How To Reduce Flooding Risk With Soakaways

As substantial rainfall becomes more common, so to does the flooding of surface water drainage systems. Once the amount of water being collected and transported exceeds the system’s capacity, it spills over the ground and causes flooding. Apart from being a huge inconvenience, it can cause significant amounts of damage to businesses, properties, and belongings. With combined sewer systems where rainwater and foul sewage flow into the same sewer, it can cause an even bigger problem if the sewage were to flood your property, causing more damage and posing a serious health risk.

Aquacrate soakaway crate or drainage box

What is a soakaway?

A soakaway (also known as an attenuation unit) collects rainwater before slowly releasing it back into the ground at a rate the soil can absorb. This means that instead of overloading the drainage system, the water is stored until it can be released harmlessly into the ground. Previously, soakaways were pits filled with gravel to create pockets for the water to sit in. Modern soakaway crates improve on the idea and usually use plastic crates wrapped with geotextile fabric. There are also more heavy-duty concrete options. The crates allow more water to be stored and the fabric has a permeable membrane allowing water to escape and keeping soil and debris from lowering the efficacy of the soakaway.

Soakaway crates come in various shapes and sizes and are usually modular in design, and are fairly simple to install. A drainage expert can calculate the size of soakaway that is appropriate for your property and usage requirements. They are a great preventative measure for avoiding months of recovery and large costs to repair the damage after a flood.

How to avoid a blocked soakaway

If a soakaway is blocked, you will often see puddles, waterlogging or dips in the ground near the site of the crate. If the blockage is particularly bad, there may be some overflow near the drains that connect to the soakaway system. At this stage it is usually best to dig up and replace the soakaway.

To prevent a blocked soakaway, the most important thing is to make sure it is installed correctly. This means that the crates are properly wrapped in the geotextile membrane, the pipes are properly installed and supported to prevent collapse, and the correct type of backfill is used to support the crate and reduce the chances of blockages preventing the soakaway from performing as it should.

You should also consider installing a pre-filter such as a silt trap. While the geotextile fabric prevents soil from clogging up the crate, debris can still enter from the surface drains. A silt trap is a simple way to prevent this and prolong the life of your attenuation unit.

Drainstore are experts in installing all kinds of drainage systems, including attenuation units. If you have any queries or are looking for advice, call us on 01773 767611 or use our contact form.