Subdrain System: Definition, Materials and Installation

What is a subdrain? Many people may not know the term yet. A subdrain system is a drainage system located below the ground surface. Its function is to speed up the flow of surface water so it does not pool.

This type of drainage is commonly found in road construction projects. Subsurface drainage is also used in areas where water flows in large volumes. Read the information below for more details.

What Is a Subdrain?

The term refers to a drainage system installed below the surface, also known as Subsurface Drainage / Underdrain. Its main function is to let water infiltrate so that it does not pool on the ground surface.

This type of drainage is often the solution for open areas such as housing estates, golf courses, football fields and green open spaces, because it is very effective at dealing with standing water when it rains.

Read Also: Water Infiltration Systems for Football Fields (Subdrain)

An underdrain lets water flow quickly from the ground surface and seep below it toward the outlet. This method prevents damage to the ground surface caused by water standing too long.

Subdrain Materials

Building an underdrain system requires several construction materials such as sand and gravel. In this type of drainage project, single-size gravel is used to absorb water.

In addition, several geosynthetic materials are needed to build a subsurface drainage system, including:

1.     Geopipe

One important material for building a subsurface drainage system is geopipe. The pipe used is corrugated and perforated (corrugated perforated pipe), designed to capture water and carry it to the outlet.

Read Also: How to Install Geopipe / Corrugated Pipe

2.     Non-Woven Geotextile

Non-woven geotextile is needed in underdrain systems to wrap the geopipe. It also acts as a filter so that soil particles are not carried away by the water.

Subdrain System Applications

Underdrain systems are used for many purposes, including drainage infrastructure in open spaces. They are the right choice because they effectively drain standing water from the ground surface. Applications include:

• Sports fields such as football pitches, volleyball courts, golf courses and stadium areas.
• Public areas including airports, stations and terminals, as well as green open spaces and parks.
• Residential and office areas, factories and warehouses.

Subdrain Project Work Stages

An underdrain construction project involves several stages, from preparation to installation of the drainage system. Here is the explanation:

Preparation Stage

• Clear the site of any materials that could damage the drainage channel.
• Survey the site and install bamboo stakes as a reference for trench excavation.
• Make sure the channel location and dimensions match the plan.
• Start excavating with an excavator, following the staked-out route.
• Lightly compact the drainage channel area to reduce the risk of the channel level dropping.

Installation Stage

• Lay non-woven geotextile as a filter, leaving extra material at the top.
• Spread gravel over the non-woven geotextile.
• Install the geopipe on top of the gravel.
• Spread a second layer of gravel beside the geopipe so it does not shift.
• Run a flow test before spreading the next layer.
• Close the top by folding over the extra non-woven geotextile.
• Lightly compact.

A subdrain is a subsurface drainage system that effectively prevents standing water on the ground surface, especially in open areas and housing estates. If you need geotextile and geopipe materials for an underdrain system, please visit https://petrane.co.id/.