Multivariate statistical modelling of the drivers of compound flood events in South Florida

Abstract. Miami-Dade County (south-east Florida) is among the most vulnerable regions to sea-level rise in the United States, due to a variety of natural and human factors. The co-occurrence of multiple, often statistically dependent flooding drivers – termed compound events – typically exacerbates impacts compared with their isolated occurrence. Ignoring dependencies between the drivers will potentially lead to underestimation of flood risk and under-design of flood defence structures. At present, design assessments of flood defence structures in Miami-Dade County assume rainfall and Ocean-side Water Level (O-sWL) are fully dependent, a conservative assumption inducing large safety factors. Here, an analysis of the dependence between the principal flooding drivers over a range of lags at three locations across the county is carried out. The conservative nature of the existing structural design assessment is subsequently explored, by combining a two-dimensional analysis of rainfall and O-sWL with regional sea-level rise projections. Finally, the vine copula and Heffernan and Tawn (2004) models are shown to outperform five standard higher dimensional copulas in capturing the dependence between the principal drivers of compound flooding: rainfall, O-sWL, and groundwater level. This leads to recommendations for revised future design frameworks able to capture and represent dependencies between different flood drivers.

Download Full-text

Multivariate statistical modelling of the drivers of compound flood events in south Florida

Natural Hazards and Earth System Science ◽

10.5194/nhess-20-2681-2020 ◽

2020 ◽

Vol 20 (10) ◽

pp. 2681-2699

Author(s):

Robert Jane ◽

Luis Cadavid ◽

Jayantha Obeysekera ◽

Thomas Wahl

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Statistical Modelling ◽

The United States ◽

South Florida ◽

Dade County ◽

Water Control ◽

Original Design ◽

Control Structures ◽

Water Control Structures

Abstract. Miami-Dade County (south-east Florida) is among the most vulnerable regions to sea level rise in the United States, due to a variety of natural and human factors. The co-occurrence of multiple, often statistically dependent flooding drivers – termed compound events – typically exacerbates impacts compared with their isolated occurrence. Ignoring dependencies between the drivers will potentially lead to underestimation of flood risk and under-design of flood defence structures. In Miami-Dade County water control structures were designed assuming full dependence between rainfall and Ocean-side Water Level (O-sWL), a conservative assumption inducing large safety factors. Here, an analysis of the dependence between the principal flooding drivers over a range of lags at three locations across the county is carried out. A two-dimensional analysis of rainfall and O-sWL showed that the magnitude of the conservative assumption in the original design is highly sensitive to the regional sea level rise projection considered. Finally, the vine copula and Heffernan and Tawn (2004) models are shown to outperform five standard higher-dimensional copulas in capturing the dependence between the principal drivers of compound flooding: rainfall, O-sWL, and groundwater level. The work represents a first step towards the development of a new framework capable of capturing dependencies between different flood drivers that could potentially be incorporated into future Flood Protection Level of Service (FPLOS) assessments for coastal water control structures.

Download Full-text

Economic damages from Hurricane Sandy attributable to sea level rise caused by anthropogenic climate change

Nature Communications ◽

10.1038/s41467-021-22838-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Benjamin H. Strauss ◽

Philip M. Orton ◽

Klaus Bittermann ◽

Maya K. Buchanan ◽

Daniel M. Gilford ◽

...

Keyword(s):

Climate Change ◽

Sea Level Rise ◽

Sea Level ◽

East Coast ◽

The United States ◽

Hurricane Sandy ◽

Water Levels ◽

Anthropogenic Climate Change ◽

Economic Damage ◽

Sea Levels

AbstractIn 2012, Hurricane Sandy hit the East Coast of the United States, creating widespread coastal flooding and over $60 billion in reported economic damage. The potential influence of climate change on the storm itself has been debated, but sea level rise driven by anthropogenic climate change more clearly contributed to damages. To quantify this effect, here we simulate water levels and damage both as they occurred and as they would have occurred across a range of lower sea levels corresponding to different estimates of attributable sea level rise. We find that approximately $8.1B ($4.7B–$14.0B, 5th–95th percentiles) of Sandy’s damages are attributable to climate-mediated anthropogenic sea level rise, as is extension of the flood area to affect 71 (40–131) thousand additional people. The same general approach demonstrated here may be applied to impact assessments for other past and future coastal storms.

Download Full-text

Sea-Level Rise and South Florida: Envisioning Public Space as a Function of a Changing Natural Environment

The Plan Journal ◽

10.15274/tpj.2021.06.01.9 ◽

2021 ◽

Vol 6 (1) ◽

Keyword(s):

Sea Level Rise ◽

Public Space ◽

Sea Level ◽

Natural Environment ◽

South Florida

Download Full-text

Long-term challenge to mangrove in the National park Xuanthuy – data released from shallow subsidence monitoring

VNU Journal of Science Earth and Environmental Sciences ◽

10.25073/2588-1094/vnuees.4221 ◽

2018 ◽

Vol 34 (3) ◽

Author(s):

Le Xuan Thuyen

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

National Park ◽

Low Cost ◽

River Mouth ◽

Biosphere Reserve ◽

The United States ◽

Red River ◽

United States Geological Survey ◽

The Core

A small mangrove colony growing for several decades on a mud flat on the left side of Balat River mouth has become today a large and healthy forest, containing a high ecosystem service value in the core of the Red River biosphere reserve. As a pioneer ecosystem located at land– water interface in the tropic, there exist always risks to mangroves, especially due to climate change and sea level rise. Sea level rise is a worldwide process, but subsidence is a local problem that can exacerbate these geo-hazards. A monitoring of shallow subsidence has been carried out by using SET-MH technique (developed by the United States Geological Survey) to track the both accretion and land sinking in the core zone of the National Park. The measurement shows the average sedimentation rate of 2.9 cm / yr and the sinking rate of 3.4 cm / yr, since Dec. 30th 2012. This is the first ground-based observation of shallow subsidence under mangroves in the Tonkin Gulf. As a simple and low cost method, so further expansion of this monitoring could provide more useful information to help identify the generally sinking trend of coastal areas in the Red River Delta and also to protect its own biosphere reserve.

Download Full-text

COLLABORATIVE STRATEGIES FOR SEA LEVEL RISE ADAPTATION IN HAMPTON ROADS, VIRGINIA

Journal of Green Building ◽

10.3992/1943-4618.13.3.193 ◽

2018 ◽

Vol 13 (3) ◽

pp. 193-214 ◽

Cited By ~ 1

Author(s):

Carol Considine ◽

Emily Steinhilber

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Regional Scale ◽

The United States ◽

Tourism Industry ◽

Collaborative Problem Solving ◽

Hampton Roads ◽

Global Rate ◽

Municipal Boundaries ◽

Sea Level Rise Adaptation

INTRODUCTION The Hampton Roads region is located in southeastern Virginia where the Chesapeake Bay meets the Atlantic Ocean. The region includes seventeen municipal governments and has a large federal government presence with 26 federal agencies represented (See Figure 1). The region has a population that exceeds 1.7 million and is home to the deepest water harbor on the U.S. East Coast. Hampton Roads' economy is dependent on the local waterways and houses the world's largest naval facility, the sixth largest containerized cargo complex and supports a thriving shipbuilding and repair industry as well as a tourism industry. However, the region's vast coastline also contributes to its vulnerability from climate change. Hampton Roads is experiencing sea level rise at twice the global rate with regional projections in the January 2017 National Oceanic and Atmospheric Administration (NOAA) report, Global and Regional Sea Level Rise Scenarios for the United States, of 1.9 feet of sea level rise at the low end and 11.5 feet of sea level rise under the most extreme case between 2000 and 2100 (NOAA, 2017). Planning for adaptation to sea level rise requires regional partnerships and strategies, especially for watersheds that cross municipal boundaries. While many of the municipalities in the region are forward thinking in their approaches to sea level rise, there is not a regional plan for adaptation and current federal funding models do not support analysis of and planning for sea level rise impacts on a regional scale. For coastal communities to be successful in sea level rise adaptation, there has to be a national understanding that water knows no borders and only collaborative problem-solving approaches that cross municipal boundaries will move regions toward adaptation. Functional boundaries of ecosystems or watersheds need to be the focus of adaptation rather than political boundaries of local, state, and federal entities. Coordination and collaboration between entities is the only way to achieve optimal outcomes.

Download Full-text

The effects of tidal changes on the frequency of nuisance flooding events in the United States

10.5194/egusphere-egu2020-12115 ◽

2020 ◽

Author(s):

Sida Li ◽

Thomas Wahl ◽

David Jay ◽

Stefan Talke ◽

Lintao Liu

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

High Tide ◽

The United States ◽

Tide Gauges ◽

Relative Sea Level ◽

Relative Sea Level Rise ◽

Tidal Changes ◽

Cape Fear ◽

The U.S

<p>Nuisance flooding (NF) or high tide flooding describes minor nondestructive flooding which can nonetheless cause substantial negative socio-economic impacts to coastal communities. The frequency of NF events has increased and accelerated over the past decades along the U.S. coast, leading to changes ranging from 300% to 900%. This is mainly a result of sea level rise reducing the gap between high tidal datum and flood thresholds. While long-term relative sea level rise is the main driver for the increased number of NF events, other factors such as variability in the Gulf stream, the storm climate, and infragravity waves can also contribute. Another important driver that is often overlooked is related to changes in coastal and estuary tides, through secular trends in the amplitudes of major tidal constituents. In this presentation we assess the role of tidal changes in modulating the frequency of NF events along the U.S. coastline. We analyze hourly records from 49 U.S. tide gauges for which the National Weather Service has defined NF thresholds. We find that (1) overall across all tide gauges the number of NF days has increased since 1950 due to changes in coastal tides, adding up to 100 NF days in recent years (on top of the increase due to relative sea level rise), (2) more tide gauges experience an increase in NF events than a decrease due to changes in tides, (3) tide gauges in major estuaries which have undergone major anthropogenic alterations experience the strongest changes; in Wilmington (Cape Fear estuary), for example, 10-40% of NF events in recent years can be attributed to tidal changes.&#160;</p>

Download Full-text