Hydrological surface processes during the early stage of a man-made catchment

View into the artificial "Hühnerwasser" catchment (photo: Mike Schwank)

Context

Within the framework of a major interdisciplinary study (SFB/TR38) of several universities from Germany and Switzerland a 0.06 km² artificial catchment has been build in the Lusation coal mining area (Germany). In miscellaneous sub-projects of the SFB/TR38 different aspects of the initial development (such as e.g. soil formation, development of the vegetation) of this artificially created ecosystem are investigated in order to identify the processes, structures, and interactions between them which control the development of an ecosystem in its initial phase.

Aims of the study

Our project aims at an improved understanding of the formation of preferential flow paths along and into to soil surface. Key tools for our investigation are two microwave radiometers (ELBARA / MORA) which enable us to remotely measure the near-surface soil moisture content. Methods to investigate and to monitor the development of hydrological surface structures from the microwave emission of the ground shall be developed in the course of this work.

The L-band radiometer ELBARA (photo: Ingo Völksch)

Experiments

Firstly, a set of irrigation experiments are carried out at the WSL in Birmensdorf. A 3 x 4 m tiltable soil box, filled with material from the artificial catchment in Germany, is irrigated to investigate the influence of different parameters such as e.g. slope angle, irrigation intensity or pre-existing heterogeneities on the soil surface on the development of the flow paths.

After completion of the irrigation experiments (approximately in spring 2008) the radiometers will be set up in the artificial catchment in Germany for a long-term monitoring of the natural development of emerging flow paths on a previously smooth slope. From these measurements we expect to gain knowledge helping us to answer the following questions:

1. When and under which circumstances do flow paths come into being?
2. How do these flow patterns evolve in the course of time (including different seasons) in response to soil frost events, snow melt, intense rainfalls, dry spells etc.?

Collaboration

This study is carried out in close collaboration with Prof. Christian Mätzler from the Institute of Applied Physics, University Bern and Prof. Hannes Flühler from the  soil physics group of the Institute of Terrestrial Ecology, ETH Zürich.

Photographs

Pictures of the experimental set-up and the investigation sites

Participants

• Ingo Völksch
• Mike Schwank
  
• Manfred Stähli
  
• Martin Scherler
  

Contact

• Ingo Völksch