Beach nourishment versus sea level rise on Florida’s coasts

Shore & Beach ◽  
2020 ◽  
pp. 3-13
Author(s):  
James Houston
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
East Coast ◽  
Beach Nourishment ◽  
Shoreline Change ◽  
Intergovernmental Panel ◽  
Shoreline Changes ◽  
The Past ◽  
Equilibrium Profile ◽  
And Sea Level

Beach nourishment and sea level rise will dominate future shoreline changes on Florida’s 665 miles of sandy coast. Shoreline changes from 2020-2100 are projected along this entire coast using equilibrium profile theory that accurately predicted shoreline changes on Florida’s east coast from 1970-2017 (Houston 2019). Projections for 2020- 2100 are made assuming past rates of beach nourishment for the 30-yr period from 1988-2017 will continue and sea level will rise according to recent projections of the Intergovernmental Panel on Climate Change (IPCC) that include the latest knowledge on ice melting in Antarctica (IPCC 2019). Using the beach nourishment and sea level rise data, equilibrium profile theory is then used to predict shoreline change from 2020-2100 for each IPCC sea level rise projection. Beach nourishment is shown to produce shoreline advance seaward on average for all IPCC scenarios for both the entire Florida coast and east coast and for all scenarios except the upper confidence level of the worst scenario for the southwest and Panhandle coasts. Some of the 30 counties on these coasts will require a greater rate of nourishment than in the past to offset sea level rise for some or all of the scenarios, whereas some will offset sea level rise for all scenarios with lower nourishment rates than in the past. The annual beach nourishment volume for which a county has a shortfall or surplus in offsetting sea level rise for each IPCC scenario can be calculated with the information provided and examples are presented. The approach can be used on coasts outside Florida if beach nourishment and sea level rise are expected to dominate future shoreline change.

The fate of beach nourishment sand placed on the Florida East Coast

Shore & Beach ◽  
2019 ◽  
pp. 3-14 ◽  
Author(s):  
James Houston
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
East Coast ◽  
Beach Nourishment ◽  
Shoreline Change ◽  
Storm Damage ◽  
Intergovernmental Panel ◽  
Longshore Transport ◽  
Beach Width ◽  
Equilibrium Profile

Over 100 million yd3 of sand have been placed on Florida east coast beaches since the start of widespread beach nourishment in 1970. What has been the fate of this sand? Has it largely disappeared as some suggest, or is it largely in place, having increased beach width as much as expected? Shoreline position measurements show that beach nourishment has dominated shoreline change with beaches widening over 80 ft on average since 1970. Nourished beaches have widened an average of almost 120 ft and adjacent beaches that have never been nourished have widened almost 50 ft due to longshore transport moving nourishment sand to them. Using equilibrium profile theory, shoreline advance due to beach nourishment minus shoreline recession caused by longshore transport, inlets that trap sand in shoals, and sea level rise is shown to equal measured shoreline change within uncertainty limits in each east coast Florida county and for the entire coastline. About 90% of beach nourishment sand remains on profiles in the active littoral zone. Shoreline advance produced by beach nourishment has been eight times greater than the magnitude of the recession caused by sea level rise from 1970-2017. If beach nourishment sand is placed along this coast at the rate of the past 40 years, the shoreline will be wider in 2100 than in 2018 for all sea-levelrise scenarios of the Intergovernmental Panel on Climate Change (IPCC). Increased beach width since 1970 has produced significant benefits by reducing infrastructure storm damage and greatly increasing beach tourism.

Salt marshes adjustment to anthropogenic pressures and sea-level rise

2021 ◽  
Author(s):  
A. Rita Carrasco ◽  
Katerina Kombiadou ◽  
Miguel Amado
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Salt Marshes ◽  
Anthropogenic Pressures ◽  
The Past ◽  
Ria Formosa ◽  
Sediment Loads ◽  
Human Interventions ◽  
South Portugal ◽  
And Sea Level

<p>It is predictable that salt marshes in regions, where sediment loads are high, should be stable against a broader range of relative sea level scenarios than those in sediment-poor systems. Despite extensive theoretical and laboratory studies, additional syntheses of marsh ‘persistence’ indicators under human interventions and accelerated sea-level rise rates are still needed. This study investigates the recent lateral changes occurring in lagoon-type marshes of the Ria Formosa lagoon (south Portugal) in the presence of human interventions and sea-level rise, to identify the major drivers for past marsh evolution and to estimate potential future trends. The conducted analysis assessed the past geomorphological adjustment based on imagery analysis and assessed its potential future adjustment to sea-level rise (~100 years) based on modelled land cover changes (by employing the SLAMM model within two sea-level rise scenarios).</p><p>Salt marshes in the Ria Formosa showed slow lateral growth rates over the last 70 years (<1 mm∙yr<sup>-1</sup>), with localized erosion along the main navigable channels associated with dredging activities. Higher change rates were noted near the inlets, with stronger progradation near the natural inlets of the system, fed by sediment influx pulses. Any potential influence of sea-level increase to an intensification of marsh-edge erosion in the past, could not be distinguished from human-induced pressures in the area. No significant sediment was exchanged between the salt marshes and tidal flats, and no self-organization pattern between them was observed in past. The related analysis showed that landcover changes in the salt marsh areas are likely to be more prominent in the future. The obtained results showed evidence of non-linearity in marsh response to high sea-level rise rates, which could indicate to the presence of critical thresholds and potential negative feedbacks within the system, with significant implications to marsh resilience.</p>

scholarly journals Decadal trends in beach morphology on the east coast of South Africa and likely causative factors

2012 ◽  
Vol 12 (8) ◽  
pp. 2515-2527 ◽  
Author(s):  
S. Corbella ◽  
D. D. Stretch
Keyword(s):  
South Africa ◽  
Sea Level Rise ◽  
Sea Level ◽  
East Coast ◽  
Storm Event ◽  
Wave Direction ◽  
Peak Period ◽  
Beach Morphology ◽  
Shoreline Changes ◽  
Causative Factors

Abstract. Sandy shorelines are dynamic with constant changes that can cause hazards in developed areas. The causes of change may be either natural or anthropogenic. This paper evaluates evidence for shoreline changes and their causative factors using a case study on the east coast of South Africa. Beach morphology trends were found to be location-specific, but overall the beaches show a receding trend. It was hypothesized that wave, tide, sea level and wind trends as well as anthropogenic influences are causative factors, and their contributions to shoreline changes were evaluated. Maximum significant wave heights, average wave direction, peak period and storm event frequencies all show weak increasing trends, but only the increases in peak period and wave direction are statistically significant. The chronic beach erosion cannot be attributed to wave climate changes since they are still too small to explain the observations. Instead, the impacts of sea level rise and reductions in the supply of beach sediments are suggested as the main causative factors. The analysis also identifies a trend in the frequency of severe erosion events due to storms that coincide with a 4.5-yr extreme tide cycle, which demonstrates the potential impact of future sea level rise.

scholarly journals Monitoring and predicting the shoreline change in Can Gio area in condition of the sea level rise

2014 ◽  
Vol 17 (3) ◽  
pp. 45-53
Author(s):  
Vinh Trong Bui ◽  
Tin Trung Huynh ◽  
Trinh Nguyen Doan Le ◽  
Hoang Minh Ly ◽  
Phong Thanh Le ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Satellite Image ◽  
River Mouth ◽  
Shoreline Change ◽  
Beach Erosion ◽  
Surface Erosion ◽  
Coastal Morphology ◽  
Shoreline Changes ◽  
Seasonal Movement

Locating on the domestic and international navigation routes (Long Tau-Tac Dinh Cau route, Soai Rap route) the Can Gio area is impacted by waterway traffic activities. The seasonal movement of sand bars on the Can Gio is significantly impacted by hydrodynamic of the river mouth. With the important roles of the area, the authors consider the coastal morphology processes under the hydrodynamic. In this paper, the authors has inherited previous studies combined the satellite image analysis to detect the shoreline changes from 1973 to 2013. Besides, numerical modeling was also applied to predict the shoreline changes under impacts of the sea level rise. Results show that, the Can Gio shoreline prolonging from Can Thanh to Dong Hoa is seriously eroded, with average of 7-10 m/year, maximum to 15 m/year. It is found that, beach erosion at Can Gio is a kind of surface erosion impacted by human trigger (shrimp ponds, beach encroachment…). In addition, natural factors (wave, long-shore current, littoral materials) also contribute to increase the erosion rate. Predicted results with sea level rise scenarios show that, the Dong Hoa and Can Thanh will be seriously eroded while the 30-4 beach will be annually deposited.

scholarly journals COMBINING COASTAL DESIGN-FLOOD ELEVATIONS AND SEA LEVEL RISE PROJECTIONS

2012 ◽  
Vol 1 (33) ◽  
pp. 26
Author(s):  
James Houston
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Design Consideration ◽  
Design Flood ◽  
Intergovernmental Panel ◽  
Flood Level ◽  
Rising Sea Level ◽  
And Sea Level

Design-flood elevations with associated exceedance probabilities are often determined for coastal projects. Rising sea level introduces another design consideration that needs to be combined with the design-flood level. However, most sea level projections do not have exceedance probabilities that can be used in conjunction with the design flood to obtain total flood elevations with exceedance probabilities. This paper shows how to combine design-flood elevations with sea level rise projections that have exceedance probabilities, such as those of the Intergovernmental Panel for Climate Change (Bindoff et al 2007) or Houston (2012a), to obtain total elevations at desired exceedance probabilities over particular intervals.

scholarly journals International Law and Sea Level Rise

2019 ◽  
Vol 2 (3) ◽  
pp. 1-86
Author(s):  
Davor Vidas ◽  
David Freestone ◽  
Jane McAdam
Keyword(s):  
International Law ◽  
Sea Level Rise ◽  
Sea Level ◽  
Human Mobility ◽  
Forced Migration ◽  
Intergovernmental Panel ◽  
Biennial Conference ◽  
State Practice ◽  
Relevant Context ◽  
And Sea Level

AbstractThis issue contains the final version of the 2018 Report of the International Law Association (ILA) Committee on International Law and Sea Level Rise, as well as the related ILA Resolutions 5/2018 and 6/2018, both as adopted by the ILA at its 78th Biennial Conference, held in Sydney, Australia, 19–24 August 2018.In Part I of the Report, key information about the establishment of the Committee, its mandate and its work so far is presented. Also, the background for the establishment of the Committee is explained, drawing on: (a) conclusions of the ILA Committee on Baselines and the related ILA Resolution 1/2012; (b) scientific assessments, such as by the Intergovernmental Panel on Climate Change (IPCC), regarding on-going sea level change and projections of future rise; and (c) more broadly, scientific findings regarding the profound changes taking place in the Earth system since the mid-20th century and predictions for their acceleration in the course of the 21st century. All of this has prompted the need, and provided the Committee with the relevant context, for the study of the options and elaboration of proposals for the development of international law.Part II of the Report addresses key law of the sea issues through a study of possible impacts of sea level rise and their implications under international law regarding maritime limits lawfully determined by the coastal States, and the agreed or adjudicated maritime boundaries. This includes the study of the effects of sea level rise on the limits of maritime zones, and the analysis of the subsequently emerging State practice regarding the maintenance of their existing lawful maritime entitlements. The guiding consideration in developing the proposals and recommendations by the Committee for the interpretation and development of international law regarding the maritime limits and boundaries impacted by sea level rise has been the need to avoid uncertainty and, ultimately, facilitate orderly relations between States and contribute to the maintenance of international peace and security. A related ILA Resolution 5/2018 addresses maritime limits and boundaries impacted by sea level rise.Part III of the Report addresses international law provisions, principles and frameworks for the protection of persons displaced in the context of sea level rise. The notion of ‘human mobility’ is used as an umbrella term that refers to all relevant forms of the movement of persons and, in the context of this report, covers displacement (which is forced), migration (which is predominantly voluntary), planned relocation and evacuations (which both may be forced or voluntary). This part of the report takes the form of principles entitled the ‘Sydney Declaration of Principles on the Protection of Persons Displaced in the Context of Sea Level Rise’ with commentaries. Accordingly, ILA Resolution 6/2018, which also contains the Sydney Declaration of Principles, addresses the protection of persons displaced in the context of sea level rise and contains recommendations by the Committee to this effect.

scholarly journals CENTURY-SCALE SHORELINE CHANGES OF FIVE BEACHES IN JAPAN

2012 ◽  
Vol 1 (33) ◽  
pp. 35
Author(s):  
Jun Yoshida ◽  
Keiko Udo ◽  
Yuriko Takeda ◽  
Akira Mano
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Human Activities ◽  
Coastal Erosion ◽  
Japan Sea ◽  
Shoreline Change ◽  
Beach Erosion ◽  
Sea Temperature ◽  
Shoreline Changes ◽  
The Future

Coastal erosion caused by sea level rise is a serious problem for people all over the world. Global sea level will rise from 0.18 to 0.59 m (IPCC, 2007). Along the coasts in Japan, sea level will rise from 0.09 to 0.27 m by the end of this century. The future estimation considers only thermal expansion due to rising sea temperature caused by global warming. However, considering the contribution of scale-down of Greenland and Antarctic ice sheet, there is potential of the increase in the rate of sea level rise. There are few studies which evaluate impacts of the future beach erosion on society by comparing with the past shoreline change resulting from natural forces and human activities. This study evaluates the long-term shoreline changes due to natural forces and human activities by using old maps. Shoreline changes were influenced by natural forces from 1900 to 1950 and were influenced by human activities from 1950 to 1990. Shoreline changes showed that the changes tended to be stable after 1990, and coastal erosion due to climate change would likely become obvious in the future.

scholarly journals SHORELINE RESPONSE TO FUTURE SEA LEVEL RISE

2018 ◽  
pp. 60
Author(s):  
James Houston
Keyword(s):  
United States ◽  
The Netherlands ◽  
Sea Level Rise ◽  
Sea Level ◽  
West Coast ◽  
Beach Nourishment ◽  
Shoreline Change ◽  
Shoreline Development ◽  
Central Coast

Florida, United States, has shoreline change measurements starting in the 1800s with spacing of about every 300 m. In addition, due to extensive shoreline development and tourism, processes causing shoreline change have been studied extensively. The 1160-km east and 275-km southwest shorelines advanced seaward on average from the 1800s even before widespread beach nourishment and despite sea level rise. Shoreline advance despite sea level rise has been noted along other coasts such as the Netherlands central coast (Stive and de Vriend, 1995). In contrast, the 335-km Florida west coast retreated landward on average almost 30 m from 1867 to 2015.

scholarly journals Beach Nourishment as an Adaptation to Future Sandy Beach Loss Owing to Sea-Level Rise in Thailand

2020 ◽  
Vol 8 (9) ◽  
pp. 659
Author(s):  
Chatuphorn Somphong ◽  
Keiko Udo ◽  
Sompratana Ritphring ◽  
Hiroaki Shirakawa
Keyword(s):  
Particle Size ◽  
Sea Level Rise ◽  
Sea Level ◽  
Sandy Beach ◽  
Beach Nourishment ◽  
Sandy Beaches ◽  
Decision Makers ◽  
Intergovernmental Panel ◽  
Bruun Rule ◽  
The Cost

A recent study suggested that significant beach loss may take place on the coasts of Thailand by the end of the 21st century as per projections of sea-level rise by the Intergovernmental Panel on Climate Change (IPCC). The present study adapts a framework and provides broad estimations for sand volumes and costs required to apply beach nourishment to each coastal zone in Thailand using a technique based on the Bruun rule assumption. Results indicate that a minimum of USD 2981 million (the best scenario) to a maximum of USD 11,409 million (the worst scenario) would be required to maintain all sandy beaches at their present width. Further, the effect of filling particle size on beach nourishment was analyzed in this study. The cost of beach nourishment ranges between USD 1983 and 14,208 million when considering filling particle size diameters of 0.5 and 0.2 mm. A zonal sand volume map for all 51 sandy beach zones in Thailand was created for use as an overview to help decision makers develop a more feasible adaptation plan to deal with the future sea-level rise for Thailand.

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