Traditional hydrogeological concepts of the unsaturated zone imply that the water is essentially static, and do not take account of the dynamic nature of the annual water cycle in the field. The basic concepts of water content, water potential and unsaturated hydraulic conductivity are defined as they are developed in soil physics and applied to the flow of water in the unsaturated zone. The emphasis is on a practical and non-numerical description of what happens in the field. An appreciation of the controls of water flow in the unsaturated zone is essential to an understanding of many hydrogeological problems.
- © 1982 The Geological Society