**7. Conclusions**

The starting point of this work is that the infiltration process on sloping surfaces observed in many laboratory experiments is not correctly represented by the existing theoretical modeling efforts.

On the basis of the main outcomes of this analysis performed using 54 laboratory experiments and a conceptual model, the following insights can be derived:


**Author Contributions:** Laboratory experiments, numerical analyses, investigation, writing—original draft preparation and writing—review and editing, R.M., C.C., C.S., A.F., J.D. and R.S.G.

**Funding:** This research was partly financed by the Italian Ministry of Education, University and Research (PRIN 2015).

**Acknowledgments:** The authors are thankful to A.G. Del Prete for his technical assistance. **Conflicts of Interest:** The authors declare no conflict of interest.
