scholarly journals A Modeling Study on the Influence of Sea-Level Rise and Channel Deepening on Estuarine Circulation and Dissolved Oxygen Levels in the Tidal James River, Virginia, USA

2020 ◽  
Vol 8 (11) ◽  
pp. 950
Author(s):  
Ya Wang ◽  
Jian Shen
Keyword(s):  
Dissolved Oxygen ◽  
Sea Level Rise ◽  
Sea Level ◽  
Three Dimensional ◽  
Vertical Stratification ◽  
Water Age ◽  
James River ◽  
Gravitational Circulation ◽  
Environmental Integrity ◽  
The Impact

The impact of channel deepening and sea-level rise on the environmental integrity of an estuary is investigated using a three-dimensional hydrodynamic-eutrophication model. The model results show that dissolved oxygen (DO) only experienced minor changes, even when the deep channel was deepened by 3 m in the mesohaline and polyhaline regions of the James River. We found that vertical stratification decreased DO aeration while the estuarine gravitational circulation increased bottom DO exchange. The interactions between these two processes play an important role in modulating DO. The minor change in DO due to channel deepening indicates that the James River is unique as compared with other estuaries. To understand the impact of the hydrodynamic changes on DO, both vertical and horizontal transport timescales represented by water age were used to quantify the changes in hydrodynamic conditions and DO variation, in addition to traditional measures of stratification and circulation. The model results showed that channel deepening led to an increase in both gravitational circulation strength and vertical stratification. Saltwater age decreased and vertical exchange time increased with increases in channel depth. However, these two physical processes can compensate each other, resulting in minor changes in DO. A comparison of the impact of a sea-level rise of 1.0 m with channel deepening scenarios was conducted. As the sea level rises, the vertical transport time decreases slightly while the strength of gravitational circulation weakens due to an increase in mean water depth. Consequently, DO in the estuary experiences a moderate decrease.

scholarly journals The competing impacts of climate change and nutrient reductions on dissolved oxygen in Chesapeake Bay

2017 ◽  
Author(s):  
Isaac D. Irby ◽  
Marjorie A. M. Friedrichs ◽  
Fei Da ◽  
Kyle E. Hinson
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
Dissolved Oxygen ◽  
Sea Level Rise ◽  
Chesapeake Bay ◽  
Sea Level ◽  
Climate Impacts ◽  
Freshwater Flow ◽  
The Impact ◽  
Impacts Of Climate Change

Abstract. The Chesapeake Bay region is projected to experience changes in temperature, sea level, and precipitation as a result of climate change. This research uses an estuarine-watershed hydrodynamic- biogeochemical modeling system along with projected changes in temperature, freshwater flow, and sea level rise for a 2050 scenario to explore the impact climate change may have on future Chesapeake Bay dissolved oxygen (DO) concentrations and the potential success of nutrient reductions in attaining mandated estuarine water quality improvements. Results indicate that warming Bay waters will decrease oxygen solubility year-round, while also increasing oxygen utilization via respiration and remineralization, primarily impacting bottom oxygen in the spring. Rising sea level will increase the volume of the Bay, pushing coastal saline water further into the Bay. Changes in precipitation are projected to deliver higher winter and spring freshwater flow and nutrient loads, fueling increased primary production. Together, these multiple climate impacts will lower DO throughout the Chesapeake Bay and negatively impact progress towards meeting water quality standards associated with the Chesapeake Bay Total Maximum Daily Load. However, this research also shows that the potential impacts of climate change will be significantly smaller than improvements in DO expected in response to the required nutrient reductions, especially at the anoxic and hypoxic levels. Overall, increased temperature exhibits the strongest control on the change in future DO concentrations, primarily due to decreased solubility, while sea level rise is expected to exert a small positive impact and increased winter river flow is anticipated to exert a small negative impact.

scholarly journals The Impact of Predicted Climate Change on Groundwater Resources in a Mediterranean Archipelago: A Modelling Study of the Maltese Islands

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3046
Author(s):  
Michele De Biase ◽  
Francesco Chidichimo ◽  
Mario Maiolo ◽  
Aaron Micallef
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Water Demand ◽  
Groundwater Resources ◽  
Three Dimensional ◽  
Fault System ◽  
Heterogeneous Model ◽  
Factors Affecting ◽  
Maltese Islands ◽  
The Impact

The effects of changes in climate predicted for 2100—reduction in recharge, increase in water demand and sea-level rise—on groundwater volume and saltwater intrusion have been quantified in the Maltese Islands, an archipelago located at the center of the Mediterranean Sea. A three-dimensional density dependent and heterogeneous model, working in transient conditions, was developed based on morphological and geological information. The hydraulic conductivity and porosity of the lithological formations were derived from previous tests and studies conducted on the islands. The complex fault system intersecting the area has also been included in the model. The results show that among the three considered factors affecting groundwater resources, the most significant is the increase in water demand, which is closely followed by the decrease in groundwater recharge. Sea-level rise plays a marginal role. The 80-year simulation period showed that these combined impacts would cause a loss of more than 16% of groundwater volume.

The Impact of Climate Change on States

2021 ◽  
Vol 23 (2-3) ◽  
pp. 115-132
Author(s):  
Łukasz Kułaga
Keyword(s):  
Climate Change ◽  
International Law ◽  
Sea Level Rise ◽  
Sea Level ◽  
The State ◽  
Fundamental Change ◽  
Sea Levels ◽  
Impact Of Climate Change ◽  
Potential Impact ◽  
The Impact

Abstract The increase in sea levels, as a result of climate change in territorial aspect will have a potential impact on two major issues – maritime zones and land territory. The latter goes into the heart of the theory of the state in international law as it requires us to confront the problem of complete and permanent disappearance of a State territory. When studying these processes, one should take into account the fundamental lack of appropriate precedents and analogies in international law, especially in the context of the extinction of the state, which could be used for guidance in this respect. The article analyses sea level rise impact on baselines and agreed maritime boundaries (in particular taking into account fundamental change of circumstances rule). Furthermore, the issue of submergence of the entire territory of a State is discussed taking into account the presumption of statehood, past examples of extinction of states and the importance of recognition in this respect.

Long-term legacy of delayed climate mitigation in global glacier response

2021 ◽  
Author(s):  
Fabien Maussion ◽  
Quentin Lejeune ◽  
Ben Marzeion ◽  
Matthias Mengel ◽  
David Rounce ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Greenhouse Gas ◽  
Sea Level ◽  
Climate Mitigation ◽  
Delayed Response ◽  
Glacier Change ◽  
Mountain Glaciers ◽  
Glacier Runoff ◽  
The Impact

<p>Mountain glaciers have a delayed response to climate change and are expected to continue to melt long after greenhouse gas emissions have stopped, with consequences both for sea-level rise and water resources. In this contribution, we use the Open Global Glacier Model (OGGM) to compute global glacier volume and runoff changes until the year 2300 under a suite of stylized greenhouse gas emission characterized by (i) the year at which anthropogenic emissions culminate, (ii) their reduction rates after peak emissions and (iii) whether they lead to a long-term global temperature stabilization or decline. We show that even under scenarios that achieve the Paris Agreement goal of holding global-mean temperature below 2 °C, glacier contribution to sea-level rise will continue well beyond 2100. Because of this delayed response, the year of peak emissions (i.e. the timing of mitigation action) has a stronger influence on mit-term global glacier change than other emission scenario characteristics, while long-term change is dependent on all factors. We also discuss the impact of early climate mitigation on regional glacier change and the consequences for glacier runoff, both short-term (where some basins are expected to experience an increase of glacier runoff) and long-term (where all regions are expecting a net-zero or even negative glacier contribution to total runoff), underlining the importance of mountain glaciers for regional water availability at all timescales.</p>

Contrasting facies patterns between river-dominated and symmetrical wave-dominated delta deposits

2021 ◽  
Vol 91 (3) ◽  
pp. 262-295
Author(s):  
BRIAN J. WILLIS ◽  
TAO SUN ◽  
R. BRUCE AINSWORTH
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Preferential Flow ◽  
Return Flow ◽  
Lateral Migration ◽  
Littoral Drift ◽  
Delta Front ◽  
Reference Case ◽  
Depositional Processes ◽  
The Impact

Abstract Process-physics-based, coupled hydrodynamic–morphodynamic delta models are constructed to understand preserved facies heterogeneities that can influence subsurface fluid flow. Two deltaic systems are compared that differ only in the presence of waves: one river dominated and the other strongly influenced by longshore currents. To understand an entire preserved deltaic succession, the growth of multiple laterally adjacent delta lobes is modeled to define delta axial to marginal facies trends through an entire regressive–transgressive depositional succession. The goal is to refine a facies model for symmetrical wave-dominated deltas (where littoral drift diverges from the delta lobe apex). Because many factors change depositional processes on deltas, the description of the river-dominated example is included to provide a direct reference case from which to define the impact of waves on preserved facies patterns. Both systems display strong facies trends from delta axis to margin that continued into inter-deltaic areas. River-dominated delta regression preserved a dendritic branching of compensationally stacked bodies. Transgression, initiated by sea-level rise, backfilled the main channel and deposited levees and splays on the submerging delta top. Wave-dominated deltas developed dual clinoforms: a shoreface clinoform built as littoral drift carried sediment away from the river month and onshore, and a subaqueous delta-front clinoform composed of sediment accumulated below wave base. Although littoral drift in both directions away from the delta axis stabilized the position of the river at the shoreline, distributary-channel avulsions and lateral migration of river flows across the subaqueous delta top produced heterogeneities in both sets of clinoform deposits. Separation of shoreface and subaqueous delta-front clinoforms across a subaqueous delta top eroded to wave base produced a discontinuity in progradational vertical successions that appeared gradual in some locations but abrupt in others. Littoral drift flows away from adjacent deltas converged in inter-deltaic areas, producing shallow water longshore bars cut by wave-return-flow channels with associated terminal mouth bars. Transgression initiated by sea-level rise initially led to vertical aggradation of wave-reworked sheet sands on the subaqueous delta top and then retreating shoreface barrier sands as the subaerial delta top flooded. Pseudo inter-well flow tests responded to local heterogeneities in the preserved deposits. As expected, abandoned channels in the river-dominated case defined shoreline-perpendicular preferential flow paths and wave-dominated delta deposits are more locally homogeneous, but scenarios for development of more pronounced shore-parallel heterogeneity patterns for wave-influenced deltas are discussed. The results highlight the need to consider the dual clinoform nature of wave-dominated delta deposition for facies prediction and subsurface interpretation.

scholarly journals Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years

2014 ◽  
Vol 8 (5) ◽  
pp. 1699-1710 ◽  
Author(s):  
H. Seroussi ◽  
M. Morlighem ◽  
E. Rignot ◽  
J. Mouginot ◽  
E. Larour ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Three Dimensional ◽  
Major Contributor ◽  
West Antarctica ◽  
Climatic Impact ◽  
Ice Shelf ◽  
Ice Dynamics ◽  
Surface Mass ◽  
Grounding Line

Abstract. Pine Island Glacier, a major contributor to sea level rise in West Antarctica, has been undergoing significant changes over the last few decades. Here, we employ a three-dimensional, higher-order model to simulate its evolution over the next 50 yr in response to changes in its surface mass balance, the position of its calving front and ocean-induced ice shelf melting. Simulations show that the largest climatic impact on ice dynamics is the rate of ice shelf melting, which rapidly affects the glacier speed over several hundreds of kilometers upstream of the grounding line. Our simulations show that the speedup observed in the 1990s and 2000s is consistent with an increase in sub-ice-shelf melting. According to our modeling results, even if the grounding line stabilizes for a few decades, we find that the glacier reaction can continue for several decades longer. Furthermore, Pine Island Glacier will continue to change rapidly over the coming decades and remain a major contributor to sea level rise, even if ocean-induced melting is reduced.

scholarly journals Assessing storm surge hazard and impact of sea level rise in the Lesser Antilles case study of Martinique

2017 ◽  
Vol 17 (9) ◽  
pp. 1559-1571 ◽  
Author(s):  
Yann Krien ◽  
Bernard Dudon ◽  
Jean Roger ◽  
Gael Arnaud ◽  
Narcisse Zahibo
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Numerical Models ◽  
Lesser Antilles ◽  
Adaptation Measures ◽  
Worst Case ◽  
Mitigation And Adaptation ◽  
The Impact

Abstract. In the Lesser Antilles, coastal inundations from hurricane-induced storm surges pose a great threat to lives, properties and ecosystems. Assessing current and future storm surge hazards with sufficient spatial resolution is of primary interest to help coastal planners and decision makers develop mitigation and adaptation measures. Here, we use wave–current numerical models and statistical methods to investigate worst case scenarios and 100-year surge levels for the case study of Martinique under present climate or considering a potential sea level rise. Results confirm that the wave setup plays a major role in the Lesser Antilles, where the narrow island shelf impedes the piling-up of large amounts of wind-driven water on the shoreline during extreme events. The radiation stress gradients thus contribute significantly to the total surge – up to 100 % in some cases. The nonlinear interactions of sea level rise (SLR) with bathymetry and topography are generally found to be relatively small in Martinique but can reach several tens of centimeters in low-lying areas where the inundation extent is strongly enhanced compared to present conditions. These findings further emphasize the importance of waves for developing operational storm surge warning systems in the Lesser Antilles and encourage caution when using static methods to assess the impact of sea level rise on storm surge hazard.

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

Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 95
Author(s):  
Phil J. Watson
Keyword(s):  
Sea Level Rise ◽  
Water Level ◽  
Sea Level ◽  
Tide Gauge ◽  
Water Levels ◽  
Extreme Value Analysis ◽  
Tide Gauge Record ◽  
Value Analysis ◽  
Mean Sea Level ◽  
The Impact

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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