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14-12-2021

How our ROVs help prevent flooding

Written by Karst Beens

Many pipes in the Dutch water network were laid years ago. Often they are more than 30 years old. Depending on the risk involved (both financial and physical risk), inspections or replacements are scheduled. But if the risk is small, aren’t these pipes/dikes being neglected? These were constructed to move water and provide a flow without obstruction. But often an obstruction is actually found there. So what should be done with that?

High risk vs. low risk:

Most high-risk pipelines are located in residential areas where many people depend on the pipeline. Think, for example, of drinking water pipes or sewers. If these suddenly break down and stop working, many streets could be without water. There is also a risk of subsidence in a densely populated area. These pipes are therefore often well mapped out and regular maintenance or an inspection can be scheduled here.

High-risk culverts often carry a large amount of damage if something goes wrong. This usually involves bridge culverts, where the integrity of a bridge can also be at stake if the culvert fails. With a busy freeway, it cannot be the case that there is a risk here.

But pipes and culverts with relatively little risk or impact are also important to the Netherlands. Culverts are maintained by municipalities and water boards but often have a somewhat lower priority. Nevertheless, the flow through a culvert can be important.

Our findings

The video above shows that a culvert is often full of silt. When the bottom of a culvert is full of silt, the flow of water is reduced. Especially at the end of the video you can see that there is a large obstruction to be found, which in the long run can stop the flow in its entirety.

If the flow of ditches, for example, stops at a culvert, water can start to accumulate and naturally overflow the banks. This can cause roads or bicycle paths to flood and become inaccessible. This can never be the intention.

Plan of action: improve flow

Nowadays, culverts, even those with low priority, are being imaged more frequently and more quickly. Nowadays it is possible to check whether the culverts have been properly flushed and therefore whether all the sludge has been removed. After this, the culvert or pipe can be properly imaged to determine its state of service.

Also, using our sonar from Blueprint Subsea, developed a method to determine the amount of silt in pipes and culverts! This is only possible with drones equipped with sonar, because it can only be read on the sonar images. In both round and square (or rectangular) tubes we have developed methodologies that can accurately determine the amount of silt or sand on the bottom. This is crucial to determine the flow of culverts and pipes.

This method can also be seen in our video above, from 40 seconds you can see how we do this, and what the result is.
In this way it is also possible to check whether a culvert has been properly cleaned, and whether there is still a risk of flooding.
In this way, large and small floods can be prevented, and there is less chance of permanent damage!


Would you like to know more about the innovative way of measuring sludge? Or are you curious about other possibilities with our drones? Then contact us here, or follow us on one of our social media channels: