Coastal Flooding & Solutions, Workshop Case Studies

Adaptation of Coastal Urban and Natural Ecosystems (ACUNE)

Location: Southwest Florida

Submitted By: Peter Sheng - University of Florida, Research Professor

Project URLs: http://coastalscience.noaa.gov/

Project Description

The ACUNE project, which is near completion, developed a Geo Tool to inform communities in southwest Florida of the future coastal flooding risk in a changing climate, using the best available climate, ciastal, ecological, and economic sciences and models with funding from the NOAA Restore Sciene Program. The Geo Tool contains such products as the probabilistic coastal flood maps and asset maps for large coastal flood plain including Collier County and the Big Cypress Basin. Value of wetland for reducing flood damage has been assessed by the vegetation-resolving surge-wave model CH3D-SWAN. The ACUNE Geo Tool is used by stakeholders for coastal resiliency planning. The ACUNE+ project, funded by the NOAA ESLR Program, is coupling models, projects, and programs to enable integrated assessment on the role of NNBF for buffering future coastal flooding risk due to compounded effects of sea level rise, intense storms, inland flooding, and evolving wetland condition in a changing climate. Currently, the coastal surge-wave model CH3D-SWAN is being coupled to the dynamic wetland model WARMER-Mangrove, BCB-FLOOD watershed model, and the FLO-2D stormwater model. The ACUNE+ project is using the integrated modeling system to assess the feasibility of proposed potential wetland restoration projects for southwest Florida.

Key Successes

Stakeholders are using the various products in the Geo Tool for adaptive and resilience planning

Challenges

Lack of detailed building data and elevation of all infrastructures

Any questions regarding this posting, email edl@gatech.edu

Coastal Flooding & Solutions, Workshop Case Studies

Engaging Stakeholders and Exploring the Effects of Sea-Level Rise in the Northern Gulf of Mexico

Location: Coastal Mississippi, Alabama, and Northwest Florida

Submitted By: Renee Collini - Coastal Climate Resilience Specialist - MSU, MS-AL Sea Grant, FL Sea Grant

Project URLs: https://coastalscience.noaa.gov/project/sea-level-rise-assessments-mitigate-surge-flooding/

Project Description

This project, spanning a decade of research and relationship building with coastal stakeholders, has shifted how we consider effects of sea-level rise and significantly increased the available information for taking adaptive action. Detailed system of systems analyses were conducted to understand changes in future conditions (e.g., future 1% and 0.2% annual chance stillwater floodplains). Communication researchers were able to conduct studies to capture foundational principles and perspectives of the stakeholders to inform future communication and outreach activities. Concomitantly with the research, coastal stakeholders were engaged to shape and scope the research. This enhanced the research and generated awareness and buy-in among potential data users; however, coastal stewards across the built and natural environments who did not participate in the project directly have also been the target of Extension and outreach activities based on this new research. By partnering with existing organizations outside the scope of this project that have a focus on resilience, this research has had a much larger sphere of influence. Strategic relationships were forged with regional partnerships, NERRs Coastal Training Program Coordinators, Sea Grant extension specialists, and NOAA management support staff.

Key Successes

Key successes of our project cover academic and coastal resilience sectors. This research has made a major contribution to a shift in the paradigm of how sea-level rise is assessed, away from bathtub models to develop and apply a system of systems approach at the coastal land margin. As a result, there is a demonstrated capability to assess the coastal dynamics of sea-level rise across the northern Gulf of Mexico under historical and future conditions. The scientific research has been published in more than 60 peer-reviewed journal articles. Further, the social science methods employed to engage stakeholders have resulted in transdisciplinary research outcomes that are recognized by the National Academy of Sciences as a model for other future work. In addition to substantial contributions to science, this research has provided a foundation on which conversations about sea-level rise impacts have changed. The discussions are more nuanced and move beyond simply planning for one foot of sea-level rise by adding one foot of water to approximate future conditions. Examples of this include, but are not limited to: • Jackson County Utility Authority planning for 6 ft of sea-level rise by examining changes in the 0.2% and 1% annual chance stillwater with sea-level rise, instead of simply adding 6 ft of water to their design • Dialogue with coastal residents about changing floodplain conditions and shifts in their flood risk over time, visualizing very effectively the adage “just because it has never flooded here before, doesn’t mean it won’t next time”. • Integration of changing flood risk into a tool to support Santa Rosa County, FL when prioritizing capital improvement projects • More accurate consideration of future conditions in engineering and other coastal projects due to training that explicitly discusses translating sea-level rise projections into information about future conditions

Challenges

Disparate timelines between the provision of modeling results and decision-making remains a challenge. Occasions for this science to be used is opportunistic at the decision-maker level. This is driven by funding availability, timing of required reporting and planning updates, and other external factors such as capacity or constituent priority.

Any questions regarding this posting, email edl@gatech.edu

Coastal Flooding & Solutions, Workshop Case Studies

Dauphin Island Adaptation Pathway: Navigating sea-level rise uncertainty on barrier islands

Location: Coastal Alabama

Submitted By: Stephanie M. Smallegan - Assistant Professor, University of South Alabama

Project URLs: www.facebook.com/nobreachdi

Project Description

An adaptation pathway is being created for Dauphin Island, AL, a low-lying barrier island vulnerable to storm surge and sea level rise (SLR). The pathway is comprised of several adaptation strategies for barrier island adaptation to future hurricanes and SLR. The strategies are sequentially arranged based on their effectiveness in protecting the island from damage during a hurricane under SLR. Tipping points are identified as the amount of SLR that causes a strategy to no longer meet its original objective of mitigating storm damage, necessitating the implementation of another strategy. The pathway is scientifically-based and community-informed, which means each adaptation strategy is analyzed using computer models and only adaptation strategies of interest to the community are considered. In January 2020, an in-person meeting was held with Dauphin Island leadership. Three vulnerable areas were determined to be of importance for this study and several adaptation strategies were discussed. Although additional in-person community meetings were planned for 2020, the meetings were transitioned to a virtual format due to restrictions imposed during the COVID-19 pandemic. Surveys were sent to residents after a series of live events to inform the pathway. We directly reached over 40 individuals through the virtual events. This presentation will provide lessons learned on hosting virtual community meetings and present recent model results being used to create the adaptation pathway.

Key Successes

Though the project is underway, there have been key successes on the modeling and stakeholder sides. From the modeling perspective, the Brier Skill Score (BSS) indicate close agreement between simulated and surveyed post-storm topography (0.77-0.98; 1 = perfect agreement). Additionally, a combination of data collection methods and comparisons has generated enhanced understanding of how community collected data of conditions post-storm on barrier islands can provide unique insights during model calibration. From the stakeholder side, there were initial challenges by residents about the purpose of the project and suggestions of nefarious attempts to take residents’ land. Through novel engagement approaches, a diversity of stakeholders across age, economics, and education were successfully reached, their questions answered, and all resistance has apparently desisted. Instead there have been expressions of gratitude for the research and for the transparency in our approach. Finally, adaptability has been a key success. The COVID-19 pandemic hit between our focused stakeholder meeting and our resident engagement effort; however, we were able to still pivot our approach to community meetings to reach a broad array of partners. Additionally, we have responded to Cristobal which provided an opportunity to collect additional data that will enhance our understanding of local processes and potential adaptation solutions.

Challenges

The current state-of-the-art numerical modeling is unable to simulate both long-term morphological or evolutionary processes and short-term storm-event driven processes. Ideally, we would be able to accurately simulate morphological change on barrier islands from a storm, through the post-storm recovery process, and over time as sea levels change and additional storms impact the study site. Although individual models exist to simulate each of those scenarios, we are unaware of any model (or coupled models) that can handle all of them. Therefore, we operate under the assumption that the Town will implement adaptation strategies, such as maintenance beach nourishment, over time to maintain present conditions, which enables us to use present-day data to represent a future state (e.g. we use the model grid representative of today’s conditions to evaluate the impacts of future sea level rise assuming the town will take measures to prevent severe island erosion between now and the time it takes for seas to rise to that level). This assumption is a limitation of the research and its impact to the results of the study are mitigated by performing extensive sensitivity analysis which requires significant computational and personnel time. Also, in situ data, including bathymetry, water levels, and waves at specific study sites, is an ongoing limitation and challenges the ability to calibrate and validate numerical models. An economist may be beneficial in quantifying the differences in cost of the different adaptation strategies which could have provided even more guidance for the Town when considering implementation. An economist may also have been able to provide creative strategies for generating those funds as well. Legal expertise would have been helpful as some of the strategies require code/permitting changes and potentially reduced access to homes which has, in some cases, been claimed as an illegal taking.

Any questions regarding this posting, email edl@gatech.edu

Coastal Flooding & Solutions, Workshop Case Studies

High-resolution (2 m) 3-D Mapping for Habitat, Biodiversity, and Flood Hazard Assessments of Coastal and Wetland Areas of the Southern US from Florida to Texas (3D Wetlands Spoke)

Location: US Gulf of Mexico wetlands, Florida, Alabama, Mississippi, Louisiana, Texas

Submitted By: Frank E. Muller-Karger - University of South Florida, College of Marine Science. Professor

Project URLs: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1762493&HistoricalAwards=false; https://lizcanosandoval.users.earthengine.app/view/hr-land-cover-gulf-of-mexico

Project Description

We developed 2 m spatial resolution topographic and land cover maps of the south States within 50 Km of the coast from Texas to Florida (>220,000 square Km). The maps were constructed using detailed historical airborne LiDAR (Light Detection and Ranging) data collected from airplanes merged with high spatial resolution (~2 m pixel) multispectral commercial satellite imagery (WorldView/Maxar). The project includes research into detailed 3D mapping of coastal areas using Structure-from-Motion (SfM) and multispectral classification methods using airborne drones (cm-scale resolution). The production of land cover maps and digital elevation models (DEMs) required fusion of large amounts of data and efficient, automated techniques. The project examines in detail areas that were directly impacted by Hurricanes Harvey and Irma. The 3D maps show habitat diversity, needed to plan for conservation and development in these important ecosystems. We seek collaborations to use these products in planning of development and land use. Products are openly available using Google Earth Engine. The program is a collaboration of researchers from the University of South Florida (College of Marine Science, School of Geosciences), Texas A&M University-Corpus Christi’s Harte Research Institute, and Google Earth Engine, joined through the NSF South Big Data Hub.

Key Successes

Open high spatial resolution (2 m) regional land cover and digital elevation maps

Challenges

Large volumes of data, validation, research and management applications, funding, data management

Any questions regarding this posting, email edl@gatech.edu

Coastal Flooding & Solutions, Workshop Case Studies

Characterization and Modeling of Compound Flooding: Introducing Texas Integrated Flooding Framework Planning Project

Location: Texas Coasts

Submitted By: Amin Kiaghadi - Coastal Flood Modeler-Texas Water Development Board

Project URLs:

Project Description

A compound flooding event can be defined as simultaneous or sequential flooding processes leading to a more significant flooding event. Combined effect from riverine flows and storm surge (or high tides) is the most common type of compound flood across Texas coasts. In this talk, several predictive hydrodynamic modeling frameworks and their capability in simulating compound flooding, as well various types of data required for building such models will be discussed. Case studies along the coast of Texas will be used to better illustrate various factors that could change the behavior of compound flooding and the need for an integrated flooding framework and reliable data. Additionally, the Texas Integrated Flooding Framework (TIFF) planning project funded by Texas General Land Office will be introduced and discussed. The TIFF planning project will develop guidelines and processes for a comprehensive, integrated framework to model, visualize, and plan for the risk of flooding across the Texas coastline.

Key Successes

Understanding the concept of compound flooding and how to develop guidelines and processes for a comprehensive, integrated framework to model, visualize, and plan for the risk of flooding across the Texas coastline.

Challenges

Missing data and integrated modeling framework

Any questions regarding this posting, email edl@gatech.edu

Coastal Flooding & Solutions, Workshop Case Studies

The WRF-Hydro Based Water Model Development For Coastal Flood Simulation

Location: Mobile, Gulf of Mexico

Submitted By: Wei Yu - Weather Tech Services, LLC

Project URLs: hydroextension.com

Project Description

WRF-Hydro has been developed as a community model in the research of the land-atmosphere water cycle and flood events. It faces the challenge of forecast accuracy and flexibility to connect with different atmospheric and ocean models. Using the Mobile Bay as a test site, we introduce a distributed parameter adjustment function into the WRF-Hydro model framework to improve the model flexibility and performance. To reproduce the complicated situation in coastal flooding, the water level at the ocean side is introduced to WRF-Hydro as a boundary condition. Interactions among ocean, river, and land surface runoff are also considered. The coastal flooding from the model simulation includes the impact from the storm surge, river flooding, and heavy precipitation. The new model can be applied for either real-time forecast or flooding risk estimation to address current and future coastal flooding and inundation scenarios.

Key Successes

The impact from the storm surge, river flooding, and heavy precipitation can be combined in the new developed model system.

Challenges

lack of funding

Any questions regarding this posting, email edl@gatech.edu

Coastal Flooding & Solutions, Workshop Case Studies

Assessing sustainable restoration measures to increase barrier island resilience through data collection, integrated modeling, and decision support – the Alabama Barrier Island Restoration Assessment

Location: Dauphin Island, AL

Submitted By: Davina Passeri - US Geological Survey St Petersburg Coastal and Marine Science Center, Research Oceanographer

Project URLs: https://cesamusace.maps.arcgis.com/apps/MapSeries/index.html?appid=ea29cd4e1f3b432e8c520df3fb7a9f8b

Project Description

The Alabama Barrier Island Restoration Assessment was a science-based effort funded by the National Fish and Wildlife Foundation in collaboration with the State of Alabama, the U.S. Geological Survey and the U.S. Army Corps of Engineers, focused on assessing viable restoration measures for Dauphin Island, Alabama to increase island sustainability and restore vital habitats for species affected by the 2010 Deepwater Horizon oil spill. Completed in 2020, the project included field data acquisition to understand present conditions on the island and to inform a suite of integrated, predictive models capable of forecasting decadal island evolution and resulting habitat suitability under scenarios of sea level rise and storm variability. Together, the predictive morphological and habitat models were used to assess a no-action alternative and stakeholder-developed restoration measures including beach and dune nourishment, marsh and back-barrier restoration, and nearshore sand placement. Structured decision-making was used to gauge the ability of each restoration measure to meet multiple stakeholder objectives for habitats, sustainability, residents, and conservation values. Working with decision-makers from Alabama, a storymap was developed to communicate the results of the restoration assessment to the citizens and other stakeholders of Dauphin Island. The State of Alabama used the findings of our assessment to target over $150M worth of restoration measures for implementation.

Key Successes

Restoration measures for this effort were developed to address multiple objectives related to the social and ecological concerns of stakeholders on Dauphin Island and surrounding areas. The stakeholder defined objectives were to: (1) maximize ecological function and physical processes (i.e., sustainability); (2) minimize social impacts and costs; (3) maximize coastal and marine resources; and (4) minimize time that it would take for a restoration action to provide benefits for the island. In all, 23 restoration and land acquisition measures were developed and assessed relative to their ability to meet these objectives on Dauphin Island. Since completion of the project in 2020, three measures have been selected for implementation thus far.

Challenges

This effort could be expanded by increasing our understanding of barrier island vegetation recovery and succession, including overwash response and marsh productivity and drowning, in response to sea-level rise and reoccurring storms. Insight from these analyses can be used to better calibrate models used in this study and lead to more thematic detail in habitat model outputs. In this study, we used expert elicitation to discern habitat importance to species of concern. Future work is needed to develop models that can be used to more explicitly understand how barrier island changes may impact important fauna (e.g., shorebirds and sea turtles) that utilize these islands. Additional enhancements are needed to increase the efficiency of data exchange between models and dissemination of outputs. Collectively, these enhancements could lead to more robust and efficient models that could be used to make operational decisions related to restoration, such as: (1) quickly running different scenarios; (2) addressing new morphologic change (e.g., a newly formed breach); and (3) re-weighting stakeholder values in risk assessment.

Any questions regarding this posting, email edl@gatech.edu

Coastal Flooding & Solutions, Workshop Case Studies

Communicating the Socio-Economic Impacts of Storm Surge Flood Plains under the Coastal Dynamics of Sea-Level Rise in the Northern Gulf of Mexico

Location: Coastal counties of Northern Gulf of Mexico: Hancock, Harrison, Jackson MS; Mobile and Baldwin, AL; Escambia, Santa Rosa, Okaloosa, Walton, Bay, Gulf, Franklin, Wakulla, Jefferson, Taylor, FL.

Submitted By: Diana C. Del Angel - Texas A&M-University Corpus Christi, Harte Research Institute for Gulf of Mexico Studies

Project URLs: gomsurge.com

Project Description

The use of sea-level rise (SLR) impact scenarios is essential for assessing risk and developing mitigation options. One of the challenges in adaptation planning is the availability of data to inform the understanding and development of options. This work used FEMA’s HAZUS to assessed the socio-economic impact of a 1% and 0.2% probability stillwater flood plain under present and future conditions. The overall transdisciplinary research effort spans a decade and involves stakeholders, including local and state community planners and natural resource managers from the study region, in collaboration with the Northern Gulf of Mexico Sentinel Site Cooperative. Stakeholders were engaged through webinars, workshops and focus groups. Challenges in producing socio-economic data result from the scale at which data is being aggregated — balancing between efficiency in data processing and modeling and visualization across the region while maintaining a useful product at the local level. This process and the resulting data lead to more effective tools for natural resource and hazard managers as it improves stakeholder familiarity with the data and refines the data product. This presentation will cover the research team background, details about the stakeholder engagement process, a summary of methods and data, upcoming data productions and solutions, and the challenges associated with modeling socio-economic impacts of climate change at the coastal land-margin.

Key Successes

a. Understanding the nonlinearity of socio-economic impact of storm surge under SLR. b. Understanding of highly vulnerable areas now, and under SLR. c. Developing easy to use visual tools and communication products

Challenges

a. Data availability b. Meeting diverse stakeholder data needs c. Producing products that are feasible to model and usable at various spatial scales

Any questions regarding this posting, email edl@gatech.edu

Coastal Flooding & Solutions, Workshop Case Studies

USGS Forecasts of Total Water Level and Coastal Change Hazards along the U.S. Gulf Coast

Location: Sandy open-ocean coastlines along the Gulf of Mexico

Submitted By: Kara Doran - U.S. Geological Survey St. Petersburg Coastal and Marine Science Center, Oceanographer

Project URLs: stal.er.usgs.gov/hurricanes/research/twlviewer/; https://marine.usgs.gov/coastalchangehazardsportal/

Project Description

The USGS provides reliable coastal hazards information to communities and local/State/Federal partners in preparation for and in response to extreme storms. Information are presented through two systems: the Coastal Change Hazards (CCH) Portal and the Total Water Level and Coastal Change Forecast (TWL&CC) viewer. The CCH Portal provides National-scale assessments on multiple coastal change hazards: extreme storms, shoreline change, and sea level rise (SLR). Probabilities of erosion during extreme storm conditions are presented for real-time storm events and scenarios. Beach profiles are compared to water levels (tides, surge, and waves) to determine the probability of collision, overwash, and inundation. Shoreline evolution in response to SLR in the Gulf of Mexico is considered through two metrics: the coastal vulnerability index that provides relative susceptibility to SLR; and a Bayesian assessment of shoreline change that incorporates multiple forcing and historical variables. Both metrics utilize the long-term shoreline change data also available in the CCH Portal. The TWL&CC viewer provides a 6-day forecast of the combined effect of tide, surge, and wave runup along the coast. Water levels and waves are extracted from NOAA models and are combined with empirically estimated wave runup. This time-varying TWL is compared to beach profiles along sandy coasts to evaluate potential coastal change. The TWL&CC viewer is available for Florida, Alabama, and portions of Texas.

Key Successes

Probabilistic forecasts of coastal change hazards are available for the entire sandy open-ocean coastline of the United State for planning purposes and in real-time. Operational total water level coastal change forecasts are available for nearly the entire US open-ocean sandy coastline. The operational forecast is used by the National Weather Service in their forecast dashboard, ensuring that this information gets to the public through their local channels.

Challenges

Lack of validation data

Any questions regarding this posting, email edl@gatech.edu

Coastal Flooding & Solutions, Workshop Case Studies

A coupled flooding modeling framework for assessing infrastructure resilience along Southeast Texas Coast

Location: Southeast Texas, Jefferson and Orange Counties

Submitted By: Yu Zhang - UT Arlington, Associate Professor

Project URLs: https://hydromet.uta.edu/noaa-csi-2019/

Project Description

The southeast Texas coast is known for its high vulnerability to fluvial floods, storm surges, and sometimes compound flooding events where storm surge is immediately followed by high riverine discharge. Flooding poses a perennial threat to regional infrastructures, and this threat is likely to magnify with a rising sea level and warming sea surface temperatures. In a project funded by NOAA Climate Program Office, a team of researchers from UTA and Lamar University created a riverine-coastal coupled flood modeling system for a region extending from the Gulf of Mexico to the downstream portions of Lower Neches River and Sabine River. The coupled modeling system was built by connecting the National Water Model (NWM) with a 2-D hydrodynamic model Delft-3D, and it allows the ingest of NWM discharge simulations into the latter’s domain. The system was used to retrospectively simulate three major tropical storm events, i.e.,Hurricanes Rita (2005), Ike (2008), and Harvey (2017), with a focus given to potential amplification of flood magnitude due to interactions between riverine flow and tides. The preliminary results indicate that the compounding effects were the most pronounced during Rita, when Sabine River happened to experience moderate discharge when the storm surge occurred. Scenarios of climate changes are introduced wherein historical storm events undergo adjustments before being used to drive the coupled modeling system to assess future flooding risks.

Key Successes

1) A coupled modeling system is built for the southeast Texas coast; 2) Climate scenarios are introduce to assess future flooding risks; and 3) A clearer understanding of impacts of fluvial-storm surge interactions during past events.

Challenges

Sustained funding; high-resolution wind data for historical events; confidence in future climate scenarios

Any questions regarding this posting, email edl@gatech.edu