Geotextile Membranes For Grass Swales
Geotextile membranes, more specifically the non-woven variety, are used in a grass swale system when they are wrapped around the soakaway crate. This is done in order to control the rate at which stormwater enters from the soil above and exits into the ground below after it has been cleaned.
Non-woven geotextile membranes have less load bearing strength than woven membranes, but they provide higher levels of infiltration as they allow for water movement whilst also blocking soil and sand particles from entering the crates, ensuring maximum infiltration and stormwater cleaning efficiency in a grass swale system.
How is a soakaway crate wrapped?
To wrap a soakaway crate in geotextile membrane, the membrane should first be laid out in the excavated area prior to the crates being lowered in. Laying the membrane out first allows for it to wrapped around a crate in a similar fashion to wrapping a present, the meeting points of which can be taped together to prevent the ingress of any soil.
What is the difference between a swale and a ditch?
While swales and ditches are similar in that both are low slopes in the ground that can collect water, a swale generally has more moisture in the soil and a greater presence of plants and vegetation. These properties make a swale a more suitable area to install a soakaway in order to create a grass swale infiltration system.
How does a swale work?
A swale aims to reduce the speed of and capture stormwater runoff by spreading it wide across a shallow, valley-like channel of permeable soil and vegetation, known as a swale. As the water is spread across the soil, the flood-resistant plants help control the rate that the water enters the permeable soil.
Once water enters the soil and reaches the soakaway, the geotextile membrane will prevent any pollutants from entering the soakaway along with the water, so that it can pass through the crate and enter the soil below in the highest quality possible. In this system, the soakaway crate wrapped in membrane essentially acts as a water cleaner.
