A structure generator for modelling the initial sediment distribution of an artificial hydrologic catchment

Abstract

Abstract. Artificially-created hydrological catchments are characterised by sediment structures from technological construction processes that can potentially be important for modelling of flow and transport and for understanding initial soil and ecosystem development. The subsurface spatial structures of such catchments have not yet been sufficiently explored and described. Our objective was to develop a structure generator programme for modelling the 3-D spatial distribution patterns of dumped sediments depending on the technical earth-moving and deposition processes. We are focussing in a first step on integrating sediment dumping, particle size, and bulk density modification processes on the catchment scale. For the model development, the artificially-constructed hydrological catchment "Chicken Creek" located in Lower Lusatia, Germany, served as an example. The structure generator describes 3-D technological sediment distributions at two scales: (i) for a 2-D-vertical cross-section, texture and bulk density distributions are generated within individual spoil cones that result from mass dumping, particle segregation, and compaction and (ii) for the whole catchment, the spoil cones are horizontally arranged along trajectories of mass dumping controlled by the belt stacker-machine relative to the catchment's clay layer topography. The generated 3-D texture and bulk density distributions are interpolated and visualised as a gridded 3-D-volume body using 3-D computer-aided design software. The generated subsurface sediment distribution for the Correspondence to: T. Maurer (maurer@tu-cottbus.de) Chicken Creek catchment was found to correspond to observed patterns already without calibration. Spatial aggregation and interpolation in the gridded volume body modified the generated distributions towards more uniform (unimodal) distributions and lower values of the standard deviations. The modelling approach is generally applicable to all situations where large masses of unconsolidated sediment are moved and dumped thereby allowing generation of basic soil structures and patterns of hydrological systems.

Initial hydro‐geomorphic development and rill network evolution in an artificial catchment

“…Infiltrometer measurements for four sectors of the slope (Figure a, Gerwin et al ., ) revealed relatively low hydraulic conductivity values at saturation. The spatial distribution of substrate properties is governed by technogenic structures (Maurer et al ., ), which limited the identification of spatial auto‐correlation patterns (Papritz et al ., ). A rapid formation of physical and biological soil crusts was observed.…”

Impact of dumped sediment structures on hydrological modelling in the artificial Chicken Creek catchment, Germany

“…However, there is no information on whether differences exist in their bulk densities. Measurements conducted by Maurer et al (2011) at comparable test sites suggest that there is a spatial variation of bulk density in the Chicken Creek catchment. Based on this result, they estimated the initial bulk density of the sediments in the Chicken Creek catchment to be 1.45 g/cm 3 .…”

“…The modelling is based on data from the monitoring program of the SFB/TRR38: hourly measured precipitation, air temperature, air humidity, wind velocity, and global radiation at a local climate station from 2006 to 2010, digital elevation model with a 1-m spatial resolution of the clay basement and the sandy top layer from 2008, soil texture and bulk density according to Maurer et al (2011), saturated hydraulic conductivity based on 22 undisturbed surface infiltrometer measurements, yearly measurements of mean vegetation coverage at approximately 100 plots of 25 m 2 each from 2006 to 2010.…”

“…This sediment segregation affects the hydraulic conductivity. Maurer et al (2011) investigated spoil-cones comparable to the Chicken Creek catchment and also found higher bulk densities at the centres and lower bulk densities at the flanks of the cones. In the Chicken Creek catchment, these cones are strung together and form pourribs running transverse to the flow-paths (Gerwin et al, 2009).…”

“…The existence of spoil-cones in the catchment and their importance for the ecosystem's development and hydrological processes was mentioned by Gerwin et al (2009) andMaurer et al (2011). The impact of spoil-cones on physical and hydraulic sediment properties was investigated by Buczko et al (2001) in lusatian lignite open-cast mine dumps.…”