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Title: Coastal Flooding and Inundation and Inland Flooding due to Downstream Blocking
Extreme atmospheric wind and precipitation events have created extensive multiscale coastal, inland, and upland flooding in United States (U.S.) coastal states over recent decades, some of which takes days to hours to develop, while others can take only several tens of minutes and inundate a large area within a short period of time, thus being laterally explosive. However, their existence has not yet been fully recognized, and the fluid dynamics and the wide spectrum of spatial and temporal scales of these types of events are not yet well understood nor have they been mathematically modeled. If present-day outlooks of more frequent and intense precipitation events in the future are accurate, these coastal, inland and upland flood events, such as those due to Hurricanes Joaquin (2015), Matthew (2016), Harvey (2017) and Irma (2017), will continue to increase in the future. However, the question arises as to whether there has been a well-documented example of this kind of coastal, inland and upland flooding in the past? In addition, if so, are any lessons learned for the future? The short answer is “no”. Fortunately, there are data from a pair of events, several decades ago—Hurricanes Dennis and Floyd in 1999—that we can turn to for guidance in how the nonlinear, multiscale fluid physics of these types of compound hazard events manifested in the past and what they portend for the future. It is of note that fifty-six lives were lost in coastal North Carolina alone from this pair of storms. In this study, the 1999 rapid coastal and inland flooding event attributed to those two consecutive hurricanes is documented and the series of physical processes and their mechanisms are analyzed. A diagnostic assessment using data and numerical models reveals the physical mechanisms of downstream blocking that occurred. more »« less
Kim, Kyoung Yoon; Wu, Wen-Ying; Kutanoglu, Erhan; Hasenbein, John J.; Yang, Zong-Liang(
, Frontiers in Climate)
null
(Ed.)
Hurricanes often induce catastrophic flooding due to both storm surge near the coast, and pluvial and fluvial flooding further inland. In an effort to contribute to uncertainty quantification of impending flood events, we propose a probabilistic scenario generation scheme for hurricane flooding using state-of-art hydrological models to forecast both inland and coastal flooding. The hurricane scenario generation scheme incorporates locational uncertainty in hurricane landfall locations. For an impending hurricane, we develop a method to generate multiple scenarios by the predicated landfall location and adjusting corresponding meteorological characteristics such as precipitation. By combining inland and coastal flooding models, we seek to provide a comprehensive understanding of potential flood scenarios for an impending hurricane. To demonstrate the modeling approach, we use real-world data from the Southeast Texas region in our case study.
Maxwell, Justin T.; Bregy, Joshua C.; Robeson, Scott M.; Knapp, Paul A.; Soulé, Peter T.; Trouet, Valerie(
, Proceedings of the National Academy of Sciences)
The impacts of inland flooding caused by tropical cyclones (TCs), including loss of life, infrastructure disruption, and alteration of natural landscapes, have increased over recent decades. While these impacts are well documented, changes in TC precipitation extremes—the proximate cause of such inland flooding—have been more difficult to detect. Here, we present a latewood tree-ring–based record of seasonal (June 1 through October 15) TC precipitation sums (ΣTCP) from the region in North America that receives the most ΣTCP: coastal North and South Carolina. Our 319-y-long ΣTCP reconstruction reveals that ΣTCP extremes (≥0.95 quantile) have increased by 2 to 4 mm/decade since 1700 CE, with most of the increase occurring in the last 60 y. Consistent with the hypothesis that TCs are moving slower under anthropogenic climate change, we show that seasonal ΣTCP along the US East Coast are positively related to seasonal average TC duration and TC translation speed.
Floods are often associated with hurricanes making landfall. When tropical cyclones/hurricanes make landfall, they are usually accompanied by heavy rainfall and storm surges that inundate coastal areas. The worst natural disaster in the United States, in terms of loss of life and property damage, was caused by hurricane storm surges and their associated coastal flooding. To monitor coastal flooding in the areas affected by hurricanes, we used data from sensors aboard the operational Polar-orbiting and Geostationary Operational Environmental Satellites. This study aims to apply a downscaling model to recent severe coastal flooding events caused by hurricanes. To demonstrate how high-resolution 3D flood mapping can be made from moderate-resolution operational satellite observations, the downscaling model was applied to the catastrophic coastal flooding in Florida due to Hurricane Ian and in New Orleans due to Hurricanes Ida and Laura. The floodwater fraction data derived from the SNPP/NOAA-20 VIIRS (Visible Infrared Imaging Radiometer Suite) observations at the original 375 m resolution were input into the downscaling model to obtain 3D flooding information at 30 m resolution, including flooding extent, water surface level and water depth. Compared to a 2D flood extent map at the VIIRS’ original 375 m resolution, the downscaled 30 m floodwater depth maps, even when shown as 2D images, can provide more details about floodwater distribution, while 3D visualizations can demonstrate floodwater depth more clearly in relative to the terrain and provide a more direct perception of the inundation situations caused by hurricanes. The use of 3D visualization can help users clearly see floodwaters occurring over various types of terrain conditions, thus identifying a hazardous flood from non-hazardous flood types. Furthermore, 3D maps displaying floodwater depth may provide additional information for rescue efforts and damage assessments. The downscaling model can help enhance the capabilities of moderate-to-coarse resolution sensors, such as those used in operational weather satellites, flood detection and monitoring.
Tsui, Martin Tsz‐Ki; Uzun, Habibullah; Ruecker, Alexander; Majidzadeh, Hamed; Ulus, Yener; Zhang, Hongyuan; Bao, Shaowu; Blum, Joel D.; Karanfil, Tanju; Chow, Alex T.(
, Limnology and Oceanography)
Abstract
Torrential rain and extreme flooding caused by Atlantic hurricanes mobilize a large pool of organic matter (OM) from coastal forested watersheds in the southeastern United States. However, the mobilization of toxic metals such as mercury (Hg) that are associated with this vast pool of OM are rarely measured. This study aims to assess the variations of total Hg (THg) and methylmercury (MeHg) levels and the isotopic compositions of Hg in a blackwater river (Waccamaw River, SC, U.S.A.) during two recent extreme flooding events induced by Hurricane Joaquin (October 2015) and Hurricane Matthew (October 2016). We show that extreme flooding considerably increased filtered THg and MeHg concentrations associated with aromatic dissolved organic matter. During a 2‐month sampling window each year (October–November), we estimate that about 27% (2015) and 78% (2016) of the average amount of Hg deposited atmospherically during these 2 months was exported via the river. The isotopic composition of Hg in the river waters was changed only slightly by the substantial inputs of runoff from surrounding landscapes, in which mass‐dependent fractionation (as δ202Hg) decreased from −1.47 to −1.67‰ and mass‐independent fractionation (as ∆199Hg) decreased from −0.15 to −0.37‰. The slight variations in Hg isotopic composition during such extreme flooding events imply that sources of Hg in the river are nearly unchanged even under the very high wet deposition of Hg derived from the intensive rainfall. The majority of Hg exported by the river (74–85%) is estimated to have been derived from dry deposition to the watersheds. An increase in frequency and intensity of Atlantic hurricanes is expected in the next few decades due to further warming of ocean surface waters. We predict that increased hurricanes will mobilize more dry‐deposited Hg and in situ produced MeHg from these coastal watersheds where MeHg can be extensively bioaccumulated and biomagnified in the downstream aquatic food webs.
Coastal urban areas like New York City (NYC) are more vulnerable to urban pluvial flooding particularly because the rapid runoff from extreme rainfall events can be further compounded by the co-occurrence of high sea-level conditions either from tide or storm surge leading to compound flooding events. Present-day urban pluvial flooding is a significant challenge for NYC and this challenge is expected to become more severe with the greater frequency and intensity of storms and sea-level rise (SLR) in the future. In this study, we advance NYC’s assessment of present and future exposure to urban pluvial flooding through simulating various storm scenarios using a citywide hydrologic and hydraulic model. This is the first citywide analysis using NYC’s drainage models focusing on rainfall-induced flooding. We showed that the city’s stormwater system is highly vulnerable to high-intensity short-duration “cloudburst” events, with the extent and volume of flooding being the largest during these events. We further showed that rainfall events coupled with higher sea-level conditions, either from SLR or storm surge, could significantly increase the volume and extent of flooding in the city. We also assessed flood exposure in terms of the number of buildings and length of roads exposed to flooding as well as the number of the affected population. This study informs NYC’s residents of their current and future flood risk and enables the development of tailored solutions to manage increasing flood risk in the city.
Pietrafesa, Leonard J., Zhang, Hongyuan, Bao, Shaowu, Gayes, Paul T., and Hallstrom, Jason O. Coastal Flooding and Inundation and Inland Flooding due to Downstream Blocking. Retrieved from https://par.nsf.gov/biblio/10166578. Journal of Marine Science and Engineering 7.10 Web. doi:10.3390/jmse7100336.
Pietrafesa, Leonard J., Zhang, Hongyuan, Bao, Shaowu, Gayes, Paul T., & Hallstrom, Jason O. Coastal Flooding and Inundation and Inland Flooding due to Downstream Blocking. Journal of Marine Science and Engineering, 7 (10). Retrieved from https://par.nsf.gov/biblio/10166578. https://doi.org/10.3390/jmse7100336
Pietrafesa, Leonard J., Zhang, Hongyuan, Bao, Shaowu, Gayes, Paul T., and Hallstrom, Jason O.
"Coastal Flooding and Inundation and Inland Flooding due to Downstream Blocking". Journal of Marine Science and Engineering 7 (10). Country unknown/Code not available. https://doi.org/10.3390/jmse7100336.https://par.nsf.gov/biblio/10166578.
@article{osti_10166578,
place = {Country unknown/Code not available},
title = {Coastal Flooding and Inundation and Inland Flooding due to Downstream Blocking},
url = {https://par.nsf.gov/biblio/10166578},
DOI = {10.3390/jmse7100336},
abstractNote = {Extreme atmospheric wind and precipitation events have created extensive multiscale coastal, inland, and upland flooding in United States (U.S.) coastal states over recent decades, some of which takes days to hours to develop, while others can take only several tens of minutes and inundate a large area within a short period of time, thus being laterally explosive. However, their existence has not yet been fully recognized, and the fluid dynamics and the wide spectrum of spatial and temporal scales of these types of events are not yet well understood nor have they been mathematically modeled. If present-day outlooks of more frequent and intense precipitation events in the future are accurate, these coastal, inland and upland flood events, such as those due to Hurricanes Joaquin (2015), Matthew (2016), Harvey (2017) and Irma (2017), will continue to increase in the future. However, the question arises as to whether there has been a well-documented example of this kind of coastal, inland and upland flooding in the past? In addition, if so, are any lessons learned for the future? The short answer is “no”. Fortunately, there are data from a pair of events, several decades ago—Hurricanes Dennis and Floyd in 1999—that we can turn to for guidance in how the nonlinear, multiscale fluid physics of these types of compound hazard events manifested in the past and what they portend for the future. It is of note that fifty-six lives were lost in coastal North Carolina alone from this pair of storms. In this study, the 1999 rapid coastal and inland flooding event attributed to those two consecutive hurricanes is documented and the series of physical processes and their mechanisms are analyzed. A diagnostic assessment using data and numerical models reveals the physical mechanisms of downstream blocking that occurred.},
journal = {Journal of Marine Science and Engineering},
volume = {7},
number = {10},
author = {Pietrafesa, Leonard J. and Zhang, Hongyuan and Bao, Shaowu and Gayes, Paul T. and Hallstrom, Jason O.},
}
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