Rising lake levels in central East Africa are driven by increasing rainfall and land-use intensification

• Published in: Journal of hydrology. Regional studies 2024-12, Vol.56, p.101999, Article 101999
• Main Authors: Byrne, Aidan, Norris, Ken, Chadwick, Michael A., Avery, Sean, Olaka, Lydia, Tebbs, Emma J.
• Format: Article
• Language: English
• Subjects: biodiversity; Climate; climate change; drought; Eastern Africa; Flooding; forests; freshwater; Hydrology; infrastructure; lakes; land use; Landcover change; population growth; rain; Remote sensing; satellites; urban development; Water levels; water storage; watershed management; watersheds
• ISSN: 2214-5818; 2214-5818
• DOI: 10.1016/j.ejrh.2024.101999

375 lakes across the East African Rift System East African Rift System lakes provide a critical region of freshwater biodiversity and support the livelihoods of millions of people. Since 2010, water levels have risen at many Kenyan Rift System lakes flooding settlements, destroying infrastructure and impacting biodiversity, whereas several Ethiopian lakes experienced declining water levels, threatening water availability. However, water storage changes have not been quantified and the drivers of hydrological change have not been assessed on a regional scale. Here, we used satellite Earth observation and open-access data products to quantify changes in lake water volumes, total catchment water storage anomalies and environmental drivers for 375 lakes across the East African Rift System from 2000 to 2023. Water storage increased across central East Africa and declined in the south of the Rift System, with lake surface areas increasing by a total of 71,822 km2 and water volumes increasing by 1375.2 km3. Increasing rainfall (Coef = 1.775, SE = 0.571, p = 0.002) and urban development (Coef = 6.270, SE = 2.260, p = 0.006) caused expanding lake surface areas, whereas population growth within catchments reduced both lake surface areas (Coef = −7.023, SE = 2.210, p = 0.002) and water volumes (Coef = −8.735, SE = 3.578, p = 0.020). Increasing rainfall trends (Coef = 4.454, SE = 1.733, p = 0.020) and the expansion of catchment forest cover (Coef = 11.284, SE = 5.263, p = 0.047) facilitated greater water storage within lake basins. With more extreme wet seasons and longer dry seasons predicted for East Africa under climate change, sustainable catchment management is required to mitigate both future flooding and drought events. [Display omitted] •Hotspots of hydrological change were identified across 375 lakes from 2000 to 2023.•In total, lakes increased in surface area by 71,822 km2 and in volume by 1375.2 km3•Water storage increased in central East Africa and declined in the south.•Rising lake levels were driven by increasing rainfall and land-use intensification.•Population growth caused observable declines in lakes across the Rift System.