What is the purpose of subsurface drainage?

Author: Mr. Don Jast  |  Last update: Wednesday, May 20, 2026

A primary goal in the design and construction of subsurface drainage systems is to remove noncapillary water from the upper layers of the soil profile as quickly as possible to ensure an adequately aerated root zone and trafficability for critical field operations such as planting and harvesting.

What is the function of subsurface drainage?

Subsurface drainage provides many long-term sustainability intangible benefits, such as: improvement in soil health due to the increased aeration of the soil. increased responses to fertiliser use. reduced mineral imbalances in the soil and sometimes in the plants as well.

What is the purpose of sub soil drainage?

What is subsoil drainage? Subsoil drainage systems can protect homes and gardens by removing excess water to prevent flooding and stopping the deluge from flowing back to your property. If the water sinks back to your house, it can cause a lot of damage.

What is the purpose of underground drainage?

What is Underground Drainage? An Underground Drainage system is used to discharge surface, foul and grey water. Surface water refers to rainwater and stormwater where foul water is the water discharged from toilets and grey water is the waste from baths, sinks, washing machines and dishwashers.

Under what conditions would sub-surface irrigation be best suited?

A subsurface system is flexible and can provide frequent light irrigations. This is especially suitable for arid, semi-arid, hot, and windy areas with limited water supply, especially on sandy type soils.

Surface vs Subsurface Drainage

What is the problem with surface drainage?

Leaves, debris, or dirt build-up can obstruct water flow, causing it to back up and pool around the property. Concrete driveways, patios, and other hard landscaping features often don't allow water to seep into the ground, leading to increased surface runoff that overwhelms drainage systems.

How deep does underground drainage need to be?

The minimum allowable depth of cover for underground drainage pipes must be at least 0.8 metres below the ground level. The minimum cover should be at least 100mm thick, although the minimum depth may be slightly lower. For drains close to foundations, extra access chambers may be necessary.

What are the advantages of below ground drainage system?

It collects excess rainwater

You might be employing water collection tanks, but these can fill up during a downpour. With an underground drainage system, excess water can be removed from the property quickly which reduces the risk of flooding and water contamination.

What is the main purpose of drainage?

The purpose of drainage is to remove unwanted water from the human environment (17). It is often difficult to make a clear separation between 'unwanted' and 'wanted' water, as people will usually use surface water, for example for irrigation or watering animals.

How much water can subsurface drainage remove from a field?

The maximum amount of water that can be removed by a subsurface drainage system is the drainable porosity times the depth of the soil layer being drained. Typically, the drainable porosity is a few percent of the soil profile volume.

What are the problems with subsoil drainage?

Poor subsoil drainage can lead to a variety of issues, such as dampness within below-ground building sections, compromised foundation strength, and deterioration of pavements.

Why do farmers use subsurface drainage in the fields?

Subsurface or tile drainage removes excess water from the soil water that prevents air and oxygen from getting to plant roots. Without artificial drainage, plants have difficulty establishing a healthy root system on poorly drained soils.

Why is surface drainage important?

Surface drainage is very useful in removing excess water from land to an artificial drainage system or natural watercourse in a controlled manner and as quickly as possible. This must be done with no damage to the environment.

What is the layout of a subsurface drainage system?

In subsurface drainage systems, there are three general layouts: conventional pattern (parallel), contour, and targeted layouts (Figure 7). The contour layout is a subset of the pattern layout, which is used when laterals are following the contours too allow for controlled drainage.

What are the main differences between surface drainage and subsurface drainage?

To summarize: 1. Surface drainage focuses on removing water from the surface of the ground to prevent pooling and damage. 2. Sub-surface drainage deals with removing water from below the surface of the ground, primarily to lower the water table or alleviate excess water.

What are the advantages of subsurface drainage system?

The primary advantage of subsurface drainage in humid regions is the water table can be lowered so soils classified as poorly drained can be improved to respond more like well drained soils, with the benefits of improved productivity and trafficability.

What are the disadvantages of underground drainage?

Disadvantages
  • Risk of clogging.
  • When saline water is used, salts accumulate at the wetting front.
  • Emitter can be damaged or blocked by root hairs.
  • Bacterial slimes and algae growing on the interior walls of the laterals and emitters combined with clay particles in the water can block the emitters.

What is the problem with ground drainage?

Common Landscape Drainage Problems
  • Improper Grading. Grading refers to the ground slope around the perimeter of a home or other structure. ...
  • Roots Invading Drain Pipes. ...
  • Flat Paved Areas. ...
  • Poorly Designed Landscaping. ...
  • Surface Depressions. ...
  • Poor Soil Quality. ...
  • Improperly Installed/Dirty Gutter Systems.

What slope should underground drainage be?

Underground drainage should be installed in accordance with the Approved Document H – Drainage and Waste Disposal Guidelines. Cut pipes should be chamfered correctly and rubber seals should be lubricated before rejoining. Drainage should be installed at a fall of 1 in 40.

Why is underground drainage pipe orange?

Drainage pipes installed underground are usually always a terracotta orange colour, as this makes them easy to identify.

How much pea gravel do I need for drainage?

If you're working with a triangular area, multiply the base by the height, divide by 2, and then multiply by the desired depth. For circular areas, determine the area of the circle and multiply by the desired depth. Understanding how to calculate volume in cubic feet helps determine how much pea gravel you need.

What do you mean by subsurface drainage?

Subsurface drainage describes the process of removal of that water which has infiltrated into the soil in excess of the amount that can be held by capillary forces against the force of gravity.

How to remove water from land?

Install rain gutters and water drainage systems so that water flows away from the land as far as possible. This will help prevent flooding in case of heavy rain. It is also necessary to pay attention to the terrain of the land.

Where should surface water drainage to?

Drains and gullies collect the surface water and this then either flows into a soakaway (whereby the water is taken away from the house, into a septic tank and distributed where it can soak into the gravel and soil), or in many cases, straight into a public sewer system.

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