Mass wasting in Lake Constance – A GIS-based geo-morphometric reconnaissance

New high-resolution hydroacoustic data from the »Tiefenschärfe« project in Lake Constance (central Europe) reveals a large amount of mass wasting events occurring on all slopes and influencing large parts of the lake floor. Within a GIS-supported geomorphologic investigation, a manual picking of mass transport deposits, as well as a digital reconnaissance were carried out, based on the visual appearance of mass transport deposits and on elevation-derived morphometric parameters, respectively. Subjective manual and objective (semi-)automatic detection strategies show the usability of the latter to be a new, easy-to-use assistive tool for identifying mass transport deposits in large bathymetric data sets and quantifying the morphological imprint of events on the lake floor. The iteratively determined algorithm divides mass wasting occurrences into the sub-features break-off edge, transport channel and depositional lobe and suggests morphometric dependencies for each sub-feature. Because Lake Constance consists of three mutually independent subbasins the algorithm success differs somewhat, which we credit to locally changing hydrodynamic and sedimentologic patterns.

Lake Constance | bathymetry | mass wasting | morphometry | GIS