with a slight rise in permanent water (3%) and a significant increase in seasonal inundations (19%). All monitored water bodies in the Sudd displayed a gradual increase in surface water height. Climate shifts are observed as rising temperatures and increased rainfall trends. Annual and seasonal temperatures rose across the basin, with the January-Feburary season experiencing the most significant increase (~ 1.3 °C). Rainfall trends were mostly flat, except for the south-central and southeastern regions, where a statistically significant increase ranging from 5 mm to 17 mm per year was observed. Conclusive evidence from this paper could be used to assess water policy and management in the region while protecting key parts of the hydrologic cycle.