Hydrological performance of multi-layered constructed soils

Blue-green infrastructure is becoming an integrated part of city design that can help to mitigate the environmental impacts of urbanization. Constructed soils along with plants are key components of blue-green infrastructure such as green roofs and infiltration swales. The aim of this project is to elucidate through invasive and noninvasive experimental methods the hydraulic functioning of multi-layered soils. Constructed soil systems comprising two or more layers of media with contrasting physical properties may provide better performance in terms of evapotranspiration loss, infiltration capacity, contaminant removal, and support for plants, than do non-layered soils. Interfaces between layers can induce effects like capillary barrier, finger flow and air entrapment that are well understood as individual phenomena in natural soils but have not yet been studied in constructed soils. Recently developed approaches to modelling fluxes of water and solutes in the soil-plant-atmosphere continuum in natural settings will be extended to multi-layered constructed soils.