Materials for subsurface land drainage systems

The purpose of this Paper is to provide this practical information to drainage engineers and contractors. The Paper is based on the current knowledge of water flow into drain pipes and envelopes, their properties and applicability. It also contains guidelines for the selection of drainage materials and practical guidelines for the implementation of laboratory and field investigations to evaluate the performance of drainage materials. The selection of the materials must also consider the required specifications, their availability, durability and cost. Guideline for selection of the most appropriate envelope material, as related to local condition