Storm surge flooding caused by tropical cyclones is a devastating threat to coastal regions, and this threat is growing due to sea-level rise (SLR). Therefore, accurate and rapid projection of the storm surge hazard is critical for coastal communities. This study focuses on developing a new framework that can rapidly predict storm surges under SLR scenarios for any random synthetic storms of interest and assign a probability to its likelihood. The framework leverages the Joint Probability Method with Response Surfaces (JPM-RS) for probabilistic hazard characterization, a storm surge machine learning model, and a SLR model. The JPM probabilities are based on historical tropical cyclone track observations. The storm surge machine learning model was trained based on high-fidelity storm surge simulations provided by the U.S. Army Corps of Engineers (USACE). The SLR was considered by adding the product of the normalized nonlinearity, arising from surge-SLR interaction, and the sea-level change from 1992 to the target year, where nonlinearities are based on high-fidelity storm surge simulations and subsequent analysis by USACE. In this study, this framework was applied to the Chesapeake Bay region of the U.S. and used to estimate the SLR-adjusted probabilistic tropical cyclone flood hazard in two areas: one is an urban Virginia site, and the other is a rural Maryland site. This new framework has the potential to aid in reducing future coastal storm risks in coastal communities by providing robust and rapid hazard assessment that accounts for future sea-level rise. / Master of Science / Storm surge flooding, which is the rise in sea level caused by tropical cyclones and other storms, is a devastating threat to coastal regions, and its impact is increasing due to sea-level rise (SLR). This poses a considerable risk to communities living near the coast. Therefore, it is crucial to accurately and quickly predict the potential for storm surge flooding. This study aimed to develop a new way that can rapidly estimate peak storm surges under different sea-level rise scenarios for any random synthetic storms of interest and assess the likelihood of their occurrence. The approach is based on historical tropical cyclone datasets and a machine learning model trained on high-quality simulations provided by the US Army Corps of Engineers (USACE). The study focused on the Chesapeake Bay area of the US and estimated the probabilistic tropical cyclone flood hazard in two locations, an urban site in Virginia and a rural site in Maryland. This new approach has the potential to assist in reducing coastal storm risks in vulnerable communities by providing a quick and reliable assessment of the hazard that takes into account the effects of future sea-level rise.

Gothenburg, Sweden's second-largest city, faces significant environmental challenges due to climate change and risks from rising sea levels. These challenges include eutrophication, spread of environmental toxins, invasive species, and habitat loss. Gothenburg needs more transformative responses, shifting towards adopting water environment changes rather than against it, a concept gaining global traction. This project goaling to making a climate-responsive urban planning to save Gothenburg from lost in economy, ecology, and residents' well-being due to sea level rise. The city is transitioning from a self-centered development approach to one that emphasizes functional ecosystems. This shift includes implementing a multi-scale network of blue-green infrastructures by four methods which are: 1) Improve urban water system; 2) Constructed wetland; 3) Build green road network; 4) Create shore parks for residents. These infrastructures not only maintain the city's water supply system but also create water buffer wetlands, dynamic dykes, and flood bypasses enhancing water environment control. They use low-impact ecological methods for urban runoff regulation and provide ecological and recreational spaces along city-center riverbanks, achieving efficient land use in density city center.

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Southwestern Alaska is a critically understudied region of Beringia, highlighted by the lack of paleoenvironmental reconstructions of the Yukon-Kuskokwim Delta (YK Delta). This sub-arctic region is a joint deltaic coastal lowland environment, home to 50 Yup’ik and Cup’ik communities. Anthropogenic climate change dramatically impacts the landscape. Increases in the intensity and occurrence of coastal flooding, the thaw of permafrost and tundra wildfire events have directly affected community resilience and their subsistence way of life. The YK Delta also contributes to the global atmospheric carbon budget as the region’s discontinuous permafrost thaws releasing stored carbon. These issues necessitate the filling of the regional paleoenvironmental knowledge to properly inform native populations and predict future changes to the landscape. Working with two communities on the outer YK Delta, namely, Kongiganak and Mekoryuk, this thesis presents initial paleoenvironmental studies which contribute to our understanding of the impacts of climate change on this region. The first effort documents the development of a loess plateau on the YK Delta during the Last Glacial Period (115,000 – 11,700 years ago), specifically during Marine Isotope Stage III (60,000 – 25,000 years ago), described in Chapter 2. This topic was developed from exposures at Kongiganak and Mekoryuk, and helps to refine the relative sea level history and aeolian processes of the YK Delta. Other efforts on Nunivak Island consist of preliminary results from the first late Holocene lacustrine reconstruction and the first attempt to provide context to coastal dune geomorphology, highlighted in Chapter 3. These efforts help to establish regional paleoenvironmental conditions in the late Holocene, methodology for future sampling, and provide important estimates of long-term coastal erosion.

Salt marshes are important habitats that provide many ecosystem services, but they are susceptible to the impacts of sea level rise (SLR), often resulting in emergent vegetation loss. In areas with enough sediment input, marshes can keep pace with SLR by gaining elevation or through upland migration. However, salt marshes in areas with limited sediment input, such as the Grand Bay National Estuarine Research Reserve, often cannot keep pace with sea level rise. Additionally, the rate of SLR is increasing making it more difficult for marshes to keep pace. To assess the short-term response of marsh vegetation to sea level rise, percent cover, stem density, and elevation, data from 2016 to 2020 in four different marsh elevation zones were analyzed in this study. Results demonstrated that the four marsh elevation zones are responding disparately to SLR. These findings indicate that it is imperative to implement restoration plans to account for site variability to conserve these vital habitats.

The disintegration of the Classic Maya throughout the Terminal Classic (750-900 C.E.) is a complex loss of human population that has presented many questions about climate change and its impact on humanity. With droughts proposed as a prominent cause, understanding the quality and availability of groundwater resources at the time is pivotal to further determining the spatial and temporal distributions of population deterioration. The Yucatan aquifer consists of karstic cave systems, with a small number of inland lakes, which have previously been termed closed to the aquifer. It is important to understand how both of these types of water bodies react to long- and short-term forcing mechanisms such drying climate, sea-level rise and precipitation events. Using a variety of spatial and temporal records to determine aquifer evolution, changes and connectivity throughout the Holocene it will further understanding of how the aquifer reacts to changes in climate and the implications this may have had on the Classic Maya. Four sediment cores from Pac Chen Lake and two sediment cores from Carwash Cenote were collected to investigate Holocene paleoclimatic trends on the Yucatan Peninsula in Mexico. Records of past climate, groundwater conditions and flooding history at both sites were determined through microfossil and micro X-Ray fluorescence data. In Pac Chen Lake, elevation and timing of flooding of the lake coincided with sea-level rise. Using Ti, Fe and K records to determine wet vs dry conditions, dry periods through the terminal classic coincided with other paleoclimate records, but with no evidence of draw-down within the lake. Both of these observations imply connection of the lake to the aquifer. The Cl record from Carwash was used alongside a core from the Yax Chen cave system to observe spatial and temporal potability of the aquifer. An overall freshening trend in the coastal groundwater occurred throughout the Holocene. The largest amount of this freshening transpired through the Terminal Classic. At this time, populations inland were experiencing deterioration, while coastal populations along the coast continued to survive. Comparing Cl records at various depths and distances from the coast proved that Cl is impacted by proximity to the halocline. / Thesis / Master of Science (MSc)

The escalating temperature, annual precipitation, sea level rise and carbon footprint will likely lead to an unimagined future which does not have a bright side. With the rise in carbon footprint particularly due to greenhouse gas emissions, burning of fossil fuels and change in land uses; carbon dioxide is 40% higher as compared to era before Industrial Revolution. The constant increase in temperature is melting the glaciers and increasing the sea levels. The Hudson River is estimated to rise by 1.5-2ft by 2050, directly affecting the low-lying areas of Staten Island, Brooklyn, Queens and Manhattan. Amongst the multiple coastal cities in the world, New York City is one of the most vulnerable to impacts of climate change. Surrounded by water from three sides, the impacts are disastrous with densely populated neighborhoods along the shoreline. The shoreline needs to be revitalized with the vibrancy and diversity city offers to the people. With the rise in hot summer days which are estimated to be 50 days against 18 days currently; it would generate a warmer island thereby increasing the overall energy demands. Hurricane Sandy struck the New York City in 2012 and had severe impacts which tested the limitations of the city’s planning capacities. The impact on houses, subway system, power stations and overall economy was a major setback costing USD 19 billion. The frequency of such floods and hurricanes would be higher by 2050. The research done observes the impact of climate change and develops a model for New York City’s riverfront in the Meat Packing District. Revitalizing the Gansevoort Peninsula by creating public, research and informative spaces would transform the neighborhood allowing locals and visitors to have a visionary approach for future. The strategies and research in the current project would provide an architectural response to the existing condition and a model to design a more resilient New York City for the future.

The Coastal Plain in the southern Chesapeake Bay area is becoming increasingly susceptible to nuisance flooding as a result of the combination of sea-level rise and land subsidence associated with aquifer compaction from excessive groundwater pumping. Detailed time-series of cumulative compaction data (land subsidence) from the three U.S. Geological Survey deployed extensometers in the regions, along with cyclical piezometer data, reflect the nature of the complex multi-aquifer/aquitard system in the Coastal Plain. Franklin, Virginia and Suffolk, Virginia extensometers were deactivated in 1995 and were reactivated in 2016 along with the addition of a high-sensitivity borehole extensometer in Nansemond, Virginia in collaboration with the Hampton Roads Sanitation District as a part of the Sustainable Water Initiative for Tomorrow (SWIFT). Yearly compaction rates estimated from the reactivated extensometers are -3.3 mm/year, 15.6 mm/year, and -20.7 mm/year in Franklin, Suffolk, and Nansemond, Virginia respectively. One-dimensional vertical compaction modeling is utilized to estimate the total compaction and differentiate which fine-grained confining units or aquifer interbeds are contributing most to total compaction historically and presently. Additionally, properties of the system can be estimated including the elastic specific storage of the aquitards and aquifers and the inelastic storage of the aquitards. The total cumulative change in aquifer system thickness estimated by the MODFLOW subsidence package can be compared to the observed total cumulative change in aquifer system thickness at each site for validation of hypothesis about the dynamics of the aquifer system to known changes in stress. Subsidence rates and aquifer/aquitard properties can be useful for managing and modeling the groundwater in the Coastal Plain of Virginia. / Master of Science / The Coastal Plain in the southern Chesapeake Bay area is becoming increasingly susceptible to flooding at high tides in low lying areas as a result of the combination of sea-level rise and sinking of the land surface (land subsidence) associated with aquifer compaction from excessive groundwater pumping from buried aquifers. Detailed time-series of land subsidence data from the three U.S. Geological Survey deployed extensometers in the region, along with water level data from nearby wells, reflect the nature of the complex multi-aquifer/aquitard system in the Coastal Plain. Franklin, Virginia and Suffolk, Virginia extensometers were deactivated in 1995 and were reactivated in 2016 along with the addition of a high-sensitivity borehole extensometer in Nansemond, Virginia in collaboration with the Hampton Roads Sanitation District as a part of the Sustainable Water Initiative for Tomorrow (SWIFT). Yearly land subsidence rates estimated from the reactivated extensometers are -3.3 mm/year, 15.6 mm/year, and -20.7 mm/year in Franklin, Suffolk, and Nansemond, Virginia respectively. One-dimensional vertical compaction modeling is utilized to estimate the total sinking of the land surface as well as to differentiate which fine-grained confining units or aquifer interbeds are contributing most to total subsidence historically and presently. Additionally, properties of the system can be estimated including the elastic specific storage of the aquitards and aquifers and the inelastic storage of the aquitards. The total cumulative change in aquifer system thickness estimated by the MODFLOW subsidence package can be compared to the observed total cumulative change in aquifer system thickness at each site for validation of hypothesis about the dynamic changes of the aquifer system with known changes in stress. Subsidence rates, understanding the dynamics of the aquifer system, and aquifer/aquitard properties can be useful for managing groundwater and modeling the aquifer system in the Coastal Plain of Virginia.

How can architects let their buildings interact with the water while protecting occupants from the potential danger? The two intents are very different and often compete with one, either protection or recreation, as the primary program in one project. Water draws people, everyone likes being near water. People visit waterfalls and the beach just to experience moving water, they go boating and kayaking just to be on the water. Water views and access are considered an amenity that drive up prices in buildings. Whenever possible architects should strive to connect their architecture and water and to let occupants interact with the water. However, water can be dangerous too. Overfull rivers wash away roads and cars. Floods inundate entire cities, and hurricanes devastate huge islands. In addition to catastrophic damage sea levels are rising around the world causing damage and rendering low lying land uninhabitable. Architects must protect against these dangers. If designed correctly buildings can offer shelter from storms and resist rising water of all kinds. For my thesis I decided to study how to reconcile these two conflicting approaches to water. / Master of Architecture

京都大学 / 新制・論文博士 / 博士(工学) / 乙第13491号 / 論工博第4200号 / 新制||工||1785(附属図書館) / (主査)教授 角 哲也, 准教授 Kantoush Sameh, 准教授 竹門 康弘 / 学位規則第4条第2項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM