Dike monitoring is the systematic inspection of dikes (levees) and embankments for weak points, seepage, settlement, cracking or other signs of imminent failure, so that intervention can take place before a breach occurs. It is a core duty of water authorities and plays a life-saving role during high-water events.
What is checked?
A dike inspector looks for:
- Seepage — water filtering under or through the dike to the inland side, visible as wet patches, water boils or even sand boils (“piping”)
- Cracking — vertical or horizontal cracks in the cover layer or slope
- Settlement and bulges — irregularities in the profile
- Erosion — face loss caused by waves or current
- Vegetation problems — poor turf, mole and mouse runs, trees with loose roots
- Leaks at structures — at sluices, pumping stations and culverts
Application and execution
Dike monitoring is carried out in several ways:
- Routine inspections — two to four times a year, water-authority staff walk the alignment
- Flood inspections — during high water, watchers patrol continuously
- Drones and aerial photography — for hard-to-reach areas
- Permanent sensors — fibre-optic cables, pressure sensors and standpipes record seepage, pressure and deformation around the clock
- Satellite monitoring (InSAR) — radar imagery from space detects millimetre-scale settlement
Regulatory framework
In countries with significant flood risk (Netherlands, UK, Germany), legislation sets out the duty of care for primary and regional flood defences. Water authorities must:
- carry out a formal assessment of the alignment at fixed intervals (12 years in the Netherlands)
- start dike watching when a warning level is exceeded
- take emergency measures in case of imminent failure (sandbags, riprap, emergency embankment)
History
The tradition of dike watching goes back to the Middle Ages, when riparian owners were responsible for “their” stretch of dike. After major flood disasters in the twentieth century, the system was professionalised and large regional water authorities took over the central role.
Related terms
- Levee
- Dewatering
- Piping
- Seepage
- Construction history
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