Highways Agency Reports

The intension of this report is to summarise the current state-of -the-art on the design of drains by presenting the basic concepts and reviewing the existing design criteria, both for traditional granular and geotextile wrapped subsurface drainage systems, primarily used in permanent works. De-watering systems, including deep vertical drains, well points, deep pumped wells, drainage by vacuum, eletro-osmois, used for consolidating and temporarily controlling groundwater, are beyond the scope of the report.