On July 5th and 6th 2017, Northern Kyûshû (Japan) experienced heavy rainfall, with more than 600 mm recorded within 6 hours near Asakura station. On the 5th of July, the rainfall intensity reached a maximum of 129.5 mm/h between 3:00 pm and 4:00 pm local time (Kawano et Kawamura, 2020). This event caused hundreds of landslides and floods, resulting in 42 fatalities and severe infrastructure damage (DPRI-KU, 2018). In Northern Kyushu, climate change is expected to increase extreme weather, in particular precipitation and their distribution patterns (MEXT and JMA, 2020; MLIT, 2020). Due to cumulative phenomena and their influence on soil moisture, lower and less intense rainfall could trigger hydro-gravity hazards (Gariano and Giuzetti, 2016). This study is based on a review of the scientific litterature and geotechnical report of July 2017 event, remote sensing (DEM analysis and multi-data images interpretation), field surveys (2022 and 2023) and laboratory analysis. We have identified the impact of July 2017 rainfall on the sedimentary cascade, specifically on structural and process-based sediment connectivity. There were no or few sedimentary sources before 2017, then several hundred sedimentary sources of hundreds to several thousand cubic metres opened up by Landslides. The majority of which are connected to torrents and propagated by hyperconcentrated and debris flows. We monitored changes, particularly those associated with the management measures implemented to mitigate the consequences of hydro-sedimentary fluxes and drifted wood. The specificity of this management reside in the Sabo works (Dumont et al., 2023) and the speed of operation.