Determining Extreme Still Water Levels for Design and Planning Purposes Incorporating Sea Level Rise: Sydney, Australia

This paper provides an Extreme Value Analysis (EVA) of the hourly water level record at Fort Denison dating back to 1915 to understand the statistical likelihood of the combination of high predicted tides and the more dynamic influences that can drive ocean water levels higher at the coast. The analysis is based on the Peaks-Over-Threshold (POT) method using a fitted Generalised Pareto Distribution (GPD) function to estimate extreme hourly heights above mean sea level. The analysis highlights the impact of the 1974 East Coast Low event and rarity of the associated measured water level above mean sea level at Sydney, with an estimated return period exceeding 1000 years. Extreme hourly predictions are integrated with future projections of sea level rise to provide estimates of relevant still water levels at 2050, 2070 and 2100 for a range of return periods (1 to 1000 years) for use in coastal zone management, design, and sea level rise adaptation planning along the NSW coastline. The analytical procedures described provide a step-by-step guide for practitioners on how to develop similar baseline information from any long tide gauge record and the associated limitations and key sensitivities that must be understood and appreciated in applying EVA.

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The Role of Mean Sea Level Annual Cycle on Extreme Water Levels Along European Coastline

Remote Sensing ◽

10.3390/rs12203419 ◽

2020 ◽

Vol 12 (20) ◽

pp. 3419

Author(s):

Tomás Fernández-Montblanc ◽

Jesús Gómez-Enri ◽

Paolo Ciavola

Keyword(s):

Water Level ◽

Sea Level ◽

North Sea ◽

Extreme Events ◽

Annual Cycle ◽

Coastal Flooding ◽

Water Levels ◽

Total Water ◽

Mean Sea Level ◽

The Impact

The knowledge of extreme total water levels (ETWLs) and the derived impact, coastal flooding and erosion, is crucial to face the present and future challenges exacerbated in European densely populated coastal areas. Based on 24 years (1993–2016) of multimission radar altimetry, this paper investigates the contribution of each water level component: tide, surge and annual cycle of monthly mean sea level (MMSL) to the ETWLs. It focuses on the contribution of the annual variation of MMSL in the coastal flooding extreme events registered in a European database. In microtidal areas (Black, Baltic and Mediterranean Sea), the MMSL contribution is mostly larger than tide, and it can be at the same order of magnitude of the surge. In meso and macrotidal areas, the MMSL contribution is <20% of the total water level, but larger (>30%) in the North Sea. No correlation was observed between the average annual cycle of monthly mean sea level (AMMSL) and coastal flooding extreme events (CFEEs) along the European coastal line. Positive correlations of the component variance of MMSL with the relative frequency of CFEEs extend to the Central Mediterranean (r = 0.59), North Sea (r = 0.60) and Baltic Sea (r = 0.75). In the case of positive MMSL anomalies, the correlation expands to the Bay of Biscay and northern North Atlantic (at >90% of statistical significance). The understanding of the spatial and temporal patterns of a combination of all the components of the ETWLs shall improve the preparedness and coastal adaptation measures to reduce the impact of coastal flooding.

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Quantifying the impact of basin dynamics on the regional sea level rise in the Black Sea

Ocean Science ◽

10.5194/os-13-443-2017 ◽

2017 ◽

Vol 13 (3) ◽

pp. 443-452 ◽

Cited By ~ 5

Author(s):

Arseny A. Kubryakov ◽

Sergey V. Stanichny ◽

Denis L. Volkov

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Black Sea ◽

Satellite Altimetry ◽

Tide Gauge ◽

The Black Sea ◽

Southeastern Part ◽

Mean Sea Level ◽

The Impact ◽

Dynamic Sea Level

Abstract. Satellite altimetry measurements show that the magnitude of the Black Sea sea level trends is spatially uneven. While the basin-mean sea level rise from 1993 to 2014 was about 3.15 mm yr−1, the local rates of sea level rise varied from 1.5–2.5 mm yr−1 in the central part to 3.5–3.8 mm yr−1 at the basin periphery and over the northwestern shelf and to 5 mm yr−1 in the southeastern part of the sea. We show that the observed spatial differences in the dynamic sea level (anomaly relative to the basin-mean) are caused by changes in the large- and mesoscale dynamics of the Black Sea. First, a long-term intensification of the cyclonic wind curl over the Black Sea, observed in 1993–2014, strengthened divergence in the center of the basin and led to the rise of the sea level in coastal and shelf areas and a lowering in the basin's interior. Second, an extension of the Batumi anticyclone to the west resulted in ∼  1.2 mm yr−1 higher rates of sea level rise in the southeastern part of the sea. Further, we demonstrate that the large-scale dynamic sea level variability in the Black Sea can be successfully reconstructed using the wind curl obtained from an atmospheric reanalysis. This allows for the correction of historical tide gauge records for dynamic effects in order to derive more accurate estimates of the basin-mean sea level change in the past, prior to the satellite altimetry era.

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Numerical Investigation of Storm Surge in Kong Port in the Persian Gulf

10.31224/osf.io/3x95p ◽

2019 ◽

Author(s):

Amir Hossein Mahdavi ◽

Hamid Ansari Sharghi

Keyword(s):

Sea Level Rise ◽

Engineering Design ◽

Sea Level ◽

Storm Surge ◽

Storm Surges ◽

Wave Model ◽

Water Level Fluctuations ◽

Extreme Value Analysis ◽

Value Analysis ◽

Mean Sea Level

Storm surge is generated by the integration of waves, tide and wind setup that is resulted in unwanted mean sea level rise and coastal flooding. The estimation of accurate storm surge is essential for the engineering design of coastal structures. In this study, we estimated the respond of mean sea level winds, tide, waves, and sea-level rise using a local coastal model. A fully coupled hydrodynamic and wave model was implemented to obtain storm surge from different phenomena. The simulations of water level fluctuations due to these parameters were analyzed with the wind forces identified with tidal observations in the Port of Kong. Extreme value analysis was performed to determine the fluctuations associated with different return periods. These data were combined by sea-level rise projections are combined with resulted value. The worst and best scenario of storm surges for each return period were determined for engineering design purposes.

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Relative water-level rise in the Flevo lagoon (The Netherlands), 5300-2000 cal. yr BC: an evaluation of new and existing basal peat time-depth data

Netherlands Journal of Geosciences – Geologie en Mijnbouw ◽

10.1017/s0016774600020680 ◽

2003 ◽

Vol 82 (2) ◽

pp. 115-131 ◽

Cited By ~ 11

Author(s):

B. Makaske ◽

D.G. Van Smeerdijk ◽

H. Peeters ◽

J.R. Mulder ◽

T. Spek

Keyword(s):

The Netherlands ◽

Sea Level Rise ◽

Water Level ◽

Sea Level ◽

Water Levels ◽

Data Set ◽

Mean Sea Level ◽

Water Level Rise ◽

Depth Data ◽

Local Water

AbstractThe rise of Holocene (ground)water level as a function of relative sea-level rise has been extensively investigated in the western Netherlands, whereas few studies focused on the Flevo lagoon in the central Netherlands. In this study, all available 14C dates from the base of basal peat overlying the top of compaction-free Pleistocene sand in the former Flevo lagoon were evaluated in order to reconstruct water-level rise for the period 5300-2000 cal. yr BC. The present basal peat 14C data set from Flevoland consists of two subsets: (1) the largely new Almere data (41 dates) representing the southern part of the former Flevo lagoon, with 26 dates especially carried out for this study, and (2) the existing Schokland data (21 dates) representing the eastern part of the lagoon. The Schokland area is located about 50 km from the Almere area. The quality of all basal peat time-depth data was palaeo-ecologically and geologically evaluated, all 14C dates were calibrated to the same standards, and error margins of age and altitude determination were estimated. After plotting the data as error boxes in time-depth graphs, lower limit curves for water-level rise were constructed for both data sets. Comparison with the mean sea-level curve for The Netherlands (Van de Plassche, 1982) suggests that water-level rise in the Almere area between 5300 and 2000 cal. yr BC corresponded closely to the rise in mean sea level. The same holds for the Schokland area for the period 5000-4200 cal. yr BC. For the period 4200-2000 cal. yr BC, however, the Schokland data suggest water-level rise to have been slower than mean sea-level rise, leading to local water levels apparently below mean sea level, which is virtually impossible. Hypothetical explanations for this discrepancy include: errors and uncertainties in mean sea-level and local water-level reconstruction, basin subsidence and temporal differences in intra-coastal tidal damping. The presently available data are inconclusive at this point and Holocene water-level rise in the Flevo lagoon awaits further investigations.

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AN ADVANCED STATISTICAL EXTREME VALUE MODEL FOR EVALUATING STORM SURGE HEIGHTS CONSIDERING SYSTEMATIC RECORDS AND SEA LEVEL RISE SCENARIO

Coastal Engineering Proceedings ◽

10.9753/icce.v32.currents.23 ◽

2011 ◽

Vol 1 (32) ◽

pp. 23 ◽

Cited By ~ 2

Author(s):

Christoph Mudersbach ◽

Juergen Jensen

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Likelihood Estimation ◽

Extreme Value ◽

Water Levels ◽

Extreme Value Analysis ◽

Value Analysis ◽

Additional Approach ◽

Extreme Value Model ◽

Value Model

In this paper, a non-stationary extreme value analysis approach is introduced in order to determine coastal design water levels for future time horizons. The non-stationary statistical approach is based on the Generalized Extreme Value (GEV) distribution and a L-Moment parameter estimation as well as a Maximum-Likelihood-estimation. An additional approach considers sea level rise scenarios in the non-stationary extreme value analysis. All the methods are applied to the annual maximum water levels from 1849-2007 at the German North Sea gauge at Cuxhaven. The results show, that the non-stationary GEV approach is suitable for determining coastal design water levels.

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A foraminiferal proxy record of 20th century sea-level rise in the Manukau Harbour, New Zealand

Marine and Freshwater Research ◽

10.1071/mf11208 ◽

2012 ◽

Vol 63 (4) ◽

pp. 370 ◽

Cited By ~ 10

Author(s):

Hugh R. Grenfell ◽

Bruce W. Hayward ◽

Ritsuo Nomura ◽

Ashwaq T. Sabaa

Keyword(s):

New Zealand ◽

Salt Marsh ◽

Sea Level Rise ◽

Sea Level ◽

20Th Century ◽

Tide Gauge ◽

Sediment Accumulation ◽

Proxy Record ◽

Tide Gauge Record ◽

Tidal Salt Marsh

The present study aimed to extract a sea-level history from northern New Zealand salt-marsh sediments using a foraminiferal proxy, and to extend beyond the longest nearby tide-gauge record. Transects through high-tidal salt marsh at Puhinui, Manukau Harbour, Auckland, New Zealand, indicate a zonation of dominant foraminifera in the following order (with increasing elevation): Ammonia spp.–Elphidium excavatum, Ammotium fragile, Miliammina fusca, Haplophragmoides wilberti–Trochammina inflata, Trochamminita salsa–Miliammina obliqua. The transect sample faunas are used as a training set to generate a transfer function for estimating past tidal elevations in two short cores nearby. Heavy metal, 210Pb and 137Cs isotope analyses provide age models that indicate 35 cm of sediment accumulation since ~1890 AD. The first proxy-based 20th century rates of sea-level rise from New Zealand’s North Island at 0.28 ± 0.05 cm year–1 and 0.33 ± 0.07 cm year–1 are estimated. These are faster than the nearby Auckland tide gauge for the same interval (0.17 ± 0.1 cm year–1), but comparable to a similar proxy record from southern New Zealand (0.28 ± 0.05 cm year–1) and to satellite-based observations of global sea-level rise since 1993 (0.31 ± 0.07 cm year–1).

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Recent Sea Level Change in the Black Sea from Satellite Altimetry and Tide Gauge Observations

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi9030185 ◽

2020 ◽

Vol 9 (3) ◽

pp. 185 ◽

Cited By ~ 1

Author(s):

Nevin Avşar ◽

Şenol Kutoğlu

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Black Sea ◽

Satellite Altimetry ◽

Tide Gauge ◽

The Black Sea ◽

Sea Level Changes ◽

Early 19Th Century ◽

Mean Sea Level ◽

The Mean

Global mean sea level has been rising at an increasing rate, especially since the early 19th century in response to ocean thermal expansion and ice sheet melting. The possible consequences of sea level rise pose a significant threat to coastal cities, inhabitants, infrastructure, wetlands, ecosystems, and beaches. Sea level changes are not geographically uniform. This study focuses on present-day sea level changes in the Black Sea using satellite altimetry and tide gauge data. The multi-mission gridded satellite altimetry data from January 1993 to May 2017 indicated a mean rate of sea level rise of 2.5 ± 0.5 mm/year over the entire Black Sea. However, when considering the dominant cycles of the Black Sea level time series, an apparent (significant) variation was seen until 2014, and the rise in the mean sea level has been estimated at about 3.2 ± 0.6 mm/year. Coastal sea level, which was assessed using the available data from 12 tide gauge stations, has generally risen (except for the Bourgas Station). For instance, from the western coast to the southern coast of the Black Sea, in Constantza, Sevastopol, Tuapse, Batumi, Trabzon, Amasra, Sile, and Igneada, the relative rise was 3.02, 1.56, 2.92, 3.52, 2.33, 3.43, 5.03, and 6.94 mm/year, respectively, for varying periods over 1922–2014. The highest and lowest rises in the mean level of the Black Sea were in Poti (7.01 mm/year) and in Varna (1.53 mm/year), respectively. Measurements from six Global Navigation Satellite System (GNSS) stations, which are very close to the tide gauges, also suggest that there were significant vertical land movements at some tide gauge locations. This study confirmed that according to the obtained average annual phase value of sea level observations, seasonal sea level variations in the Black Sea reach their maximum annual amplitude in May–June.

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Scenarios of Twenty-First Century Mean Sea Level Rise at Tide-Gauge Stations Across Canada

ATMOSPHERE-OCEAN ◽

10.1080/07055900.2020.1792404 ◽

2020 ◽

Vol 58 (4) ◽

pp. 287-301

Author(s):

Guoqi Han ◽

Zhimin Ma ◽

Aimée B.A. Slangen

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Tide Gauge ◽

First Century ◽

Mean Sea Level ◽

Twenty First Century

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The significance of coastal bathymetry representation for modelling the tidal response to mean sea level rise in the German Bight

Ocean Science ◽

10.5194/os-16-31-2020 ◽

2020 ◽

Vol 16 (1) ◽

pp. 31-44 ◽

Cited By ~ 2

Author(s):

Caroline Rasquin ◽

Rita Seiffert ◽

Benno Wachler ◽

Norbert Winkel

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

North Sea ◽

German Bight ◽

Coastal Areas ◽

Tidal Dynamics ◽

Mean Sea Level ◽

The North ◽

The North Sea ◽

The Impact

Abstract. Due to climate change an accelerated mean sea level rise is expected. One key question for the development of adaptation measures is how mean sea level rise affects tidal dynamics in shelf seas such as the North Sea. Owing to its low-lying coastal areas, the German Bight (located in the southeast of the North Sea) will be especially affected. Numerical hydrodynamic models help to understand how mean sea level rise changes tidal dynamics. Models cannot adequately represent all processes in overall detail. One limiting factor is the resolution of the model grid. In this study we investigate which role the representation of the coastal bathymetry plays when analysing the response of tidal dynamics to mean sea level rise. Using a shelf model including the whole North Sea and a high-resolution hydrodynamic model of the German Bight we investigate the changes in M2 amplitude due to a mean sea level rise of 0.8 and 10 m. The shelf model and the German Bight Model react in different ways. In the simulations with a mean sea level rise of 0.8 m the M2 amplitude in the shelf model generally increases in the region of the German Bight. In contrast, the M2 amplitude in the German Bight Model increases only in some coastal areas and decreases in the northern part of the German Bight. In the simulations with a mean sea level rise of 10 m the M2 amplitude increases in both models with largely similar spatial patterns. In two case studies we adjust the German Bight Model in order to more closely resemble the shelf model. We find that a different resolution of the bathymetry results in different energy dissipation changes in response to mean sea level rise. Our results show that the resolution of the bathymetry especially in flat intertidal areas plays a crucial role for modelling the impact of mean sea level rise.

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