• Soil and water bioengineering is an ecological engineering solution providing several benefits to both humans and nature. • There is an emphasis on the necessity to reconcile both natural hazard control and ecological restoration. • Applied research in geosciences and ecology can be used in an interactive process with practitioners to reach this aim. • Sound soil and water bioengineering methods that reconcile both objectives are proposed.

Eco-engineering techniques involve the use of both plants and inert materials where, in the latter, non-treated wood is usually present. The two different elements will both evolve with time and change their mechanical properties differently. On one hand, the wood will degrade decreasing its effective cross sectional area with time. On the other hand, the live plant material will grow and propagate new roots as time progresses. Both root development and inert material changes must be accounted for in order to realistically simulate a bioengineered slope evolution and design effective eco-engineering solutions.The dynamic nature of a bioengineered work sets different scenarios throughout the slope design life. All these different stages must be taken into account in the work design process. In this work, we propose an adaptation of the existing routines and procedures of both geotechnical practice and civil engineering design scheme in order to closely reflect the inclusion of bioengineering methods in the classic geotechnical 2 engineering problems. A design methodology covering different critical points within the lifecycle of a bioengineered slope is proposed and put into practice into the design stage for a case study in Scotland. By detecting critical points at the design stage the proposed methodology was proven to offer an improved eco-engineering work design scheme. With the use of the proposed method both external and internal stability checks with their corresponding safety factor values increase with time and there are no conflicts between the two evolving processes involved in this kind of works.

Asymmetric root distribution pattern on steep terrain is analysed by combining GPR(Ground Penetrating Radar) image analysis with a theoretical root distribution model and is verified with field investigation data. Root distribution and morphology of a mature deciduous tree were analysed in terms of the plant's anchorage needs in an asymmetric loading condition scenario. The GPR method was combined with trench profile and root excavation techniques for both the structural and non-structural root data collection.Good correlations between the field analysis, the theoretical model outcome and the GPR output imagery were found. GPR was proven to be an efficient tool for both root lateral distribution characterisation and vertical root cluster distribution. The combination of the GPR output with a theoretical root distribution model seemed to be a viable non-invasive methodology for assessing root system vertical and horizontal distribution.

Climate change means that fire damage and torrential rains are major issues in many parts of the world, stripping water courses and their ability to attenuate flow in ponds and weirs. Soil bioengineering methods integrate civil engineering techniques with natural materials to obtain fast, effective and economic methods of protecting, restoring and maintaining the natural slowing of water run-off.This study combines both the theory and the practical installation involving slope instability, erosion, soil hydrology, mountain plant ecology, and land use restoration to protect the slope against erosion and soil mass loss. Using a multidisciplinary approach, we explore the exchange of the stabilising role between an initially inert structure and the living material used in a bioengineering work to protect the slope against erosion and soil mass loss. From a case study investigation in Spain we investigate bioengineering structures installed within erosion gullies or on eroded slopes and propose a similar measure for a site in Nepal,. The know-how transfer between eco-engineering works from different geo-climatic conditions is considered where bamboo is not a native species.

A new methodology to incorporate the mechanical root anchorage effects in both short-and long-term slope stability analysis is proposed based on observed and assumed behaviour of rooted soil during shear failure.The main focus of the present work is the stress-strain range comparison for both soil and roots and development of a stability model that would incorporate relevant root and soil characteristics based on the fact that available soil-root composite shear resistance depends on the magnitude of the shear strain. This new approach, combining stress-strain analysis, continuum mechanics, and limit equilibrium stability assessment, allows for a more realistic simulation of the rooted soil composite whereby the stabilising effect of the rooted soil is incorporated in the slope stability calculations by means of the synchronisation of root and soil mechanical behaviour during failure.The stability of vegetated terraces in a study area in Spain is used as a case study to demonstrate the proposed methodology and to compare the results with the traditional use of the perpendicular root reinforcement model. The results of the study show that as the shear displacement (strain) increases, the stress is transferred from the soil that provides most of the resistance at low strains onto the roots that provide the most of the resistance to shear at high strains. Including this behaviour in the overall resistance to failure of the root-soil continuum resulted in a more conservative and realistic assessment of the stability of a vegetated slope immediately after a precipitation event when a progressive failure is most likely to be triggered.