scholarly journals From river valley to estuary: the evolution of the Rhine mouth in the early to middle Holocene (western Netherlands, Rhine-Meuse delta)

2009 ◽  
Vol 88 (1) ◽  
pp. 13-53 ◽  
Author(s):  
M.P. Hijma ◽  
K.M. Cohen ◽  
G. Hoffmann ◽  
A.J.F. Van der Spek ◽  
E. Stouthamer
Keyword(s):  
Cross Sections ◽  
River Mouth ◽  
Tidal Basin ◽  
Large Set ◽  
Rhine River ◽  
Middle Holocene ◽  
The North ◽  
The North Sea ◽  
Core Descriptions ◽  
River Mouths

AbstractThe aim of this paper is to reconstruct the evolution of the early to middle Holocene Rhine-Meuse river mouths in the western Netherlands and to understand the observed spatial and temporal changes in facies. This is achieved by constructing three delta wide cross-sections using a newly accumulated database with thousands of core descriptions and cone penetration test results, together with a large set of pollen/diatom analyses and OSL/14C-dates. Most of the studied deposits accumulated in the fluvial-to-marine transition zone, a highly complex area due to the interaction of terrestrial and marine processes. Understanding how the facies change within this zone, is necessary to make correct palaeogeographic interpretations.We find a well preserved early to middle Holocene coastal prism resting on lowstand valley floors. Aggradation started after 9 ka cal BP as a result of rapid sea-level rise. Around 8 ka most parts of the study area were permanently flooded and under tidal influence. After 8 ka a bay-head delta was formed near Delft, meaning that little sand could reach the North Sea. Several subsequent avulsions resulted in a shift from the constantly retreating Rhine river mouth to the north. When after 6.5 ka the most northerly river course was formed (Oude Rijn), the central part of the palaeovalley was quickly transgressed and transformed into a large tidal basin. Shortly before 6 ka retrogradation of the coastline halted and tidal inlets began to close, marking the end of the early-middle Holocene transgression.This paper describes the transition from a fluvial valley to an estuary in unprecedented detail and enables more precise palaeo-reconstructions, evaluation of relative importance of fluvial and coastal processes in rapid transgressed river mouths, and more accurate sediment-budget calculations. The described and well illustrated (changes in) facies are coupled to lithogenetic units. This will aid detailed palaeogeographic interpretations from sedimentary successions, not only in the Netherlands, but also in other estuarine and deltaic regions.

The influence of wind on the evolution of freshwater fronts in the Rhine ROFI

2020 ◽  
Author(s):  
Lennart Keyzer ◽  
Sabine Rijnsburger ◽  
Firmijn Zijl ◽  
Martin Verlaan ◽  
Mirjam Snellen ◽  
...  
Keyword(s):  
Tidal Flow ◽  
River Mouth ◽  
Propagation Speed ◽  
River Plume ◽  
Rhine River ◽  
Freshwater Lens ◽  
The North ◽  
Near Shore ◽  
The North Sea ◽  
Freshwater Lenses

<p>The Rhine River discharges freshwater into the North Sea, forming one of the largest Regions of Freshwater Influence (ROFI) in Europe. Every tidal cycle, a freshwater lens is released. These fronts were captured by the STRAINS (STRAtification Impacts Near-shore Sediment) field campaign of 2014. The data consists of current velocity, temperature and salinity at a fixed location 10 km northeast of the river mouth. Here, we explore the effect of the wind on the evolution of the freshwater lenses using a high-resolution 3D model, which is validated against the field data. We find a stratified river plume that consists of multiple freshwater fronts. On every ebb tide, a new freshwater lens is formed, which is subsequently advected by the tidal flow. Remaining lenses from previous tidal cycles are still present when the next one is formed. The properties and evolution of the lenses strongly depends on the wind magnitude and direction. Under upwelling winds, they evolve separately and the downstream plume is detached from the coast. The thickest lenses are found under downwelling winds, when their propagation speed is maximum and the downstream river plume is pushed against the coast. During storm conditions, when the wind speed exceeds 15 m/s, the river plume becomes well-mixed and no separate lenses are found. The model shows a detailed picture of the formation and evolution of the freshwater lenses in the Rhine ROFI and the vertical structure of the water column. We find a multiple front system, where lenses interact under the influence of tidal flow and prevailing winds; diverging flows causes the lenses to separate, while they seem to merge under converging flows.</p>

Study of ISO 19901-3 Building Code Correspondence Factor for Eurocode 3

2013 ◽  
Author(s):  
Nicolas Neumann
Keyword(s):  
Cross Sections ◽  
Steel Structures ◽  
Building Code ◽  
Structural Components ◽  
The North ◽  
A Value ◽  
Eurocode 3 ◽  
European Code ◽  
The North Sea ◽  
Design Resistance

For topside structures ISO 19901-3 rely on national or regional building codes to derive the resistance of structural components. It is, however, required that the design resistance(s) of the building code is matched to the design resistance(s) of ISO 19902 through the use of a building code correspondence factor Kc. Recently, Kc was proposed in the literature to be taken as 0.95 for the European code for steel structures, Eurocode 3 (EN 1993). The present study does not support this value. Instead a value of 0.86 is derived. This lower value is based on the investigation of a topside project in the North Sea, and intends to cover for the stricter requirements to component resistance in ISO 19902 compared to Eurocode 3 for plastic and compact cross-sections.

scholarly journals The simultaneous occurrence of surge and discharge extremes for the Rhine delta

2013 ◽  
Vol 13 (8) ◽  
pp. 2017-2029 ◽  
Author(s):  
S. F. Kew ◽  
F. M. Selten ◽  
G. Lenderink ◽  
W. Hazeleger
Keyword(s):  
North Sea ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Storm Surges ◽  
Future Climate ◽  
Simultaneous Occurrence ◽  
Rhine River ◽  
The North ◽  
The North Sea

Abstract. The low-lying Netherlands is at risk from multiple threats of sea level rise, storm surges and extreme river discharges. Should these occur simultaneously, a catastrophe will be at hand. Knowledge about the likelihood of simultaneous occurrence or the so-called "compound effect" of such threats is essential to provide guidance on legislation for dike heights, flood barrier design and water management in general. In this study, we explore the simultaneous threats of North Sea storm surges and extreme Rhine river discharge for the current and future climate in a large 17-member global climate model ensemble. We use a simple approach, taking proxies of north-northwesterly winds over the North Sea and multiple~day precipitation averaged over the Rhine basin for storm surge and discharge respectively, so that a sensitivity analysis is straightforward to apply. By investigating soft extremes, we circumvent the need to extrapolate the data and thereby permit the model's synoptic development of the extreme events to be inspected. Our principle finding based on the climate model data is that, for the current climate, the probability of extreme surge conditions following extreme 20-day precipitation sums is around 3 times higher than that estimated from treating extreme surge and discharge probabilities as independent, as previously assumed. For the future climate (2070–2100), the assumption of independence cannot be rejected, at least not for precipitation sums exceeding 7 days.

scholarly journals ĐẶC ĐIỂM ĐỊA MẠO VÙNG CỬA SÔNG VEN BIỂN SÔNG THẠCH HÃN VÀ TAI BIẾN TỰ NHIÊN LIÊN QUAN

2018 ◽  
Vol 18 (1) ◽  
pp. 27-38
Author(s):  
Nguyen Cong Quan ◽  
Pham Van Hung ◽  
Nguyen Van Dung
Keyword(s):  
Coastal Erosion ◽  
Late Holocene ◽  
River Mouth ◽  
Middle Holocene ◽  
Han River ◽  
The North ◽  
Coastal Landform ◽  
North And South ◽  
Geomorphological Features ◽  
Tectonic Movements

Study on the geomorphological features, landform changes and correlated natural hazardous events was based on analyzing available literature and data. The coastal landform of Thach Han river mouth is a result from fluvial, fluvial - marine and marine accumulation along with local tectonic activities during Pliocene - Quaternary. During Pliocene - Pleistocene, western uplift and eastern subsidence movements were forming the types of landforms such as hills, erosion and abrasion terraces and accumulated plains of fluvial and fluvial - marine sediments. From early to middle Holocene, subsidence movements and fluvial, fluvial - marine and marine accumulation formed 4 types of accumulated plains as follows: Fluvial - marine plain in the central part, marine plains extending to the north and south of the studied area. From late Holocene to present, differentiated tectonic movements and fluvial and fluvial - marine accumulation have formed 6 types of different landforms (fluvial, lacustrine, marshy and marine origins ...etc.). Morphodynamic processes including erosion and sedimentation are natural hazards which cause damage to economy and people's life in the coatal zone of Thach Han river mouth. The erosion has been scattered along the banks of the Thach Han and Cam Lo rivers, at Gio Viet, Gio Mai, Trieu Giang, Ai Tu, and coastal erosion occurred north of Cua Viet.

scholarly journals STABILITY OF TIDAL CHANNELS DEPENDENT ON RIVER IMPROVEMENT

1976 ◽  
Vol 1 (15) ◽  
pp. 102 ◽  
Author(s):  
Volker Barthel
Keyword(s):  
North Sea ◽  
Cross Sections ◽  
Main Channel ◽  
Tidal Channels ◽  
Weser Estuary ◽  
The North ◽  
Investigation Area ◽  
German Coast ◽  
Improvement Measures ◽  
The North Sea

Many authors have dealt with the migration of sand in front of the German coast of the North Sea. Especially the movement of sand-banks and deep channels in the Weser-estuary was subject matter of several investigations with different results. Thorough investigations of selected cross-sections point out, that the movement goes on in some regions. The important shipping channel however has obtained a certain stability during the last 3o - 4o years, because the migration of sand occurs otherwise than in former days. This phenomenon coincides with the extensive and decisive river improvement measures in the inner part of the Weser-estuary. Current measurements in the investigation area demonstrate, that concentrated tidal currents in the deep channels guarantee a sufficient clearance for shipping purpose. It seems to be sure, that for the present no essential shifting of the main channel calls for important measures in the field of shipping, dredging and building of sea-marks.

The geology of the Amstel river in Amsterdam (Netherlands): Man versus nature

2015 ◽  
Vol 94 (4) ◽  
pp. 361-373 ◽  
Author(s):  
W. de Gans
Keyword(s):  
Cross Sections ◽  
Coastal Plain ◽  
Storm Surges ◽  
Sediment Supply ◽  
Peat Layer ◽  
13Th Century ◽  
Borehole Data ◽  
The North ◽  
The North Sea ◽  
Natural Channel

AbstractThe Amstel river is located in the peat-covered coastal plain of the Netherlands and gives Amsterdam its name (Amstel dam). It is a small secondary branch of the repeatedly bifurcating Rhine delta system. Historically, the Amstel debouched into the peat-fringed former Oer-IJ estuary, which was connected to the North Sea, but after the closure of this inlet the estuary was transformed into an inland sea (IJ) due to erosion of the adjacent peat. The Amstel river was active between 3000 BP and 1122 AD after which time the supply water from the Rhine was stopped due to the construction of a dam far upstream near Wijk bij Duurstede. On the basis of borehole data from various sources, four cross-sections were constructed in the Amstel branch to study the unknown lithology and lithostratigraphy of the Amstel sediments in the Amsterdam area. The deposits show the Amstel was a low-energy river which carried mainly clay. The cross-sections reveal that the Amstel in its downstream part was flanked by two lithologically identical layers of overbank clay, intercalated by a peat layer. The lowermost overbank clay was deposited from 3000 BP to about 1000 AD. The intercalated peat layer is estimated to have developed between the 11th and 12th centuries AD, indicating a decreased sediment supply in the Amstel, and rise of water level in the downstream river caused by Zuiderzee influences such as storms and tide. The uppermost overbank clay was deposited during major storm surges such as those documented in 1164 and 1170 AD, and was derived from the brackish Zuiderzee; it has been traced upstream along the Amstel for over 10 km. Near the mouth of the Amstel channel in the Oer-IJ estuary its bottom has been scoured by estuarine processes to a lower level. On the basis of archaeological and geological data it is argued that the Amstel channel of medieval Amsterdam had a water depth of about 6 m before the construction of a dam in the 13th century. Soil scientists, historical geographers and historians have argued that the Amstel once consisted of two separate rivers: a northern Oer-IJ connected channel draining from the Amsterdam Stopera to the north, and a southern peat draining channel draining from the Amsterdam-Watergraafsmeer to the south. The relatively straight stretch of the present-day Amstel now positioned within the urban area has been hypothesised to be man-made between the 11th and 13th centuries AD. In this paper, on the basis of geological arguments such as channel depths, overbank clays, peat composition and other characteristics, it is concluded that the Amstel had a natural channel in the Amsterdam area.

scholarly journals Thrust-fault architecture of glaciotectonic complexes in Denmark

1969 ◽  
pp. 17-20
Author(s):  
Stig A. Schack Pedersen ◽  
Lars Ole Boldreel
Keyword(s):  
Sea Level ◽  
Cross Sections ◽  
Thrust Fault ◽  
Basal Part ◽  
The North ◽  
The North Sea ◽  
Fault Deformation ◽  
Seismic Sections ◽  
Structural Levels ◽  
Fault Architecture

Cross sections of glaciotectonic complexes are exposed in coastal cliff s in Denmark, which allow structural studies of the architecture of thin-skinned thrust-fault deformation (Pedersen 2014). However, the basal part of the thrust-fault complex is never exposed, because it is located 50 to 100 m below sea level. It is in the basal part the most important structure – the décollement zone – of the complex is found. Th e décollement zone constitutes the more or less horizontal surface that separates undeformed bedrock from the displaced thrust-sheet units along the décollement level. One of the most famous exposures of glaciotectonic deformations in Denmark is the Møns Klint Glaciotectonic Complex. Th e structures above sea level are well documented, whereas the structures below sea level down to the décollement level are poorly known. Modelling of deep structures was carried out by Pedersen (2000) but still needs documentation. A glaciotectonic c omplex aff ecting comparable rock units, such as the chalk at Møns Klint, was recently recognised in seismic sections from Jammerbugten in the North Sea (Fig. 1). Th ese sections provide an excellent opportunity for comparable studies of the upper and lower structural levels in thin-skinned thrust-fault deformation, which is discussed in this paper with examples from three major glaciotectonic complexes.

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