Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/hess-2017-498
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
Education and communication
10 Aug 2017
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Hydrology and Earth System Sciences (HESS).
Demonstrating the "Unit Hydrograph" and flow routing processes involving active student participation – A university lecture experiment
Karsten Schulz1, Reinhard Burgholzer1,2, Daniel Klotz1, Johannes Wesemann1, and Mathew Herrnegger1 1Institute of Water Management, Hydrology and Hydraulic Engineering (IWHW), University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
2VERBUND Trading GmbH, Am Hof 6a, 1010 Vienna, Austria
Abstract. The unit-hydrograph (UH) has been one of the most widely employed hydrological modelling techniques to predict rainfall-runoff behavior of hydrological catchments, and is still used up-to-date. Its concept is based on the idea that a unit of effective precipitation per time unit (e.g. mm h-1) will always lead to a specific catchment response in runoff. Given its relevance, the UH is an important topic addressed in most of the (engineering) hydrology courses at all academic levels. While the principles of the UH seem to be simple and easy to understand, teaching experiences in the past suggest strong difficulties in students' perception of the UH theory and application.

In order to facilitate a deeper students' understanding of the theory and application of the UH, we developed a simple and cheap lecture theatre experiment involving an active student participation. The seating of the students in the lecture theatre represented the "hydrological catchment" in its size and form. A set of plastic balls, prepared with a piece of magnetic strip to be tacked to any white/black board, each represented a unit amount of effective precipitation. The balls are evenly distributed over the lecture theatre and routed by some given rules down the catchment to the "catchment outlet", where the resulting hydrograph is monitored and illustrated at the black/white board.

The experiment allowed an illustration of the underlying principles of the UH, including stationarity, linearity and superposition of the generated runoff and subsequent routing. In addition, some variations of the experimental setup extended the UH-concept to demonstrate the impact of elevation, different runoff regimes and non-uniform precipitation events on the resulting hydrograph.

In summary, our own experience in the classroom, a first set of student exams, as well as student feedback and formal evaluation suggest that the integration of such an experiment deepened the learning experience by active participation. The experiment also initialized a more experienced based discussion of the theory and assumptions behind the UH. Finally, the experiment was a welcome break within a 3-hour lecture setting, and great fun to prepare and run.


Citation: Schulz, K., Burgholzer, R., Klotz, D., Wesemann, J., and Herrnegger, M.: Demonstrating the "Unit Hydrograph" and flow routing processes involving active student participation – A university lecture experiment, Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2017-498, in review, 2017.
Karsten Schulz et al.
Karsten Schulz et al.
Karsten Schulz et al.

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Short summary
The unit-hydrograph has been one of the most widely employed modelling techniques to predict rainfall-runoff behavior of hydrological catchments. We developed a lecture theatre experiment including some student involvment to illustrate the principles behind this modelling technique. The experiment only uses very simple and cheap material including a set of plastic balls (representing rainfall), magnetic stripes (tacking the balls to the white board) and sieves (for ball/water gauging).
The unit-hydrograph has been one of the most widely employed modelling techniques to predict...
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