Geomorphology and hydrology of a sediment-soil sequence in Dessel: studying natural analogues for engineered earth covers

The feasibility of studying natural analogues to constrain the long-term evolution of engineered earth covers is investigated. A suitable sediment-soil sequence in Dessel was selected and investigated using an interdisciplinary approach. Geomorphological, pedological and hydrological techniques were used to characterise the solid and liquid phase of the profile. As such, various earth surface processes and their potential effect on the redistribution of solid and liquid phase within the profile could be quantified. Integration of the results shows that the hydraulic properties of the vadose zone at the investigated site are influenced by soil formation processes in a time period ranging from as low as 100 years to more than 1000 years. These changes may be as high as two orders of magnitude for, e.g., the hydraulic conductivity. The main conclusion is that natural analogues provide a unique means to study the phenomenology of the long-term evolution of earth covers and vadose zones in general.