The vulnerability of flood-prone areas is determined by the susceptibility of the exposed assets to the hazard. It is a crucial component in risk assessment studies, both for climate change adaptation and disaster risk reduction. In this study, we analyse patterns of vulnerability for the residential sector in a frequently hit urban area of Milan, Italy. The conceptual foundation for a quantitative assessment of the structural dimensions of vulnerability is based on the modified source–pathway–receptor–consequence model. This conceptual model is used to improve the parameterization of the flood risk analysis, describing (i) hazard scenario definitions performed by hydraulic modelling based on past event data (source estimation) and morphological features and land-use evaluation (pathway estimation) and (ii) the exposure and vulnerability assessment which consists of recognizing elements potentially at risk (receptor estimation) and event losses (consequence estimation). We characterized flood hazard intensity on the basis of variability in water depth during a recent event and spatial exposure also as a function of a building's surroundings and buildings' intrinsic characteristics as a determinant vulnerability indicator of the elements at risk. In this sense the use of a geographic scale sufficient to depict spatial differences in vulnerability allowed us to identify structural vulnerability patterns to inform depth–damage curves and calculate potential losses from mesoscale (land-use level) to microscale (building level). Results produces accurate estimates of the flood characteristics, with mean error in flood depth estimation in the range 0.2–0.3 m and provide a basis to obtain site-specific damage curves and damage mapping. Findings show that the nature of flood pathways varies spatially, is influenced by landscape characteristics and alters vulnerability spatial distribution and hazard propagation. At the mesoscale, the “continuous urban fabric” Urban Atlas 2018 land-use class with the occurrence of at least 80 % of soil sealing shows higher absolute damage values. At microscale, evidence demonstrated that even events with moderate magnitude in terms of flood depth in a complex urbanized area may cause more damage than one would expect.

The increasing availability of SAR images and processing results over wide areas determines the need for systematic procedures to extract the information from this dataset and exploit the enhanced quality of the displacement time series. The aim of the study is to propose a new pre-operational workflow of an A-DInSAR-based land subsidence monitoring and interpretation service. The workflow is tested in Turano Lodigiano (Lombardy region, Italy) using COSMO-SkyMed data, processed using the SqueeSAR™ algorithm, and covering the time span from 2016 to 2019. The test site is a representative peri-urban area of the Po plain susceptible to land subsidence. The results give insight about new value-added products and enable non-expert users to exploit the potential of the interferometric results.

The frequency and the accumulation of medium–small flood events can cause severe impacts. In a climate change context, real-time monitoring and a fast risk assessment are needed to support the post-disaster phases. The present work presents a novel methodology that leverages the potential of earth observation data to produce a proof-of-concept for flood vulnerability assessment, serving as the basis for a Map Operational Service for the Lombardy region. The proof-of-concept is related to both flood hazard estimation and vulnerability assessment, considering the evaluation of the potentialities of the synthetic aperture radar data when used to feed a downstream service. Using the city of Pavia (Italy), which was affected by a flood event in November 2019, as a case study, we present an integrated flood impact approach that includes a combination of social and physical parameters. The results contribute to a processing chain designed as a pre-operational service where each data analytic retrieves thematic products to support the exposure and damage estimates based on earth observation-derived hazard products for emergency and recovery responses. Three different satellites covered more than 40 h of the flood’s evolution, supporting the great potential of the multi-sensor approach. Therefore, different sensor configurations in terms of spectral bands (X and C bands) and resolutions (from 10 to 1 m) provide a near real-time view of the event. Comparing the results obtained through the three hazard scenarios, a final social and physical Integrated Impact Index is obtained. The added value information leads to the determination of hotspots with which to prioritize effective interventions during emergency and recovery phases, crucial for capturing inherent conditions that allow communities to absorb impacts and cope with a damaging flood event.

The vulnerability of flood-prone areas is determined by the susceptibility of the exposed assets to the hazard. It is a crucial component in risk assessment studies, both for climate change adaptation and disaster risk reduction. In this study, we analyse patterns of vulnerability for the residential sector in a frequently hit urban area of Milano, Italy. The conceptual foundation for a quantitative assessment of the structural dimensions of vulnerability is based on the modified Source-Pathway-Receptor-Consequence model. This conceptual model is used to improve the parameterization of the flood risk analysis describing: (i) hazard scenarios definition performed by hydraulic modelling based on past event data (Source estimation) and morphological features and land use evaluation (Pathway estimation); (ii) the exposure and vulnerability assessment which consists of recognizing elements potentially at risk (Receptor estimation) and event losses (Consequence estimation). The structural dimension of vulnerability is mapped at building level and used in loss estimation for the residential sector at meso and micro-scale. Results produces accurate estimates of the flood characteristics, with mean error in flood depths estimation in the range 0.2–0.3 m and provide a basis to obtain site-specific damage curves and damage mapping. Findings show that the nature of flood pathways varies spatially and is influenced by landscape characteristics and alters vulnerability spatial distribution and hazard propagation. At the mesoscale, the ‘Continuous urban fabric’ Urban Atlas 2018 land-use class with the occurrence of at least 80 % of soil sealing shows higher absolute damage values. At microscale, evidence demonstrated that even events with moderate magnitude in terms of flood depth in a complex urbanized area may cause more damage than it would expect.

Earth Observation (EO) environments have been increasing exponentially in the last decades. New generation of satellites are designed for monitoring climate related hazards, providing higher spatial and temporal resolution images. Hazards processes are triggered by anomalies in precipitation. The service will be able to provide information on the extent of the flood footprint. The test area is located south of the city of Milan, where the urban area of Pavia is located. There was an unexpected high runoff of the Ticino river that produced high water in the flood-plain surface, affecting the local population for three consecutive days and with a total damage estimate of 250,699 euro.The identification of datasets counts on a broad availability of EO data processed, such as C-band Synthetic Aperture Radar (SAR) data from the Sentinel 1 satellite constellation together with X-band SAR data provided by the TerraSAR-X.  Methods include in-SAR coherence, by cross-multiplying the two SAR images or techniques like threshold with a final pixel size of Sentinel 1 of 8.9 m and 1.8 m of TerraSAR-X. Imagery from the 25th of November (Sentinel 1) with a VV (vertical transmit, vertical receive) polarization and from the 27th of November (TerraSAR-X) with a HH (for horizontal transmit and horizontal receive) polarization were selected. Different bands have different characteristics, for instance in penetration and spatial resolution.Obtained products include urban footprint and flood detection maps. Results could provide an important decision support tool for a wide range of actors, including public authorities to support the preparedness, mitigation and response phases of the emergency management cycle. In addition, adaptation measurements, intervention and urban planning, as well as flood mitigation activities are additional benefits. Future analysis will include impact estimates and vulnerability analysis on the urban footprint area.