Identifying flood-prone zones and their geographic drivers in Northwest China under a changing climate

Northwest China is one of the driest regions in the world experiencing noticeable changes in regional hydroclimate. A warming climate and intensifying rainstorms have led to more flood inundation across the region. To enhance flood management under a changing hydroclimate, this study focuses on identifying flood-prone zones (FPZs) and the geographic drivers shaping them, while also examining how these zones are shifting in response to climate change. High-resolution satellite-based observations and hydroclimate data are used to identify FPZs and drivers of their spatial and temporal variations. The findings show that from 2000 to 2020, FPZs in the region span approximately 14,120.2 km², primarily concentrated around perennial rivers and lakes, particularly in their lower reaches. Elevation and soil water content are found to be the dominant geographic factors shaping the FPZs. FPZs’ dynamics in the southern region are primarily affected by precipitation and soil water, while in the northern region are closely related to snowmelt and runoff. Approximately 53% of FPZs exhibit a significant increase trend in inundation frequency, expanding at the rate of 221.4 km² per year in response to the warmer and wetter climate. These findings can be conducive to developing site-specific flood management strategies under climate change.