Thesis Colloquium LENNART JONGEN

This study tests the suitability of inferring storage in a catchment according to the Kirchner Approach. This research was done in collaboration with Hohai University in Nanjing, China

Organised by Hydrology and Quantitative Water Management

Mon 21 August 2017 14:30 to 15:00

Venue Lumen, building number 100
Room E112 (HWM Meeting room)

Artificial Hillslopes as Simple Dynamical Systems

Inferring storage from streamflow variations in the Hohai Soiltank and Biosphere II

Using a hydrological model implies simplifications and generalizations of complex catchment processes. The most extreme simplification made in hydrology is to lump the catchment to one system and integrate all complex catchment processes. The recent work of Kirchner (2009) shows it's full potential with his theory on 'catchment as simple dynamical systems'. According to this approach, storage in a catchment can be inferred from stream flow variations. This has never been tested. Hereby, the purpose of this research is to check whether this approach is valid to infer storage from stream flow variations. The study is conducted under heavily controlled conditions at two experimental hill slopes, the Hohai Soiltank and the Biosphere II. Experiments are done in the Hohai Soiltank, at the Hohai University Research facility. A dense network of soil moisture sensors was installed, allowing an accurate calculation of the total storage. Tipping buckets were installed to measure the total discharge. For the Biosphere II, high quality storage and discharge data is used from experiments done by Geveart et al. (2014). Results show 1; inferred storage is very sensitive to the choice of parameters, 2; storage inferred results in an overestimation of the observed storage and 3; the modeled discharge only shows good agreement with observed discharge using the approach, but not when using parameters derived from fitting a line directly on the unique discharge storage relationship. Although the two experimental hillslopes differ in various ways, results were similar. The results highlight the unsuitability of inferring storage from stream flow variations. The simple dynamical system approach is not suitable for inferring storage from stream flow variations. However, the Hohai Soiltank and the Biosphere II behave partly as a simple dynamical system, since the discharge is modeled with good agreement with observed discharge.