Activity_create

Activity Name:

B-OF01 Overflow Test (reference test)

Activity Numbre:

Activity type

Strength test

Involved Workpackage

Flood defences

Emergency response

Knowledge infrastructure

Objective

Establish reference measurements on Belgian side.

Activity Brief descriptor

By generating overflow over a levee crest, using a custom built overflow generator, the strength of the levee cover against erosion and/or failure is evaluated. The B-OF01 test is performed on a visually good quality section in order to establish a reference for the other tests on Belgian parts of the HPP levee.

Linked to theme(s):

Breaching

Animal- & vegetation-induced anomalies

Erosion processes

Temporary levee repairs

Levee survey & monitoring technique

Prolonged collaboration

Activity Time

Start Date:

Oct. 30, 2020, midnight

End Date:

Nov. 3, 2020, 11:59 p.m.

Active time length:

Days:

None

Hours:

21.0

Other:

Location

Levee stretch:

Coordinates/ Latitude (WGS):

51.34125

Coordinates/ Longitude (WGS):

4.23881

Coordinates/ Altitude (mTAW):

11.2

Descriptor:

Landward sdie of the levee.

Other references:

Lambert'72 coordinates: X=140944.8m; Y=225726.5m.

Data

Data: 1

Data type: Factual data report

Description: Factual data report describing the tests on the Belgian part of the HPP levee.

Date availability: None

Find at: https://stowanl-my.sharepoint.com/:w:/g/personal/llhpp_stowa_nl/EVpQIrpc_n1MhDLPmEL2Qh0BgEH8RdDV7ncL0iksYdxubw?e=fvXzeo

Media avaliable:

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Data: 2

Data type: Monitoring data

Description: - Hydraulic timeseries - Photographs - ... (variable per test)

Date availability: None

Find at: https://stowanl-my.sharepoint.com/:f:/g/personal/llhpp_stowa_nl/EoZX1na1wQ9Jkt6nJSUFK-ABSJiJnm7TFAJ2fUsDrpR6ow?e=s7jRxO

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Relationships with other activities

Activities that are linked to 76/ B-OF01 Overflow Test (reference test) :

No activities
DB_id: 76/ B-OF01 Overflow Test (reference test)
DB_id: 76/ B-OF01 Overflow Test (reference test) linked to the following activities:
DB_id: 88/ P2C Overflow tests

Detaled information about the activity

Pre-conditions

Levee slope in visually good conditions.

Activity Descriptor

Overflow during 21:00 hours (performed in 19 blocks) with a typical discharge of 180 L/s.m over a width of 2 m.

Equipments

Equipment: 1

Overflow generator.

The setup is described in Vercruysse et al. (2022): "Design and application of an overflow generator." (Ref WL2022R20_047_1)

Monitoring & Sensors

- Overhead cameras (4) - Acoustic water height sensors - Electromagnetic current velocity sensors - Discharge sensor (EM or acoustic)

Description of the hydraulic conditions of the overflow. The setup is described in Vercruysse et al. (2022): "Design and application of an overflow generator." (Ref WL2022R20_047_1)

this activity does not have sensors

Limits

During Activity

During the test, it was observed that soil eroded slowly and exposed grass roots, without creation of any significant damage that would lead to imminent failure of the levee slope.

Post-activity conditions

Slope surface shows signs of erosion and barren patches where vegetation is removed, but the clay cover layer is intact. No failure has occurred.

Immediate Results

The overflow generator is able to generate a steady flow pattern over the levee crest. A levee cover in a good condition, 20 hours of overflow with a specific discharge of 180 l.(s.m) leads to some soil erosion and vegetation root exposure, but it does not lead to major or critical damage.

Results /Conclusion

Factual data report + Annexes: https://stowanl-my.sharepoint.com/:f:/g/personal/llhpp_stowa_nl/EvdAZOO-zylAqEWS8-SEiC4BQ5xCAuFXklsysJXnkcVYaQ?e=XDeXq8

Infrastructure Knowledge

An integration report will be added later (February 2023) as knowledge document.

The integration report discusses insights gained from both the steady overflow and wave overtopping tests.

under development

Other key information