Development and testing of a new time variant approach for streamwater transit times

• Applicant: Professor Dr. Julian Klaus
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: from 2012 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 211141820

Water and contaminant transport through the environment are major research challenges across the field of hydrology. These processes are often difficult or impossible to observe because the majority of the flow and transport is below ground. Since the advent of isotope tracers, one can now sample (for a distinct time) the stream and quantify the whole catchment¿s transit time. Indeed the time water spends travelling through the subsurface of a catchment to the stream network (i.e., the catchment water transit time, TT) fundamentally describes storage, flow pathway heterogeneity and sources of water in a catchment. The distribution of transit times (TTD) reflects how catchments retain and release water and solutes that in turn set biogeochemical conditions and affect contamination release or persistence. Thus, quantifying the transit time distribution provides an important valuable constraint of water and contaminant transport on biogeochemical processes and catchment sensitivity to anthropogenic inputs and land-use change. Today there remain several major research challenges for the use of TT and for understanding how TT can lead to new breakthroughs in catchment flow process conceptualization and the development of new generations of hydrological models. In this project several of current research questions are addressed. The overall topic is the recently determined time-variant behaviour of the TTs. Within the experimental tasks of the research project, a high temporal sampling resolution for the isotopic composition of stream and precipitation water (15 min) will be used to investigate the role of the sampling interval on the results, the time-variant characteristic of TT and how catchment parameters govern the shape of the TTD. The modelling part deals with TTs at the hillslope scale. A model will be employed to determine a time variant description of TT and TTD and to identify the controlling hillslope properties on them by a virtual modelling approach.

• DFG Programme: Research Fellowships
• International Connection: Canada, USA
• Host: Professor Dr. Jeffrey J. McDonell