Vegetation-based climate change adaptation measures for earth infrastructure

Climate change will affect the performance of existing earth infrastructure. Heavy and/or prolonged rainfall events may cause i) soil swelling with the infrastructure failing to meet its serviceability limit state criteria and/or ii) reduction in soil shear strength eventually triggering instability of natural or engineered slopes (failure to meet its ultimate limit state criteria). Prolonged droughts may cause shrinkage-induced differential settlements with the infrastructure failing to meet their serviceability limit state criteria (e.g., excessive differential track settlement). Vegetation mediates the soil-atmosphere interaction and can therefore be engineered to be turned into a nature-based adaptation measure. Water uptake by transpiration occurs through the Soil-Plant-Atmosphere Continuum (SPAC). This project explores possible manipulation of the in-series components of the SPAC to correct the water exchange between the soil and the atmosphere and potentially mitigate the effect of climate change.

The hydraulic behaviour of the root zone and water uptake due to transpiration are controlled by coupled interactions between biotic (e.g., physiological and anatomical plant traits, root architecture, saprophytic and symbiotic microbial communities) and abiotic factors (e.g., soil water chemistry, nutrients, soil water content and suction, solar radiation, air relative humidity). Understanding the ‘geotechnical’ impact of these factors is key to envisage biotic and abiotic manipulation of the soil-plant-atmosphere continuum to mitigate landslide hazard. This PhD project can be developed along different lines all relevant to the development of nature-based mitigation measures for earth infrastructure subjected to climatic hazard. We welcome inputs from different backgrounds including geotechnical engineering, environmental engineering, and plant science. Possible topics include but are not limited to:

i)    Effect of temporary water stress conditions on transpiration-induced water uptake

ii)   Effect of soil bacterial community on transpiration-and hydraulic behaviour of the root zone

iii)   Effect of mycorrhizal community on transpiration-and hydraulic behaviour of the root zone

iv)  Effect of leaf anatomical traits on stomatal response and transpiration in the water-limited regime

v)   Effect of root architecture on stomatal response and transpiration in the water-limited regime

vi)   Effect of root exudates on the hydraulic behaviour of the root zone.