Year: 2025
Type: article
Abstract: Understanding the interaction between land use and climate variability in regulating the hydrology of tropical watersheds remains a significant scientific and policy challenge, particularly in regions with limited data. This study applied the InVEST Annual Water Yield model to assess hydrological dynamics in the Asa watershed, Nigeria, over the period 1991–2020, using three decades of precipitation and land-use/land-cover (LULC) data, along with uncertainty quantification. The results revealed a non-linear trend in water yield, with total annual yield increasing by 6.89% between 2000 and 2010, despite declining precipitation and rising evaporative demand, primarily driven by land-use modifications. Between 2010 and 2020, yield declined by 5.39% under further precipitation reduction, where precipitation sensitivity increased eightfold, marking a shift from land-use-dominated to precipitation-dominated hydrological controls. Surrogate modeling further confirmed precipitation as the dominant driver after 2010, highlighting that cumulative land degradation weakened the watershed’s natural buffering capacity and amplified climatic responses. These findings establish a threshold at which cumulative land degradation transforms watershed hydrology from land-use-dominated to climate-sensitive regimes, providing a transferable framework for identifying vulnerability thresholds in data-scarce African tropical watersheds.
Source: Water
DOI: 10.3390/w17243477
Language: English
Subfield: Water Science and Technology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,137
Award: G3321109835
OpenAlex ID: W4417113260