Reliability of flood marks and practical relevance for flood hazard assessment in southwestern Germany

Abstract. Flood marks are rarely utilized in hazard assessment, mainly because of a lack data availability and accessibility mistrust their reliability. Challenging these common assumptions, we present an approach for evaluation practical utilization flood by the example Kinzig River, Rhine tributary from Black Forest with history severe floods. We combined written documents describing field mapping at three study sites collected information relating to 89 – about 50 % them still preserved which refer ?15 large floods between 1824 1991. The inclusion detailed historical-mark survey enabled assessment changes through time each mark: they extend small (±15 cm) imprecisions mark heights considerable uncertainties position, height, displayed date some modified marks. Plausibility checks further nevertheless demonstrated good overall consistency. then juxtaposed current, modeled maps. A wide agreement is apparent, that majority situated probable within flooding area associated extreme For few exceptions, see plausible historically sound reasons changed local hydraulic conditions protection walls, exceptional processes during massive ice jam, possibly also underestimation along River tributaries. Overall, this highlights (1) broad data, both on larger spatial scale regard already vanished marks, (2) significance verified demonstrates (3) possibility straightforward assessment. thus encourage systematic collection, maintenance, integration as responsible risk management, not least regarding value wider context awareness memory.