Assessment of vadose zone hydrology: concepts, methods, applications and guidelines

Vadose zone hydrology is a developing science influenced by earth scientists (soil scientists, pedologists, hydrogeologists, engineering geologists and geomorphologists) and engineers (geotechnical). However, problems faced are associated with lack of agreement between basic concepts, different approaches and definitions, and difficulty in communicating findings to other technical or non-technical audiences. The need for better cross-disciplinary dialogue and understanding subsequently becomes increasingly important, notably given the sensitivity of investigation related to ephemeral wetlands, contamination and water impacting infrastructure development This thesis therefore aims to address basic concepts, accepted methodologies and highly variable and sensitive case studies in order to minimise risk in the assessment of the vadose zone. Terminologies, quantification, methods and existing guidelines are critically appraised and validated based on three case studies. Findings are reported in order to improve investigation techniques and to minimise risk. Final recommendations are made regarding a proposed vadose zone assessment protocol to ensure compliance to a set of minimum requirements for vadose zone assessment. It is hoped that such a methodology will be implemented towards protection of the natural environment, notably in urban areas, as well as to prevent damage to infrastructure.