Guide to Silt Traps and Why You Should Consider One!

blog header of a guide to silt traps and why you should consider one!

If you have found that the area surrounding your property is often covered in surface water, you might be considering installing a soakaway drainage system to handle it. If you don’t already know, this is basically a system that involves a crate that catches water through a drain and slowly re-disperses it back into the soil at a rate the ground can handle. This reduces or completely solves the flooding issues in that area, making soakaways a great solution for clogged lawns and gardens with standing surface water.

While soakaways were as simple and straightforward as digging a trench in the ground in years gone by, modern additions like soakaway crates have improved the efficiency of these systems significantly.

However, the lifespan of your soakaway crate can be dramatically reduced if it becomes damaged, leading to some major problems and replacement costs – this is where a silt trap comes into play. Here, we’ll go over why you should include a silt trap in your soakaway system, the different types of silt trap you can use, and how you go about installing a silt trap. After all, what’s the point in buying and installing a whole drainage system if it’s only going to last you a few years at most?

Why Silt Traps Are Important

When you put something like a soakaway system into place, you want to make sure that it’s functional for as long as possible – otherwise, you could have some costly issues on your hands. The main reason why soakaway crates become less effective is damage caused by debris, which can include silt, soil, pesticides, sediment, metals, and other particles. If these substances enter your system in the rainwater, they can make the crate far less effective, and you may need to buy a new one in the long run after you notice that your lawn is flooding again!

To prevent this, you can install a silt trap. These look like vertical pipes, and have an inlet higher than the outlet to help trap dirt. They function by holding the water that flows in via the inlet before it reaches the crate, causing any debris to sink to the bottom below the invert of the pipe. The water then runs into the outlet pipe (usually a 110mm drainage pipe), leaving the silt and other substances behind. They pretty much function as a filter – this means that less debris is damaging your system and that your soakaway (or attenuation system) can remain effective for longer.

blog image of why silt traps are important

Types of Silt Trap

While all silt traps serve basically the same purpose in keeping your soakaway system free of debris, different types are better for different soakaway systems. This is primarily to do with the size of the area covered by your system – the larger the area, the larger the silt trap you should use. Additionally, if you live in a coastal area or a place with heavy amounts of sand or silt, you may want to invest in a larger silt trap for the increased amount of debris you can expect.

They are often available in a range of sizes, so make sure to choose the one that best suits your environment.

How to Install a Silt Trap

If you choose to install a silt trap, you just need to dig out a hole and place it upstream from your soakaway crate between the crate and the drain, then connect it up to the pipes that are running the surface water underground. The silt trap should be higher than the soakaway crate to encourage the water to flow through it. The trap can be cut down and the lid reattached to suit the depth of the system, and you’ll also need to include an access point for when you need to clean your silt trap.

blog image of silt trap and soakaway graphic

Silt Trap Maintenance

You might not notice the effect of your silt trap often, but you can rest assured that having one in your system can do a lot for its lifespan. Silt traps aren’t the kind of thing you can install and just forget about, though – they need regular maintenance or you may as well not even have one!

You can usually clean out smaller silt traps by taking out and emptying the removable bucket/basket before putting it back in place. You’re bound to be surprised by the amount of dirt and other muck that can build up in your silt trap – and that would have otherwise been wreaking havoc in your soakaway crate system. To clean out a larger silt trap, you may need to suck out the silt and other materials mechanically.

If you’re cleaning your silt bucket on a regular basis – two to three months should be enough – it will remain effective in preventing debris from reaching and damaging your soakaway. It’s a good idea to make this a part of your general home maintenance schedule, so stick it in your calendar!

blog image of silt trap cleaning diagram

Silt Trap Advice

If you’re looking to install a soakaway system on your property and want to extend its lifespan and improve its efficiency, you can contact us for advice via phone or email. Whether you have questions about how to install your system, or just what kind of silt trap unit would be right for your area, we can help.

At EasyMerchant, we sell a 320mm silt trap that we designed – so we’re confident that you can trust it! Made from durable and lightweight material, it can be modified to provide a minimum invert of 20cm, and you can also extend the height of the base silt trap with standard risers to suit your needs. While you can go to the trouble of building your own silt trap, going pre-made is much more straightforward, and we know that you’ll be happy with the result!


Silt Trap Infographic

silt trap infographic

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