The stability of foreland types under dike breach conditions - an experimental study

Due to accelerating climate change, which entails more extreme storm conditions and exponential sea level rise, the protective function of our dikes and levees is under growing pressure. The presence of so-called forelands (e.g., beach, mudflat, and tidal marsh) are promising Nature-based Solutions to reduce the probability of dike failure and...

Numerical investigation of plastic fragment accumulation against a sluice gate

The ramifications of plastic pollution on the environment are becoming increasingly serious in various forms throughout the world. In this context, rivers are the most important suppliers of plastics entering the marine environment. However, rivers that contain high loads of plastic waste also directly harm the livelihoods of people living near...

New method to measure dune erosion processes using a mobile, contained environment on a real beach

The Netherlands has 254 km of coastline that is covered with sandy dunes. As these dunes function as primary flood defences, intensive research has been conducted into dune erosion in recent years. This research mainly took place in laboratories, because all boundary conditions could be controlled and measurements could take place very...

Bed-load transport over inlet sills of longitudinal training walls: Experimental study

This experimental study is about the bed-load transport over inlet sills of longitudinal training walls. The focus is on the flow structures around the inlet: the shape, the processes and the effect on sediment transport. Groynes have been replaced by longitudinal training walls in an 11-km long pilot project to optimize training of the river...

Tsunami induced failure of bridges: Determining failure modes with the use of SPH-modeling

Recent major tsunami events generated by earthquakes inundated coastal cities and caused extreme destruction and loss of human lives. The collapse of coastal bridges due to tsunami wave impact represents a huge obstacle for rescue works. The need to understand tsunami effects and develop tsunami-resilient bridges became apparent in the aftermath...

Quantifying the effect of woody vegetation on the wave loads on a dike using remote sensing: Large scale physical model tests

It is already acknowledged that Nature-based Solutions can be used to attenuate waves, however it is still uncertain to what extent the vegetation can contribute to decreasing the flood risk. So far mainly small-scale tests have been performed to quantify wave attenuating properties of vegetation. To quantify the effect of more extreme wave...

Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission

Due to the removal of mangrove forests, coastal zones can suffer from severe erosion. One of the proposed solutions is the construction of permeable structures. This study aims to optimise the design of permeable (brushwood) structures in order to restore the sediment balance and encourage mangrove re-establishment on tropical mud coasts....

Hydraulic load reduction as a function of depth in a filter layer consisting of logs

The formation of scour holes is a vital thread of retaining the water infrastructure of rivers. Nowadays, protective filters are used to prevent washing away of the underlying material. Rijkswaterstaat started the program 'Stroomlijn’, in which trees (logs) are cut from the floodplains and placed in a sheltered zone of the river to test whether...

Experimental research on hydrodynamic failure of river bridges on spread footings

Collapse of partially or fully submerged river bridges as a result of river floods is investigated. To this end, post-failure analysis of a bridge in Japan’s Iwate Prefecture that collapsed in 2013 is conducted. Failure of this particular bridge is atypical because piers have also toppled over, which can be attributed to the spread footing...

Improving the filling jet schematisation through a lock door by taking into account the presence of a ship

This study treats the calculation of longitudinal forces on a ship in a lock chamber due to the levelling procedure. The focus will be on the force resulting from the filling jet through the levelling door in the lock, with the main point of interest being the interaction between the ship and the flow resulting from the jet. To understand more...

A new physics-based method for estimating the excess turbulence downstream of a structure

Erosion and sedimentation are natural processes that occur in natural flows.<br/>If the erosion is a threat for a structure, a bed protection is necessary to stop this process. A bed protection usually consists of relatively large stones.<br/>For calculating the required dimeter of the stones several formulae are available, of which the formula...

Flow patterns in partially vegetated channels: Combining physical experiments and numerical modelling

As coastal wetland ecosystems, thriving at the interface between land and water,<br/>mangroves can benefit us in lots of ways: providing food and timber, purifying water and sequestrating carbon, protecting coastal area through wave attenuation and coastal stabilization. Regarding the protection of coastal area, mangroves damp the flow in short...

Dispersion and dynamically one-dimensional modeling of salt transport in estuaries

An estuary forms the transition between the ocean/sea and a river. Within its boundaries salt and fresh water mix. Fresh water intake points may be located within the reach of salt intrusion. In order to justify political and managerial decisions it is thus necessary to understand and be able to predict the process of salt intrusion in estuaries...

Retardation of breach growth under high flow velocities: Applicability of a bentonite-additive

People all around the world live and work in low-lying areas. Low-lying areas have to be protected against high water levels in rivers and at sea by a water protection system (e.g. by dunes, dikes and barriers). Dikes are an important component within water protection systems. Generally, dikes are described as elongated naturally occurring or...

Sediment transport in a fringing reef environment: Analysis using laboratory experiments and numerical modelling

Coral reefs are highly valuable structures in many respects and it is increasingly important to understand hydrodynamics and morphodynamics around reefs to be able to better protect them and their hinterland. Flume experiments were performed on a scaled fringing reef in the laboratory facilities of Deltares in Delft. The objective of this thesis...

Stability of open filter structures

Granular filters are used for protection against scour and erosion. For a proper functioning it is necessary that interfaces between the filter structure, the subsoil and the water flowing above the filter structure are stable. Stability means that there is no transport of subsoil material through the filter to the water above the filter, and...