@misc{SchneiderGerkeMaureretal., author = {Schneider, Anna and Gerke, Horst H. and Maurer, Thomas and Seifert, Stefan and Nenov, Rossen and H{\"u}ttl, Reinhard F.}, title = {Evaluation of remotely-sensed DEMs and modification based on plausibility rules and initial sediment budgets of an artificially-created catchment}, series = {Earth Surface Processes and Landforms}, volume = {37}, journal = {Earth Surface Processes and Landforms}, number = {7}, issn = {1096-9837}, pages = {708 -- 725}, language = {en} } @misc{MaurerGerke, author = {Maurer, Thomas and Gerke, Horst H.}, title = {Modelling aeolian sediment transport during initial soil development on an artificial catchment using WEPS and aerial images}, series = {Soil \& Tillage Research}, volume = {117}, journal = {Soil \& Tillage Research}, issn = {0167-1987}, pages = {148 -- 162}, language = {en} } @misc{SchneiderGerkeMaureretal., author = {Schneider, Anna and Gerke, Horst H. and Maurer, Thomas and Nenov, Rossen}, title = {Initial hydro-geomorphic development and rill network evolution in an artificial catchment}, series = {Earth Surface Processes and Landforms}, volume = {38}, journal = {Earth Surface Processes and Landforms}, number = {13}, issn = {1096-9837}, doi = {10.1002/esp.3384}, pages = {1496 -- 1512}, abstract = {The formation of erosion rills and gullies is a critical step in land surface development, but possibilities to study initial unaffected surface development under natural conditions and with well-defined initial and boundary conditions are rare. The objective of this study was to characterize rill network development from 'point zero' in the artificially-created catchment 'H{\"u}hnerwasser'. To ensure unaffected development, the study was largely restricted to the analysis of remotely-sensed data. We analyzed a series of photogrammetry-based digital elevation models (DEMs) for 10 points in time, over a period of five years and beginning with the initial state. The evolving erosion rill network was quantitatively described based on mapping from aerial photographs. DEMs and rill network maps were combined to specifically analyze the development of morphometry for different parts of the network and to characterize energy dissipation and connectivity. The restriction to remote-sensing data did not allow for analyzing specific processes governing rill network development, nevertheless, two major development phases could be characterized. We observed a phase of growth of the rill network along with variations in drainage patterns during the first two years of development and a subsequent phase of reduction of its area along with comparably stable patterns. Region-specific analysis of morphometry indicates that, besides effects of changing sediment characteristics and vegetation cover development, locally evolving hydro-geomorphic feedback cycles influenced this development. Results show an increasing similarity of overall statistical characteristics (e.g. drainage density) for two parts of the catchment, but a persistent influence of initial conditions on specific rill geometry. The observed development towards higher orderliness and increased connectivity is consistent with experiments and concepts on drainage network evolution across scales; however, we did not observe major influences of rill piracy and cross grading or a reduction of energy dissipation with network development.}, language = {en} } @misc{GerkeMaurerSchneider, author = {Gerke, Horst H. and Maurer, Thomas and Schneider, Anna}, title = {A Three-Dimensional Structure and Process Model for Integrated Hydro-Geo-Pedologic Analysis of a Constructed Hydrological Catchment}, series = {Vadose zone journal}, volume = {12}, journal = {Vadose zone journal}, number = {4}, issn = {1539-1663}, doi = {10.2136/vzj2013.02.0040}, abstract = {A structure model describes the boundary geometries and the three-dimensional solid phase distributions of the catchment. In contrast to an established ecosystem, feedback relations can be assumed for an initial geosystem between the development of spatial structures and the water and element fluxes. The objective was to develop a hydrological catchment model as a three-dimensional spatial database of the solid phase that allows an integrative analysis, a periodical mass balance, and the generation of distributed model parameters for the developing system. Data were from the constructed catchment "Chicken Creek." The initial texture and bulk density distributions were generated by imitating sediment dumping, segregation, and compaction. Boundary geometries and changes in surface topography due to erosion and sedimentation processes were quantified on the basis of digital elevation models (DEMs) derived from aerial photographs. The catchment was visualized with the three-dimensional software GoCad; the "emergence" of the water table and other structures (e.g., soil horizons, root zone) could be spatially assigned and quantified to identify regions with specific processes. A combination of three-dimensional catchment with time-dependent two-dimensional surface models allowed generating the development of spatially distributed erosion-deposition patterns that formed new initial surfaces. The three-dimensional distributed solid phase structure of the catchment allowed for a more direct comparison with observations using minimal invasive methods. The mass balance of the solids could be related with pedologic development and transfer to other geopedologic systems achieved by adapting sediment transport and deposition in the descriptions of the model. This model may help improve the integrative analysis of hydrological catchments.}, language = {en} } @misc{NgoGerkeBadorreck, author = {Ngo, Viet V. and Gerke, Horst H. and Badorreck, Annika}, title = {Estimability Analysis for Optimization of Hysteretic Soil Hydraulic Parameters Using Data of a Field Irrigation Experiment}, series = {Transport in Porous Media}, volume = {103}, journal = {Transport in Porous Media}, number = {3}, doi = {10.1007/s11242-014-0315-6}, pages = {535 -- 562}, abstract = {To improve the quality of parameter optimization, estimability analysis has been proposed as the first step before inverse modeling. When using field data of irrigation experiments for the determination of soil hydraulic parameters, wetting and drying processes may complicate optimization. The objectives of this study were to compare estimability analysis and inverse optimization of the soil hydraulic parameters in the models with and without considering hysteresis of the soil water retention function. Soil water pressure head data of a field irrigation experiment were used. The one-dimensional vertical water movement in variably saturated soil was described with the Richards equation using the HYDRUS-1D code. Estimability of the unimodal van Genuchten-Mualem hydraulic model parameters as well as of the hysteretic parameter model of Parker and Lenhard was classified according to a sensitivity coefficient matrix. The matrix was obtained by sequentially calculating effects of initial parameter variations on changes in the simulated pressure head values.Optimization was carried out by means of the Levenberg-Marquardt method implemented in the HYDRUS-1D code. The parameters α, Ks, θs, and n in the nonhysteretic model were found sensitive and parameter θs strongly correlated with parameter n. When assuming hysteresis, the estimability was decreased with soil depth for Ks and αd , and increased for θs and n. Among the shape parameters, αw was the most estimable. The hysteretic model could approximate the pressure heads in the soil by considering parameters from wetting and drying periods separately as initial estimates. The inverse optimization could be carried out more efficiently with most estimable parameters. Despite the remaining weaknesses of the local optimization algorithm and the inflexibility of the unimodal van Genuchten model, the results suggested that estimability analysis could be considered as a guidance to better define the optimization scenarios and then improved the determination of soil hydraulic parameters.}, language = {en} } @misc{MaurerSchneiderGerke, author = {Maurer, Thomas and Schneider, Anna and Gerke, Horst H.}, title = {Scenario-Based Three-Dimensional Distributed Sediment Structures for a Constructed Hydrological Catchment}, series = {Vadose zone journal}, volume = {12}, journal = {Vadose zone journal}, number = {4}, issn = {1539-1663}, doi = {10.2136/vzj2013.02.0047}, abstract = {Many processes in a developing catchment can only be fully understood if the spatial heterogeneity is adequately described. Process-based modeling allows reproducing specific key structural elements of catchments. Constructed catchments are ideal test objects because of the well-known spatial conditions. In our study, we (i) modeled the entire process chain of catchment construction, (ii) established a consistent sediment mass/ volume balance between the excavated outcrop and the generated catchment model, and (iii) provided consistent three-dimensional distributions of texture and bulk density for deriving soil hydraulic properties. Data are from the 6 ha H{\"u}hnerwasser catchment (Chicken Creek, Lower Lusatia, Germany), which was constructed from overburden sediments in an open-cast lignite mine. Uncertainty about the parent material origin was captured in a multiscenario approach based on a geological model of the outcrop site and the simulation of excavation procedures. Generated distributions are incorporated in a gridded threedimensional volume model (GOCAD), and results were evaluated by semivariogram analysis and by quantifying point-to-point deviations. Filling and compaction are modeled based on three-dimensional volume analysis and mass balances of dumped sediments. Heterogeneities reflect both the batch-wise sediment variation and the succession of excavated geological units. The scale of the generated spatial models can be adjusted for three-dimensional hydrological catchment modeling while three-dimensional sediment mass balances can be used for analyzing soil and ecosystem development processes.}, language = {en} } @incollection{GerkeGruenewaldBiemeltetal., author = {Gerke, Horst H. and Gr{\"u}newald, Uwe and Biemelt, Detlef and Badorreck, Annika and Bartl, Steffen}, title = {Project A4 - Development and interactions of flow paths on the surface and in the soil}, series = {Structures and processes of the initial ecosystem development phase in an artificial water catchment (Final report CRC/TR 38)}, booktitle = {Structures and processes of the initial ecosystem development phase in an artificial water catchment (Final report CRC/TR 38)}, editor = {H{\"u}ttl, Reinhard F. and K{\"o}gel-Knabner, Ingrid and Schulin, Rainer and Gerwin, Werner}, publisher = {BTU, Forschungszentrum Landschaftsentwicklung und Bergbaulandschaften (FZLB)}, address = {Cottbus}, pages = {37 -- 44}, language = {en} } @inproceedings{BadorreckGerkeVontobel, author = {Badorreck, Annika and Gerke, Horst H. and Vontobel, Peter}, title = {Neutronenradiographische Untersuchungen der kleinr{\"a}umig heterogenen Wasserbewegung in kohlehaltigen B{\"o}den}, series = {B{\"o}den - eine endliche Ressource, 5. - 13. September 2009, Bonn, Jahrestagung der Deutschen Bodenkundlichen Gesellschaft}, booktitle = {B{\"o}den - eine endliche Ressource, 5. - 13. September 2009, Bonn, Jahrestagung der Deutschen Bodenkundlichen Gesellschaft}, publisher = {Deutsche Bodenkundliche Gesellschaft (Selbstverlag)}, address = {Bonn}, language = {de} } @inproceedings{BadorreckGerkeWelleretal., author = {Badorreck, Annika and Gerke, Horst H. and Weller, Ulrich and Vontobel, Peter}, title = {Soil sealing and vesicular layer formation as initial structure development and its effect on infiltration}, series = {EGU General Assembly 2009, Vienna, Austria, 19 - 24 April 2009}, booktitle = {EGU General Assembly 2009, Vienna, Austria, 19 - 24 April 2009}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, language = {en} } @inproceedings{BadorreckGerkeVontobel, author = {Badorreck, Annika and Gerke, Horst H. and Vontobel, Peter}, title = {Unsaturated flow patterns observed in mine soils with embedded porous fragments using neutron radiography}, series = {EGU General Assembly 2009, Vienna, Austria, 19 - 24 April 2009}, booktitle = {EGU General Assembly 2009, Vienna, Austria, 19 - 24 April 2009}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, language = {en} }