Monitoring the role of soil hydrologic conditions and rainfall for the triggering of torrential flows in the Rebaixader catchment (Central Pyrenees, Spain)

• DOI: 10.1007/s10346-022-01975-8
• Publication Date: 2022-11-14T06:03:56Z
• Authors: Raül Oorthuis; Marcel Hürlimann; Jean Vaunat; José Moya; Antonio Lloret
• Keywords: Debris flow; Flash flood; Intensity

Abstract Torrential flows (debris and debris floods) are mainly triggered by precipitation soil hydrological processes. Most early warning systems in torrential catchments rainfall-based. However, this approach can result frequent false positives, due to its pure black-box nature, which water conditions neglected. We aim contribute the understanding of required for triggering considering also situ measurements content. Herein, monitoring data 12 years rainfall flow occurrence (2009–2020) 8 hydrologic (2013–2020) Rebaixader catchment (Central Pyrenees, Spain) analyzed. The dataset includes more than 1000 events 37 flows. First, thresholds using maximum intensity (I max ) mean defined. For 2013–2020 dataset, 15 events, I threshold predicted 2 negatives 73 positives (positive predictive value, PPV, 15.1%) best but only 11 (PPV 54.2%). our observations confirmed quantitatively that lower is moisture higher trigger Then, we combined volumetric content at 30 cm depth define a hydro-meteorological threshold. This latter reduced 1 increased PPV 63.6%. These results confirm key factors may improve early-warning predictions.