The continuous rise of the sea water level and the water level means that the dikes in the Netherlands are under pressure. Particularly in extreme weather conditions, this leads to unsafe situations.
Because of its specific characteristics, the HDDW offers possibilities for dike stabilisation. In this in-depth article teaches you the basics of the DMC system that can be installed by using the HDDW technology. Moreover, this text is a transcription of our video which explains the principles even better. For those who prefer to read, continue reading. We recommend our video though.
Video about the DMC System:
The importance of a Dike Monitoring and Conditioning System
The Netherlands has approximately 17.000 kilometres of dikes. The changing climate and increasing precipitation, are more often putting the dikes in the Netherlands under pressure. This may result in unsafe circumstances during extreme weather. Therefore, the inspection and monitoring of dikes is of vital importance.
VolkerWessels Telecom and Landustrie Sneek B.V. developed a system that checks the dikes from the inside, and can even take action. The ‘Dike Monitoring and Conditioning System’ or ‘DMC system’ keeps Dutch dikes in perfect condition.
Basics of the DMC system
The DMC system uses fibreglass sensors to collect information on the condition of the dike. The sensors measure the water pressure and water temperature in the dike to indicators that provide information on the stability of the dike.
The system is activated when indicators provide information that requires contra measures. The system makes sure water is infiltrated into (or extracted from) the dike, which increases the stability of the dike.
The DMC system has been tested in practice during the Ijkdijk experiments and the results were positive. A dike absorbs even more water during long periods of high water levels. The dike runs a risk of becoming saturated and weakens. In this situation, the dike loses some of its original strength. Long periods of high water levels can lead to the collapse of the dike.
Piping can also lead to the breaching of dikes. Piping is when water flows under or through a dike due to a difference in water levels, whereby the water also carries soil particles. This process starts very slowly, but the longer piping occurs, the faster and more extensive the flashing of soil particles from the dikes becomes. The ground under the dike gradually erodes and the dike weakens. If piping does not stop, this process may lead to a subsideness of the dike and ultimately, its collapse.
A large section of Dutch dikes consist of ‘peat dikes’ or ‘peat embankments’. When peat dikes become too wet, the same processes occur as in non-peat dikes. The dike softens and partially loses its strength. When a peat dike dries out, the effect is different. A lack of water – drying out – causes the peat to oxidise, decreasing the stability of the dike. The water pressure dislocates these dry peat elements, causing dike sheering. Result: the dike ultimately collapses.
DMC system & HDDW technology
HDDW technology is used to install the DMC system. HDDW – Horizontal Directional Drilled Wells – is a proven drilling technology, which makes the underground installation of filter screens possible. These filters are sustainable, high quality drainage pipes with a gravel pack which prevents the filters from clogging. A drill hole is completely filled in to prevent subsideness of the dike.
This method allows the horizontal extraction or infiltration of water in the dike. HDDW technology allows the installation of a filter over long distances without having to disturb the the environment. The only visible disturbance of the system are the ends of the filter. Once the filter screens have been installed, the entire system is completely underground.
The DMC system segments the dike into sections of approximately 150 metres. Flow meters, control valves and, if required, pumps are installed per segment. The water is extracted to decrease the internal water pressure of the dike or infiltrates, preventing the dike drying out. These measures can, if required, be performed automatically based on predefined settings. The measured values are forwarded using a data connection. This means the values measured in the dike can be read at the water board, on any internet enabled PC or mobile phone, allowing real-time control of the dike condition.
Advantages of the DMC system
The DMC system allows us to:
- Guarantee dike stability through real-time monitoring from within; and
- To quickly and successfully intervene in the event of high pressure, piping, or drying out of the dike.
In short (summary)
In short, the Dike Monitoring and Conditioning System keeps dikes in perfect condition. Would you like to know more about the specific advantages applicable for your use? Please feel free to contact us via our contact page.