TY - GEN A1 - Byizigiro, Rutazuyaza Vaillant A1 - Raab, Thomas A1 - Maurer, Thomas T1 - Small-scale opencast mining: an important research field for anthropogenic geomorphology T2 - Die Erde N2 - Artisanal and small-scale mining (A&SM) is a growing economic sector in many third-world countries. This review focuses on anthropo-geomorphic factors and processes associated with small-scale opencast mining (SSOM), a form of A&SM in which near-surface ores are extracted by removing relatively thin covers of soil, bedrock or sediments. Being widespread and commonly conducted without proper planning and beyond the control of local authorities, this form of mining has potentially large impacts on landforms and landscape dynamics, often resulting in drastic consequences for the local environment and agriculture. SSOM should be regarded as a component of anthropogenic geomorphology because it involves the role of humans in creating landforms and modifying the operation of natural geomorphological processes, such as weathering, erosion, transport and deposition. By initiating new and modifying natural geomorphic processes, SSOM causes and/or accelerates geomorphic processes, resulting in various forms of land degradation. While the direct geomorphic impact of SSOM is in general easily discernible and leads to characteristic features, such as excavated pits and overburden spoil heaps, many secondary impacts are attributed to geomorphic processes triggered in the wake of the primary mining-induced landscape alterations. The magnitude of such secondary implications may well extend beyond the actual mining areas, but these effects have not been thoroughly addressed in the research so far. This review summarizes the known studies on the geomorphic impacts of SSOM operations and highlights common geomorphic processes and landforms associated with this type of anthropogenic activity, thus establishing a starting point for further in-depth research. Y1 - 2015 U6 - https://doi.org/10.12854/erde-146-21 VL - 146 IS - 4 SP - 213 EP - 231 ER - TY - GEN A1 - Raab, Thomas A1 - Krümmelbein, Julia A1 - Schneider, Anna A1 - Gerwin, Werner A1 - Maurer, Thomas A1 - Naeth, M. Anne T1 - Initial Ecosystem Processes as Key Factors of Landscape Development - A Review T2 - Physical Geography Y1 - 2012 SN - 1930-0557 VL - 33 IS - 4 SP - 305 EP - 343 ER - TY - GEN A1 - Maurer, Thomas A1 - Gerke, Horst H. T1 - Processes and modeling of initial landscape development – a review T2 - Vadose Zone Journal N2 - The development pathway of a landscape depends to a degree on the initial spatial distributions of mineral and organic components. The interaction between structures and ecohydrological processes during the critical initial development period is scarcely understood and often difficult to observe. While viable modeling approaches exist for most aspects of initial development (e.g., landscape evolution, vegetation succession), a deeper understanding of the prevailing feedback mechanisms requires a comprehensive, integrated modeling approach. We present a review of the current literature regarding the description of initial structures, the state-of-the-art of research on structure-forming processes and their interaction with existing and newly emerging structures, as well as the corresponding modeling efforts. The most relevant aspects are (i) sediment translocation processes and initial evolution of topography, (ii) surface crusting, (iii) vegetation succession, and (iv) the evolution of the soil pore space. Based on existing conceptions for integrated modeling of the coevolution of structures and ecohydrological behavior, we outline an integrative modeling framework that is based on a three-dimensional spatial structural model of initial sediment distributions, which can be used to: (i) analyze the spatiotemporal development dynamics depending on initial structures; and (ii) relate the simulated structural development to available observations of initial ecohydrological development. We discuss possible validation and generalization strategies of modeling results, and propose to define three-dimensional spatial functional catchment units (process domains) characterized by specific structural dynamics and the dominant ecohydrological processes. Y1 - 2016 UR - http://vzj.geoscienceworld.org/content/15/12/vzj2016.05.0048.full U6 - https://doi.org/10.2136/vzj2016.05.0048 SN - 1539-1663 VL - 15 IS - 12 ER - TY - GEN A1 - Rösch, Janina J. A1 - Seidlitz, Holger A1 - Pfeifer, Robin A1 - Burlefinger, Hubert A1 - Maurer, Thomas T1 - Preform joints in embroidered fabrics – influence on the mechanical properties T2 - Advanced Composite Materials N2 - Preforms with large complex geometry, for example, body parts for the automotive industry, are consisted into multiple elements – so-called sub-preforms. Hereby the sub-preforms can be adjusted to different local load cases but joining of these sub-preforms also raises challenges. The preform joints are decisive to the mechanical properties of the final component. The state-of-the-art joint, a single lap, results in a variation of wall thickness with local redirection of fibre orientation. In this paper, the influence of alternative joints of embroidered fabrics is analysed regarding the resulting mechanical properties of the part. The built test specimen contains different preform joints with different process-relevant parameters. Such as gaps between the sub-preforms, to analyse the influence on the mechanical performance. To reveal the various defects like voids, air pockets and to validate the fibre orientation, computer tomography (CT) investigation was performed on the built plates. In addition, the influence in mechanical properties was also analysed. The overlapping is analysed with tensile strength test according to DIN EN ISO 527-4. Y1 - 2020 UR - https://www.tandfonline.com/doi/abs/10.1080/09243046.2020.1744345 SP - 1 EP - 16 ER - TY - GEN A1 - Schneider, Anna A1 - Gerke, Horst H. A1 - Maurer, Thomas A1 - Seifert, Stefan A1 - Nenov, Rossen A1 - Hüttl, Reinhard F. T1 - Evaluation of remotely-sensed DEMs and modification based on plausibility rules and initial sediment budgets of an artificially-created catchment T2 - Earth Surface Processes and Landforms Y1 - 2012 SN - 1096-9837 VL - 37 IS - 7 SP - 708 EP - 725 ER - TY - GEN A1 - Maurer, Thomas A1 - Gerke, Horst H. T1 - Modelling aeolian sediment transport during initial soil development on an artificial catchment using WEPS and aerial images T2 - Soil & Tillage Research Y1 - 2011 SN - 0167-1987 VL - 117 SP - 148 EP - 162 ER - TY - GEN A1 - Schneider, Anna A1 - Gerke, Horst H. A1 - Maurer, Thomas A1 - Nenov, Rossen T1 - Initial hydro-geomorphic development and rill network evolution in an artificial catchment T2 - Earth Surface Processes and Landforms N2 - 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 ‘Hühnerwasser’. 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. Y1 - 2013 U6 - https://doi.org/10.1002/esp.3384 SN - 1096-9837 VL - 38 IS - 13 SP - 1496 EP - 1512 ER - TY - GEN A1 - Gerke, Horst H. A1 - Maurer, Thomas A1 - Schneider, Anna T1 - A Three-Dimensional Structure and Process Model for Integrated Hydro-Geo-Pedologic Analysis of a Constructed Hydrological Catchment T2 - Vadose zone journal N2 - 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. Y1 - 2013 U6 - https://doi.org/10.2136/vzj2013.02.0040 SN - 1539-1663 VL - 12 IS - 4 ER - TY - GEN A1 - Maurer, Thomas A1 - Schneider, Anna A1 - Gerke, Horst H. T1 - Scenario-Based Three-Dimensional Distributed Sediment Structures for a Constructed Hydrological Catchment T2 - Vadose zone journal N2 - 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 Hühnerwasser 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. Y1 - 2013 U6 - https://doi.org/10.2136/vzj2013.02.0047 SN - 1539-1663 VL - 12 IS - 4 ER - TY - GEN A1 - Herrmann, Ludger A1 - Jahn, Reinhold A1 - Maurer, Thomas T1 - Mineral dust around Sahara - from source to sink. A review with emphasis on contributions of the German soil science community in the last twenty years T2 - Journal of Plant Nutrition and Soil Science Y1 - 2010 SN - 1522-2624 VL - 173 IS - 6 SP - 811 EP - 821 ER - TY - GEN A1 - Maurer, Thomas A1 - Herrmann, Ludger A1 - Stahr, Karl T1 - The effect of surface variability factors on wind-erosion susceptibility: A field study in SW Niger T2 - Journal of Plant Nutrition and Soil Science Y1 - 2009 U6 - https://doi.org/10.1002/jpln.200800141 SN - 1522-2624 VL - 172 IS - 6 SP - 798 EP - 807 ER - TY - GEN A1 - Maurer, Thomas A1 - Herrmann, Ludger A1 - Stahr, Karl T1 - Wind erosion charcteristics of Sahelian surface types T2 - Earth Surface Processes and Landforms Y1 - 2010 SN - 1096-9837 VL - 35 IS - 12 SP - 1386 EP - 1401 ER - TY - GEN A1 - Pohle, Ina A1 - Niebisch, Michael A1 - Müller, Hannes A1 - Schümberg, Sabine A1 - Zha, Tingting A1 - Maurer, Thomas A1 - Hinz, Christoph T1 - Coupling Poisson rectangular pulse and multiplicative microcanonical random cascade models to generate subdaily precipitation time series T2 - Journal of Hydrology N2 - To simulate the impacts of within-storm rainfall variabilities on fast hydrological processes, long precipi-tation time series with high temporal resolution are required. Due to limited availability of observed data such time series are typically obtained from stochastic models. However, most existing rainfall models are limited in their ability to conserve rainfall event statistics which are relevant for hydrological pro-cesses. Poisson rectangular pulse models are widely applied to generate long time series of alternating precipitation events durations and mean intensities as well as interstorm period durations. Multiplicative microcanonical random cascade (MRC) models are used to disaggregate precipitation time series from coarse to fine temporal resolution. To overcome the inconsistencies between the temporal structure of the Poisson rectangular pulse model and the MRC model, we developed a new coupling approach by introducing two modifications to the MRC model. These modifications comprise (a) a modified cascade model (“constrained cascade”) which preserves the event durations generated by the Poisson rectangular model by constraining the first and last interval of a precipitation event to contain precipitation and (b) continuous sigmoid func-tions of the multiplicative weights to consider the scale-dependency in the disaggregation of precipita-tion events of different durations. The constrained cascade model was evaluated in its ability to dis-aggregate observed precipitation events in comparison to existing MRC models. For that, we used a 20-year record of hourly precipitation at six stations across Germany. The constrained cascade model showed a pronounced better agreement with the observed data in terms of both the temporal pattern of the precipitation time series (e.g. the dry and wet spell durations and autocorrelations) and event char-acteristics (e.g. intra-event intermittency and intensity fluctuation within events). The constrained cas-cade model also slightly outperformed the other MRC models with respect to the intensity-frequency relationship. To assess the performance of the coupled Poisson rectangular pulse and constrained cascade model, precipitation events were stochastically generated by the Poisson rectangular pulse model and then disaggregated by the constrained cascade model. We found that the coupled model performs satisfac-torily in terms of the temporal pattern of the precipitation time series, event characteristics and the in-tensity-frequency relationship. KW - Rainfall generator KW - Disaggregation KW - Precipitation event KW - Autocorrelation KW - Within-event variability KW - Intra-event intermittency Y1 - 2018 U6 - https://doi.org/10.1016/j.jhydrol.2018.04.063 SN - 0022-1694 VL - 562 SP - 50 EP - 70 ER - TY - GEN A1 - Schaaf, Wolfgang A1 - Pohle, Ina A1 - Maurer, Thomas A1 - Gerwin, Werner A1 - Hinz, Christoph A1 - Badorreck, Annika T1 - Water Balance Dynamics during Ten Years of Ecological Development at Chicken Creek Catchment T2 - Vadose Zone Journal N2 - Difficulties in quantitatively closing the water balance of catchments arise when upscaling point measurements and from insufficient knowledge of the physical boundaries, inner structure, and storage volumes of natural catchments. In addition, there is a strong need for generalizing the relationship between catchment characteristics and hydrological response. Therefore, experimental catchments with well-known boundaries and conditions could contribute valuable data to hydrological and critical zone research. One of the most well-established and largest constructed catchments is the Chicken Creek catchment (6 ha including a pond, Brandenburg, Germany) representing an initial ecosystem undergoing highly dynamic ecological development starting from clearly defined starting conditions. Directly after completion of the construction, extensive monitoring equipment was installed to track the ecosystem development and to capture the spatiotemporal variability of meteorological, hydrological, ecological, and soil conditions and vegetation succession. In this study, we focused on the water balance dynamics of the Chicken Creek catchment for the period 2005 to 2015 as influenced by ecological development. Water storage in the catchment was calculated from a three-dimensional model of groundwater volumes, soil moisture measurements, and water level recordings of the pond. The catchment water balance equation was resolved for evapotranspiration, the only part that was not measured directly. Time series of meteorological, hydrological, and ecological data for 10 yr enabled us to characterize the transient development of the catchment and to evaluate the effect of different feedback mechanisms on catchment hydrology. Y1 - 2017 U6 - https://doi.org/10.2136/vzj2017.04.0074 SN - 1539-1663 VL - 16 IS - 11 ER - TY - GEN A1 - Schneider, Anna A1 - Gerke, Horst H. A1 - Maurer, Thomas T1 - 3D initial sediment distribution and quantification of mass balances of an artificially-created hydrological catchment based on DEMs from aerial photographs using GOCAD T2 - Physics and Chemistry of the Earth Y1 - 2011 UR - http://www.sciencedirect.com/science/article/pii/S1474706510000380 U6 - https://doi.org/10.1016/j.pce.2010.03.023 SN - 1474-7065 VL - 36 IS - 1-4 SP - 87 EP - 100 ER - TY - GEN A1 - Maurer, Thomas A1 - Schneider, Anna A1 - Gerke, Horst H. T1 - A structure generator for modelling the initial sediment distribution of an artificial hydrologic catchment T2 - Hydrology and earth system sciences Y1 - 2011 SN - 1607-7938 VL - 15 IS - 12 SP - 3617 EP - 3638 ER -