Numerical Investigation into the effects of rainfall and long stem plants spacing on Root Water Uptake (RWU)

Woody plants on earthen slopes are a bioengineering solution for the prevention of shallowlandslides that occur mostly during a wet season. From a soil-hydrological point of view, slope stability isinfluenced by plant roots reducing soil water content through transpiration. Despite this, conventionalengineering practice tends to ignore the effects of Root Water Uptake (RWU), in part due to the complexityof soil-vegetation-atmosphere interactions. This paper investigates the hydrological effects of plants, whichinvolved seepage simulations performed on two different soil types. Each soil was exposed to differentrainfall intensities, and the influence of plants over time was seen from the RWU over time for differentconfigurations of plant spacing and canopy densities. This information with in-situ rainfall data, is useful toassess the effectiveness of plants for slope stability. Further, the relative importance of different mechanismsacting in soil-plant-atmosphere interactions was seen in the RWU data. Although the conducted simulationsrefer to a horizontal soil profile, the results are useful in more complex geometries such as earthen slopesand may help the design of bioengineering solutions (woody plants) and slope stability assessment. Futureresearch is aimed to investigate additional soil-vegetation-atmosphere mechanisms and additional model geometries and plant species.