Integrating SMART Principles in Flood Early Warning System Design in the Himalayas

Abstract. Extreme precipitation events have increased community and asset vulnerability to hazards like flash floods, particularly in mountainous regions. In response to this challenge, we employ the SMART principle, which emphasizes Inclusiveness and a bottom-up approach, in the development of a comprehensive early warning system for urban floods in lesser Himalayas. A hydrometeorological monitoring network comprising three LiDAR water level sensors and four rain gauges was deployed across the Bindal watershed in Uttarakhand after a meticulous assessment of topography and consultations with local communities. Monitoring reveals that during a monsoon month, a 187 mm difference in rainfall was recorded, with correlations between rainfall at different stations with r = 0.82 down to 0.20 across distances increased from 2.74 to 8.24 km, highlighting significant spatial variability. A southwest movement of rainfall storms, with a 15-minute lag, was observed within the watershed. In contrast to the locally collected data, secondary datasets failed to accurately capture the magnitude and heterogeneity of precipitation patterns, raising concerns about their reliability for flash flood studies at this scale. This study underscores the advantage of SMART approach integrating hydrometeorological insights, utilizing low-cost monitoring systems and community engagement to strengthen urban Himalayan resilience against floods.