Strength of grass covers on dikes

Wave overtopping, in which a wave washes over the crest of a dike and damages its inner slope, is one of the many mechanisms that is found to be responsible for dike failures. As these dikes are generally covered with grass, insight into the erosion resistance of these grass covers against wave overtopping is desired. To assess the performance...

Prediction method for grass erosion on levees by wave overtopping: Linking models to experiments

Large areas of the world are protected by flood defence systems. A common part of flood defence systems is a levee with grass cover, with the primary function to protect hinterland against floods. Waveovertopping might lead to erosion of the grass cover, followed by erosion of the inner slope and potentially levee breaching. The wave overtopping...

Strength of grass covers on dikes

Wave overtopping is responsible for many dike failures, dike breaches and severe flooding. The erosion resistance of dikes to overtopping waves is determined by the strength of the grass cover. Therefore, a thorough understanding of the erosion resistance of grass covers is desired to enable a good and effective dike management. In the existing...

Measuring (Oblique) Wave Run-Up and Overtopping with Laser Scanners

Wave overtopping is commonly measured using overtopping tanks. In this paper, an alternative system is developed by using two laser scanners. It measures wave run-up, as well as layer thicknesses and front velocities, both during normally and obliquely incident waves on a dike in the field. The paper considers the first field validation tests...

Measuring oblique wave run-up and overtopping with laser scanners

Damage to grass dikes due to wave overtopping

Grass covers have been applied as an effective measure for protecting river levees and sea dikes. We conducted experiments to show how roots considerably improve the shear strength of soil on dike slopes. Roots of 1-year-old Bermuda and Carpet grass may increase the total shear strength of up to 20 kPa. Exposed to severe overtopping flow, dike...

Wave overtopping simulator tests on Vietnamese sea dikes

Little is known about the strength of the land-side slopes of the Vietnamese sea dikes under overtopping attack. Some grass-covered slopes were tested by a wave overtopping simulator. The paper describes the simulator and presents the test results. The tested grass covers could withstand overtopping rates varying from 20 l/s to 100 l/s per meter...

Strength of the landward slopes of sea dikes in Vietnam

The landware slopes of sea dikes in the north of Vietnam are steep and solely constructed by soil covered with grass due to the budget constraints and also the out-of-date design guidelines.The resistance against erosion due to wave overtopping of several grass covered slopes were tested with the Wave Overtopping Simulator to show if a slope...

Wave impact on grass covered outer slopes

Against the background of enhanced hydraulic loads due to climate change there will be a need for improvement of the flood defence system in the Netherlands in the future. These days there is a growing interest in grass as a dike cover because it is a cheap and a sustainable dike protection. Yet at the moment there is a hiatus in the knowledge...

Grass cover as a dike revetment

A large part of the Netherlands’ dikes are covered with grass. Dikes with hard revetments also have grass cover on a significant part of the dike surface, such as the crown and inner slope. Research and experience since the mid-eighties have shown that grass coverings can be of high quality in terms of erosion resistance and encouragement of...