An improved rainfall-threshold approach for robust prediction and warning of flood and flash flood hazards

• DOI: 10.1007/s11069-020-04405-x
• Publication Date: 2020-11-03T10:02:46Z
• Authors: Geraldo Moura Ram...; Victor Hugo Rabel...; Emerson da Silva ...; Yunqing Xuan; Cristiano das Nev...
• Keywords: Flash flood; Threshold limit value; Natural hazard; Intensity

Abstract This paper presents an improved method of using threshold peak rainfall intensity for robust flood/flash flood evaluation and warnings in the state São Paulo, Brazil. The improvements involve use two tolerance levels delineating intermediate by incorporating exponential curve that relates Antecedent Precipitation Index (API). application average increase 14% Probability Detection (POD) flash occurrences above upper threshold. Moreover, a considerable exclusion (63%) non-occurrences floods between thresholds significantly reduce number false alarms. curves also exhibits almost all time steps both hydrological hazards, with best results found correlating 8-h 8 days API, POD Positive Predictive Value (PPV) values equal to 81% 82%, respectively. study provides strong indications new proposed threshold-based approach can help uncertainties predicting floods.