Towards Predicting Street-Level Inundation: using Operational Forecast Modeling Techniques during 2011 Hurricane Irene

Storm surge-induced coastal inundation poses numerous personal, commercial, industrial, and sociopolitical challenges for society. Flooding can be caused by the combination of storm surge and river-induced inland flooding in many locations throughout the coastal plain. The cross-disciplinary nature of the hydrodynamics involved (hydraulics, oceanography, and hydrology), coupled with the complexity of the atmospheric forcing, makes a numerical model the best approach for a comprehensive study of the dynamics of coastal inundation. This study builds upon the lessons learned from forecast modeling experiences during 2011 Hurricane Irene in Tidewater Virginia, to ascertain the most effective way to approach predicting street-level inundation. During the storm event, a large-scale ocean model (SCHISM) was provided atmospheric forcing from the National Oceanic and Atmospheric Administration’s Global Forecast System, updated every 6 hours to simulate 9 separate 30-hour simulations, which were provided to emergency managers and the National Weather Service in Wakefield, VA. Forecast water level predictions were evaluated at 5 stations near the Hampton Roads region in the Lower Chesapeake Bay to yield an aggregate RMSE=19.9 cm. To accurately predict street-level inundation, water elevations at key points near the mouths of vulnerable tributaries can be used to drive a separate street-level high-resolution sub-grid model (UnTRIM) to simulate localized flooding events on the scale of 5-meter resolution. To this end, high-resolution Digital Elevation Models including building and roadway infrastructure were developed from Lidar-derived topography for the Hampton Roads Region of Virginia, and used to accurately predict flooding in low-lying areas of the Cities of Norfolk, Portsmouth, and Chesapeake along the Elizabeth and Lafayette Rivers. Additionally, grids were prepared for the City of Virginia Beach along the Lynnhaven River, and along Hampton, York, and Poquoson along the Back River. Tropical storm surge flood heights were validated via temporal comparison with water level observations from NOAA, the USGS, and NASA; aggregated to an average RMSE=0.18 cm. Spatial extent of flooding was evaluated using USGS data retrieved from high water marks and from rapid deployment overland water level gauges during Hurricane Irene to reveal favorable agreement with the model’s inundation predictions

Statistical Methods for Detecting Ichthyoplankton Density Patterns that Influence Entrainment Mortality

Samples of drifting American shad eggs were collected at two transects in the Savannah River near industrial water intakes. At each transect the river was divided into four sectors that were sampled at two hour intervals over a 24 hour period. The actual risk of entrainment was approximately 35-50% lower that if the shad eggs were uniformly distributed, and the risk of entrainment was lower at one intake than the other

Effects of Tidal Flooding on Estuarine Biogeochemistry: Quantifying Flood-Driven Nitrogen Inputs in an Urban, Lower Chesapeake Bay Sub-Tributary

Sea level rise has increased the frequency of tidal flooding even without accompanying precipitation in many coastal areas worldwide. As the tide rises, inundates the landscape, and then recedes, it can transport organic and inorganic matter between terrestrial systems and adjacent aquatic environments. However, the chemical and biological effects of tidal flooding on urban estuarine systems remain poorly constrained. Here, we provide the first extensive quantification of floodwater nutrient concentrations during a tidal flooding event and estimate the nitrogen (N) loading to the Lafayette River, an urban tidal sub-tributary of the lower Chesapeake Bay (USA). To enable the scale of synoptic sampling necessary to accomplish this, we trained citizen-scientist volunteers to collect 190 flood water samples during a perigean spring tide to measure total dissolved N (TDN), dissolved inorganic N (DIN) and phosphate concentrations, and Enterococcus abundance from the retreating ebb tide while using a phone application to measure the extent of tidal inundation. Almost 95% of Enterococcus results had concentrations that exceeded the standard established for recreational waters (104 MPN 100 mL−1). Floodwater dissolved nutrient concentrations were higher than concentrations measured in natural estuarine waters, suggesting floodwater as a source of dissolved nutrients to the estuary. However, only DIN concentrations were statistically higher in floodwater samples than in the estuary. Using a hydrodynamic model to calculate the volume of water inundating the landscape, and the differences between the median DIN concentrations in floodwaters and the estuary, we estimate that 1,145 kg of DIN entered the Lafayette River during this single, blue sky, tidal flooding event. This amount exceeds the annual N load allocation for overland flow established by federal regulations for this segment of the Chesapeake Bay by 30%. Because tidal flooding is projected to increase in the future as sea levels continue to rise, it is crucial we quantify nutrient loading from tidal flooding in order to set realistic water quality restoration targets for tidally influenced water bodies

Effects of tidal flooding on estuarine biogeochemistry: Quantifying flood-driven nitrogen inputs in an urban, lower Chesapeake Bay sub-tributary

Sea level rise has increased the frequency of tidal flooding even without accompanying precipitation in many coastal areas worldwide. As the tide rises, inundates the landscape, and then recedes, it can transport organic and inorganic matter between terrestrial systems and adjacent aquatic environments. However, the chemical and biological effects of tidal flooding on urban estuarine systems remain poorly constrained. Here, we provide the first extensive quantification of floodwater nutrient concentrations during a tidal flooding event and estimate the nitrogen (N) loading to the Lafayette River, an urban tidal sub-tributary of the lower Chesapeake Bay (USA). To enable the scale of synoptic sampling necessary to accomplish this, we trained citizen-scientist volunteers to collect 190 flood water samples during a perigean spring tide to measure total dissolved N (TDN), dissolved inorganic N (DIN) and phosphate concentrations, and Enterococcus abundance from the retreating ebb tide while using a phone application to measure the extent of tidal inundation. Almost 95% of Enterococcus results had concentrations that exceeded the standard established for recreational waters (104 MPN 100 mL−1). Floodwater dissolved nutrient concentrations were higher than concentrations measured in natural estuarine waters, suggesting floodwater as a source of dissolved nutrients to the estuary. However, only DIN concentrations were statistically higher in floodwater samples than in the estuary. Using a hydrodynamic model to calculate the volume of water inundating the landscape, and the differences between the median DIN concentrations in floodwaters and the estuary, we estimate that 1,145 kg of DIN entered the Lafayette River during this single, blue sky, tidal flooding event. This amount exceeds the annual N load allocation for overland flow established by federal regulations for this segment of the Chesapeake Bay by 30%. Because tidal flooding is projected to increase in the future as sea levels continue to rise, it is crucial we quantify nutrient loading from tidal flooding in order to set realistic water quality restoration targets for tidally influenced water bodies

Five Years Measuring the Muck: Evaluating Interannual Variability of Nutrient Loads from Tidal Flooding

Due to sea level rise, tidal flooding is now common in low-lying coastal systems around the world. Yet, the contribution of tidal flooding to non-point source nutrient loads and their impact on the quality of adjacent waters remains poorly constrained. Here, we quantified dissolved nutrient loading and Enterococcus abundance during annual autumnal king tides (i.e., perigean spring tides), between 2017 and 2021, in a sub-watershed of the lower Chesapeake Bay. To calculate nutrient loading from tidal flooding, we used geospatial inundation depths from a street-level hydrodynamic model to estimate floodwater volumes during each of the five sampling events and the difference between nutrient concentrations in floodwater and pre-flood measurements. Results showed that dissolved nutrient concentrations were higher in floodwaters than in estuarine waters and resulted in dissolved nitrogen and phosphorus loads that reached 58.4 × 103 kg and 14.4 × 103 kg, respectively. We compared our load estimates to the tributary-specific total and land-based federal allocations (i.e., total maximum daily loads (TMDL)) for total nitrogen (TN) and total phosphorus (TP). Even the more conservative calculations indicate that inputs of dissolved nutrients during a single tidal flooding event can exceed 100% of the annual load allocation. Additionally, more than 80% of the floodwater samples collected each year showed Enterococcus abundance that exceeded the threshold for recreational water use in Virginia (104 MPN 100 ml−1). Failing to account for non-point source loading of nutrients and contaminants from tidal flooding as sea level rises could result in worsening eutrophication and deterioration of coastal economies and the health of coastal communities around the world

Modeling Storm Surge and Inundation in Washington, DC, during Hurricane Isabel and the 1936 Potomac River Great Flood

Abstract: Washington, DC, the capital of the U.S., is located along the Upper Tidal Potomac River, where a reliable operational model is needed for making predictions of storm surge and river-induced flooding. We set up a finite volume model using a semi-implicit, Eulerian-Lagrangian scheme on a base grid (200 m) and a special feature of sub-grids (10 m), sourced with high-resolution LiDAR data and bathymetry surveys. The model domain starts at the fall line and extends 120 km downstream to Colonial Beach, VA. The model was used to simulate storm tides during the 2003 Hurricane Isabel. The water level measuring 3.1 m reached the upper tidal river in the vicinity of Washington during the peak of the storm, followed by second and third flood peaks two and four days later, resulting from river flooding coming downstream after heavy precipitation in the watershed. The modeled water level and timing were accurate in matching with the verified peak observations within 9 cm and 3 cm, and with R2 equal to 0.93 and 0.98 at the Wisconsin Avenue and Washington gauges, respectively. A simulation was also conducted for reconstructing the historical 1936 Potomac River Great Flood that inundated downtown. It was identified that the flood water, with a velocity exceeding 2.7 m/s in the downstream of Roosevelt Island, pinched through the bank northwest of East Potomac Park near DC. The modeled maximum inundation extents revealed a crescent-shaped flooding area, which was consistent with the historical surveyed flood map of the event

Integrated ocean, earth, and atmospheric observations for resilience planning in Hampton roads, Virginia

Building flood resilience in coastal communities requires a precise understanding of the temporal and spatial scales of inundation and the ability to detect and predict changes in flooding. In Hampton Roads, the Intergovernmental Pilot Project\u27s Scientific Advisory Committee recommended an integrated network of ocean, earth, and atmospheric data collection from both private and public sector organizations that engage in active scientific monitoring and observing. Since its establishment, the network has grown to include monitoring of water levels, land subsidence, wave measurements, current measurements, and atmospheric conditions. High-resolution land elevation and land cover data sets have also been developed. These products have been incorporated into a number of portals and integrated tools to help support resilience planning. Significant challenges to building the network included establishing consistent data standards across organizations to allow for the integration of the data into multiple, unique products and funding the expansion of the network components. Recommendations to the network development in Hampton Roads include the need to continue to support and expand the publicly available network of sensors; enhance integration between ocean, earth, and atmospheric networks; and improve shallow water bathymetry data used in spatial flooding models

A Case of Hemorrhagic Myositis Associated With Prophylactic Heparin Use in Dermatomyositis

Dermatomyositis (DM) is a rare systemic autoimmune disease that is associated with inflammation of the skin and muscles. It typically presents with weakness of the proximal muscles along with characteristic skin lesions such as Gottron\u27s papules and heliotrope rash. One of the most feared complications of this disease is the appearance of spontaneous hemorrhagic myositis, as most reported cases are fatal. The mechanism or risk factors of this condition have not been elucidated; however, prophylactic anticoagulation has been correlated with it in previous case reports, although idiopathic hemorrhagic myositis may also be present. We present a case of spontaneous intramuscular hemorrhage (SIH) in a recently diagnosed DM patient. A 59-year-old Hispanic male with a medical history of recently diagnosed prostate cancer and DM presented to the emergency department (ED) due to worsening anemia. His previous hemoglobin (Hgb) was 9 g/dl, but repeated laboratory tests revealed a level of 6.5 g/dl and later 5.5 g/dl at the ED. On admission, the patient was afebrile, tachycardic, and normotensive, with no overt sign of gastrointestinal bleeding. The physical exam revealed an ecchymosis on the right medial aspect of the thigh, and a digital rectal exam was negative. Computer tomography (CT) of the abdomen and pelvis without contrast was ordered due to suspicion of a retroperitoneal hematoma, revealing an interval development of a right groin complex fluid collection of up to 6 cm, concerning a possible hematoma. The patient did not have any previous vascular procedures in the area but was exposed to deep vein thrombosis (DVT) prophylaxis during the previous admission. Vascular surgery was consulted, and the recommendation was made to proceed with conservative management. On the third day, the patient developed new-onset, left-sided pleuritic chest pain. Upon examination, significant swelling and tenderness were noted in his left pectoral region, which was not present on admission. A CT chest without contrast was ordered due to concerns of underlying hematomas, revealing bilateral thickening of the pectoralis muscles, more on the right side, with a fluid collection of 2.5 cm × 1.3 cm. In addition, there was thickening of the right lateral chest wall muscles in the posterior right trapezius or supraspinatus muscles, most likely from intramuscular hemorrhage. The patient was transferred to the step-down unit for close monitoring. Conservative management was continued with as-needed transfusions for three days until hemoglobin stabilized at 9.8 mg/dL. Once stable, the patient was resumed on steroids and immunosuppressive therapy with posterior resolution of the SIH. SIH has been reported in DM, particularly more prominent in those with anti-MDA-5 antibodies. A case series and literature review showed 60.9% mortality within six months in those presenting with SIH, with a poorer prognosis (80% mortality) in those with deep muscle bleeding versus superficial (25%). There is currently no consensus on the treatment approach, and arterial embolization has not been proven effective. In our patient, conservative management with close surveillance and frequent transfusions helped achieve hemodynamic stability. Clinicians should be more aware of these rare but life-threatening complications in patients presenting with DM

StormSense: A New Integrated Network of IoT Water Level Sensors in the Smart Cities of Hampton Roads, VA

Propagation of cost-effective water level sensors powered through the Internet of Things (IoT) has expanded the available offerings of ingestible data streams at the disposal of modern smart cities. StormSense is an IoT-enabled inundation forecasting research initiative and an active participant in the Global City Teams Challenge, seeking to enhance flood preparedness in the smart cities of Hampton Roads, VA, for flooding resulting from storm surge, rain, and tides. In this study, we present the results of the new StormSense water level sensors to help establish the “regional resilience monitoring network” noted as a key recommendation from the Intergovernmental Pilot Project. To accomplish this, the Commonwealth Center for Recurrent Flooding Resiliency’s Tidewatch tidal forecast system is being used as a starting point to integrate the extant (NOAA) and new (United States Geological Survey [USGS] and StormSense) water level sensors throughout the region and demonstrate replicability of the solution across the cities of Newport News, Norfolk, and Virginia Beach within Hampton Roads, VA. StormSense’s network employed a mix of ultrasonic and radar remote sensing technologies to record water levels during 2017 Hurricanes Jose and Maria. These data were used to validate the inundation predictions of a street level hydrodynamic model (5-m resolution), whereas the water levels from the sensors and the model were concomitantly validated by a temporary water level sensor deployed by the USGS in the Hague and crowd-sourced GPS maximum flooding extent observations from the sea level rise app, developed in Norfolk, VA