https://doi.org/10.5194/hess-2020-296 Preprint. Discussion started: 31 July 2020 c Author(s) 2020. CC BY 4.0 License. User-oriented hydrological indices for early warning system. Validation using post-event surveys: flood case studies on the Central Apennines District. Annalina Lombardi1, Valentina Colaiuda1,2, Marco Verdecchia2 and Barbara Tomassetti1 5 1CETEMPS, Centre of Excellence University of L’Aquila, via Vetoio, 67010 Coppito (L’Aquila), Italy 2Department of Physical and Chemical Sciences, University of L’Aquila, via Vetoio, 67010 Coppito (L’Aquila) Italy Correspondence to: Annalina Lombardi (
[email protected]) Abstract. Flood and flash floods are complex events, depending on weather dynamics, basin physiographical characteristics, land use cover and water management. For this reason, prediction of such events usually deals with very accurate model tuning 10 and validation, which is usually site-specific and based on climatological data, such as discharge time series or flood databases. In this work, we developed and tested two hydrological stress indices for flood detection in the Central Italy Apennine District: a heterogeneous geographical area, characterized by complex topography and medium-to-small catchment extension. Proposed indices are threshold-based and developed taking into account operational requirements of civil protection end-users. They are calibrated and tested through the application of signal theory, in order to overcome data scarcity over ungauged areas, as well 15 as incomplete discharge time series. The validation has been carried out on a case study basis, through the use of flood reports from various source of information, as well as hydrometric level time series, which represent the actual hydrological quantity monitored by civil protection operators.