Stefan Wirtz Vom Fachbereich VI (Geographie/Geowissenschaften ...

Experimentelle Rinnenerosionsforschung vs. Modellkonzepte – Quantifizierung der hydraulischen und erosiven Wirksamkeit von Rinnen
(SEEGER et al. 2005). Due to sheep grazing, the vegetation succession is strongly retarded
and absent on many trails (RIES et al. 2000b; RIES et al. 2003).
Figure 1 shows the Arnás catchment with the dominating runoff processes in winter, when the
experiments were carried out and the positions of the rill experiments. The tested rills have
developed in regions with dominating surface runoff generation processes: the first rill in a
Hortonian overland flow (HOF) area, rill 2 and rill 3 in an saturation overland flow (SOF)
area.
Fig. 1: Overview over the Arnás catchment with the dominating runoff processes in winter:
HOF= Horton overland flow, SOF=saturation overland flow, SSF= subsurface flow, DP=
deep percolation (modified according to BUTZEN et al. 2009 submitted).
Tested rills:
In the Arnás catchment the experiment was accomplished in three rills that are very similar to
each other for the first 12 m. The slope stays constant at about 8° in rill 1 whereas rill 2 and
rill 3 become steeper. (Fig. 3). All three rills drain over a track and finish with a step at the
track scarp.
The first rill has developed along a motorcycle trail, thus it is an anthropogenically initiated
rill with an average slope of 7.6°, the maximum slope is 12°. The rill is weakly developed, the
width is between 1 and 10 cm, the depth between 1 and 5 cm. The rill is nearly completely
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