Commonly hydrological models are calibrated and evaluated by considering differences of simulated and observed discharges summarized over time (e.g. Nash-Sutcliffe efficiency). However, these measures omit a lot of the actually available information that is used when experimental hydrologists characterise the system.

This MSc thesis will explore the value of data analysis methods from experimental hydrology (e.g. recession analysis, base flow separation, correlation between discharge and water quality parameters, principal component/factor analysis, flow duration curves, etc.) for model calibration and evaluation. Time series of discharge and water quality data of the Barton Springs (Texas, USA) are available to be applied on a given hydrological model. Barton Springs are the primary drainage of the Edwards Aquifer, which is an important water provider for economy and agriculture. The results of the thesis will help to improve the model and to obtain more robust predictions of future water availability.

The student will use a data set and a model provided by the USGS to produce simulations of spring flow. Observed and simulated spring discharge and water quality will be compared using methods from experimental hydrology. That way strengths and weaknesses of the model can be identified and improvements of the model structure or parameters can be provided.

Andreas Hartmann, Barbara Mahler/Andy Long (USGS Texas Water Science Center)

A visit of the site is not obligatory but it will be supported if the student desires to do so.

Andreas Hartmann andreas.hartmann@hydrology.uni-freiburg.de

Combined application of hydrological modeling, model calibration/evaluation schemes and methods for time series analysis using R as programming language.

English

Mahler, B.J., Garner, B.D., Musgrove, M., Guilfoyle, A.L., and Rao, M.V., 2006, Recent (2003–05) water quality of Barton Springs, Austin, Texas, with emphasis on factors affecting variability: U.S. Geological Survey Scientific Investigations Report 2006–5299, 83 p., 5 appendixes.

Mahler, B. J., et al. „Linking climate change and karst hydrology to evaluate species vulnerability: The Edwards and Madison aquifers.“ AGU Fall Meeting Abstracts. Vol. 1. 2013.

Hartmann, A., M. Weiler, T. Wagener, J. Lange, M. Kralik, F. Humer, N. Mizyed, A. Rimmer, J. A. Barberá, B. Andreo, C. Butscher, and P. Huggenberger (2013), Process-based karst modelling to relate hydrodynamic and hydrochemical characteristics to system properties, Hydrology and Earth System Sciences, 17(8), 3305-3321.10.5194/hess-17-3305-2013