Huib de Vriend

The past decades have witnessed frequent flood peak discharges increase in the Lower Yellow River (LYR). Yet no consensus for its mechanism has been achieved. Here 21 events of the peak discharge increase (PDI) in the period of 1973-2012 are analysed. It is shown that the mean increment of peak discharge increases from 811 m³/s to 1158 m³/s and the...

Before you lies the book ‘Ports and Waterways - Navigating the changing world’, written by the Ports and Waterways team, part of the Civil Engineering and Geosciences faculty at Delft University of Technology. It integrates the content of a number of separate lecture notes we used in our teaching activities and updates this information where releva...

Hydraulic engineering infrastructure is supposed to keep functioning for many years and is likely to interfere with both the natural and the social environment at various scales. Due to its long life-cycle, hydraulic infrastructure is bound to face changing environmental conditions as well as changes in societal views on acceptable solutions. This...

By definition, Building with Nature solutions utilise services provided by the natural system and/or provide new opportunities to that system. As a consequence, such solutions are sensitive to the status of, and interact with the surrounding system. A thorough understanding of the ambient natural system is therefore necessary to meet the required s...

We present a new 2DV nonlinear process-based morphodynamic model to investigate the effects of storms, specifically wind-driven flow and wind waves, on finite amplitude tidal sand wave evolution. Simulations are performed on periodic domains of two lengths: (i) on a 350-m domain, comparable to the wavelength of observed sand waves, we study the evo...

Chu A.; Wang Z.B.; de Vriend H.J., and Tai J.A., 2018. Parallel morphodynamic modelling for the Yangtze Estuary. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 641–645. Coconut Creek (Florida), ISSN 07...

The downstream peak discharge increase during hyperconcentrated floods in the Yellow River has been attributed to bed erosion, roughness reduction and floodplain effects. While great improvements have been made on the understandings of the roles of bed erosion and roughness reduction, the effects of floodplain remain poorly understood. Here, as a f...

We present an idealized process-based morphodynamic model to study the effect of storms on sand wave formation. To this end, we include wind waves, wind-driven flow and, in addition to bed load transport, suspended load sediment transport. A linear stability analysis is applied to systematically study the influence of wave and wind conditions on gr...

All North Sea countries are confronted by climate change impacts such as accelerated sea-level rise, increasing storm intensities resulting in as well higher set-up of storm surges as growing wave energy and a follow-up of morphological changes. Thus it is necessary to question the effectiveness of existing coastal protection strategies and to exam...

Ecosystem destruction not only incurs large costs for restoration but also increases hydraulic forces on existing flood defence infrastructure. This realisation has made the inclusion of ecosystems and their services into flood defence schemes a rapidly growing field. However, these new solutions require different design, construction and managemen...

Over the course of centuries, river systems have been heavily trained for the purpose of safe discharge of water, sediment and ice, and improves navigation. Traditionally, dikes are used to be reinforced and heightened to protect countries from ever higher flood levels. Other types of solutions than technical engineering solutions, such as measures...

Various studies have identified a strong relation between the hydrodynamic forces and the equilibrium profile for intertidal flats. A thorough understanding of the interplay between the hydrodynamic forces and the morphology, however, concerns more than the equilibrium state alone. We study the basic processes and feedback mechanisms underlying the...

Rivers respond to changes in their geometry or their controls in various ways and at a wide range of space and time scales. The response consists of changes in properties such as cross-sectional shape and area, slope, planform pattern, bed roughness and bed sediment composition. Usually, attention for the morphological impact of engineering works f...

The analytical expression for residual coarse sediment transport of Van de Kreeke and Robaczewska (1993) is extended for estuaries. The major extension concerns the contribution to sediment transport by residual current, which is ignored by Van de Kreeke and Robaczewska (1993). Tidal constituents M0, M2, S2, N2, M4, MS4, MN4, M6, K1 and O1 are used...

Hydraulic engineering infrastructures are of concern to many people and are likely to interfere with the environment. Moreover, they are supposed to keep on functioning for many years. In times of rapid societal and environmental change this implies that sustainability and adaptability are important attributes. These are central to Building with Na...

The peak of river floods usually decreases in the downstream direction unless it is compensated by freshwater inflow from tributaries. In the Yellow River (China) the opposite is regularly observed, where the peak discharge of river floods increases in the downstream direction (at a rate far exceeding the contribution from tributaries). This flood...

River floods are usually featured by a downstream flattening discharge peak whereas a downstream increasing discharge peak is observed at a rate exceeding the tributary discharge during highly silt-laden floods (hyperconcentrated floods) in China's Yellow River. It entails a great challenge in the downstream flood defence and the underlying mechani...

Abstract: Water diversions along alluvial rivers cause water and sediment loss, and thereby affect morphological development. Assuming spatially continuous diversions along a constant-width channel, previous studies suggest a longitudinally convex bed at the equilibrium state. However, the validity of a convex bed profile for practically discrete d...

There is extensive experience in adaptive management of exposed sandy coastlines through sand nourishment for coastal protection. However, in complex estuarine systems, coastlines are often shortened through damming estuaries to achieve desired safety levels. The Dutch Deltaworks illustrate that this approach disrupts natural sediment fluxes and ha...

The Netherlands has adopted a new, proactive approach to developing its extensive coastal and river works called 'building with nature'. Rather than simply minimising or mitigating the environmental impact of harbours, navigation channels, land reclamation and flood defences, the idea is to make use of the dynamics of the natural environment and pr...

The risk of flood disasters is increasing for many coastal societies owing to global and regional changes in climate conditions, sea-level rise, land subsidence and sediment supply. At the same time, in many locations, conventional coastal engineering solutions such as sea walls are increasingly challenged by these changes and their maintenance may...

We present a 3-D physics-based high-resolution modeling approach to the dynamics of underwater ripples and dunes. The flow is modeled by large eddy simulation on a Cartesian grid with local refinements. The sediment transport is modeled by computing pickup, transport over the bed, transport in the water column, and deposition of rigid spherical par...

The paper describes a numerical model for simulating sediment transport with eddy-resolving 3-D models. This sediment model consists of four submodels: pickup, transport over the bed, transport in the water column and deposition, all based on a turbulent flow model using large-eddy simulation. The sediment is considered as uniform rigid spherical p...

[1] High-resolution morphological modeling of fluvial processes with complex, rapidly varying flows has been limited so far by model accuracy or computational efficiency. One of the most widely used numerical algorithms is based on the total variation diminishing method, solved by either upwind or centered approaches. An upwind scheme preserves hig...

[1] Reduced-order models remain essential tools for meander modeling, especially for processes at large length scales and long time scales, probabilistic simulations, rapid assessments, or when input data are scarce or uncertain. Present reduced-order meander models consider their dependent variables either as small-amplitude variations compared to...

Low-lying, densely populated coastal areas worldwide are under threat, requiring coastal managers to develop new strategies to cope with land subsidence, sea-level rise and the increasing risk of storm-surge-induced floods. Traditional engineering approaches optimizing for safety are often suboptimal with respect to other functions and are neither...

We present a three-dimensional high-resolution hydrodynamic model for unsteady incompressible flow over an evolving bed topography. This is achieved by using a multilevel Cartesian grid technique that allows the grid to be refined in high-gradient regions and in the vicinity of the river bed. The grid can be locally refined and adapted to the bed g...

Low-lying, densely populated coastal areas worldwide are under threat, requiring coastal managers to develop new strategies to cope with land subsidence, sea-level rise and the increasing risk of storm-surge-induced floods. Traditional engineering approaches optimizing for safety are often suboptimal with respect to other functions and are neither...

This paper compares the Yangtze Estuary in China and the Western Scheldt Estuary in The Netherlands by their morphodynamic and ecological systems, their engineering works and estuarine management issues, and the major challenges in studying them. Physically speaking, the two estuaries are very different. The Yangtze Estuary is much larger and much...

Working in coastal planning is nearly always innovative, since no two coasts are the same. Even if they appear to be physically similar, local conditions and governance settings are usually different, thus requiring a different approach. Each project is unique, which makes coastal projects exciting and diverse.

Using the coastal evolution of the Netherlands in the Holocene up to the present as an example and a test case, a coastal evolution concept is proposed and materialized with which shoreline position changes for different sea level rise scenarios are predicted. The (more generally applicable) model applies to quasi-uniform coastal stretches. It acco...

Despite the rapid evolution of computational power, simulation of meander dynamics by means of reduced and computationally less expensive models remains practically relevant for investigation of large-scale and long-term processes, probabilistic predictions, or rapid assessments. Existing meander models are invariantly based on the assumptions of m...

Experiments have been carried out in a mobile-bed laboratory flume in order to study the sediment exchange process between the main channel and the groyne fields. The flume represented half the width of a schematized river reach with a series of groynes. The experiment was designed to represent typical dimensions of the Dutch River Waal at a geomet...

Experiments have been carried out in a fixed-bed flume for a schematised straight river reach with groynes on one side to study the dynamics of the flow near groynes. The flume had a geometrical scale of 1∶40, based on typical dimensions of the Dutch River Waal. Both emergent and submerged groynes were studied. The measurements demonstrate the diff...

A process-based model for the Yangtze Estuary is constructed to study the sediment transport in the estuary. The proposed model covers the entire tidal region of the estuary, the Hangzhou Bay and a large part of the adjacent sea. The dominant processes, fluvial and tidal, are included in the model. The calibration of the model against extensive flo...

The Hangzhou Bay is a macro-tidal bay located to the south of the Changjiang estuary in China. Along its northern shore, a large-scale tidal channel system has developed, which includes a main northern tidal channel, with a length of more than 50 km and a width up to 10 km, and a secondary southern tidal channel. A process-based morphodynamic model...

Many scientists feel that scientific outcomes are not sufficiently taken into account in policy-making. The research reported in this paper shows what happens with scientific information during such a process. In 2001 the Dutch Ministry of Transport, Public Works and Water Management commissioned their regional office in Limburg to assess how flood...

Measurements of the depth-averaged main flow velocity in two consecutive sharply curved short bends in the river Dommel, The Netherlands, are compared with results of a mathematical model. The computed main velocity distribution agrees rather well with measured one in the larger part of each bend. Near the bend exits, however, deviations occur whic...

Publisher's note. We regret that in the course of production the address and e-mail of the corresponding author were entangled with that of a co-author; also an acknowledgement had not been incorporated into the final version. The correct versions are as given below.

A state-of-art process-based model is applied to simulate the hydrodynamics in the Yangtze Estuary in China, as a basic step to acquaint ourselves with the morphological development and the effect of human interference in the estuary. A major improvement with respect to previous models for the Yangtze Estuary is that the present model covers the en...

Hangzhou Bay is a macro-tidal bay located south of the Yangtze Estuary in China. Along the northern shore of this bay a large-scale tidal channel system has developed, with a length of more than 50 km and a width of 10 km, and a secondary southern tidal channel. A process-based morphodynamic model based on Delft3D, is used to analyze the physical m...

We investigate the hydrodynamic effects and morphodynamic impact of large-scale offshore sand extraction, for a variety of pit designs. We use a process-based idealized model for flow, sediment transport and bed evolution in a tide-dominated environment. Legislation and other practical considerations motivate our assumption that sandpits are both w...

For a channel-shoal system in a funnel-shaped basin the impact of dredging and dumping is investigated using a complex process-based model. First, the residual flow and sediment transport circulations are analysed for the channel-shoal pattern, which has emerged after a long-term model simulation. Results are compared to the Western Scheldt estuary...

In this paper we carry out a theoretical analysis based on the general one-dimensional morphodynamic model for rivers in order to show how the morphological equilibrium of a river is influenced by water and sediment diversion/supply along the river. The results of the analysis show that large scale water diversions, like those along the Lower Yello...

Predicting the long-term morphological development of estuaries and tidal lagoons is a challenging topic, despite the progress made recently. One of the advancements is the development and successful applications of the semi-empirical models ASMITA and ESTMORF. They combine empirical relations for morphological equilibriums with aggregated descript...

This article shows how Dutch technological culture has historically dealt with and developed around vulnerability with respect to flooding and indicates recent developments in attitude towards the flood threat. The flooding of New Orleans in the wake of Hurricane Katrina temporarily made the Dutch public worry about the flood defense infrastructure...

The question whether it is time for marine morphodynamic models to take into account the 3-D nature of water and sediment motion is discussed starting from practical demand and the state-of-the-art in basic knowledge and model development. This leads to the observation that there is a clear practical demand, and that suitable software environments...

The construction or designation of detention areas along lowland rivers is considered along many European rivers. Since Croatia accommodates large detention areas, both natural (e.g., Mokro Polje) and controlled (Lonjsko Polje), it serves as an excellent example for planned detention areas elsewhere in Europe. This modelling study focuses on the co...

The objective of the study presented in this paper is to investigate the predictive capabilities of a process-based sand–mud model in a quantitative way. This recently developed sand–mud model bridges the gap between noncohesive sand models and cohesive mud models. It explicitly takes into account the interaction between these two sediment fraction...

The article describes flow, sediment transport, and morphological processes in regulated lowland rivers and the impact of human activities thereon. It gives some elementary examples of the morphological response to deviations from a prismatic straight channel, in an attempt to bridge part of the gap between textbook knowledge and reality. Moreover,...

A modeling framework is developed for taking into account the effects of sediment sorting in the morphodynamic modeling of bed-form-dominated rivers for the case of equilibrium or stationary conditions dominated by bed load transport. To this end, the Blom and Parker (2004) framework for sediment continuity is reduced to an equilibrium sorting mode...

River flooding is a problem of international interest. In the past few years many countries suffered from severe floods. A large part of the Netherlands is below sea level and river levels. The Dutch flood defences along the river Rhine are designed for water levels with a probability of exceedance of 1/1250 per year. These water levels are compute...

In spite of its practical relevance, little is known about the turbulence characteristics in sharp open-channel bends, which may largely be attributed to a lack of accurate experimental data. This paper reports an experimental investigation of the turbulence structure in one cross-section of an open-channel bend. The flow pattern in this section is...

In spite of its importance, little is known about the turbulence characteristics in open-channel bends. This paper reports on an experimental investigation of turbulence in one cross section of an open-channel bend. Typical flow features are a bicellular pattern of cross-stream circulation (secondary flow) and a turbulence activity in the outer ben...

We model branching channel patterns in short tidal basins with two methods. A theoretical stability analysis leads to a relationship between the number of channels and physical parameters of the tidal system. The analysis reveals that width and spacing of the channels should decrease as the slope of the bottom profile and the Shields parameter incr...

A complex process-based model (Delft3D) is used to simulate the formation of channels and shoals in a schematised estuary. The model set-up enables a comparison with results obtained from other studies using idealised models. Initial (one tidal cycle) as well as long-term (up to 300 years) simulations are made. Dominant wavelengths of channel–shoal...

The influence of sand and mud transport on the morphological behaviour of a short tidal basin is investigated in this paper. For this purpose, a morphological model is applied in which sand and mud transport are included and the temporal and spatial bed composition variations are taken into account. Initially, the morphological development shows a...

Secondary currents are a characteristic feature of flow in open-channel bends. Besides the classical helical motion (centre-region cell), a weaker and smaller counter-rotating circulation cell (outer-bank cell) is often observed near the outer bank, which is believed to play an important role in bank erosion processes. The mechanisms underlying the...

Secondary currents are a characteristic feature of flow in open-channel bends. Besides the classical helical motion (centre-region cell), a weaker and smaller counter-rotating circulation cell (outer-bank cell) is often observed near the outer bank, which is believed to play an important role in bank erosion processes. The mechanisms underlying the...