Globally, sea levels have risen in the last century, and various projections suggest substantial increases in sea level due to climate change in this century. In Nigeria, there are no up-to-date sea level rise (SLR) assessments for the coast. Much of the Nigerian coast is low lying with the consequence that a 1 to 3 metres rise in sea level, which may result from eustatic or climate change, will have a catastrophic effect on the human activities in these regions. This study examines the consequences of continued sea level rise with a focus on erosion and inundation for the Nigerian coast and considers the coastal management practices of coastal partnerships (CPs). The Nigerian coast has been delineated according to distinct geomorphological units, which include the Barrier, Mud, Delta and Strand coasts. The Bruun model has been used to compute shoreline recession along the Nigerian coast with the exception of the Mud coast. A Geographic Information System (GIS) was used to develop inundation models and examine the impact scenarios that SLR will have on critical elements, which include land, population, economic activity (Gross Domestic Product), urban extent, agriculture and wetlands with the aid of high quality spatially disaggregated global data. A case study approach was used to assess the management practices of Pro-Natural International Nigeria; Niger Delta Wetland Centre, Niger Delta Development Commission; and Flood Erosion and Coastal Zone Management, Rivers State with the aid of a suite of systemic sustainability appraisal indices. Results indicate that shoreline recession will be mild along the coast while substantial loss due to inundation of the critical elements is expected for all the scenarios considered. The sustainability assessment indicates that the CPs did not meet the required standard for sustainability, however there was evidence of constructive management in some of them. This study has been able to provide up-to-date baseline data concerning the vulnerability of the coast to SLR for the four coastal systems in Nigeria. The coastal sustainability assessment, which is the first ever in Nigeria, reflects the need for corrective measures in the management practices of the CPs to achieve a sustainable coast in the light of coastal hazards.

Accelerating sea-level rise (SLR) poses an imminent threat to salt marshes, which sit within meters of mean sea level. In order to assess marsh vulnerability to SLR, we must first understand the fundamental processes governing marsh response to SLR. The objective of this dissertation work is to examine how marsh sedimentation and erosion affect the morphological development of marshes as sea level rises, over a broad range of spatial and temporal scales. At the smallest scale, the effects of bioturbation by Sesarma reticulatum crabs on sediment erodibility are examined using a laboratory flume. Measurements of surface elevation, erosion, and turbidity show that S. reticulatum bioturbation repackages formerly compacted sediment and deposits it above the surface, decreasing the threshold velocity for erosion and increasing eroded volume. S. reticulatum-induced sediment erosion can have broader impacts on creek development and marsh morphology. S. reticulatum has facilitated drainage network expansion in salt marshes at Sapelo Island, GA and Cape Romain, SC in response to local SLR. Burrowing by this crab directly adjacent to tidal creeks at these locations leads to rapid headward growth. The effects of site-specific conditions on creek expansion are examined through comparison of sediment properties, surface elevations, and historical rates of creek growth at each site. Results suggest that while similar processes are occurring at both locations, the higher elevation of the marsh in GA leads to greater shear strength and a larger volume of material to be eroded by creeks. These combined effects have led to slower creek growth compared to SC. At the largest spatial scale, and projecting forward over a 100-year period, a model for marsh response to SLR at the Great Marsh in Massachusetts is developed. This model takes into account limitations imposed by both low sediment availability and steep topography in the surrounding uplands. Results indicate that while the marsh may persist for several decades, it undergoes a dramatic shift in ecology and hydrology. As the rate of SLR accelerates, marsh loss increases due to the lack of sediment available for accretion and the physical barriers to migration presented by surrounding topography.

In environmental terms, New Orleans is a city that should not exist. With the Mississippi River eager to escape its engineered confinement, the topography of the city sinking slowly due to subsidence, and the steady rise of sea level partnered with wetland and coastal erosion, the future of New Orleans is wet and it is fast approaching. Initial settlers built on the naturally elevated sediment deposits of the Mississippi River, but over time and as the city grew, swamps were drained and occupation spread into lower, more saturated ground. For over two hundred years, humans have interfered with water's natural authority over this area. We have contained, diverted, drained, and regulated rivers, lakes, and swamps to maintain a constructed version of the ground plane that subverts natural processes to the regions' detriment. Plans for the future of New Orleans have been debated since Hurricane Katrina served as an expose to our synthesized and extremely fragile system. From the Dutch Dialogues, a comprehensive u an redevelopment plan, to smaller scale water management studies such as the Mirabeau Water Gardens, the drawing board has rarely been empty. Proposals have met resistance from the community, and ten years after the disaster, no coherent plan has been outlined. New Orleans isn't the only city searching for answers; delta and coastal cities the world over are recognizing the need to rethink resiliency and sustainability in light of global environmental changes. This project proposes neighborhood-scale interventions that bring previously concealed water processes to light by exhibiting them in a sustainable community-centered resource. Rather than altering existing infrastructure, this strategy would utilize current neutral ground conditions in order to take pressure off the City's drainage network. By accepting and accommodating water within the urban fabric, New Orleans can address the deficiencies in defensive water infrastructure to define a new resilience. / 0 / SPK / specialcollections@tulane.edu

While repeated transgressive and regressive sea level cycles have shaped south Florida throughout geological history, modern rates of sea level rise pose a significant risk to the structure and function of the freshwater wetland ecosystems throughout the low-lying Everglades region. Current regionally corrected sea level projections for south Florida indicate a rise of 0.42m by 2050 and 1.15m by 2100, suggesting the salinization of previously freshwater areas of the Everglades is conceivable. As freshwater areas become increasingly exposed to saltwater they experience shifts in vegetation composition, soil microbial populations, plant productivity, and physical soil properties that ultimately result in a phenomenon called peat collapse. Recent work in the Everglades has sought to further explain the mechanisms of peat collapse, however the physical changes to the peat matrix induced by saltwater intrusion are still uncertain. Moreover, the combination of physical alterations to the peat matrix associated with peat collapse and shifts in wetland salinity regimes will also likely disrupt the current carbon gas dynamics of the Everglades. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

Coastal communities along the eastern seaboard are continuously exposed to flooding and related impacts, compromising the health and safety of their residents and especially of more vulnerable older populations. In cases where structural protection and floodproofing measures may not protect households from all types of flooding, relocation may represent the most effective long-term adaptation option. However, the extent to which older residents in Hampton Roads, Virginia are exposed to such flooding is not well understood, nor are the factors influencing their relocation attitudes. Thus, the main objective of this research is to understand both the exposure to flooding and evaluate attitudes towards relocation among older residents in Hampton Roads. This study uses a mixed methods approach to analyze flood exposure and attitudes towards relocation among older adults living in this area. First, a geospatial analysis was conducted to assess the change in flood risk in Hampton Roads over a period of 60 years and exposure to older populations, aged 60 and over. Then the survey data were used to conduct a correlation analysis to examine the relationship between survey responses and respondents' willingness to consider relocation. The geospatial analysis showed that flood exposure in this area does not increase linearly with time, with several block groups experiencing accelerated levels of flood increases from 2000-2060. Most of the municipalities which experience high overlap between flood extent and older population percentages are urban and see dramatic increases in flood exposure from 2000-2060. The statistical results show that willingness to consider relocation is correlated to several variables measuring sociodemographic characteristics, place attachment, and flood exposure, and less to other considerations influencing the decision to permanently relocate. The most influential factors driving relocation attitudes are financial, where residents would consider relocation if compensated or offered similar housing elsewhere. Finally, a large proportion of respondents (40.28%) would prefer to permanently move to either a different region or different state should flooding continue in their community. The results of this study can help community leaders and policymakers to better understand the flood outcomes and assistance needs of their older populations living in flood-prone areas. / Master of Science / Coastal communities along the Eastern United States are constantly exposed to flooding and related impacts. Hampton Roads, Virginia is experiencing higher-than-average sea level rise, which is increasing flooding and its impacts. This area is also a preferred retirement region, where older populations prefer to move. Older populations are more negatively affected by these impacts due to chronic health conditions like diabetes and hypertension, which require easy access to health care services, as well as mobility constraints. The objective of this research is to identify areas within Hampton Roads that have a significant overlap between flooding and older populations and to understand what factors are affecting older residents' attitudes towards relocation. This study answers the following questions regarding the overall objective: 1) What is the exposure to coastal flooding of older populations living in urban areas in Hampton Roads? and 2) Which aspects of socioeconomic circumstances, experiences with flooding, and flood-related concerns affect attitudes about permanent relocation among older coastal residents? To answer these questions, a geospatial analysis was conducted, followed by a survey analysis. There are high levels of overlap between older populations and flooding in urban municipalities, and flood exposure is expected to dramatically increase between the years 2000 and 2060. From the survey, older respondents favor monetary incentives for relocation as opposed to other factors. The results from this study should be used by local policymakers for more well-informed decisions that incorporate community members in the planning and relocation process.

Coastal communities face threats of flooding associated with episodic storm events and high tides that are increasing in severity and frequency due to climate change and sea level rise (SLR). The Mid-Atlantic U.S. is experiencing SLR at rates faster than the global average, especially in Hampton Roads, Virginia where the rate of SLR is accelerating due to land subsidence. Adaptation plans for coastal flooding are mostly made at the municipality level, ignoring the propagation of water across its administrative boundaries. Impact assessment at the watershed scale identifies areas where municipalities will need to collaborate to mitigate the flood impact. The main purpose of this project was to evaluate the impact of flooding among watersheds in Hampton Roads and identify those most at risk that overlap one or more municipal boundary. Additionally, this research assessed the impact on land use/cover and population throughout the Hampton Roads region and within a case study watershed. To meet these objectives, we used U.S. Army Corps of Engineers 50-year floodplain and NOAA intermediate SLR scenarios for 2030, 2060, and 2090 to calculate the percent land area inundated for each watershed in Hampton Roads. Further, we assessed the flood impact on populations and specific land use/covers throughout the region for each SLR scenario, as well as within the Elizabeth River watershed. Key findings show that five watersheds will see a greater increase in inundated area than the surrounding watersheds, with two that overlap multiple municipalities. The anticipated land use impacts indicate significant inundation of land occupied by military, followed by commercial, industrial, and wetland covers both in Hampton Roads and within the Elizabeth River watershed. These findings not only highlight the need for more synchronized collaboration on adaptation between municipalities in Hampton Roads, but also provide a framework for the impact assessments in similar settings globally. / Master of Science / Coastal communities face numerous threats of flooding due to storm events and high tides. These events are becoming more frequent due to climate change and sea level rise (SLR). The Mid-Atlantic U.S. is experiencing SLR at rates faster than the global average, especially in Hampton Roads, Virginia where the rate of SLR is accelerating due to sinking land. Water movement does not recognize administrative boundaries but rather reflects physical features of the land. At the same time most plans to combat rising water levels are often made within administrative boundaries. The main objective of this research is to evaluate the flood impacts at the watershed scale and identify areas where localities will need to collaborate to reduce flood impact. This research further explores answers the following questions: 1.)Which watersheds in Hampton Roads are most prone to flooding?; and 2.) How many people will be impacted by flooding, and what kinds of land uses will be impacted? To answer these questions, we used floodplain data and SLR scenarios for 2030, 2060, and 2090 to determine land area inundated for each watershed in Hampton Roads. Further, we summarized population and land use impacts within the floodplain for the entire region, as well as within a case study of the Elizabeth River watershed in Norfolk and Portsmouth. Key findings include five watersheds that will see a greater increase in inundated area with SLR than surrounding watersheds, two of which contain multiple municipalities. Finally, we identified significant impacts for military, commercial, industrial, and wetland land covers both in Hampton Roads and within the Elizabeth River watershed.

Storm surges induced by tropical cyclones have been ravaging coastal communities worldwide, where a growing number of people reside. Tremendous life and economic losses are caused by tropical cyclones, contributing to more than half of the damages induced by natural hazards. To improve the resilience of coastal communities to surge hazards, it is of great importance to provide reliable and efficient real time forecasts of the spatiotemporal evolution of storm surge, as well as reliable predictions of the probabilistic surge hazards under future conditions. Three specific goals are addressed in this work. Studies on characterization and prediction of surge before a hurricane landfall show that a dimensionless relationship between intensity scaled surge magnitude and wind-duration scaled surge timing may effectively be used for rapid and reliable forerunner surge forecasting. Investigation of how probabilistic surge hazard changes with sea level rise (SLR) shows that the probabilistic surge with SLR can be 1.0 m larger, while different individual storm's surge with the same magnitude can be 1.5 m larger or 0.1 m smaller, indicating the importance of not relying on results from a limited number of storm surge events to assess the probabilistic surge hazard change to SLR. Finally, studying the temporal evolution of coastal flooding changes with SLR shows forerunner surge responds differently to SLR than peak surge, and that storm forward speed is a key factor determining the forerunner-SLR response. / Ph. D. / Flooding induced by tropical cyclones have been ravaging coastal communities worldwide, where a growing number of people reside. Tremendous life and economic losses are caused by tropical cyclones, contributing to more than half of the damages induced by natural hazards. To improve the resilience of coastal communities to flood hazards, it is of great importance to provide reliable and efficient real time forecasts of the flooding time series, as well as reliable predictions of the statistical flood elevation under future conditions. Three specific goals are addressed in this work. Studies on forecasting early coastal flooding show that a dimensionless relationship between storm characteristics and flood elevation may effectively be used for rapid and reliable early flood forecasting. Investigation of how statistical flood elevation changes with sea level rise show the importance of modeling the physical processes and of the storm sample size to address this issue. Finally, studying the coastal flooding time series with sea level rise shows early flooding responds differently to sea level rise, compared to maximum flooding, and that storm’s moving speed is a key factor determining flooding response to sea level rise.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Global warming will result in a sea level rise of between 0.25 and 0.82 m by 2090, as well as an increase in intensity and frequency of both extreme sea level and extreme rainfall events. In consequence, low-lying areas will be permanently inundated, extreme waves will penetrate further inland and flood intensity and frequency will increase. Estuaries are subject to the effect of both extreme sea levels and extreme floods and water levels in estuaries are expected to increase, under both open and closed conditions. As a response to expected higher flood levels, setback lines have been legislated in South Africa. For cases where a flood level study has not been undertaken, a minimum setback line at the 5 m above mean sea level (MSL) contour is prescribed in terms of the National Environmental Management Act (Act 107 of 1998). This study assessed the adequacy of the 5 m setback line, under the effects of climate change, for Great Brak estuary. Local features of the Great Brak estuary may influence flood levels. Specifically, the lagoon of the Great Brak estuary, below the N2 Bridge, is small at 1.1 x 0.7 km. Further, it is constrained at the upstream end by road and rail embankment, and on the left bank by steep slopes. A sand barrier at the mouth is at times breached, both naturally and artificially. Artificial breaching is initiated when the sand barrier is between 1.5 and 2.0 m high, or when a flood is forecast. The barrier has previously reached 2.7 m, higher than the still water level of the sea, which has not exceeded 2 m above MSL. There is a populated island about 180 m upstream of the mouth. The greater extent of the island is below 2.5 m above MSL. Mike11 software was used to generate flood levels on which the conclusions of this study are based. The study determined that the influence of the increased sea levels does not extend much beyond the N2 Bridge. This may be a peculiarity of the Great Brak estuary, due to the influence of the three bridges and the road and rail embankments. For the scenario where Mean High Water Springs coincides a with an extreme sea storm and there is a 100-year riverine flood, the flood level in the estuary is 3.16 m at the mouth, increasing to 4 m upstream of the N2 bridge. In the scenario where the barrier height was raised to 4 m above MSL, the flood levels were 4.52 m downstream of, and 5 m upstream of, the N2 Bridge. Extensive inundation of properties in the floodplain and on the Island will occur, as well as the inundation of the N2 embankment. The probability of such an extreme sea level event occurring at the same time as peak runoff of a 100-year riverine flood is unlikely. It is the conclusion of this study that, for the Great Brak River, the 5 m setback line, as prescribed, is sufficient for an extreme situation where a future 100-year flood coincides with the MHWS coincides and an extreme sea storm raising the sea level to 2.65 above current MSL. / AFRIKAANSE OPSOMMING: Aardverwarming sal lei tot 'n styging van seevlakke van tussen 0.25 en 0.82 m teen 2090, sowel as 'n toename in intensiteit en frekwensie van beide stormseevlak en reënval. Gevolglik sal laagliggende gebiede permanent oorval word, stormgolwe verder in die binneland dring en vloed intensiteit en frekwensie toeneem. Riviermondings is onderhewig aan die effek van beide hoë seevlakke en vloede. Om die negtaiewe effekte van hoër vloedvalktes te bekamp word ‘n minimum terugsetlyn van 5 m bo seevlak voorgeskryf, in terme van die Wet op Nationale Omgewingsbestuur (Wet 107 van 1998). Hierdie is van toepassing waar ‘n vloedlyn studie nie onderneem is nie. Hierdie studie beoordeel die geskiktheid van die 5 m terugsetlyn, onder die invloed van klimaatsverandering, vir Groot Brak rivier monding. Plaaslike kenmerke van die Groot Brak monding mag vloed vlakke beïnvloed. Spesifiek, die Groot Brak monding meer het ‘n oppervak van net 1,1 x 0,7 km; is in die stroomop rigting beperk deur pad en spoor walle; en word op linkeroewer deur steil hellings vesper. Die sandversperring by die word kunsmatig oopgemmak wanneer die sand versperring tussen 1,5 en 2,0 m hoog is, of wanneer 'n vloed voorspel word. Hierdie sandversperring het al voorheen 2.7 m hoogte beriek, hoër as die 2 m maksimum historiese stilwater vlak van die seë. Daar is 'n bevolkde eiland sowat 180 m stroomop van die mond. Die die eiland is meestelik onder 2.5 m bo seevlak. Mike11 sagteware is gebruik om vloed vlakke, waarop die bevindinge van hierdie studie gebaseer is, te bepaal. Hiedie studie bevind dat die effek hoër voedvlakke trek nie veel verder stroomop as die N2 brug, oontlike weens die voorkoms van die drie bruë. In die geval waar ‘n uiterste seëstorm terselfde tyd voorkon as die lente hoogwater gety endie 100 jaar river vloed, sal die watervlak in the mondingsmeer tot 3.16 m bo huidiglike seëvlak styg by die mond, en tot 4 m bo huidiglike seëvlak by die N2 brug. In die geval waar die sandversperring by the riviersmond 4 m verhoog is, sal die watervlak in the mondingsmeer tot 4.5 m bo huidiglike seëvlak styg by die mond, en tot 5 m bo huidiglike seëvlak by die N2 brug. Faktore nie in ag geneem in hierdie studie sluit in die uitwerking van die verhoogde afloop, sediment verandering en die effek van windgolwe oor die ondingsmeer. Wydverspreide vloeding van ontwikkelde areas aangrensend to vloedvlakte sal voorkom, insluitend die oorstroing van die N2 padwal. Die waarskynlikheid is klein dat ‘n uiterste seëstorm terselfde tyd voorkom as the lengte hoogwater gety en die 100 yaar rivier vloed. Dit is dus die gevolgtrekking van hierdie studie dat die 5 m terugsetlyn soos voorgeskryf, voldoende is vir Groot Brak rivier vir so ‘n uiterste geval.

The rapid development of space geodesy over the last two decades has had a profound effect on geologic studies by allowing measurements of crustal motion with sub-millimeter per year precision. The focus of this work is to better understand microplate kinematics, intraplate deformation and sea level rise in Europe by use of Global Positioning System (GPS) measurements of crustal deformation. This is accomplished in three separate studies. The first study focuses on crustal motion and sea level rise along the eastern margin of Adria. We use data from tide gauge and continuous GPS (CGPS) stations. We develop a new method to separate common-mode relative sea level from spatially variable signals. From tide gauge data, we find uniform relative sea level rise along the coast that is 2-4 times lower than the estimates for global average sea level rise. In constrast, vertical motion of coastal rocks determined by CGPS varies appreciably from an average of -1.7 ± 0.4 mm/yr in the southern Adria to 0.0 ± 0.4 mm/yr in northern Adria. The most enigmnatical result of this study is that the combination of tide gauge and CGPS data shows that absolute sea level varies in such a way that relative sea level remains constant. The second study focuses on diffuse intraplate deformation of western Eurasia measured by CGPS. We find that our preferred model involves four subplates, separated by the Pyrenees, Rhine Graben, and Trans European Suture Zone, and yields residual velocities indistinguishable from random samples. We interpret the intraplate dormation as the surface manifestation of downwelling mantle lithosphere. The final component of this work is a study of the Northern and Southern Adria microplates' internal stability and tectonic motion. Results show that both Adria microplates are kinematically distinct from one another and from the slowly converging Eurasia and Nubia plates, with implications for the dynamics of the Nubia-Eurasia plate boundary zone. We also find that internal strain within the Adria microplates is statistically insignificant. We estimate appreciable fault slip rates around the periphery of Adria, with implications for slip rates and seismic hazards associated with circum-Adria fault zones.

During 1998-2012, climate change and sea level rise (SLR) exhibit two notable features: a slowdown of global surface warming (hiatus) and a rapid SLR in the tropical western Pacific. To quantify their relationship, we analyze the long-term control simulations of 38 climate models. We find a significant and robust correlation between the east-west contrast of dynamic sea level (DSL) in the Pacific and global mean surface temperature (GST) variability on both interannual and decadal time scales. Based on linear regression of the multimodel ensemble mean, the anomalously fast SLR in the western tropical Pacific observed during 1998-2012 indicates suppression of a potential global surface warming of 0.16 degrees 0.06 degrees C. In contrast, the Pacific contributed 0.29 degrees 0.10 degrees C to the significant interannual GST increase in 1997/1998. The Pacific DSL anomalies observed in 2015 suggest that the strong El Nino in 2015/2016 could lead to a 0.21 degrees 0.07 degrees C GST jump.