Rainfall-Conditioned Safety Screening of Mountain Nature-Based Recreation Spaces Under Relative Flash-Flood Potential in Guizhou, China

Mountain nature-based recreation spaces often combine high ecological quality with practical accessibility, yet they may also be constrained by sudden flash floods. Existing studies generally assess recreation opportunities and flood hazards separately, making it difficult to determine how potential recreation spaces progressively enter the scope of safety attention under different rainfall conditions. Taking Guizhou Province, China, as a case study, we developed history-informed standardised event-rainfall scenarios, assessed relative flash-flood potential using an NRCS-CN–HAND framework, and identified potential nature-based recreation opportunities from habitat quality and road proximity. We then analysed how areas requiring safety attention changed across rainfall conditions. The results show that the spatial extent of high relative flash-flood potential increased with event-total rainfall, but the rate of expansion varied markedly among rainfall stages, with the greatest province-wide expansion occurring between 30 and 40 mm. When potential recreation opportunities were intersected with high-potential areas, the resulting safety-attention areas expanded rapidly between 40 and 60 mm, with the largest increment between 40 and 50 mm. Activation rainfall for potential recreation opportunities was concentrated mainly between 50 and 70 mm and differed among prefecture-level units. By evaluating recreation opportunities and flash-flood constraints independently and linking them under comparable rainfall conditions, this study extends static recreation-opportunity mapping into dynamic safety screening and provides a practical spatial basis for prioritised site review, tiered inspection, and differentiated management of mountain nature-based recreation spaces.