As an island in the Atlantic Ocean, Nantucket intimately understands the impacts of increased flooding frequency and storm events. For our community, adopting ways to increase our Coastal Resiliency is essential to maintaining quality of life, community function and ecological integrity on our little island.
Maximum Annual Storm Tides and Storm Surges recorded at the Nantucket Harbor Tide Station 1965-2015. (Storm Surge and Inundation Pathways Report, 2016)
So what is Coastal Resiliency? Essentially, it is the ability of a coastal community to resist, absorb, adapt to, and recover from the impacts of sea level rise, the increasing magnitude and frequency of storm events and shoreline change. The faster and more effectively we can respond to these hazards or mitigate their impacts all together, the better our Resiliency as a community. On Nantucket our Town government, municipal departments, historical preservation groups, community civic leagues and conservation groups are all talking about Coastal Resiliency and how to make our community more resilient to the environmental change already impacting us. On the Town website, you can learn more about the Town’s current efforts to develop a community level Coastal Resiliency Plan to direct actions we can take as a community as well as position Nantucket to receive grant money.
On Tuesday, January 11, 2019, staff from NCF, Select Board members, DPW staff, Town Natural Resources staff, other conservation groups and many more all participated in a day long Community Resiliency Workshop with a number of objectives including:
- Develop a mutual understand of the natural hazard risks, vulnerabilities and resilience options for Nantucket
- Identify vulnerabilities and strengths of Nantucket in response to Climate Change
- Identify ACTION ITEMS that can reduce Nantucket’s vulnerability
The workshop defined the risk Nantucket faces to the hazards of climate change as:
Risk = Vulnerability x frequency
The frequency (and intensity) of hazardous events is both increasing and largely out of our control to impact. The thing that our community CAN do is mitigate or reduce our VULNERABILITY to these hazards. And one of the top Action Items identified at the workshop was to preserve, restore and potential create coastal wetlands to function as buffers against storm surges and increased flooding hazards.
Why Spend our Efforts on Coastal Wetlands?
Coastal wetlands are naturally designed to protect and buffer uplands from the impacts of storm surge, coastal flooding and sea level rise – shielding our communities from the worst storm impacts and helping us recover more quickly after major storm events. One of the best steps we can take to provide longer term resiliency to our coastal communities is the restoration and protection of our natural coastal defenses.
Research following the devastation of Hurricane Sandy showed that functioning coastal wetlands prevented an estimated $625 in potential property damages across the path of the hurricane. In part of New Jersey it was estimated that the presence of coastal wetlands reduced the expected losses to hurricane damage by 20% on average and up to 50% for area just above sea level.
Reductions in annual flood losses to properties that have a marsh in front (blue) versus properties that have lost the marshes in front (orange). Narayan et al., Nature Scientific Reports 7, 9463 (2017)., CC BY
Communities along the eastern coast of the United States are actively working towards converting their coastlines back to natural communities that can buffer our infrastructure and our towns from the effects of increased floods and storm surges. Resilient Boston Harbor is maintaining and increasing open vegetated parks to buffer from storms but also provide areas for flood waters to sit, preventing inundation of adjacent roadways, homes and business. The state of North Carolina has implemented the Coastal Resilience Initiative to restore or protect more than 5,000 acres of wetlands over the next three years through the creation of living shorelines and the protection of existing wetlands.
Nantucket already has significant wetland resources along both of Madaket and Nantucket Harbors. Protecting those wetlands and looking for ways to enhance them will help protect our island. Downtown is particularly susceptible to flooding during high tides and storm surges events, likely because it was all once a wetland itself! Softening how the town connects to the harbor by increasing vegetated parks (as the Land Bank has been doing) and restoring low-lying areas to wetlands and/or retention basins will go a long way to mitigating those flood waters.
Imagine vegetated waterfront parks to absorb and mitigate flood waters and storm surges (Parks being created at the base of Brooklyn Bridge in New York City following Hurricane Sandy).
Restoring and creating wetlands along Easton st and in the Brant Point area will help mitigate flooding. These areas are often underwater during normal high tide events, likely because they were once all one large connect wetland that has been filled for development. Check behind the Nantucket Hotel or in the few open lots along Easton st the next time you walk that part of Town – you’ll find the hints of wetlands that once were.
Extent of water flows over the Town of Nantucket under 5ft (green) and 7ft (blue) storm surges. This is without taking into account future sea level rise. (Storm Surge and Inundation Pathways Report, 2016)
Finding ways to soften the bulkheads and hard shorelines using many of the tested proven methods of Living Shoreline research could alleviate much of the storm and flood impacts.
A variety of shoreline protection options exist.
Pie in the sky action? Convert the bulkheads downtown to a living shoreline wetland backed by grassy parks. Protective harder structures can be incorporated to these living shorelines to provide stability as well. Living shoreline marshes are significantly better than strict bulkheads at protecting shorelines and mitigating storm damage and flooding. The significant flooding behind the Dreamland and near Straight Wharf could potentially be helped by these ideas.
There are a lot of options to providing Coastal Resiliency while promoting and maintaining natural resources and hopefully retaining the natural beauty that makes Nantucket so special. Even mainstream media is recognizing that walls won’t protect our coastal areas from these hazards – thinking proactively may help save our island in the future. And as one of the largest land owners on the island, The Nantucket Conservation Foundation is excited to be par tof the conversation and hopefully part of the solution.
Futher Resources:
https://www.nantucket-ma.gov/DocumentCenter/View/19053/Storm-Surge-and-Inundation-Pathways—2016