Since 2015, NHERI, or the Natural Hazards Engineering Research Infrastructure, began research operations supported by the United States National Science Foundation (NSF) as a distributed, multi-user national facility that provides the natural hazards research community with access to a powerful research infrastructure. NHERI is comprised of separate research infrastructure awards for a Network Coordination Office (NCO), Cyberinfrastructure, a Computational Modeling and Simulation Center, eight Experimental Facilities, and CONVERGE (an initiative to advance social sciences and interdisciplinary research). Awards made for NHERI contribute to NSF's role in the National Earthquake Hazards Reduction Program and the National Windstorm Impact Reduction Program of the United States. The mission of NHERI is to provide the earthquake, wind, coastal engineering, and social sciences communities with access to research infrastructure, education, and community outreach activities focused on improving the resilience and sustainability of the civil infrastructure against earthquakes, windstorms, and associated natural events such as tsunami and coastal storm surge. In this paper, the role and key NHERI activities are described for the NCO, which is led by Purdue University, along with partner institutions—the University of Texas at San Antonio, North Carolina State University, Texas Tech University, the U.S. Naval Research Laboratory, and the University of Hawaii at Manoa. The NHERI NCO serves as a focal point and leader of a multi-hazards research community, and maintains a community-based NHERI science plan. It manages scheduling for partner NHERI Experimental Facilities and coordinates all components to ensure effective and fair governance, efficient testing, and user support within a safe environment. Another important role of the NCO is to lead NHERI-wide educational and outreach activities: the network facilitates educational experiences ranging from summer programs for undergraduates to workshops for post-docs and early-career faculty that also both involve development of K-12 lesson plans. The NCO works to develop strategic national and international partnerships and to coordinate NHERI activities with other awardee components to form a cohesive and fully-integrated global natural hazards engineering research infrastructure that fosters collaboration in new ways.

This study presents a fully coupled numerical approach to study wave energy converters interaction with water waves. The open-source Smoothed Particle Hydrodynamics model GPUSPH is used to resolve wave dynamics and compute the hydrodynamic force on wave energy converters. The dynamics of wave energy converter is computed by the open-source physics engine, Project Chrono. The capability of the coupled numerical model to handle wave-body interaction is validated by considering a floating body in still water. The results show that the coupled model correctly predicts the balance between the floating body weight and the buoyancy force. Furthermore, the effectiveness of density diffusion method in reducing acoustic noise in a weakly compressible SPH model is also justified. In addition, the model is validated by laboratory experiment on floating body interaction with nonlinear wave packet. The model is then applied to simulate two types of wave energy converters. We conduct a thorough study of GPUSPH modeling of surface-piercing oscillating wave surge converter under waves. GPUSPH accurately predicts both wave gauge measurements and the device rotation as recorded in the laboratory. By virtue of the Project Chrono library we examine the power take-off scenario of the oscillating wave surge converter by introducing kinematic constraint into the system. The device performance under storm condition is further examined. We further present and simulate a conceptualized catenary mooring wave energy converter device, CSI-Device, under real sea states. We not only examine the interaction of CSI-Device with waves, but also we obtain the mooring force on the device that can facilitate the design of wave energy converters. We show that to maximize the energy extraction, it is important to design the device to have a natural frequency similar to the wave period of deployment site to maximize the swing motion of the pendulum. Finally the interaction of CSI-Device under different sea states with both relatively small and large wave heights are evaluated by placing the device in a directional spectral wave basin. Overall, this study shows that the open-source model GPUSPH is an efficient tool for modeling wave energy conversion devices in directional nonlinear sea states.

North Carolina and Florida are likely the only two states on the US east coast that have practical access to energy extraction from the Gulf Stream. After leaving the Florida Straits, the Gulf Stream in the region offshore of Cape Hatteras, NC exhibits the least variability in position of any location on the east coast, while simultaneously being closest to land. Gulf Stream current speeds exceed 2 m/s. These important characteristics have made this area the focus of observations and regional model estimates to quantify the hydrokinetic energy that may be available from the Gulf Stream for the state of North Carolina.Three types of observations to quantify the energy resource off NC began in 2013. A 150 kHz Acoustic Doppler Current Profiler ( ADCP) was moored on the 225-m isobath at the location estimated to be best for energy extraction, and recovered after two consecutive nine-and ten-month deployments, respectively. Another ADCP was moored in nearly the same location to continue observations, and will be retrieved in August 2015. Currents from the first deployment averaged 1.15 m/s, and the power density was 779 W/m(2) at a depth of 30m over the 9-month duration. Significant variability in current speed, and thus power, occurred over the deployment period. Additionally, current measurements from a vessel mounted 300 kHz ADCP were made from water depths of 100m to 1000 m on a cross-isobath transect that passed over the location of the ADCP mooring. Currents measured from the vessel compare favorably with those from the moored 150 kHz ADCP in both magnitude and direction, and provide valuable information about the spatial variability of the current and its dependence on depth.In 2013, a coastal ocean radar ( Codar) was added to an existing radar network that had been measuring ocean surface currents for more than a decade in the region to expand coverage over the entire study area. The radar current measurements provide consistent spatial and temporal coverage throughout the Gulf Stream cyclonic shear zone, and are being used to measure the variability in Gulf Stream position off of Cape Hatteras, NC.One method being developed using measurements from individual radars assumes the landward Gulf Stream front lies along selected maxima in the radial current shears chosen for consistency over the time period sampled, and magnitude. The locations where the Gulf Stream first enters and exits the radar coverage area are apparent in the large radial speeds measured by the radar, and the width and variability of the Gulf Stream cyclonic shear zone is estimated using maxima in velocity and velocity shears.Favorable comparisons between the three current observations will provide confidence that power estimates can be extrapolated from the radar surface currents alone over long time periods when ADCP information may not be available. Finally, observations are being compared with a regional specific Mid-Atlantic Bight and South Atlantic Bight ( MABSAB) Model. Moored ADCP current measurements compared favorably with the model, demonstrating the skill of the model for power estimates in this area. Averaged current measurements 30 m below the surface from the ADCP mooring made between August 2013 - April 2014 and model estimates at the same location were nearly identical, both having average current speeds of 1.15 m/s. The model is more conservative than the observations with respect to higher frequency fluctuations in speed and direction.

Christi Bay is a relatively flat, shallow, wind-driven system with an average depth of 3–4 m and a mean tidal range of 0.3 m. It is completely mixed most of the time, and as a result, depth-averaged models have, historically, been applied for hydrodynamic characterization supporting regulatory decisions on Texas coastal management. The bay is highly stratified during transitory periods of the summer with low wind conditions. This has important implications on sediment transport, nutrient cycling, and water quality-related issues, including hypoxia which is a key water quality concern for the bay. Detailed hydrodynamic characterization of the bay during the summer months included analysis of simulation results of 2-D hydrodynamic model and high-frequency (HF) in situ observations. The HF radar system resolved surface currents, whereas an acoustic Doppler current profiler (ADCP) measured current at different depths of the water column. The developed model successfully captured water surface elevation variation at the mouth of the bay (i.e., onshore boundary of the Gulf of Mexico) and at times within the bay. However, large discrepancies exist between model-computed depth-averaged water currents and observed surface currents. These discrepancies suggested the presence of a vertical gradient in the current structure which was further substantiated by the observed bi-directional current movement within the water column. In addition, observed vertical density gradients proved that the water column was stratified. Under this condition, the bottom layer became hypoxic due to inadequate mixing with the aerated surface water. Understanding the disparities between observations and model predictions provides critical insights about hydrodynamics and physical processes controlling water quality.

The upper Texas coast has been severely eroded and beach erosion is going on. It is not extreme comparing past one but its strength is still strong by a magnitude. There are some methods and numbers to determine stability of beach by historical beach observation but they are evaluated only for a certain location. It may not be available in the places which have rare observation data such as the upper Texas coast. The study focused on factors to determine the stability of beach against beach erosion. The pattern recognition of neural network was applied to classification of the factors such as beach width, dune height from field observed data.

Smooth Particle Hydrodynamics is a Lagrangian meshless numerical method with substantially improved capabilities in simulation of both fluid dynamics and solid mechanics due to its meshless nature. GPUSPH is an implementation of Smoothed Particle Hydrodynamics (SPH) on Nvidia CUDA-enabled (graphics) cards. In this paper the GPUSPH is applied to runup and overtopping applications and compared with experimental results from Roos and Battjes for a plane slope and Oaks, Edge and Lynett for complex bathymetry representing a complex levee transition. Results for both models show good comparison with experimental data and suggest GPUSPH as a reasonable tool for complex runup and overtopping problems.

The breakwater at Cherbourg, France, was constructed over nearly a century, although the conception began with the desire of Louis XIV to provide a strategic position in the English Channel for the French Navy in 1750. The original concept employed a caissontype structure filled with stone. Problems with materials, labor and finances proved this not to be constructable and the long-term solution of a rubble mound detached breakwater was developed. The structure was competed in 1850. No significant changes to the final design have been made and only limited maintenance is required.

An analysis of potential flooding by storm surge and wave run-up and overtopping can be used to evaluate protection afforded by the existing storm protection system. The analysis procedure can also be used to evaluate various protection alternatives for providing typhoon flood protection. To determine risk, the storm surges for both historical and hypothetical are compiled with tide conditions to represent high, slack and low water for neap, spring and mid range tides to use with the statistical procedure known as the Empirical Simulations Technique (EST). The EST uses the historic and hypothetical events to generate a large population of life-cycle databases that are used to compute mean value maximum storm surge elevation frequency relationships. The frequency-of-occurrence relationship is determined for all relevant locations along the shoreline at appropriate locations to identify the effect using the Empirical Storm Simulation (EST). To assist with understanding the process, an example is presented for a study of storm surge analysis for Freeport, Texas. This location is in the Gulf of Mexico and is subject to hurricanes and other tropical storms that approach from the Atlantic Ocean.

Coastal regions are continually plagued by high water levels induced by river flooding or hurricane-induced storm surge. As with any protective structure, it is essential to understand potential problematic locations that could result in structural failure and devastating loss. Common coastal protective systems are composed of floodwalls and levees, for each of which practiced methodologies have been used to estimate their performance under design conditions. Methodologies concerning spatial variability are limited, however, and transitions where earthen levees merge with floodwalls are considered areas vulnerable to erosion and possible breaching. Physical modeling of a levee transition is undertaken in a three-dimensional wave basin to evaluate this hypothesis, and the detailed results of this assessment are presented in this paper. From the physical model testing, analysis of the data reveals that overtopping rates tend to be larger immediately near the transition than away from it. The run-up values and floodwall wave heights tend to show potential problematic areas and mimic the variation of overtopping along the levee transition. Under the design conditions tested, extreme overtopping conditions and associated water level values indicate that for the structure to sustain the hydraulic conditions, it must be well armored. It is shown that the variation of the still water level plays the largest role in the magnitude of the measured values, and increasing the peak wave period and wave heights also yields greater overtopping and water levels at the structure. This study highlights the need to understand specific spatial variability along coastal protective systems, and provides a better understanding of the mechanisms affecting overtopping for the specific structure tested. DOI: 10.1061/(ASCE)WW.1943-5460.0000103. (C) 2012 American Society of Civil Engineers.

Hurricane Ike was a large storm as it crossed the Gulf of Mexico. When it entered into Texas it caused a storm surge of up to 4 m and substantial waves with high winds represented by a Category 2 hurricane. The storm caused extensive flooding and erosion which led to significant property damage on Boliver Peninsula and on Galveston Island. COPRI (Coasts, Oceans, Ports and Rivers Institute) of the ASCE (American Society of Civil Engineers) sponsored a team of engineers and scientists to observe the coast and collect perishable data approximately one month after the storm. One of the main conclusions from the inspection of buildings was that elevation was a key determinant for survival. Members of the team returned for another visit approximately one year later to observe how the recovery had progressed. Those observations show some redevelopment but also some serious flaws in the coastal management implementation.

This paper summarizes the findings of an ASCE/COPRI team assembled to investigate the coastal impacts of the magnitude 8.8 Chilean earthquake and tsunami of February 27, 2010. The visit was made six weeks after the event, and included 6 days in the field. Observations included port/harbor pile-supported structures, breakwaters and sea walls, coastal zone damage, and other damage, including damage and observations associated with the tsunami. Ten sites were investigated: Talcahuano, San Vincente, Dichato, Port of Lirquen, Port of Coronel, Isla Santa Maria, Punta Tumbes, Port of Valparaiso, and Port of San Antonio. Coastal zone damage was assessed on the Isla Santa Maria, and the Chilean mainland at Talcahuano, Dichato, and Punta Tumbes. Port facilities were assessed for structural, geotechnical, and tsunami related damage. The team also visited with local universities in Concepcion, Valparaiso, and Santiago and met with the Ministry of Public Works.

Tens of millions of people around the world are already exposed to coastal flooding from tropical cyclones. Global warming has the potential to increase hurricane flooding, both by hurricane intensification and by sea level rise. In this paper, the impact of hurricane intensification and sea level rise are evaluated using hydrodynamic surge models and by considering the future climate projections of the Intergovernmental Panel on Climate Change. For the Corpus Christi, Texas, United States study region, mean projections indicate hurricane flood elevation (meteorologically generated storm surge plus sea level rise) will, on average, rise by 0.3 m by the 2030s and by 0.8 m by the 2080s. For catastrophic-type hurricane surge events, flood elevations are projected to rise by as much as 0.5 m and 1.8 m by the 2030s and 2080s, respectively.

The oceans' systems offer significant potential for electrical power generation for hydrokinetic, ocean current and ocean thermal energy. Currently, the technologic readiness is premature for implementation on a grid scale. There has been limited testing of tidal and wave devices in the US on the east and west coasts. However no full-scale field tests for ocean current have been conducted. There is ample opportunity for crosscutting, multidisciplinary research and development to bring ocean energy to the grid. The North Carolina Legislature has taken the initiative to create the opportunity for exploring renewable ocean energy for the mid-Atlantic region and specifically for the State by funding a significant research program primarily directed at the technology.