Through research and in practice, and with energy and vision, women engineers, STEM professionals, and nonprofits are layering resilience into the built environment. From living breakwaters to eco-efficient cement to repurposing obsolete infrastructure, they’re making a difference.
By Seabright McCabe, SWE Contributor
In 2012, Hurricane Sandy devastated the south shore of Staten Island, New York, an example of the more frequent and severe storms fueled by climate crisis. From that event came the inspiration for Living Breakwaters, an innovative coastal green infrastructure project, first covered by SWE Magazine in 2018. Conceived by MacArthur Foundation “genius grant” recipient and founder of SCAPE Landscape Architecture Kate Orff, the project broke ground in fall 2021, with a mission to build physical, ecological, and social resilience in the still-recovering community. It’s set for completion in 2024.
“It’s been a long time coming,” said Pippa Brashear, resilience principal and partner at SCAPE and a leading national expert on resilience planning and design for climate adaptation. “But good things take time, and large, nature-based infrastructure projects like this did. It’s very exciting to see it come to fruition.”
What’s just as exciting for Brashear is how close the reality is to the concept. “If you look at the design evolution, it’s true to the original performance goals,” she said. “It’s going to meaningfully reduce coastal risk from wave erosion, but it’s also going to provide habitat and continue that engagement with the public. It will provide a place and a venue for education about ecology and resilience around the harbor, and physically make the beach better and more accessible for people.”
The project, largely funded with $60 million from the New York Governor’s Office of Storm Recovery, is well on its way to completion and serving as a model for climate-adaptive, green infrastructure, particularly for others formulating coastal risk reduction plans. “For me, it’s been a great opportunity to share what we’ve learned,” Brashear said. “You can’t just copy/paste this kind of thing. Nature-based strategies are very site specific, but the principles and process behind them are transferable and that’s a very positive thing.”
Not just a pile of rocks
Living Breakwaters consists of about 2,400 linear feet (730 linear meters) of partially submerged rubble mound structures anchored in Raritan Bay, set between 790 and 1,800 feet (240 and 550 meters) from shore. Each mound is engineered with a stone core, a base layer of either bedding stone or marine mattress (depending on the bay-floor conditions) to protect against scour, and outer layers of armor stones and ecologically enhanced concrete armor blocks.
The armor blocks, strategically set in the intertidal and subtidal areas of the breakwaters, are uniquely designed to attract marine species and provide them habitat. Manufactured from a bio-enhanced concrete mixture, ECOncrete, their textured surfaces help protect, nourish, and encourage such native species as oysters, corals, and barnacles as they grip, grow, and multiply, forming a biological “glue” that adds to structural stability and longevity. The technology also helps support the food chain for top predators, such as seals.
“There’s a tension between ecological design wanting more variation and variability — different sizes of rocks and crevices — and uniformity,” Brashear noted. “Engineers definitely know that these are not just ‘piles of rocks.’ They’re very carefully placed, interlocking breakwater structures. We had a lot of conversations about where and how we should design and engineer these to create the uniformity needed for structural stability, but also create complexity and variation in the reef ridges where we didn’t need as much stability.”
Three breakwaters are complete and five more are under construction. Hundreds of manufactured tide pools have been installed, providing additional habitat. Living Breakwaters also features “reef ridges” — rocky protrusions on the ocean-facing sides of the breakwaters — and “reef streets,” narrow spaces between the ridges. These features also help modify wave behavior and though not designed to stop flooding like a sea wall would, the breakwaters will attenuate waves, lessening their ability to erode the shore or damage homes.
A vital part of Living Breakwaters’ mission is public outreach, both local and citywide. “Maintaining interest is part of the process, constantly answering the question, ‘Why aren’t they done yet?’” Brashear said. “I give the New York Governor’s Office of Resilient Homes and Communities a lot of credit for working with us and the team on continuous outreach and engagement.”
SCAPE is also collaborating with the Billion Oyster Project (BOP), a nonprofit dedicated to restoring oyster reefs in New York Harbor. Once construction and permitting are complete, BOP will install live oysters on about half of the breakwaters and in a floating nursery.
SCAPE and BOP are also delivering for young people. “We’re actively engaging with them to expand educational programs on Staten Island, doing science events, exhibits, and outreach to schools,” Brashear said. “Billion Oyster also developed an open source public school STEM curriculum for science students in sixth to eighth grade, emphasizing the history and importance of oysters to Staten Island and its ecology and showcasing Living Breakwaters as an example of building coastal resilience. It’s about more than just the physical breakwaters,” Brashear said. “It’s about seeding interest and excitement around them.”
Meeting the challenges
“Any time you do something new and innovative it’s a challenge, particularly in the realm of regulatory review, environmental review, and permitting,” Brashear said. “But those regulations protect us from doing harm. The reason they’re in place is that America has a pretty bad track record of building in the water. Part of the New York Harbor’s problem today is that people filled in wetlands they shouldn’t have to create more land. So we’re very careful about putting things in the water.”
One of the biggest challenges was explaining why the breakwaters were beneficial. “We had to clearly explain that they would reduce the impact of waves and provide habitat,” she said. “At times, it felt like writing a Ph.D. dissertation, but now it’s there and backed up by facts, in addition to the typical modeling and analysis that you have in an engineering project.”
Engineers have been instrumental at every stage of Living Breakwaters, which collaborated with many engineering firms on different aspects and stages of the project, including COWI and WSP. “Their geotechnical teams did the investigations and design, very important for any kind of building, even if it’s what some people see as a pile of rocks,” Brashear said. “Geotechnical engineering is critical to the features, landscapes, structures. They’ve got to last and be stable. Engineers also did survey work and helped us throughout the review process. Having that hardcore expertise — they tested our ideas and didn’t say, ‘No, that won’t work.’ They found us solutions that would.”
Paving the way for eco-efficient concrete
Take a walk through your town or city and notice the concrete in driveways, roads, bridges, and buildings. It’s the sidewalk under your feet, the foundation of your home, and the bridges you cross. Why so much of it? Concrete is cheap to make from cement, aggregates, water, and heat, and one of the strongest, most durable building materials in existence. So available, the world uses 30 billion tons of it a year, producing 8% of global greenhouse gas emissions.
Sabbie Miller, Ph.D., associate professor of civil and environmental engineering at the University of California, Davis, has been working toward developing environmentally friendly concrete since 2016. In late 2022, her team reported that 1.3 gigatons of carbon emissions across the globe could be diverted by using secondary materials in concrete.
Paving the Way for Better Permeable Concrete
Alalea Kia, Ph.D., is a UK Research and Innovation Future Leaders Fellow and a Royal Academy of Engineering Associate Research Fellow in the UK Collaboratorium for Research in Infrastructure and Cities (UKCRIC) Centre for Infrastructure Materials at the Imperial College of London. She has invented a high-strength, clogging-resistant permeable pavement, dubbed Kiacrete, that can drain stormwater without requiring frequent maintenance.
“Climate change increases likelihood of major storm events by 59%. We need sustainable solutions to tackle urban flooding,” Dr. Kia said in a web presentation for Britpave.
Kiacrete has an engineered pore structure 10 times more permeable than current options. It can also accommodate rebar, opening up new applications that weren’t possible before. Where sediments and water take a torturous path through the pore network of conventional concrete, Kiacrete’s flow path is straight up and down, and less likely to clog. Its formulation, design, and performance are drawing particular interest from India because it can withstand both monsoon flooding and increased sediments during droughts.
Kiacrete can also help mitigate urban heat island effects — it’s light in color, and water drains straight through it into the ground, where it cools the pavement. Kiacrete has been installed at Imperial College’s White City Campus since 2020, and its long-term drainage and durability monitoring continues to show excellent performance.
“We’ve shown that it works,” Dr. Kia said. “It’s the first permeable pavement that has high-strength potential for highways and some parts of airport infrastructure, and provides significant contributions toward the United Nations goal of net zero by 2050. This will hopefully enable widespread adoption of permeable pavements that can help us deal with climate change events.”
“Concrete is a very interesting problem, because it’s our most consumed material, after water,” she said. “We use it everywhere. It ends up having large impacts, not because the material is bad, but because we use so much of it. That enormous scaling factor also means that making just small changes could dramatically reduce global impacts. If we do just a couple of things better, we can make a huge difference, and that’s what’s so exciting for me.”
Dr. Miller wants to move past conventional discussions in industrial manufacturing around clean energy in production and accelerating carbon capture and sequestration. “Just looking at the material itself, there’s huge potential for change,” she said. “There are a lot of us researching the use of higher levels of minerals in concrete, and leveraging carbon-sequestering additives, to counteract the fact that cement is carbon emitting.”
“Concrete is cement plus water plus crushed rocks,” Dr. Miller said. “The vast majority of it is the aggregate. We mix it with cement and water to form synthetic stone in whatever shape we want.”
Cement is a hydraulic binder, reacting with water to form different mineral phases. To make it, limestone is mixed with silicates from clays. First, it must be decarbonized, by “breaking off” its CO2, leaving carbon monoxide and lime. Lime then reacts with amorphous silicates in a kiln at a high temperature to form calcium silicates.
“Breaking off that CO2 creates huge emissions,” Dr. Miller said. “On top of that, heating it takes a huge amount of energy, also with high emissions. On a per kilogram basis, cement’s really not that bad, even with those two emissions sources. Not when you compare it to things like plastic. Again, it’s not the process, it’s the scale.”
Cement interacts with water to form hydrate minerals, calcium silicate hydrates, which hold the aggregates together. “At that stage we have a lot of control over what we’re mixing and in what proportions,” Dr. Miller said. “We can reduce the amount of cement we’re putting in or the reactive compounds from that cement and lower emissions that way — use less cement and still get similar products.”
Researchers are also studying types of cement that don’t require a kilning process or don’t have high emissions from limestone decarbonizing. Others are investigating mineral additives that are carbon uptake, such as biomass resources that absorb CO2 through photosynthesis.
“What’s cool from my perspective is there is a lot we can do right now without changing anything,” Dr. Miller said. “Our structural design code allows some flexibility. It’s OK to be within a certain range of steel reinforcement and other properties associated with reinforced concrete structures. If we stay within the code and still have a safe building, we could begin using things that have lower environmental impact. We could get substantial reductions just by picking appropriately at the design stage.”
“I want to understand whether or not we can turn the built environment into a carbon sink,” she continued. “If we use a large amount of material for a long period of time, how can we bind atmospheric CO2 in those materials and undo some of the damage we’ve done? That’s what takes a huge chunk of my time — how do we quantify it, what are these new materials; if they sequester CO2, are they going to perform, long term?”
Biomass is an option
Biomass treatments, such as ash generation or biochar, could lead to a compound that is more resistant to cement’s high alkalinity and potentially won’t lose its mechanical properties. “That pathway is getting more exciting — how can we use these biogenic resources,” Dr. Miller said. “Energy generation with a byproduct of ash or char, that can be used in a building material.”
Dr. Miller is leading research on using rice hull ash as a concrete additive. UC Davis is conveniently located near the vast majority of California’s rice fields, and farmers are interested in what researchers can do with rice to make viable products.
“Rice kernels are just a fraction of the whole plant,” she said. “The rest of the plant is low-value byproducts. After harvest, rice kernels are hulled at a separate site, and the hulls get left outside in huge piles. They can be used to generate bioenergy, but it’s not yet profitable enough to be self-sustaining.”
Dr. Miller’s team had an idea. “Maybe you can still produce energy, but now you’ve got that byproduct of ash,” she said. “Rice hulls have high silica content, something we need in cement-based materials. So why don’t we use that biochar material in our concrete to lower its CO2 emissions?”
Her research looks promising and, looking into the future, Dr. Miller is brimming with optimism and energy. “I’m excited that so many people are this interested in making movement,” she said. “The climate crisis is a huge problem and the vast majority of us know it. What energizes me is there are so many people addressing the problem head on, finding a vision to fix or at least mitigate it.
“I wanted to understand how to shape the world, so I became an engineer,” she said. “To me, it’s exciting to tackle something this monumental.”
Repurposing Infrastructure: Walking the High Line
Once considered an engineering marvel, the High Line was an elevated railway built in the 1930s to move freight along the west side of Manhattan. Made obsolete by the trucking industry just 30 years later, it stood, abandoned and decaying, for decades. That is, until Friends of the High Line saw a way to preserve it through adaptive reuse and opened it as a public park in 2009.
New Yorkers and visitors have been flocking to it ever since. Today, a stroll on the High Line is a happy experience — both sides of its broad pathway packed with native perennial flowers, shrubs, and grasses; dotted with public art; and plenty of spots to rest and reflect. It’s a unique tourist attraction and a pollinator heaven running above the city streets, and full of unexpected views of West Chelsea and Hudson Yards.
This summer, Friends of the High Line teamed with architecture giant Skidmore, Owings & Merrill (SOM); developers; engineers; and city officials to build two pedestrian bridges connecting a series of civic spaces between midtown and the West Village to the 1.45-mile (2.3-kilometer) park.
“The High Line — Moynihan Connector knits the city’s open spaces together, bringing greater accessibility to pedestrians across Midtown West’s major public amenities,” SOM design principal Kim Van Holsbeke said. “Both the Timber Bridge and the Woodland Bridge have distinct identities and expand the High Line’s rich tapestry of experiences. When walking from Moynihan Train Hall, through Manhattan West, across the two bridges, and to the historic High Line, travelers, residents, and commuters experience an episodic journey through some of the best civic spaces that New York has to offer.”
The 260-foot-long (80-meter-long) Timber Bridge is a glulam Warren truss made from sustainably sourced, engineered wood. It was designed and structured with minimal connections to the ground so construction wouldn’t disrupt the traffic or roads below. The 340-foot-long (104-meter-long) Woodland Bridge features deep, built-in soil beds, supported by exposed columns and angled bracket arms that vary dynamically with soil depths. The beds will support native trees, shielding pedestrians from the traffic below and providing habitat for birds and pollinators.
The bridges are visually unified by weathered steel decking and bronze handrails, their intersection shifting the view from east-west to north-south and revealing the entrance to the High Line.
Like Living Breakwaters, Friends of the High Line emphasizes social resilience. It works to inspire stewardship, offering hands-on opportunities for young people to explore the park, its history of community-driven design, and encouraging multidisciplinary learning. Collaborating with schools to offer learning opportunities, the Friends of the High Line curriculum delves into infrastructure reuse projects, beginning with the challenges of creating the park, and fans out to include engineering, urban design, and public art.