What Is a Culvert and Why Are Blockages an Issue?
Posted on 27th June 2022 at 09:56
Have you ever walked over a bridge and noticed a large opening where water tends to flow out from? If so, you’ve most likely found a culvert. Culverts are so common in the UK that they usually blend in. We often don’t think too much about them, but they play a very important role.
What is a drainage culvert?
A drainage culvert is a structure designed to allow water to flow underneath infrastructures such as roads, railways, and bridges. They’re typically located underground and covered in soil. Culverts are usually made from reinforced concrete, but can also be made from materials such as plastic, aluminium, or steel.
Culverts are still widely used in the UK, but because of harsh weather conditions combined with ageing, it has led to faster erosion and decomposition. When this happens, it can affect how much water can be held, which can lead to blockages and floods.
It’s worth knowing the different types of culverts, so next time you can identify each one.
The different types of culverts
Drainage culverts come in different shapes and sizes. They are usually based on hydraulic, roadway height, water surface elevation, and other environmental conditions. The most found culvert in the UK is the pipe culvert.
Pipe Culvert (single or multiple)
Pipe culverts are the most common in the UK due to their easy installation, competitive prices, and flexibility when it comes to desired strength. They vary in size and structure based on their surrounding conditions. Because they’re circular in shape, on a small scale they represent ordinary pipes.
Pipe-Arch culvert (single or multiple)
Due to the shape of a pipe-arch culvert, it allows fish and sewage to pass more freely to the outlet without stocking at the inlet or bottom of the channel. Pipe arches are particularly useful for sites with limited headroom because they have a hydraulic advantage at low flows.
Box culverts are rectangular in shape and are made with concrete, used to dispose of rainwater. They can also function as a passageway for animals to cross the rail or roadway during dry periods.
Metal Box Culvert
The metal box culvert is more economic as an alternative to a bridge and is made with standard structural plates or deep-corrugated structural plates. They are the ideal bridge replacement because they maintain the same road grade level.
An arch culvert is like a pipe arch culvert but has an artificial floor provided. They’re often termed low-profile culverts because they don’t disturb the water current, and a water diversion isn’t necessary. They’re typically more visually appealing than other types. Arch culverts are made up of stone masonry, metal, etc.
The bridge culvert has a dual purpose; As the name suggests, it is a bridge as well as a culvert and is usually rectangular in shape. Because they have more than one purpose, they need a solid foundation and are very sturdy.
What happens when a culvert becomes blocked?
There are a variety of things that can cause a drainage culvert to become blocked. In autumn especially, debris such as branches and leaves can cause blockage extremely fast. Things like silt, mud, and other types of debris can cause large culverts to become blocked when built up over time. We recommend having a drainage professional regularly maintain your culvert to help prevent blockages.
When a drainage culvert becomes blocked, it can cause big problems for the natural environment. It can affect the migration of aquatic life such as fish, as well as flooding on built infrastructures, such as roads and bridges.
How do you clear a blocked culvert?
If you do find a drainage culvert that has become blocked or partially blocked, the first thing you should do is contact your local drainage company, and they’ll advise you on the best thing to do from then on. If the blockage is severe, then you’ll most likely need them professionally unblocked and cleaned.
Need a Drainage Expert?
At Semilong Services, we use a variety of different methods to fully clean out or unblock a drainage culvert.
If you’re in need of assistance, contact us today on 01604 492 701, and we’ll be with you in no time.
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