Nine years after Hurricane Sandy made landfall in Lower Manhattan, residents are still grappling with how best to safeguard their homes against rising waters. But what options are available?
Adaptation measures can be costly. To offset some of those costs, the city is supporting initiatives such as cooling centers and educational outreach for vulnerable communities.
Understanding Sea Level Rise
As glaciers melt and the ocean expands, coastal cities face an ever-increasing sea level challenge as sea levels rise at an accelerating rate. Even with aggressive efforts to curb greenhouse gas emissions, sea levels could reach 50 inches or higher by 2100 in New York City – potentially placing high-value property at risk and necessitating managed retreat from some areas such as Manhattan.
Hurricane Sandy served as an alarming wake-up call, flooding subway tunnels and neighborhoods, cutting power supplies off, washing away century-old structures, swamping roads and highways and disrupting transportation networks. But what once seemed extreme will become the new norm as sea levels rise and storm surges increase in frequency and intensity.
NYC must reevaluate its relationship to water in order to manage rising seas, and this requires more than simple dike-building projects or elevated berms – although these may provide valuable protection along the coasts and open new recreational opportunities in waterfront parks. Comprehensive long-term protection plans combining engineering (elevating roads or building sea walls) with ecological strategies like habitat restoration or buyout programs will provide adequate solutions.
Coastline ecosystems have long been capable of keeping pace with sea level fluctuations; provided they remain protected from other stresses like human activity and nutrient inputs, coastal ecosystems can remain resilient over the course of millions of years. New York must preserve this “adaptive capacity” when planning for their future.
Restoration and enhancement of natural “sponges,” including wetlands, oyster reefs, marshes, sand dunes, and wildflower meadows can serve as buffers against storm surge, slowing and absorbing the speed of water entering inland communities as it enters sea level rise, thus mitigating coastal flooding and erosion impacts. Other adaptation strategies may involve decommissioning polders (undeveloped land reclaimed from the sea with dikes).
An effective plan to protect against rising seas requires raising existing buildings and changing zoning regulations to stop risky development in flood zones, as well as creating a regional network of municipalities to share challenges and best practices in creating long-term resilience strategies.
Resilience Planning in New York
Resiliency planning can be a complex and challenging process. As New York recovers from Hurricane Sandy, city agencies are undertaking projects and plans designed to strengthen New York City’s shoreline and other infrastructure in preparation for future storms.
Some of New York City’s resiliency efforts are making significant headway. Mayor de Blasio revived one such effort – East Side Coastal Resiliency Project – which had been put on pause in 2016. Once completed, it will include 18 flood gates that can be raised or lowered as needed to protect 110,000 residents, including 28,000 low-income public-housing tenants from potential storm surge damage.
Financial District and Seaport Climate Resilience Master Plan, developed by NYCEDC and MOCR with assistance from other city agencies as well as an interdisciplinary consulting team led by Arcadis engineering firm, seeks to protect waterfront against rising sea levels and future coastal storms due to climate change. Community engagement was integral in shaping this plan through workshops and meetings, an online engagement portal, youth outreach in partnership with local schools and other forms of creative engagement.
The plan also addresses inequities in access to New York City’s waterfront. While over 2 million New Yorkers live within half a mile’s walking distance of a waterfront park or public space, 800,000 remain disconnected from nearby coastlines – an inequality especially evident in poorer neighborhoods and communities of color; hence its aim of opening up coastal spaces to them.
The City is taking measures to reshape coastal neighborhoods through zoning changes requiring resilient design. In addition, they have established NYC Climate Resiliency Design Guidelines – step-by-step instructions on how to design buildings more resiliently against climate risks – which is being considered for incorporation into a revised building code. A third initiative of resilience for their coastal neighborhoods involves plans to redevelop Brooklyn, Queens and Staten Island harbors to provide greater flood protection as well as recreational opportunities on water.
From Highways to Greenways
Since the 1980s, NYC Audubon has advocated for the preservation of natural areas based on two goals: wildlife conservation and stormwater management services. Given New York’s sewer system and high percentage of impervious surfaces, heavy rainstorms often result in sewer overflows (CSOs).
The City is actively taking steps to reduce CSOs through various strategies that combine “gray” infrastructure with green alternatives such as green roofs, rain barrels and gardens, permeable pavement, tree pits with below-ground catchments for water collection purposes and bioswales that capture stormwater before filtering it back into the soil for uptake by plants or natural evaporation.
Urban cooling and water management solutions with green and blue roofs are key in protecting New York from its unprecedented population growth. Conundrum’s occasional group features flared drum construction on cocktail and end tables featuring solid acacia as its surface material for an exquisite and durable design suitable for coastal as well as urban decor settings; additionally it is eco-friendly due to being composed entirely from eco-friendly material acacia wood.
The Big U
Climate infrastructure projects are underway along New York City’s waterfront. Billions of dollars have already been invested in seawalls, jetties, breakwaters and reinforced dunes that promise to protect neighborhoods against future storm surges.
Rebuild by Design’s 2013 competition called for solutions that would protect low-lying coastal areas like Manhattan from future disasters and one of these was The Big U, designed by Danish architect Bjarke Ingels and Dutch firm One Architecture from Denmark and the Netherlands respectively. As its top prize winner, The Big U was presented by Danish architect Bjarke Ingels and One Architecture from Denmark/Netherlands collaboration, while offering safeguards against any future natural disasters.
The Big U’s coastal defenses aim to prevent the catastrophic flooding that struck Lower Manhattan during Hurricane Sandy. The project protects 10 miles of Manhattan’s shoreline spanning from West 57th Street southwards up to the Battery and East 42nd Street in all.
Ingels and his team combined Robert Moses’ grand vision and Jane Jacobs’ fine-grained sensibility in creating The Big U, creating a landscape that both enhanced quality of life for residents during normal times as well as protecting against floods or storm surges during emergencies. Their designs included movable barriers, buildings, berms, all designed to safeguard 10 continuous miles of Lower Manhattan.
The three primary components of the project include the Big Bench, Battery Berm and Bridging Berm. The Big Bench serves as an adaptable protective element that mediates new and existing infrastructure – similar to how street furniture does around the world – much as street furniture does in cities around the globe. Battery Berm provides an elevated path through Battery Park where visitors can observe tide fluctuations and sea level rise from public space while enjoying public space as a public amenity. Finally, Bridging Berm rises 14 feet above highways, capping off highways with greenways that connect shorelines and communities together.
The BIG U’s success at meeting the city’s pressing issues serves as a timely reminder of how essential thoughtful climate planning can be. While climate change presents many daunting obstacles, we must overcome them to build sustainable and prosperous futures for all.
New York City’s coastal conundrum is a challenge that the city must face head on. With sea levels projected to rise, it is essential for the city to take a comprehensive and forward-looking approach to protecting its coastal areas. The city’s efforts so far have included resiliency planning, restoration and enhancement of natural ecosystems, and the development of climate infrastructure projects such as The Big U. While these efforts have made significant headway, more work needs to be done to ensure that New York City is adequately protected against the impact of rising seas.
The challenge of climate change is daunting, but it presents an opportunity for the city to think critically about its relationship with water and to put in place measures to ensure its long-term resilience. By combining engineering and ecological strategies, the city can create effective and sustainable solutions to protect against rising seas. It is essential that the city continues to prioritize climate resilience planning, to protect its residents and to ensure that New York remains a prosperous and vibrant city for generations to come.