Geotextile as a Drainage Filter

Drainage is an important part of any construction project, and a geotextile drainage filter keeps it working. Drainage systems can be built in many ways; common types use perforated pipes and filter drains. A general weakness of drainage systems is that soil particles can enter along with the water. Aggregate can be used to deal with this, but soil particles may still pass through. The solution to stop soil particles passing through is non-woven geotextile, which can act as a water-permeable filter layer.

Below is a drainage system design using perforated pipe and non-woven geotextile:

With this drainage design, the water entering the perforated pipe carries no soil particles. Soil particles usually clog the perforations; with geotextile, the perforations are protected and can keep taking in water. Here is the detail for figure 1A:

Below is a drainage system design using non-woven geotextile:

Figure 3 shows a design that can be used in soil layers for landscaped gardens. It prevents soil particles from entering the drainage and causing soil loss. Soil that clogs the drainage system can cause water to pond in the garden, which is bad for the plants (over-saturated conditions). That is why non-woven geotextile is a good choice as a drainage filter.

Garden drainage designs usually use aggregate to help the drainage system. However, there is an alternative that can replace the aggregate: the drainage cell, made from HDPE polymer, which acts as a base and assists drainage. Here is what a drainage cell looks like: