Salinity effects on pressure-based tide gauges in a macro-tidal estuary

2021 ◽  
Author(s):  
Joanne Williams
Keyword(s):  
Storm Surge ◽  
River Flow ◽  
Tide Gauges ◽  
Measurement Systems ◽  
Tidal Estuary ◽  
Salinity Effects ◽  
Estuarine Salinity ◽  
The Uk ◽  
Freshwater River

<div>Estuarine salinity can be highly variable, resulting in significant density variability. So tide-gauges measuring pressure (either directly or as bubblers) can experience salinity-induced pressure variations of up to 1% of their range. They can therefore record depths with up to 1% variability that is not seen in other measurement systems. In most places this is a small effect compared to other sources of varibility but in macro-tidal estuary such as the Severn in the UK it amounts around 10cm difference between high and low tide. This is comparable to levels of accuracy being sought by current surge forecasts. </div><div> </div><div>This effect can be seen in neighbouring radar and pressure gauges in the Severn. It could result in spurious seasonal and spring-neap constituents. Elsewhere, similar errors could result related to unusual freshwater river flow in estuarine locations that are usually saline, or unusual saline storm surge in usually freshwater sites. It has implications for assessment of storm surge and multi-hazard forecasting, and accurate calibration of new gauge installations.  </div><div> </div>

scholarly journals A Basin- to Channel-Scale Unstructured Grid Hurricane Storm Surge Model Applied to Southern Louisiana

2008 ◽  
Vol 136 (3) ◽  
pp. 833-864 ◽  
Author(s):  
Joannes J. Westerink ◽  
Richard A. Luettich ◽  
Jesse C. Feyen ◽  
John H. Atkinson ◽  
Clint Dawson ◽  
...  
Keyword(s):  
Storm Surge ◽  
Unstructured Grid ◽  
River Flow ◽  
Computational Cost ◽  
Skill Assessment ◽  
Open Boundary ◽  
Wind Fields ◽  
Hurricane Wind ◽  
Hurricane Storm Surge ◽  
Southern Louisiana

Abstract Southern Louisiana is characterized by low-lying topography and an extensive network of sounds, bays, marshes, lakes, rivers, and inlets that permit widespread inundation during hurricanes. A basin- to channel-scale implementation of the Advanced Circulation (ADCIRC) unstructured grid hydrodynamic model has been developed that accurately simulates hurricane storm surge, tides, and river flow in this complex region. This is accomplished by defining a domain and computational resolution appropriate for the relevant processes, specifying realistic boundary conditions, and implementing accurate, robust, and highly parallel unstructured grid numerical algorithms. The model domain incorporates the western North Atlantic, the Gulf of Mexico, and the Caribbean Sea so that interactions between basins and the shelf are explicitly modeled and the boundary condition specification of tidal and hurricane processes can be readily defined at the deep water open boundary. The unstructured grid enables highly refined resolution of the complex overland region for modeling localized scales of flow while minimizing computational cost. Kinematic data assimilative or validated dynamic-modeled wind fields provide the hurricane wind and pressure field forcing. Wind fields are modified to incorporate directional boundary layer changes due to overland increases in surface roughness, reduction in effective land roughness due to inundation, and sheltering due to forested canopies. Validation of the model is achieved through hindcasts of Hurricanes Betsy and Andrew. A model skill assessment indicates that the computed peak storm surge height has a mean absolute error of 0.30 m.

Gamma Spectrometry Systems for the Assay of Uranium Residues and Potentially Contaminated Low Level Wastes at the Capenhurst Site

2003 ◽  
Author(s):  
P. A. Clark ◽  
D. F. Parvin ◽  
C. Y. Powrie ◽  
C. H. Orr ◽  
G. Mottershead ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Matrix Correction ◽  
Uranium Recovery ◽  
Measurement Systems ◽  
Low Level ◽  
Fuel Fabrication ◽  
Wide Range ◽  
Contaminated Waste ◽  
The Uk ◽  
High Level

BNFL has produced and operates a wide range of DrumScan® gamma measurement systems for monitoring packages, drums and boxed wastes arising from nuclear power plant reprocessing, fuel fabrication and decommissioning operations. The challenges associated with decommissioning operations are met by employing a range of technologies predominantly High Resolution and Low Resolution spectrometry (HRGS & LRGS). This paper describes how BNFL Instruments’ LRGS and HRGS DrumScan® gamma measurement systems have been used for the assay of uranium resides and potentially contaminated low level wastes by Capenhurst Integrated Decommissioning Project (IDP) in the UK. A description of the two Capenhurst segmented HRGS systems is included. Whilst Segmented Gamma Scanning is a well established technique for the non-destructive assay of gamma emitting radioisotopes in drummed waste, these systems utlise unique features to address the specific measurement requirements. The first system is configured for the accurate measurement of both small sized containers of uranium residues arising from recovery operations and low level wastes potentially contaminated with uranium contained in 200 litre drums. To achieve a high level of accuracy, this system uses a novel mechanical arrangement to overcome the wide variety of container sizes, and the unique “TransWeight” and “Transmission” matrix correction techniques which provide significant improvements over conventional Segmented Gamma Scanner matrix correction techniques. The second system is configured for Nuclear Safety purposes to provide an upper limit of the 235U present in 200 litre drums of potentially contaminated waste prior to the opening of the drums for sorting and uranium recovery operations. This system is configured to report an appropriately pessimistic upper estimate of the 235U present. A brief description of the LRGS systems used by Capenhurst is also provided. These systems have served to quantify the 235U content within a variety of potentially contaminated waste items ranging from 200 litre drums to 1m3 boxed waste.

scholarly journals Coastal Tidal Effects on Industrial Thermal Plumes in Satellite Imagery

2019 ◽  
Vol 11 (18) ◽  
pp. 2132 ◽  
Author(s):  
Agnieszka Faulkner ◽  
Claire E. Bulgin ◽  
Christopher J. Merchant
Keyword(s):  
Sea Water ◽  
Open Water ◽  
Ecological Impacts ◽  
Coastal Environments ◽  
Tide Gauges ◽  
Tidal Effects ◽  
Thermal Plumes ◽  
Different Types ◽  
Coastal Features ◽  
The Uk

Coastal tidal effects on thermal plumes are investigated, exploiting remote sensing of two major coastal industrial installations. The installations use sea water as a coolant, which is then released back into coastal environments at a higher-than-ambient temperature, allowing the plume to be delineated from the ambient waters. Satellite-based thermal sensors observing the Earth at spatial resolutions of 90 and 100 m are used. It is possible to identify coastal features and thermal spatial distributions. This paper presents coastal tidal effects on detected plumes for two case studies: an intertidal embayment and open water exposure, both on the coast of the UK. We correlated the behaviours of thermal plumes using remotely sensed high resolution thermal imagery with tidal phases derived from tide gauges. The results show very distinct behaviours for the flood and ebb tides. The detected surface plume location was dependent on flow switching direction for the different types of tide. The detected surface area was dependent on the strength of the currents, with the largest area observed during the strongest currents. Understanding the dispersion of the plume is essential to influence understanding of any potential ecological impacts.

scholarly journals Using continuous GPS and absolute gravity to separate vertical land movements and changes in sea-level at tide-gauges in the UK

2006 ◽  
Vol 364 (1841) ◽  
pp. 917-930 ◽  
Author(s):  
F.N Teferle ◽  
R.M Bingley ◽  
S.D.P Williams ◽  
T.F Baker ◽  
A.H Dodson
Keyword(s):  
Time Series ◽  
Sea Level ◽  
Tide Gauge ◽  
Absolute Gravity ◽  
Tide Gauges ◽  
Tide Gauge Record ◽  
Vertical Movements ◽  
Movement Component ◽  
The Uk ◽  
Continuous Gps

Researchers investigating climate change have used historical tide-gauge measurements from all over the world to investigate the changes in sea-level that have occurred over the last century or so. However, such estimates are a combination of any true sea-level variations and any vertical movements of the land at the specific tide-gauge. For a tide- gauge record to be used to determine the climate related component of changes in sea-level, it is therefore necessary to correct for the vertical land movement component of the observed change in sea-level. In 1990, the Institute of Engineering Surveying and Space Geodesy and Proudman Oceanographic Laboratory started developing techniques based on the Global Positioning System (GPS) for measuring vertical land movements (VLM) at tide-gauges in the UK. This paper provides brief details of these early developments and shows how they led to the establishment of continuous GPS (CGPS) stations at a number of tide-gauges. The paper then goes on to discuss the use of absolute gravity (AG), as an independent technique for measuring VLM at tide-gauges. The most recent results, from CGPS time-series dating back to 1997 and AG time-series dating back to 1995/1996, are then used to demonstrate the complementarity of these two techniques and their potential for providing site-specific estimates of VLM at tide-gauges in the UK.

Uncertainty in coastal flooding: modelling and visualisation

2020 ◽  
Author(s):  
John Maskell
Keyword(s):  
Water Level ◽  
Storm Surge ◽  
Return Period ◽  
Flood Risk ◽  
High Water ◽  
Coastal Flooding ◽  
Water Levels ◽  
Tidal Range ◽  
The Uk ◽  
Flood Maps

<p>Two case studies are considered in the UK, where uncertainty and drivers of coastal flood risk are explored through modelling and visualisations. Visualising the impact of uncertainty is a useful way of explaining the potential range of predicted or simulated flood risk to both expert and non-expert stakeholders.</p><p>Significant flooding occurred in December 2013 and January 2017 at Hornsea on the UK East Coast, where storm surge levels and waves overtopped the town’s coastal defences. Uncertainty in the potential coastal flooding is visualised at Hornsea due to the range of uncertainty in the 100-year return period water level and in the calculated overtopping due to 3 m waves at the defences. The range of uncertainty in the simulated flooding is visualised through flood maps, where various combinations of the uncertainties decrease or increase the simulated inundated area by 58% and 82% respectively.</p><p>Located at the mouth of the Mersey Estuary and facing the Irish Sea, New Brighton is affected by a large tidal range with potential storm surge and large waves. Uncertainty in the coastal flooding at the 100-year return period due to the combination of water levels and waves is explored through Monte-Carlo analysis and hydrodynamic modelling. Visualisation through flood maps shows that the inundation extent at New Brighton varies significantly for combined wave and surge events with a joint probability of 100 years, where the total flooded area ranges from 0 m<sup>2</sup> to 10,300 m<sup>2</sup>. Waves are an important flood mechanism at New Brighton but are dependent on high water levels to impact the coastal defences and reduce the effective freeboard. The combination of waves and high-water levels at this return level not only determine the magnitude of the flood extent but also the spatial characteristics of the risk, whereby flooding of residential properties is dominated by overflow from high water levels, and commercial and leisure properties are affected by large waves that occur when the water level is relatively high at the defences.</p>

scholarly journals RECONNAISSANCE LEVEL STUDY MISSISSIPPI STORM SURGE BARRIER

2012 ◽  
Vol 1 (33) ◽  
pp. 69 ◽  
Author(s):  
Mathijs Van Ledden ◽  
Joost Lansen ◽  
Hennes De Ridder ◽  
Billy Edge
Keyword(s):  
New Orleans ◽  
Sea Level ◽  
Storm Surge ◽  
Mississippi River ◽  
River Flow ◽  
Construction Costs ◽  
Levee System ◽  
Feasible Alternative ◽  
Hurricane Storm Surge ◽  
The City

This paper reports a reconnaissance level study of a storm surge barrier in the Mississippi River. Historical hurricanes have shown storm surge of several meters along the Mississippi River levees up to and upstream of New Orleans. Future changes due to sea level rise and subsidence will further increase the risk of flooding due to hurricane storm surge. A surge barrier downstream of New Orleans has been considered as an alternative to levee raise along the Mississippi River. Hydraulic computations show that the build-up of water behind the barrier due to the Mississippi River flow is (much) lower than the hurricane surge protruding up the river in the no-barrier situation. The barrier will probably eliminate the need to upgrade the system upstream of the barrier while providing the same level of hurricane risk reduction. A hybrid barrier (a combination of different gate types) with a primary swing gate for navigation (and flow) and secondary lift gates to accommodate for flow is a technically feasible alternative. The barrier remains open for almost the entire year and would only to be closed during severe tropical events (say once every 2 - 3 years). Several measures are included in the conceptual design to mitigate the navigation impact. The construction costs of the barrier are estimated at $1.6 - 2.6 billion. It is recommended to compare the investment costs of a barrier including adjacent tie-ins to the existing HSDRRS to the costs of upgrading and maintaining the levee system throughout the city of New Orleans.

Sign in / Sign up

Export Citation Format

Share Document