Land Drainage

Drainage pipe installation in humid countries

The main reasons for installing drainage systems, especially in Western Europe, the USA and other countries with a similar climate, are to remove surface water, to improve accessibility and to improve the growth of crops.  Lowering the groundwater table improves the aeration of the soil and rooting conditions for plants and reduces the amount of energy the soil requires to warm up in the spring.  In turn, this encourages early plant growth.  Drainage also improves the load-bearing capacity of the topsoil which is advantageous to animals, to machinery and, in the case of sportsfields or golf courses, to players.

Drainage pipe installation in arid and semi arid countries

The main reason for installing drainage pipes in arid and semi-arid areas is to remove salts and other contaminating minerals out of the root zone. Groundwater and irrigation water contains salts and other minerals that in arid or semi-arid countries can accumulate in the root zone and at the soil surface after evaporation.  Over a period of time, this results in the soil becoming unsuitable for crops.  The accumulated salts and minerals can be removed by means of a surplus of irrigation water.  The water then dissolves the salts and minerals, carrying them towards the drainage system.  Lateral drains are typically installed at a depth up to 2.0 m and collectors up to a depth of 3.0 to 3.5 m.  In irrigated fields, a stable and well-balanced machine is essential for the proper installation of drainage pipes.

Drainage pipe installation in waterlogged areas.

Salinization results from irrigation and when irrigation has been executed over many years, and sometimes also results from high water tables.  In the case of high water tables, the risk of salinization can often be reduced by preventing the capillary rise of saline groundwater to the root zone. This can be achieved by maintaining a low groundwater table and so the drains are installed deep in the ground.  Laterals are usually installed at a depth of 1.75 m to 3.0 m and collector pipes at 2.0 m  to 4.0 m. Due to a low daily discharge and often a higher hydraulic conductivity, the pipes are spaced well apart.  The diameters of the pipes are typically 4” to 8” for the lateral pipes and collectors are up to 16”.

The installation of pipes in extremely waterlogged areas can be very difficult and the use of specialised equipment with the right control systems is essential.  Mastenbroek has extensive experience of installing drainage pipes in these kinds of conditions and has developed a range of control systems to ensure proper and accurate installation.

Drainage pipe installation in rocky soils, arid areas

In rocky soils, the main reason for installing drainage pipes is to remove salts and other contaminating minerals out of the root zone.  Groundwater and irrigation water contains salts and other minerals that in arid or semi-arid countries can accumulate in the root zone and at the soil surface after evaporation.  Over a period of time, this results in the soil becoming unsuitable for crops.  The accumulated salts and minerals can be removed by means of a surplus of irrigation water.  The water then dissolves the salts and minerals carrying them towards the drainage system.  In rocky soils, the drainage system consists of lateral drains installed between 2.0 and 4.0 metres deep including a gravel envelope installed by specialised rock drainage machines.  The collectors consist mainly of open drains which are connected back to the river by means of channels.