Assessment of hydraulic properties of technosols using Beerkan and multiple tension disc infiltration methods

The increasing global urban sprawl requires large amounts of materials, putting huge pressure on numerous natural resources. In particular, vast quantities of soils are used to create infrastructures or green spaces associated with new developments. Alternative solutions aimed at alleviating soil consumption are thus being encouraged. Creating urban soils by recycling waste from industrial and construction activities is feasible, but apart from their support function the resulting technosols should also be able to provide some ecosystem services such as the capacity to infiltrate water and filter contaminants. Various methods are routinely used for in situ characterization of the hydraulic behaviour of natural soils, but their ability to assess the hydraulic properties of technosols remains unclear. Indeed, technosols formed from recycled waste differ markedly from natural soil because they often contain a considerable proportion of coarse artefacts that affect their structure. In this study, results obtained by two distinct methods (ponding and tension infiltrometry), associated with two data processing methods (Beerkan estimation soil transfer (BEST) and numerical inversion), on a set of infiltration data measured on experimental plots made of technosols have been compared with each other. Both methods provided similar results and thus proved to be reliable when applied to technosols. Highlights: Reuse of by-products from anthropogenic activities is crucial to alleviate the consumption of natural soil. Hydraulic properties of technosols must be monitored to assess some of the ecosystem services they can provide. BEST and numerical inversion of multiple tension disc infiltration data gave consistent results. Reliability of the hydraulic characterization methods used for technosols deserves further inquiry.