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Neglected Culverts Can Potentially Cause Major Floods

Neglected culverts can cause serious flooding events, and the consequences of a culvert blockage during a severe storm can be huge. Neglect leads to a build-up of debris, and this build-up has a clear link to the likelihood of a flooding catastrophe.

Unfortunately, extreme rainfall events are becoming commonplace, and culverts are more likely to cause flooding than open channels. Culverts range from narrow pipes to larger constructions made from concrete, metal, stone, or plastic.

The size of the culvert’s opening is one factor that determines if a culvert might become blocked. Small culverts are more prone to flooding compared to culverts with an opening wider than six metres. Although wide culverts are unlikely to become blocked by floating debris, a partial blockage can cause flooding. Secondary storms will add to the accumulation of debris to cause a major flood during periods of subsequent rainfall.


What Happens When a Culvert Becomes Blocked or Partially Blocked

A blocked culvert can cause local and wider flooding incidents with severe consequences. Flooding occurs when a blockage reduces the culvert’s capacity, and water flow only needs to be reduced by 20% for serious drainage problems to occur. The types of debris that accumulate include organic matter such as fallen leaves, branches, weeds, and grass, along with discarded rubbish.

When culverts are neglected, and experience reduced capacity, the flow of waterways such as streams can become diverted overland as water levels rise suddenly. New flow paths open up before the culvert or further upstream, and these can cause significant damage to residential and commercial properties, as well as public infrastructure.

When a culvert becomes blocked, there is a heightened danger to the public, a business may not be able to operate, wildlife habitats can be damaged or destroyed, and expensive clean-up operations may be required.

Whose Responsibility is Culvert Maintenance?

The responsibility of maintenance and keeping culverts clear lies with the landowner. Their actions should in no way exasperate the potential of flooding, which means that they should use a culvert maintenance and repair company. They will ensure culvert screens are well-maintained if fitted and remove any build-up of debris.

Preventative actions are extremely important because it can be difficult to access problem areas and remedy them during flooding events. Strict safety procedures must be followed, and specialist equipment may be required.

When culverts are not neglected, they enjoy an extended life and help landowners avoid expensive repairs. A culvert inspection will identify potential lining and construction problems before they cause a major flooding incident.