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Scientific Project C1 - Determination and modelling of water and matter balance in the artifically created catchment area „Huehnerwasser“

Staff

In hydrology, hypotheses and concepts for the analysis of hydrologic processes, in particular of water and matter fluxes at the catchment scale, are usually based on field observations in natural water catchment areas. The obtained observation results are more or less detailed but always point information only. By the application of modelling and parameter identification, the findings shall be interpolated, generalised and finally transferred to unknown catchments. Often, the results achieved with the applied hydrological models (e.g. precipitation runoff models) are not as close to reality as aspired. The model formation and calibration are usually based on the discrete field observations in the considered area, which is normally characterised by large parameter heterogeneity in time and space. Due to the large natural heterogeneity, the number of parameters degrees of freedom is very high in hydrological models. Consequently, the natural system is strongly underdetermined and there is a large scope for model interpretations.

The main advantage of the artificially created water catchment is the considerably reduced number of degrees of freedom. Thereby, the uncertainties normally resulting from the natural parameter variation are limited. The option to investigate the development of the artificial catchment during the initial period of structure formation shall allow the better calibration and validation of applied hydrological models for various system stages. This will enable to derivate new basic principles for the description of water and matter balances in natural catchment areas.

By means of the open but spatially relatively well defined and comparatively simple structured artificial catchment, e. g. the following questions are to be answered:

• Which effects of the ecosystem development can be identified by the discharge quantity and quality at the catchment outlet?
• In which manner are structures of different scales with respect to the catchment scale to be considered?
• Does an improved physically based description of processes at a smaller scale result in improved model output for the catchment area?
• In which way can strategies be derived to identify different development stages from observed spatial and temporal changes in water and matter fluxes?

The model-supported analysis of the catchment area include e. g. the processes of infiltration and percolation, the changes in storage in the saturated and unsaturated zone, the formation of runoff components, the changes of surface water levels and of the water quality.
The water and matter balance in the artificial catchment will be monitored in high temporal and spatial resolution using integrating hydrological, tracer hydrological and hydrochemical investigation methods as well as non invasive techniques. The obtained results shall enable to generalise the information about the runoff formation processes, the travel and retention times of water constituents as well as the matter transport in the hydrologic system.