Εngineering with nature to face down hurricane hazards
Natural and engineered nature-based structures offer promise for storm-related disaster risk reduction and flood mitigation, as long as researchers can adequately monitor and study them.
The 2020 and 2021 Atlantic tropical storm seasons were extremely busy, ranking as the first and third most active on record, respectively. Thirty named storms occurred in 2020 alone, with 11 making landfall in the United States (a record) and 13 making landfall elsewhere (also a record) around the Caribbean, the Gulf of Mexico, and even Portugal (a first). The 2021 Atlantic season produced another 21 named storms. The 2022 season, which ended officially on 30 November, was closer to average, producing 14 named storms, although several—Hurricane Ian especially—caused extensive damage.
In addition to direct impacts of episodic tropical storms, much of the coastal Atlantic region increasingly has experienced extreme rainfall, storm surges, and even fair-weather inundation exacerbated by sea level rise. Such compound weather-related disasters reveal new and heightened vulnerabilities affecting broad swaths of people, particularly in marginalized and underserved communities.
Protecting coastal communities from the effects (and aftereffects) of repeated pummeling by tropical storms and other disasters requires an all-hands-on-deck approach, with contributions from physical, biological, chemical, and social scientists as well as from engineers, policymakers, and community members. Building this resilience also requires new solutions.
Much of the needed innovation to meet the challenges of natural disasters will come from modern engineering expertise. Yet nature itself provides time-tested examples of resilience and recovery from which we can learn. Natural and nature-based features (NNBFs) can support coastal resilience and mitigate flood risk while providing ecosystem services. Berms and dunes, for instance, are nature-based features that can be engineered or enhanced along coastlines to minimize flooding and storm damage in communities and to achieve ecosystem restoration goals.
Understanding how NNBFs perform under extreme hydrometeorological hazards and in other natural disasters in comparison with traditional infrastructure is critical. This understanding requires thorough monitoring across the life cycles of disaster events, including data on conditions before, during, and after, which allow researchers to evaluate how physically effective and cost-effective NNBF projects are in achieving their intended purposes, whether they involve coastal engineering, sustainable management, wetland restoration, or natural hazard reconnaissance. But collecting these data presents major challenges.
In a 2021 workshop hosted by the Network for Engineering with Nature (N-EWN), a multidisciplinary group of experts discussed the current state of coastal disaster monitoring, necessary communication and collaboration among researchers, improving experimental design and data collection, funding for monitoring and studies of NNBFs and natural features that serve as proxies for EWN approaches, and enhancing community involvement in monitoring projects. N-EWN, launched in 2020 through a partnership between the U.S. Army Corps of Engineers (USACE) Engineering With Nature (EWN) program and the University of Georgia’s Institute for Resilient Infrastructure Systems, is a community of researchers, educators, and practitioners advancing EWN solutions. As founding partners of N-EWN, our interest here is in identifying and applying lessons learned from this workshop to improve the case for EWN approaches as a means to raise community resilience to climate change and extreme weather events.
Communication, Collaboration, and Mobilization
The increasing frequency and intensity of disasters make organizational communication and collaboration among disaster monitoring groups, such as emergency management agencies, other state and federal agencies, and academic research groups, more important than ever. Growing coastal populations and competition for limited disaster-planning and response resources from federal, state, and local organizations trying to cope with other types of disasters, including the COVID-19 pandemic, further increase this need. Effective communication allows groups and agencies to share essential knowledge, information, and warnings among each other and with affected communities.
The need to establish avenues of communication between lab groups (including between field and office collaborators) and determining the severity levels of events that require responses before the tropical storm season starts are important lessons. Preseason conversations allow researchers and planners to share approaches, coordinate monitoring efforts, and develop collaborations in advance.
Outlining exact plans for storm monitoring is challenging because real-world events present unexpected twists and turns, so researchers must have flexibility in their methodologies. Knowing the approaches of other groups studying similar natural features or disaster types helps researchers develop this flexibility, refine methods, and standardize data collection and reporting. Furthermore, collaborating in multiregional teams with diverse disciplinary expertise can allow for more combinations of opportunistic data gathering and formal experimental designs to be used to gather information and respond to events as they happen with a wider array of approaches.
Another lesson workshop participants reported is that when monitoring storm impacts in the field, having site-specific information and local assets accessible, along with knowledge of available methods, helps facilitate successful deployments and retrievals of sensors for data collection. The accessibility of study sites, for example, can be determined by leveraging local knowledge and experience of the best access points and most vulnerable locales at sites.
A team’s ability to mobilize organized responses before and after disaster events is as crucial as communication. This ability requires time and preparation. Researchers must design responses that account for the type of coastline affected and for compounding events like associated flooding or saltwater intrusions. The planned response will differ, for example, in an urban area versus a natural area like an oyster reef or an engineered area such as near seawalls or submerged breakwaters.
Before an impending storm, response teams typically check storm surge forecasts and venture to areas that might be affected to assess infrastructure and the accessibility and safety of potential sites. This sort of preparatory procedure maximizes organized and standardized data collection and can help researchers avoid using a more haphazard shotgun approach, which may be costly and unfruitful. For example, stronger-than-expected winds or storm surges may dismantle sensors and equipment that aren’t well sited, contributing to data loss and damage. Proper preparation also improves poststorm analysis, and standardized data collection allows for comparative analyses across multiple storm events.
Workshop discussions revealed several important elements that research teams must consider in planning effective postdisaster monitoring. These include identifying where to collect data, obtaining permits and access to sites, and planning safe travel to and from sites. Having enough time to address these issues can be the most important factor in determining which storm events to respond to. This decision can also be driven by what equipment needs to be deployed or removed to avoid damage during an event. Depending on the capabilities of a given group and conditions on the ground, the events chosen may be relatively small, like compounding sequential tropical storms, rather than big events like major hurricanes.
Supporting Baseline Data Collection
Collecting time-sensitive disaster event data is costly. Most research groups have focused on monitoring after storms because of difficulty obtaining funding to gather prestorm data. Workshop participants actively involved in such monitoring pointed to the National Science Foundation, the U.S. Coastal Research Program, the NOAA Effects of Sea Level Rise Program, NOAA’s Office of Oceanic and Atmospheric Research, and state-level funding as sources that fund poststorm evaluations.
Prestorm monitoring is just as important, however. Baseline data are necessary to understanding environmental and natural infrastructure changes related to storm protection and resilience and to informing stakeholders and policymakers of these changes. Future storm seasons will provide excellent opportunities to assess NNBFs if baseline data are collected and available beforehand and resources and plans are in place to pair them with data collected after storm events.
Teams must convince funding sources of the importance of baseline studies so that these sources understand the opportunities for and value of gathering prestorm data and conducting long-term monitoring. This funding will allow researchers to better prepare research questions, such as how different structures and environments will handle—and bounce back from—extreme weather damage. It can also offer additional advantages, including facilitating more statistically sound planning, inclusion of complex experimental designs, and clarification of and coordination across data sets to be collected (e.g., flooding, bathymetry, soil inundation, vegetation impacts, erosion).
In addition to collecting baseline data in future storm seasons, there are opportunities to identify and use existing data from past storm seasons to demonstrate the performance of natural features during storms and relate that performance to NNBFs. For example, researchers used data from Hurricane Sandy in 2012 to evaluate how effectively natural ecosystems, such as coastal wetlands, reduced wave impacts, absorbed floodwaters, and mitigated damage across 12 states. They found that wetlands in the region studied prevented $625 million in damages from flooding, pointing to the importance of incorporating natural and restored habitats into NNBF designs.
Involving Affected Communities
Another major point of discussion at the workshop was the need to enhance engagement and share knowledge from disaster monitoring work with—and gain partners among—affected communities. Participants suggested attending community outreach events for these purposes, because there is much to be learned from people living in affected areas. Engaging local stakeholders such as homeowners and local natural resource users also helps research groups identify specific areas of interest when conducting regional surveys. Locals can direct research groups to important recreational areas, fisheries, and reefs, for example, and to residential areas and vulnerable infrastructure, such as hospitals and care facilities, that may be heavily affected by storms.
An important recommendation is for scientists to encourage federal agencies like the U.S. Geological Survey, NOAA, and the Federal Emergency Management Agency to facilitate community participation. These agencies can provide additional vital resources such as historical data, computing infrastructure to process and share data, access to sites, equipment, and personnel outside the monitoring teams. Such efforts can enable marginalized, underrepresented, and frontline communities often excluded from the scientific process to produce knowledge valuable for local safety and well-being.
Hurricanes Katrina in 2005, Harvey in 2016, and Michael in 2018, among other events, have revealed racial, socioeconomic, and geographic disparities in how communities recover from extreme events. For example, more affluent communities rebuilt or repaired infrastructure, whereas many communities of color and impoverished areas still show signs of damage from these storms, years later. Considerations of equity, vulnerability, and resilience should be woven into project planning in disaster monitoring and studies. Partnering with social scientists, physical and biological scientists, and community members can help reduce gaps in the understanding and quantification of climate vulnerability of disenfranchised and marginalized communities through multidisciplinary approaches.
Community science is an emerging way to engage community members in observational monitoring rather than being only subjects of study by outsiders. Pointing residents toward community science projects benefits both communities and researchers exploring storm events.
Many such projects exist, including those related to NNBFs. SandSnap, for example, is a collaborative crowdsourcing application created by USACE, James Madison University, and MARDA Science LLC that allows community scientists to assist in building a globally accessible, public database of coastal sediment grain sizes simply by uploading mobile phone photos of beach sand. Researchers use the database to quantify storm resilience and gather information on beach nourishment projects that use sediments dredged from navigation channels. These efforts, in turn, can lead to more effective and cost-efficient approaches to coastal protection.
Other efforts in which government and nongovernmental agencies have partnered include citizenscience.gov and iCOAST. These partnerships provide resources to help design and initiate community science projects and show how communities can be trained to carry out local measurements and testing. Programs such as these allow community members to gain crucial firsthand knowledge that broadens their understanding of their environment and may inform local and regional policy.
Building the Case for Nature-Based Solutions
EWN-type solutions that align natural and engineered processes—through NNBFs, for example—offer huge potential to support coastal resilience to hurricanes and tropical storms, reduce associated flood risks, and boost beneficial ecosystem services. Making a case for these nature-based solutions requires dedicated and detailed monitoring of how they respond to the compounding effects of storms and flooding.
Amid ongoing climate change, which is amplifying risks from these events, researchers must be equipped with the necessary tools and resources to conduct this monitoring. The knowledge gained will ultimately inform the design and implementation of NNBFs and EWN solutions to equitably protect communities in the face of potential disasters.