Land Drainage Installation - The Basics

The purpose of a Land Drain is to drain excess water from gardens, fields or public grassed areas that suffer from water retention. Perforations in the pipe enable water to be collected and carried to away to a soakaway, water course of surface water drain.

1. Land Drain should be laid in a trench that is approximately 250mm wide. Depth may vary according to the particular soil makeup but an ideal depth is 900mm.
2. The sides of the trench should be vertical or tapered in towards the bottom.
3. Once the trench has been prepared it should be lined with Geotextile membrane, allowing enough to cover over the top of the backfill material. This membrane prevents soil particles from being washed into the drain and clogging up the perforations, and keeps the gravel within the trench.
4. The land drain pipe itself should be laid on a bed of pea shingle. The same material is used to backfill the trench above the pipe, up to a depth of approximately 150mm from the surface. There is no need to try to compact the pea shingle.
5. The remainder if the Geotextile membrane can now be laid over the top of the pea shingle, and the topsoil that was excavated earlier can be relaid, along with the turf.