One-month research stay of Jana Glass at the University of California Riverside, USA

As part of the INOWAS qualification program, Jana Glass visited the Department of Environmental Sciences at the University of California Riverside between 30May and 23 June 2017. The research group led by Prof. Jirka Simunek is mainly focusing on the evaluation of water flow and solute transport in variably-saturated soils using numerical models, especially the HYDRUS software package. The focus of the stay was to learn more about unsaturated zone modeling as well as to modify the HYDRUS code so that it is more applicable to simulate the processes taking place during the laboratory tank experiments.

The infiltration of river water or treated wastewater in infiltration basins causes the soil to clog over time which leads to a reduction of the infiltration capacity and hence a decrease of the performance of a MAR system. To evaluate the occurring clogging rates, a new option in HYDRUS 1D and 2D was implemented where it is possible to decrease hydraulic conductivity over time using an exponential function. Furthermore, a non-standard boundary condition for the infiltration basin was combined with the time-variable hydraulic conductivity scaling factors to simulate the MAR laboratory experiment. The boundary condition allows the user to specify the inflow into the infiltration basin and the respective infiltration rate are calculated by HYDRUS depending on the water level in the basin.