Geomorphologically based early warning system for flood events in minor hilly catchments and local urban areas: a case study in the Abruzzo region (Central Italy)

Urban and small catchments flooding is a common type of natural hazard caused by intense rainfall, which may cause inundation to roads, buildings, and infrastructure, interrupting transportation, power lines and, other critical urban infrastructure systems, damaging properties and threatening people’s lives. The expansion of urban areas and infrastructure over the last 50 years has led to a marked increase in flood risk.

The coastal and hilly areas of Central Italy have been largely affected by heavy rainfall and flood/flash-flood events in recent times. The Apennine hilly piedmont and the coastal hills of Abruzzo have been affected by moderate to heavy events (rainfall >35 mm/h and 100-220 mm/d), which caused damages to minor and major urban areas. In this study, the Feltrino Stream area and the Lanciano town were investigated for the realization of a local early warning system for heavy rainfall events and flooding. The project is funded by the Abruzzo Region within the frame of a regional Project named “Communicate to protect” and developed in collaboration with the Lanciano Municipality and with the Regional Civil Protection office.

The Feltrino Stream basin is located in the hilly area of southeastern Abruzzo, in the eastern piedmont of the Maiella massif (Central Apennines). The basin ranges from about 400 m a.s.l. to sea level, with an overall morphology characterized by a mesa and plateau relief and SW-NE elongated valleys. The Lanciano Town is developed on a mesa relief carved by minor valleys, largely modified and filled by anthropic activities.

In this work, the Feltrino Stream was investigated through a drainage basin scale geomorphological analysis incorporating (i) the morphometry of orography and hydrography, (ii) temperature and rainfall data analysis, (iii) acquisition of available geological, geomorphological, and hazard data, (iv) detail urban hydrography analysis and geomorphological field mapping, for the definition of a geodatabase of the geo-hydrological critical areas. The analysis allowed defining the arrangement of a rainfall, hydrometry and flood monitoring system integrating at local scale the existing regional monitoring network. The integration of the monitoring system and the critical areas in a web cloud digital system allowed to plan and realize an early warning system, based on the use of a digital app for smartphone. The warning system is being calibrated for the effectiveness during heavy rainfall events. After calibration, the system will support the local civil protection activities of the Lanciano Municipality. Moreover, under the supervision of the civil protection responsible, it is expected to be implemented as an automatic system for smartphone-based early warning of people exploiting the inbuilt geolocalization features of the recent smartphone.