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Activity Name:

N-OT01 Overtopping Test (Reference)

Activity Numbre:


Activity type

Strength test

Involved Workpackage

Flood defences
Emergency response
Knowledge infrastructure


The test was conducted on a ‘test section with a uniform vegetation cover’, i.e. well maintained, and serves as a reference.

Activity Brief descriptor

The test was conducted on a ‘test section with a uniform vegetation cover’, i.e. well maintained, and would serve as a reference. The test section of wave overtopping experiment has a width of 4 m. The length of the vegetation is about 10 cm (which is considered ‘short’). Besides some bare spots, molehills are present along the slope. The thickness of the cover layer equals ~70 cm. The slope is 1:2,5.

Linked to theme(s):

Animal- & vegetation-induced anomalies
Erosion processes
Temporary levee repairs
Levee survey & monitoring technique
Prolonged collaboration

Activity Time

Start Date:


End Date:


Active time length:






5 consecutive wave sets + the 5th repeated


Levee stretch:


Coordinates/ Latitude (WGS):


Coordinates/ Longitude (WGS):


Coordinates/ Altitude (mTAW):



Landward slope of levee.

Other references:


This activity has no data

Relationships with other activities

Detaled information about the activity


Levee slope is visually in good condition.

Activity Descriptor

The following wave sets were consecutively applied: 0,5m60lsm, 0,5m60lsmov, 1m190lsm, 2m50lsm and 2m100lsm (repeated).


this activity does not have equipments

Monitoring & Sensors

Wave front velocities are measured along the slope for predefined overtopping volumes ranging from 300 l/m to 3400 l/m.
Action Cams are used.

this activity does not have sensors


During Activity

Interesting phenomena took place. Mole holes rince out gradually with time. From the third wave set on, a gravel box at the toe, which serves as drain, became visible. Near the end of the third set, sand from the levee core was released from a mole hole outside the test section.

Post-activity conditions

No critical damage after 5 wave sets. Continuing the experiments by repeating the 5th set, the area with an undermined slope (likely following erosion of the sandy core via mole holes with sand leaving through a hole outside the test section), suddenly failed after 3 hours. 45 minutes later, an erosion pit of 3m by 4m and a depth up to 1m was formed.

Immediate Results

A well-maintained levee cover with a uniform vegetation, even with presence of some bare spots and/or molehills, was able to withstand consecutively all 5 wave sets.

Results /Conclusion

Infrastructure Knowledge

Other key information