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  2. Activity : N-OT02 Overtopping Test (Wet spot)
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Activity Name:

N-OT02 Overtopping Test (Wet spot)

Activity Numbre:

170

Activity type

Strength test

Involved Workpackage

Flood defences
Emergency response
Knowledge infrastructure

Objective

The N-OT02 overtopping test is executed at a levee section characterized by the presence of a wet spot.

Activity Brief descriptor

Overtopping test to assess the resistance against overtopping events of a soft, moist soil patch on the lower slope of the levee slope.

Linked to theme(s):

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

Activity Time

Start Date:

None

End Date:

None

Active time length:

Days:

5

Hours:

None

Other:

4 consecutive wave sets + 1h of the 5th

Location

Levee stretch:

VI

Coordinates/ Latitude (WGS):

None

Coordinates/ Longitude (WGS):

None

Coordinates/ Altitude (mTAW):

12.0

Descriptor:

Landward slope of levee.

Other references:

Data

This activity has no data

Relationships with other activities

Detaled information about the activity

Pre-conditions

This test was conducted on a ‘test section with a uniform vegetation cover’, exempt at the lower part of the slope where a wet (soggy) spot was present (with bare spots as well). In addition, some mole and mice holes were noticed. The slope is 1:2,5.

Activity Descriptor

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

Equipments

this activity does not have equipments

Monitoring & Sensors

this activity does not have sensors

Limits

During Activity

A wet spot along the slope showed considerable erosion (~25 cm) of the clay cover at the end of the third set of waves. During the first set local bare spots became visible and enlarged gradually. The second set led to removal of the vegetation over a larger area and yielded superficial erosion up to 15 cm. A maximum erosion depth up to 35 cm was noticed after applying the 4th set and 1 hour of the 5th.

Post-activity conditions

A maximum erosion depth up to 35 cm was noticed after applying 4 sets of waves and 1 hour of the 5th.

Immediate Results

Een wet spot (soft soil) along the slope shows faster occurrence of erosion.

Results /Conclusion

Infrastructure Knowledge

Other key information