@inproceedings{GerkeSchneiderMaureretal., author = {Gerke, Horst H. and Schneider, Anna and Maurer, Thomas and Raab, Thomas}, title = {Quantification and reconstruction of Initial 3D Sediment Mass Distribution in an Artificially-Created Catchment Area Using GOCAD}, series = {American Geophysical Union, Fall Meeting - Eos transactions}, volume = {90}, booktitle = {American Geophysical Union, Fall Meeting - Eos transactions}, number = {52, Suppl.}, abstract = {For systems such as soils or watersheds, the initial distribution of sediment mass and composition at the starting point of the development are mostly not well-known. The development of such systems, however, has frequently been assumed to depend on boundary and initial conditions including the solid phase. Here, an experimental watershed of about 6 ha surface area was artificially-created in order to imitate an initial stage just at the beginning of the geo-ecosystem development. However, sediment homogeneity could not be achieved for this large-scale field experiment, and the 3D spatial distribution of structures and components remained uncertain. The objective of this study was to quantify and reconstruct the initial sediment distribution and the first development stages using aerial photographs, point information, and a 3D model. The watershed was made of coarse-textured sediments of quaternary origin with a low permeable clay liner as the bottom boundary. A 2D horizontal digital elevation model (DEM) of the surface and a DEM of the subsurface clay layer are used to construct a 3D triangulated numerical grid of the catchment's initial spatial structure using the 3D-GIS software GOCAD. Physical and chemical soil properties obtained from borehole samples are assigned to this model and interpolated onto the 3D grid. The volumetric changes in space and time are quantified and related to material properties to obtain the mass changes. Correlations between terrain attributes, sediment properties, and mass changes are explored specifically in regions of differing source materials. A temporal sequence of surface DEMs is obtained from photogrammetric, high-precision ground based laser scanning and airborne laser scanning data. 3D models of elevation change are constructed from these DEMs. The processes following the initial state are mainly characterized by runoff-induced erosive mass relocations related to the distribution of surface and subsurface structures and sediment properties. The results suggest that both sediment structures and mass translocations differ between the western and eastern parts of the watershed and that correlations between initial surface structures and subsequent mass changes exist.}, language = {en} }