Assessment of water retention dynamic in water resource formation area: A case study of the northern slope of the Qinling Mountains in China

The northern slope of Qinling Mountains (NQL) is an important water retention (W R ) area in China, which guarantees the utilization of water resources in the plain area. However, the effects of significant changes in climate and land cover on W R have not been quantitatively studied in recent years. In this study, we quantified the relative impacts of climate and land cover changes on W R at NQL and predicted the future changes of W R under different climate scenarios (SSP2–4.5 and SSP5–8.5). The results indicated that W R in NQL has exhibited an overall increase from 1985 to 2020 at a rate of 1.10 mm/a, with climate and land cover change explaining 86.3 % and 13.7 % of this change, respectively. Although precipitation has increased since 1998, the compounding effects of land cover change and precipitation intensity increase have led to a slight decline of W R magnitude and efficiency due to their offsetting impacts. Under future climate change, the W R capacity changes in the SSP2–4.5 are relatively stable, while the significant increase in temperature under the SSP5–8.5 lead to a decreasing trend in W R efficiency. In addition, we proposed an indicator framework to evaluate W R using W R efficiency and baseflow lag time. Our results may provide valuable insights for sustainable utilization and scientific management of water resources. • We quantified the impacts of climate (86.3 %) and land cover (13.7 %) changes on water retention (W R ). • The increase of vegetation in high vegetation areas may not be conducive to W R . • The W R efficiency in this region will show a decreasing trend along this century under SSP5–8.5. • Combining WRE and baseflow lag time can well evaluate the W R function.