Integrated Assessment of Water Yield in Northern China's Mountain Using Remote Sensing and Modeling

The mountainous “water towers” of Northern China are crucial for regional water security but face threats from climate change and ecological restoration projects. Understanding their hydrological responses requires tools that capture both intense climatic events and long-term land cover changes. This study presents an integrated assessment using multi-source remote sensing data and hydrological modeling across two critical regions: the Taihang Mountains and the broader Beijing-Tianjin-Hebei (BTH) mountainous area.

We employed the InVEST model to simulate water yield (WY). For the Taihang Mountains (1990–2020), we introduced a detrending analysis framework coupled with the Optimal Parameters-based Geographical Detector (OPGD) to attribute drivers. Results show a significant WY decline (-0.66 mm/yr), primarily (86.46%) driven by climate change. Crucially, OPGD analysis revealed that in areas of sharp decline, precipitation intensity (Q=0.369) was a more dominant factor than total precipitation (Q=0.305), highlighting the key role of changing precipitation patterns.

To assess the long-term impact of large-scale vegetation restoration, we extended the analysis to the BTH mountains over four decades (1980–2020). Multi-period scenario analysis showed that while land use/cover change (LUCC) exerted a short-term negative effect on WY during initial afforestation (2000–2020), it shifted to a positive contribution over the full 40-year period, especially in the Bashang region (+37.80%). This indicates that ecological restoration, despite initial water consumption, can enhance water retention and yield benefits over decadal scales.

Our integrated approach demonstrates that combining process-attribution tools (OPGD) with long-term scenario analysis provides a holistic view of mountain hydrology. The findings underscore that sustainable water management must simultaneously address increasing precipitation extremes and harness the long-term hydrological benefits of ecological restoration.