Accumulation of floating particles at hydraulic structures

Plastic pollution is a threat for all ecosystems due to its effects on people, animals, and environment (Mai et al., 2020). Rivers are estimated to transport around 0.5 millions tons of plastic per year (Strokal et al., 2023). When plastic enters a river system, it is transported downstream towards the sea but it is also likely to accumulate at...

Overflow Tests on Grass-Covered Embankments at the Living Lab Hedwige-Prosperpolder: An Overview

In regions with a temperate climate, a well-maintained grass sod on a clay layer is considered a reliable protection for dams and dikes. In the Living Lab Hedwige-Prosperpolder, on the left bank of the Scheldt river straddling the border between Belgium and the Netherlands, a series of 27 overflow tests with a purpose-built overflow generator...

Detachment of dilatant soil due to high hydraulic shear stresses explained

When soil surfaces are exposed to high shear stresses induced by high-velocity water flows, they erode. Erosion consists of the detachment, entrainment and transport of soil particles. When exposed to high shear stresses the process of soil detachment is no longer given by the pick-up of individual particles but by the continuous shear failure...

Project Hue: Report and field study on the water related problems and solutions in and around the Cau Hai lagoon and the Tu Hien inlet, Vietnam

The Tam Giang-Cau Hai lagoon system, lying in the Thua Thien-Hue province in central Vietnam, is affected by a tropical monsoon climate. This among others is the reason the Cau Hai Lagoon area has a long history of floods and other water related problems. Inhabitants are very dependent on the lagoon, as the main sources of income of people...

Design of a breach retardant dike

Sand dikes have a sand core and a clay layer to protect the core against erosion. It is not unlikely that this layer fails due to several failure mechanisms, exposing the sand core to water. This can be catastrophically when water is overtopping the dike. In case the protective cover fails, water can flow over the core and erode the sand,...

Analyses grass erosion in wave run-up and wave overtopping conditions

Within the framework of WTI, Research and Development of Flood Defence Assessment Tools (Wettelijk Toetsinstrumentarium), which is called in Dutch: WTI-2017 "Onderzoek en ontwikkeling landelijk toetsinstrumentarium", research was carried out to develop an erosion model for grass in the wave run-up zone consistent with the current model in use...

Master of Science thesis “Bypass - Itajaí-Açu”

The city of Itajaí is located in the province of Santa Catharina in Brazil. The people of Itajaí have been coping with flood risk for the past decades. During normal conditions the Itajaí-Açu River is a rather calm river that is used for navigation and the harbour area. Recovering from the past two floods in 2008 and 2011 have cost more than...

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...

Breach growth in clay-dikes

Numerous flood disasters occur every year worldwide, mostly resulting from failure of dikes, some with catastrophic outcomes. Examples are the dike failures along the Yangtze River in China in 1931 due to heavy rainstorms and those in the Netherlands in 1953 due to a storm surge at the North Sea. Both floods induced many deaths and enormous...

Waihi Beach to the future: An objective review

Waihi Beach is a village consisting out of 2300 inhabitants, located in the Bay of Plenty on the North Island of New Zealand. It can be seen as a 9 km long tombolo beach. Dunes used to protect most of the land, but have decreased in size through natural erosive processes and through urban development in the dune areas. The long and short-term...

Low cost rock structures for beach control and coast protection: Practical design guidance SR 631

Coastal rock structures are widely used in coastal engineering for a variety o f purposes, includiag controlling the morphological development of beaches and providing protection against coastal erosion or flooding by wave overtopping. Strict adherence to existing design guidance has resulted in many of these structures being built using...

Cross-shore profile development during storm conditions: Analysis of field data gathered at Petten sea defence

The majority of population in the Netherlands live well below the mean sea level. At some locations people and infrastructures are only protected from the sea by a narrow stretch of sandy beaches and dunes, so reinforcement works will be necessary to prevent a break through during storm surges. Therefore it is necessary to study problems...

Principles and guidelines for the environmental protection of drainage basins prone to flash floods: Experimental intervention in a pilot drainage basin

The second Chapter refers to the institutional and legislative framework, that is, the laws in force at the different levels, from local to global, in each partner’s country and concludes with considerations on optimal levels of coordination. Chapter III begins with the methodology recommended for the study of small-medium basins, based upon the...

A study concerning the influence of the relative local turbulence on local-scour holes

Scour is the lowering of the sea or river-bed as a result of non-equilibrium sediment transport conditions and can be divided into several categories (Breusers and Raudkivi, 1991). Local scour, which may occur at the base of a structure because of the affected flow pattern, can severely endanger the stability of this structure. Many varieties of...

The influence of upstram turbulence on local-scour holes

Excessive local scour can progressively undermine the foundation of a structure. Because complete protection against scour is too expensive generally, the maximum scour-depth and the upstream slope of the scour hole have to be predicted to minimize the risk of failure. In 1961 a systematical research 'tY'ith respect to scour holes started in the...

Flood-control measures that utilize natural functions of rivers

Describes the process of bank erosion by currents and (ship) waves, investigations in prototype and model.