Erosion Resistance Assessment of Grass-Covered Embankments: Insights from In Situ Overflow Tests at the Living Lab Hedwige-Prosper Polder
Depreiter, D.; Vercruysse, J.B.; Verelst, K.; Peeters, P. (2025). Erosion Resistance Assessment of Grass-Covered Embankments: Insights from In Situ Overflow Tests at the Living Lab Hedwige-Prosper Polder. Water 17(13): 2016. https://dx.doi.org/10.3390/w17132016
In: Water. MDPI: Basel. ISSN 2073-4441; e-ISSN 2073-4441, more
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| Keywords |
Burrows
Dikes (embankments)
Grass
Hydraulic structures > Dikes, shores and other flood defenses > Erosion protection
In situ tests > Field tests
In-situ measurements
Outflow > Overflow
Overtopping
Slope failure
Topographic features > Banks (topography) > Embankments > Levees
Brackish water |
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| Abstract |
Grass-covered levees commonly protect river and estuarine areas against flooding. Climate-induced water level changes may increasingly expose these levees to overflow events. This study investigates whether grass-covered levees can withstand such events, and under what conditions failure may occur. Between 2020 and 2022, full-scale overflow tests were conducted at the Living Lab Hedwige-Prosperpolder along the Dutch–Belgian Scheldt Estuary to assess erosion resistance under varying hydraulic conditions and vegetation states. A custom-built overflow generator was used, with instrumentation capturing flow velocity, water levels, and erosion progression. The results show that well-maintained levees with intact grass cover endured overflow durations up to 30 h despite high terminal flow velocities (4.9–7.7 m/s), without structural damage. In contrast, levee sections with pre-existing surface anomalies, such as animal burrows, slope irregularities, surface damage, or reed-covered soft soils, failed rapidly, often within one to two hours. Animal burrows facilitated subsurface flow and internal erosion, initiating fast, retrograde failure. These findings highlight the importance of preventive maintenance, particularly the timely detection and repair of anomalies. Once slope failure begins, the process unfolds rapidly, leaving no practical window for intervention. |
| Datasets (3) |
- Depreiter, D.; Verelst, K.; Vercruysse, J.; Peeters, P. (2025). Interreg Polder2C's: Discharge and equilibrium velocity values of hydraulic measurements for derivation of Manning roughness of the grass cover layer [DATA SET]. Flanders Hydraulics, more
- Depreiter, D.; Verelst. K.; Vercruysse, J.; Peeters, P. (2025). Interreg Polder2C's: Erosion resistance grass cover - limiting velocity as function of duration [DATA SET]. Flanders Hydraulics, more
- Depreiter, D.; Verelst. K.; Vercruysse, J.; Peeters, P. (2025). Interreg Polder2C's: General information and results of overflow tests on a grass covered levee [DATA SET]. Flanders Hydraulics, more
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