Headed for New Heights: Employing Unmanned Aerial Vehicles for Resiliency Evaluation

by Emily Schlickman, ASLA

Aerial photos of Buffalo Bayou Park in Houston
Buffalo Bayou Park in Houston during and after Hurricane Harvey in 2017 / images: Jonnu Singleton

Over the past four decades, the United States has experienced 241 distinct climate and weather-related disasters, each incurring over $1 billion dollars in damage. From catastrophic wildfires and landslides in the West, to hail storms and tornados in the Midwest, to unexpected freezes and destructive hurricanes in the Southeast, these events are becoming more common and more expensive. While the overall average since 1980 has been 6.2 billion-dollar events per year, the average for the last five years has doubled, to 12.6.

In response to this trend, landscape architects, urban designers, and urban planners are not only embedding resiliency-focused strategies into their work, they are also assessing the performance of their built work in the face of these events. To do this, they are expanding the traditional designer toolbox to include emerging devices that might help with this assessment. Unmanned aerial vehicles (UAVs) represent one type of tool currently being tested for resiliency analysis.

Commonly known as drones, UAVs have a complicated history rooted in the military. For over 150 years, they have been used both on the defensive, for reconnaissance, and on the offensive, with predatory exercises. In the last 10 years, though, with the rise of the consumer drone, applications for UAVs have significantly increased. For the architecture, engineering, and construction (AEC) industry, many professionals have been experimenting with UAVs to document built work, focusing primarily on marketing and promotional functions.

At SWA, the imaging team led by David Lloyd has been working with UAVs for the past three years. In the beginning, their primary objective was, like many others, to capture images and video of recently constructed projects from a new angle. Then, in 2017, Hurricane Harvey hit. The catastrophic storm stalled for four days over southeastern Texas, dropping more than 60 inches of rain across the landscape. In Houston, this sustained downpour caused unprecedented swelling in the Addicks and Barker reservoirs, prompting the Harris County Flood Control District to release the water into the Buffalo Bayou, a meandering slow-moving river that snakes its way through downtown. Having been involved in the planning and design of many projects along the bayou, designers at SWA were anxious to understand the impact of the storm on their designed-to-flood efforts.

Buffalo Bayou Park during Hurricane Harvey / image: Jonnu Singleton

Shortly after Harvey made landfall, Kinder Baumgardner, ASLA, Managing Principal of SWA’s Houston studio, placed an urgent call to the imaging team, asking if someone could capture the bayou in the wake of the flood. This information would not only document the devastation brought by the storm but also be used to assess future upgrades to the park. While travel logistics were complicated—airports were shut down for days during and after the storm and rental cars were impossible to come by—Jonnu Singleton, one of SWA’s in-house photographers, managed to make it to town. Over the course of three days, Jonnu traced Buffalo Bayou from downtown Houston up to the reservoirs on the far west side of the city. Along the way, he captured aerial footage of neighborhoods adjacent to the bayou which were severely impacted from the flooding.

Sediment and debris build-up in Buffalo Bayou Park during Hurricane Harvey / image: Jonnu Singleton

In describing some of his observations of the bayou from above, Jonnu stated: “The sheer volume of sediment and debris that was deposited along the banks of the bayou was amazing to witness first-hand. In some spots where the bayou twisted its way towards downtown, the silt had accumulated so much that it engulfed entire sections of the park and trail network in four feet of impassable quicksand-like sediment. Vegetation took a substantial hit, not just from the water’s thrashing, but also from being submerged for such a prolonged period of time. Very few sections of the lower trails were passable, but Houstonians are resilient folks and I noticed quite a few locals determined to get in their afternoon jog along the bayou regardless.” In a new way, the UAV allowed SWA to safely assess the impact of Hurricane Harvey on its projects in near-real time, providing a new method for quickly collecting qualitative data on floodwater, material damage, sediment accumulation, and vegetation.

Water being released from reservoirs into Buffalo Bayou / image: Jonnu Singleton

Since Harvey, SWA’s research and innovation lab, XL, has begun collaborating with the firm’s imaging team to explore new ways that UAVs could function as analytical tools for design and evaluation. This effort is a part of the lab’s visualization and simulation track, which experiments with and critically evaluates various emerging tools to better understand their potential for the fields of landscape architecture, urban planning, and urban design. Most recently, XL Lab worked with Bill Tatham, another in-house photographer at SWA, to experiment with UAVs in assessing the performance of Hunter’s Point South Waterfront Park, Phase I, which was designed by Thomas Balsley Associates (now SWA/Balsley) and Weiss/Manfredi, with ARUP as a prime consultant. One output of the study was an experimental heat map indicating areas of high and low occupation across the park, created using drone footage and a machine-learning algorithm.

Machine learning overlay, Hunter’s Point South / images: Bill Tatham, XL Lab, SWA

So what does all of this mean for campus planning and design? While SWA has yet to conduct a campus-focused research study, we believe there is great potential in using UAVs to strengthen campus resilience before, during, and after climate and weather-related events. Prior to an event, UAVs can aid in creating up-to-date aerial surveys and base maps for risk assessment and data-driven decision making. During an event, UAVs can assess damage and hazards in near-real time, and help coordinate emergency response efforts. And following an event, UAVs can monitor landscape changes and restoration efforts, as well as support the visualization of reconstruction-related design work. Also, given their size and relative affordability, UAVs can reach more places across campuses and are more cost-effective than traditional manned aircraft. Lastly, we think that partnering with academic institutions could lead to even more UAV innovation, with the potential for creating “living laboratories” across a range of campuses.

References

NOAA National Centers for Environmental Information (NCEI), “U.S. Billion-Dollar Weather and Climate Disasters,” accessed February 12, 2019.

Eric S. Blake and David A. Zelinsky, “National Hurricane Center Tropical Cyclone Report: Hurricane Harvey,” May 9, 2018, accessed February 12, 2019.

Acknowledgements

The author would like to thank: Kinder Baumgardner, Julie Eakin, David Lloyd, Jonnu Singleton and Bill Tatham from SWA, Tom Balsley and Brian Staresnick from SWA/Balsley, Anya Domlesky from the XL Research and Innovation Lab at SWA, and Lisa Du Russel and Aastha Singh from the Penn State University Stuckman School of Architecture and Landscape Architecture for their support during the research and writing of this article.

Emily Schlickman, ASLA, is Co-Lead, XL: Experiments in Landscape and Urbanism at SWA Group.

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