14106 research outputs found
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Instandsetzung massiver Verkehrswasserbauwerke – Dauerhaftigkeit, Instandsetzungen und (Regelwerks-)Entwicklungen im Überblick
No full textUmsetzung der WRRL an der Oder – von der WRRL-Bewirtschaftungsplanung zum integrativen Projekt
No full textDie Wasserstraßen- und Schifffahrtsverwaltung des Bundes (WSV) ist neben den verkehrlichen Belangen auch für die ökologisch- wasserwirtschaftliche Entwicklung der Bundeswasserstraßen im Bereich der Hydromorphologie als Beitrag zur Zielerreichung der Wasserrahmenrichtlinie (WRRL) verantwortlich.
Über ein zweistufiges Verfahren werden potenziell umsetzbare Maßnahmen gesammelt, bewertet und priorisiert. An der Oder liegt der Fokus dabei auf einer integrativen Planung, die verkehrliche und ökologisch-wasserwirtschaftliche Anforderungen gleichermaßen berücksichtigt. Großräumigere Projekte, die sich über Fluss und Ufer hinaus bis in die Aue erstrecken, können über Kooperationen zwischen der WSV und Dritten ermöglicht werden
Modellierung der räumlichen Infiltrationsdynamik durch undichte Schlösser einer Uferspundwand
No full textGlobal lakes and reservoirs. An investigation to which extent dynamic water body shapes have an impact on the estimates of the total water storage derived from GRACE
No full textThe satellite mission Gravity Recovery and Climate Experiment (GRACE) measures gravity field variations caused by mass redistributions across the atmosphere, the continents and the oceans. Since the redistributions over the continents are linked to changes in the total water storage (TWS), expressed as equivalent water heights (EWH), the observations can be used to quantitatively assess global freshwater variations, which is of great social importance in times of increasingly scarce water resources. If the focus of interest refers to groundwater related variations explicitly, all other storage compartments (here: surface waters) have to be reduced from the GRACE observations. Therefore, the retrieved signal has to be decomposed into its individual components. To achieve this, the water volume can be estimated by forward modelling satellite altimetry and remote sensing data, considering both static and dynamic surface expansions. It will be discussed, that using a dynamic instead of a static surface area extent (1) will change the equivalent water height values in a magnitude between 0.006 cm and 0.243 cm, (2) causes the largest deviation for the Lake Mead and (3) that the question whether a dynamic or a static water body shape should be considered is driven by the interaction of various parameters
Die Ostseesturmflut vom Oktober 2023 an den sandigen Flachküsten und Binnenküsten von Mecklenburg-Vorpommern
No full textDie Sturmflut an der deutschen Ostseeküste im Oktober 2023 war im Bereich von Mecklenburg-Vorpommern eine mittlere (im Westen) bzw. leichte Sturmflut (im Osten). Auf die Beschreibung der Genese der Sturmflut folgt die statistische Einordnung und der Vergleich zu früheren Ereignissen. Die Bilanzierung der Schäden fokussiert auf die vom Land Mecklenburg-Vorpommern unterhaltenen Landesküstenschutzdünen. Strategische Aspekte zur langfristigen Sicherung dieser Hochwasserschutzbauwerke werden erläutert. Die Auswirkungen der Sturmflut an den inneren Küsten des Landes schließen den Artikel ab.
Im Bereich von Landesküstenschutzdünen kam es durch die Kombination von hohen Wasserständen und Seegang lokal zu teilweise erheblichen Sandumlagerungen aus dem Dünenkörper in Richtung Strand und Schorre. Diese Sandumlagerungen waren aber weder überraschend noch mit negativen Auswirkungen für das Schutzniveau an der Außenküste von Mecklenburg-Vorpommern. Die lange Verweilzeit der Sturmflut führte dazu, dass es auch an den inneren Küsten erhebliche Wasserstandserhöhungen gegeben hat. Dies hat zu einer hydraulischen Belastung der Deiche geführt. Entgegen der in den Medien verbreiteten Informationen ist kein Deich gebrochen
Visualization of Water Surface Profile in Obstructed Open Channel Flows
No full textThe construction of bridge structures needs laying bridge piers and abutments within the channel of natural waterways. These piers or abutments got blocked, which might raise the water level upstream of the bridge structure and compromise the integrity of the structure. Much research deals with calculating the drag characteristics of bridge piers concerning their shapes, numbers, etc., but few articles deal with water surface profile effects and behavior around bridge abutments.
This research measures water surface profile (WSP) and backwater effects for flows through bridge openings under three flow situations. These flows are free-to-flow, orifice flow, and overtopping flow. Two types of constrictions were investigated. The first was a lateral constriction, while the second was a bridge deck. The study focused on two distinct flow phenomena, namely orifice flow and weir flow, within the framework of the submerged bridge model. For the lateral constriction model, the study has also provided the effect of the blockage ratio on the water surface profile. Results showed that for the free flows, the opening ratio significantly impacts the water surface profile. The flow features around the obstacle show that the 3-D surface maps program is very well at capturing the water distribution depths along the free stream-wise direction in the obstructed open channel flows
Influence of 3D-VAR Dissimilarity Measure on Flood Model Calibration with Satellite Data
No full text
Magnetic data optimisation for advanced UXO interpretation
No full textCollaborative industry research was undertaken to provide insight into survey planning, processing and modelling of magnetic data for UXO mitigation. The outcomes should help to increase understanding factors relevant if advanced interpretation is desired, which could then be used to improve accuracy and reduce false positives during target discrimination. Current industry methods are explored to provide practicable insight for developers, UXO consultants and survey companies. The data sets comprised magnetic data from 220 found munitions, a controlled drone test over an inert munition, a vertical gradient test series over a surrogate item and synthetic data. Significant research was undertaken on a variety of topics, however, here we have confined the discussion to just the key results regarding altitude correction, munition response, synthetic items, modelling and acquisition sampling. This document closes with a summary of a potential workflow for advanced interpretation as supported by the research
A field measurement
No full textDuring berthing operations of large vessels, the bow thruster jet deflecting on the quay wall and the bed can lead to high flow velocities near the bed. This may scour the bed when it is left unprotected, causing instability of the adjacent quay wall. Due to the complex flow field of the reflected jet, the decay in near-bed flow velocities perpendicular to the quay wall is unknown. This results in uncertainties in the design of bed protections, especially in the required width.
In this research, the decay of the near-bed flow velocity perpendicular and parallel to the quay wall induced by a 4-channel bow thruster is studied. Field measurements have been conducted in the North Sea Port of Gent with one of the largest Dutch inland vessels. The near-bed flow velocities have been measured at multiple distances from the quay wall.
For the flow velocity measurements four main parameters have been varied: the applied bow thruster power, quay wall clearance, number of thrusters, and the lateral distance between jet axis and measurement sensors.
The highest flow velocities were measured near the quay wall, rapidly declining while moving away from the quay. Comparison of the measurement results to the Dutch and German guidelines generally leads to the conclusion that these guidelines are conservative. In addition, the dependency of the velocity on the total travelled distance by the jet as given in the Dutch method is not reflected in the measurement results. Furthermore, fundamentally different outcomes on the influence of the quay wall clearance on the near-bed flow velocity have been found.
When the measured near-bed flow velocities are used as the sole input to calculate the required bed protection, significantly smaller rock sizes and asphalt mattress thickness would be necessary to withstand the hydraulic load of the jet in comparison to current guidelines. Further studies with different vessels and direct measurement of the efflux velocity of the thrusters are recommended