Floods, often triggered by heavy rainfall or snowmelt, are the most common natural disasters worldwide. The 2021 Western European Floods (Germany, Netherlands, Belgium) provided the opportunity to study geotechnical and geo-environmental flood damage within the impacted areas throughout two separate reconnaissance missions and data collections visits (Aug 2021 and March 2022). This case study provides an overview of reconnaissance observations and field measurements specific to infrastructure in Altenahr, Germany. The role of river-soil-structure interaction and local geological conditions on the extent of flood damages, as well as the rehabilitation of flood-damaged areas around the town of Altenahr, and the well-known Altenahr roadway tunnel entrance/exit areas are discussed. Local failure observations, damage patterns, and measurements are presented and compared with general observations recorded in the remainder of the flooded Ahr Valley region. Reconnaissance data collection methods included LiDAR and structure-from-motion from unmanned aerial vehicles, sediment sampling, multispectral imaging, soil strength testing (in and out of water), riverbed imaging through side scan sonar imaging, bathymetric mapping using single beam sonar, and mapping of in-water deposits from low-frequency acoustic surveying. An overview of available data, data access, and ongoing/future studies using the information collected will be presented.