* To monitor and quantify preferential flow through the vadose zone of various representative soil types in Europe at different climatic conditions by executing tracer experiments according to uniform experimental procedures
* to improve computer simulation models by incorporating preferential flow



To meet the project objectives both field data collection and modelling activities are being undertaken. Within the project, seven experimental sites of varying texture/structure were selected. To study the process of preferential flow on each of the selected sites well-defined tracer experiments are carried out according to uniform experimental set-up and uniform experimental procedures. This allows for comparability between the different experimental sites and at the same time guarantees identical experimental data-sets to be used during the modelling and simulation phase. All participants are involved in further development and improvement of models capable for simulating preferential flow. The improved models will be calibrated and validated for simulating water and compound transport using the standardized data-set from the field sites.

Besides the tracer experiments and modelling activities, complementary research activities within the project focus on:

* Collection of data on seasonal dynamics of preferential flow in sandy soil

* determination of wetting rates to study the persistence of dry soil bodies

* Micromorphometrical analysis to predict flow behaviour from visual inspection of soil structure

* Determination of soil hydraulic properties

* Determination of model parameters on soil monoliths in the laboratory and in the field

* Monitoring and comparing different measurements at different spatial scales