Lorenz Ammann

HS Hydrological Sciences

The 2019 Outstanding Student Poster and PICO (OSPP) Award is awarded to Lorenz Ammann for the poster/PICO entitled:

Fast herbicide transport in a small agricultural catchment: modellers meet experimentalists (Ammann, L.; Doppler, T.; Stamm, C.; Reichert, P.; Fenicia, F.)

Click here to download the poster/PICO file.

Lorenz Ammann is a PhD candidate at ETH Zurich and at Eawag, the Swiss Federal Institute of Aquatic Science and Technology. His research focuses on modeling of pesticide transport in small agricultural headwater catchments and the statistical quantification of the associated uncertainties.
The awarded PICO describes a modeling study conducted to predict high-frequency concentration dynamics of different herbicides in a small headwater stream. Experimental knowledge of the study site was explicitly included in the model developing process through the split of the landscape into response units, the selection of the model structure in each unit, and the selection of the prior parameter distribution in a Bayesian uncertainty quantification setting. Joint inference of hydrological, chemical and error model parameters was conducted relying on a recently developed likelihood framework. The resulting model is conceptual in nature, cheap to evaluate, shows a realistic behavior of internal states, and manages to predict observed high-frequency concentration time series with reasonable accuracy. This modeling study contributes to a better assessment of the risk related to rainfall-triggered peak herbicide concentrations in headwater streams.