SWAT and CMIP6-driven hydro-climate modeling of future flood risks and vegetation dynamics in the White Oak Bayou Watershed, United States

Climate change and urbanization are primary drivers of significant changes in water regimes and ecosystem sustainability. This study presents a predictive framework to evaluate the long-term effects of a changing climate on water resources and crop productivity in the White Oak Bayou Watershed (WOBW) in Texas, United States. In this work, the Soil and Water Assessment Tool (SWAT) was employed along with four different greenhouse gas (GHG) emission scenarios under the Intergovernmental Panel on Climate Change (IPCC)’s Sixth Assessment Report (AR6). Additionally, regional data on land use land cover (LULC), and historical disasters were integrated to provide context on local dynamics. The analysis focuses on climate extremes, such as flood peaks and vegetation health, across various timeframes, including near- (2024–2044), mid- (2045–2069), and far-future (2070–2100). Key findings include: (1) under high GHG scenarios, WOBW is projected to experience a substantial increase in flood risks, with flood peaks anticipated to rise by 2100; (2) a noticeable improvement in vegetation health (2015–2020), particularly in areas transitioning from cropland to shrubland and tree cover, correlates with reduced flood risks; and (3) increased runoff during the wet season with potential declines in water availability during the dry season. This study identifies high-risk areas for water scarcity and flood vulnerability, offering critical insights for sustainable watershed management and climate adaptation. This scientific basis provides practical guidance for local authorities and communities to mitigate climate impacts.