Apr 06

MS / PhD Student Opportunity

I am looking for highly motivated graduate students interested in studying coastal engineering/resiliency. See the student opportunity below for additional information.

University of Georgia

MS / PhD Student Assistantship in Coastal Engineering / Resiliency

Position Description: The University of Georgia (UGA) School of Environmental, Civil, Agriculture, and Mechanical Engineering (https://engineering.uga.edu/schools/ecam) is seeking a highly-motivated MS or PhD student to begin Spring 2021. The graduate student will work under Dr. Matthew Bilskie. The general scope of work includes high-performance computational modeling of astronomic tides, hurricane storm surge, and wind-waves and their impacts on coastal systems and communities for present and future conditions (including climate change and sea level rise). Specific themes of focus for independent research include real-time hurricane storm surge forecasting; compound flood modeling (rainfall-runoff, high river flows, and coastal storm surge); event-driven and long-term barrier island evolution; unstructured mesh generation; and natural- and nature-based feature implementation and assessment.

Qualifications: Candidates should have been awarded a B.S. degree in Civil, Environmental, or Coastal Engineering or related field (M.S. is preferred for PhD students). The ideal candidate will have experience with computer programming /scripting (Matlab, Fortran, Python, R, bash scripting, etc.), the Linux command line, and GIS. Strong communication and writing skills are essential as well as the ability to work within a lab group setting. Although it is not necessary to have all of these skills at the start, the ideal candidate will have a willingness to learn from others and the motivation to self-teach skills.

Please contact Dr. Matthew Bilskie by email (click here) with the subject heading “UGA Graduate Student Inquiry – Dr. Bilskie” and provide a cover letter, CV and contact information for at least three references.

Permanent link to this article: http://www.mattbilskie.com/ms-phd-student-opportunity/

Apr 06

Publication | Coastal decision‐makers’ perspectives on updating storm surge guidance tools

D.E. DeLorme, S.H. Stephens, M.V. Bilskie, S.C. Hagen (2020). “Coastal decision-makers’ perspectives on updating storm surge guidance tools.” Journal of Contingencies and Crisis Management. Accepted 03-11.

Abstract This paper reports on the process and results of focus groups conducted as stakeholder engagement for a two‐year, marine extension agency‐sponsored interdisciplinary project in coastal Louisiana, USA. The project involved refining the topographic features (eg flood protection infrastructure) of a computational storm surge model using local knowledge of elevation data. Coastal Louisiana experiences continual changes to the built and natural environment and persistent land loss, necessitating frequent adjustments to real‐time storm surge and restoration planning models to make them more useful for decision‐makers. Stakeholder involvement ensured accurate updates to the real‐time computational system and accessible and understandable modelling results displayed by an interactive decision‐support tool. The findings provide insights and recommendations from various practitioners that are applicable to decision‐support model and tool development for coastal hazard emergency response.

Permanent link to this article: http://www.mattbilskie.com/publication-coastal-decision%e2%80%90makers-perspectives-on-updating-storm-surge-guidance-tools/

Feb 17

Publication | Unstructured finite element mesh decimation for real-time Hurricane storm surge forecasting

Bilskie, M. V., S. C. Hagen, and S. C. Medeiros (2020), Unstructured finite element mesh decimation for real-time Hurricane storm surge forecasting, Coastal Engineering, Vol. 156. https://doi.org/10.1016/j.coastaleng.2019.103622

Abstract A previously developed research-grade (e.g. high-resolution) unstructured mesh of the northern Gulf of Mexico (named NGOM3) is optimized to produce a computationally efficient forecast-grade mesh for deployment in a real-time hurricane storm surge early warning system. The real-time mesh is developed from a mesh decimation scheme with focus on the coastal floodplain. The mesh decimation scheme reduces mesh nodes and elements from the research-grade mesh while preserving the representation of the bare-earth topography. The resulting real-time unstructured mesh (named NGOM-RT) contains 64% less mesh nodes than the research-grade mesh. Comparison of (ADCIRC + SWAN) simulated times-series and peak water levels to observations between the research-grade and real-time-grade meshes for Hurricanes Ivan (2004), Dennis (2005), Katrina (2005), and Isaac (2012) show virtually no difference. Model simulations with the NGOM-RT mesh are 1.5–2.0 times faster than using NGOM3 on the same number of compute cores.

Permanent link to this article: http://www.mattbilskie.com/publication-unstructured-finite-element-mesh-decimation-for-real-time-hurricane-storm-surge-forecasting/

Aug 29

Visualization of Hurricane Michael | PEARC19

Below is a scientific rendering of our simulation results for Hurricane Michael on the high-resolution NGOM3 mesh. This effort is a product of the XSEDE ECSS Program. Thanks to David Bock at the University of Illinois National Center for Supercomputing Applications for being part of this project!

Abstract Hurricane Michael made landfall near Mexico Beach, FL on October 10 as a Category 5 storm. Measurements of peak water levels revealed storm surge as high as to 4.37 m (NAVD88). Areas surrounding Mexico Beach, Port St. Joe, St. George Island, and Apalachicola experienced wide-spread flooding and extensive damage. To gain an understanding of storm surge and related overland flooding, we simulate the water level and wave response from Hurricane Michael using a tightly-coupled ADCIRC+SWAN model of the northern Gulf of Mexico (NGOM), NGOM3. The ADCIRC (Advanced Circulation) code computes water levels and depth-averaged currents via the shallow water equations while SWAN (Simulating Waves Nearshore) computes relative frequency and direction of wind-waves from the action balance equation. Both models utilize the same NGOM3 unstructured finite element mesh (5.5 million nodes) that spans the western north Atlantic Ocean, Caribbean Sea, and Gulf of Mexico and includes detailed representation of the Mississippi, Alabama, and Florida panhandle coastal floodplain. Model resolution ranges from 20 m – 200 m across the overland regions and describes the significant hydraulic features such as bay/inlet systems, sounds, estuaries, coastal river, and the Gulf Intracoastal Waterway that can convey or inhibit storm surge flows. The NGOM3 model is a result of over a decade of effort and improvements. A custom visualization system is used to visualize a variety of parameters including wave height, water surface elevation, wind, and current.

Permanent link to this article: http://www.mattbilskie.com/visualization-of-hurricane-michael-pearc19/

Jun 25

Publication | A comprehensive review of compound inundation models in low-gradient coastal watersheds

F.L. Santiago-Collazo*, M.V. Bilskie, S.C. Hagen (2019). “A  comprehensive review of compound inundation models.” Environmental Modelling & Software. 119, pp. 166-181. https://doi.org/10.1016/j.envsoft.2019.06.002

Abstract Extreme coastal flooding poses a major threat to human life and infrastructure. Low-gradient coastal watersheds can be vulnerable to flooding from both intense rainfall and storm surge. Here we present a comprehensive review of the most recent studies that quantify extreme flooding using variations of a compound inundation model. A compound inundation model may consist of different numerical models, observed data, and/or a combination of these. The definitions, advantages, and limitations of each joining technique are discussed with the goal of enabling and focusing subsequent research. Future investigation should focus on the development of a tight-coupling procedure that can accurately represent the complex physical interactions between storm surge and rainfall-runoff. A more accurate compound flood forecast tool can help decision-makers, stakeholders and authorities converge on better coastal resiliency measures that can potentially save human lives, aid in the design of structures and communities, and decrease property damage.

Permanent link to this article: http://www.mattbilskie.com/publication-a-comprehensive-review-of-compound-inundation-models-in-low-gradient-coastal-watersheds/

May 01

Publication | Assessment of the temporal evolution of storm surge across coastal Louisiana

C.G. Siverd, S.C. Hagen, M.V. Bilskie, D.H. Braud, S. Gao, R.H. Peele, R.R. Twilley (2019). “Assessment of the temporal evolution of storm surge across coastal Louisiana.” Coastal Engineering, 150, pp. 59-78. https://doi.org/10.1016/j.coastaleng.2019.04.010.

Abstract The co-evolution of wetland loss and flood risk in the Mississippi River Delta is tested by contrasting the response of storm surge in coastal basins with varying historical riverine sediment inputs. A previously developed method to construct hydrodynamic storm surge models is employed to quantify historical changes in coastal storm surge. Simplified historical landscapes facilitate comparability while storm surge model meshes developed from historical data are incomparable due to the only recent (post-2000) extensive use of lidar for topographic mapping. Storm surge model meshes circa 1930, 1970 and 2010 are constructed via application of land to water (L:W) isopleths, lines that indicate areas of constant land to water ratio across coastal Louisiana. The ADvanced CIRCulation (ADCIRC) code, coupled with the Simulating WAves Nearshore (SWAN) wave model, is used to compute water surface elevations, time of inundation, depth-averaged currents and wave statistics from a suite of 14 hurricane wind and pressure fields for each mesh year. Maximum water surface elevation and inundation time differences correspond with coastal basins featuring historically negligible riverine sediment inputs and wetland loss as well as a coastal basin with historically substantial riverine inputs and wetland gain. The major finding of this analysis is maximum water surface elevations differences from 1970 to 2010 are 0.247 m and 0.282 m within sediment-starved Terrebonne and Barataria coastal basins, respectively. This difference is only 0.096 m across the adjacent sediment-abundant Atchafalaya-Vermilion coastal basin. Hurricane Rita inundation time results from 1970 to 2010 demonstrate an increase of approximately one day across Terrebonne and Barataria while little change occurs across Atchafalaya-Vermilion. The connection between storm surge characteristics and changes in riverine sediment inputs is also demonstrated via a sensitivity analysis which identifies changes in sediment inputs as the greatest contributor to changes in storm surge when compared with historical global mean sea level (GMSL) rise and the excavation of major navigation waterways. Results imply the magnitude of the challenge of preparing this area for future subsidence and GMSL rise.

Permanent link to this article: http://www.mattbilskie.com/publication-assessment-of-the-temporal-evolution-of-storm-surge-across-coastal-louisiana/

Mar 28

Publication | Advancing the Understanding of Storm Processes and Impacts

N Elko, JC Dietrich, M Cialone, H Stockdon, MV Bilskie, B Boyd, B Charbonneau, D Cox, KM Dresback, S Elgar, A Lewis, P Limber, J Long, TC Massey, T Mayo, K McIntosh, N Nadal-Caraballo, B Raubenheimer, T Tomiczek, A Wargula (2019). “Advancing the Understanding of Storm Processes and Impacts.” Shore & Beach, 87(1), 41-55.

Abstract In 2017, Hurricanes Harvey, Irma, and Maria caused more than $200 billion dollars of damage in the United States, as well as the incalculable cost of the loss of life and mental trauma associated with these disasters. In a changing climate, sea level rise and the potential for increasing tropical cyclone intensity can result in even more devastating damages. Therefore, engineers, community planners, and coastal residents need accurate, timely, and accessible forecasting of storm processes and their impact on coastal communities to bolster national resilience and reduce risk to life and property during these events. However, along with uncertainties in understanding and modeling of storm processes, there are complex challenges associated with determining and meeting the needs of end users who rely on these forecasts for emergency management decisions.

To determine needed advancements in storm forecasting, the U.S. Coastal Research Program (USCRP) hosted a Storm Processes and Impacts workshop for coastal stakeholders 16-18 April 2018, in St. Petersburg, Florida. The attendees included local coastal managers, emergency managers, state and regional agencies, federal agency scientists and engineers, academics, and private industry scientists and engineers. Workshop objectives were to synthesize present capabilities for modeling storm processes and forecasting impacts and to prioritize advancements. In addition, the workshop provided an opportunity to bridge the apparent gap between the research of coastal scientists and engineers and the information being distributed publicly and to emergency managers before, during, and after storm events.

Permanent link to this article: http://www.mattbilskie.com/publication-advancing-the-understanding-of-storm-processes-and-impacts/

Jan 04

Publication | Development of Return Period Stillwater Floodplains for the Northern Gulf of Mexico under the Coastal Dynamics of Sea Level Rise

M.V. Bilskie, S.C. Hagen, J. Irish (2018). “Development of return period stillwater floodplains for the northern Gulf of Mexico under the coastal dynamics of sea level rise.” ASCE Journal of Waterway, Port, Coastal, and Ocean Engineering, 145(2), https://doi.org/10.1061/(ASCE)WW.1943-5460.0000468.

Abstract Rising seas increase the exposure, vulnerability, and thus the risk associated with hurricane storm surge flooding across the coastal floodplain. A methodology is applied to down select a suite of synthetic storms from recent flood insurance studies. The purpose is to force wind-wave and hurricane storm surge models of the northern Gulf of Mexico (NGOM) coast (Mississippi, Alabama, and the Florida Panhandle) that represent the future landscape and derive the 1 and 0.2% annual chance floodplain for present-day and four sea-level-rise (SLR) scenarios. Vast new regions become part of the 100-year floodplain by the end of the century. In Mississippi, the present-day 500-year return period event is likely to be the 100-year event under an SLR of 1.2 m. Throughout most of Alabama and the Florida Panhandle, the present-day 500-year return period event becomes a 100-year event with just 0.5 m of SLR. Results indicate the need to apply a coastal dynamic modeling approach to plan and prepare for the effects of SLR across the NGOM and other low-gradient coastal landscapes.

Permanent link to this article: http://www.mattbilskie.com/publication-development-of-return-period-stillwater-floodplains-for-the-northern-gulf-of-mexico-under-the-coastal-dynamics-of-sea-level-rise/

Apr 09

Publication | Defining Flood Zone Transitions in Low‐Gradient Coastal Regions

M.V. Bilskie & S.C. Hagen (2018). “Defining Flood Zone Transitions in Low-Gradient Coastal Regions.” Geophysical Research Letters, In Press, doi: 10.1002/2018GL077524.

Abstract Worldwide, coastal, and deltaic communities are susceptible to flooding from the individual and combined effects of rainfall excess and astronomic tide and storm surge inundation. Such flood events are a present (and future) cause of concern as observed from recent storms such as the 2016 Louisiana flood and Hurricanes Harvey, Irma, and Maria. To assess flood risk across coastal landscapes, it is advantageous to first delineate flood transition zones, which we define as areas susceptible to hydrologic and coastal flooding and their collective interaction. We utilize numerical simulations combining rainfall excess and storm surge for the 2016 Louisiana flood to describe a flood transition zone for southeastern Louisiana. We show that the interaction of rainfall excess with coastal surge is nonlinear and less than the superposition of their individual components. Our analysis provides a foundation to define flooding zones across coastal landscapes throughout the world to support flood risk assessments.

Permanent link to this article: http://www.mattbilskie.com/publication-defining-flood-zone-transitions-in-low%e2%80%90gradient-coastal-regions/

Dec 05

Publication | Astronomic tides and nonlinear tidal dispersion for a tropical coastal estuary with engineered features (causeways): Indian River Lagoon

IRL_EnergyDissipationM.V. Bilskie, P. Bacopoulos, S.C. Hagen (2017). “Astronomic tides and nonlinear tidal dispersion for a tropical coastal estuary with engineered features (causeways): Indian River Lagoon.” Estuarine, Coastal, and Shelf Science. In Press. doi: 10.1016/j.ecss.2017.11.009

Abstract Astronomic tides and nonlinear tidal dispersion were assessed for the Indian River lagoon system, a tropical coastal estuary (located in central east Florida) with engineered features (causeways). The four inlets, which choke the tides entering the system, together with the expansive size and shallowness of the estuary (and the associated energy dissipation) are the prominent mechanisms leading to the microtidal environment of the lagoon. Inside the shallows, there are 12 causeway abutments that cause a compartmentalization of the waters into separate basins, whereby the causeway openings act mechanistically as acceleration-inducing throttles to promote local regions of high kinetic energy (velocities). The causeways lead to a furthered decay of tidal amplitudes, phase lags in the tides and an enhanced generation of harmonic overtides and tidal residuals relative to the natural domain (i.e., fully open—no causeways). Numerical modeling of astronomic tidal flows (Advanced Circulation—ADCIRC) employed an unstructured, triangular mesh that resolved the entire scale of the lagoonal system with element sizes of 10–100 m and captured its many intricate domain features, including: the causeways in Indian River lagoon proper and Banana River lagoon; over 150 km of sinuous channels in Mosquito lagoon; and the hydraulic connections of the individual lagoons—one of which, Haulover Canal, is only 55 m wide. The model performed well with an index of agreement of (on average) 94% when compared with tidal data from 23 stations located throughout the system. Tides in the shallows are small at just millimeters in range; the model captured the tidal signal at the stations located there with an index of agreement of (at worst) 79%. Considering previous tidal studies of the Indian River lagoon system and tropical coastal estuaries in general, this level of domain definition and model validation of astronomic tide behavior is unprecedented and provides a benchmark for numerical simulation of lagoonal tidal flow.

Permanent link to this article: http://www.mattbilskie.com/publication-astronomic-tides-and-nonlinear-tidal-dispersion-for-a-tropical-coastal-estuary-with-engineered-features-causeways-indian-river-lagoon/

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