What happens when you wrap a hurricane inside a winter storm and have it come ashore during extremely high tides? Unexpected and significant coastal impacts, including major beach erosion, flooding and structural damage concentrated in areas where beach and dune defenses were inadequate to absorb the surge and waves from this record-setting storm.
While official analysis of the storm's components for catastrophe will be months, there are some broad-brush takeaways from the storm:
n Wider beaches with high dunes work. Except where Sandy made direct landfall, wide sandy beaches and high dune systems kept waves away from upland property and infrastructure, and prevented flooding.
Even in areas where beaches and dunes were lost, they minimized the amount of damage. They absorbed the first onslaught of wave energy and storm surge before they were overcome. Where the beach was narrow or the dunes too low, Sandy overtopped the coastal protections, flooded upland homes and structures and pushed beach sand into the streets.
Beach designers normally don't prepare a coastal system for a direct hit by a once-in-a-lifetime (we hope) storm - any more than seat belts and air bags protect you when your car is hit by a train. High dunes and wide beaches were no match for a 15-foot storm surge and a mountain of water that built momentum for days in areas north of Sandy's landfall. Even though the engineered systems were not designed to provide protection for a super storm, they performed beyond all expectations.
One reason for having a wide beach is to create a buffer so sand will be "sacrificed" to help protect inland; similarly high dunes behind the beach serve as a levee, preventing flooding. Sandy afflicted coastal communities with differing amounts of damages, the width and height of beach and dune systems was the deciding factor.
Fact Box
Ken and Kate Gooderham of The American Shore & Beach Preservation Association can be reached at asbpa.org/news/newsroom_beachnews.htm.
n Coastal protection doesn't stop at the coastline. In the face of storms such as Sandy, keeping coastal communities safe isn't just about wide healthy beaches. Some of the worst destruction happened in towns and cities where floodwaters could run amok once seawalls and other hard structures were overtopped because ground-level buildings and aging infrastructure were no match for rising tides. Worse, some cities had no easy way to drain floodwaters once tides receded, because barriers and geography kept gravity from doing its job - making a bad situation worse and delaying recovery and repair.
n We need to heed the warning of coastal scientists and implement coastal protection plans developed by coastal engineers. Along the coast, plans and preparations are often shaped by politics and personal preferences rather than by prudence - doing "what's possible" rather than "what's necessary." Politicians need to heed warnings based on coastal facts and science (rather than being based on volume and stridency. We must demand "good" science - reproducible, redundant and reliable - be used as the basis for policy decision-making whenever possible, rather than accepting the assertions of well-meaning but unqualified "experts" as the inspiration for coastal action.
Wider beaches and high dune systems, along with elevated structures built to tested building codes and siting plans, can provide significant protection and sustainability of our coastal infrastructure. The cost of doing it right is higher than what has been spent in the past, but significantly less than the cost to clean up and repair the impact of a single storm such as Sandy.
n Protecting coastal infrastructure is a crucial investment. Particularly in those areas so close to the coast with crucial public infrastructure such as tunnels, power plants, airports, major roadways. A sound protection plan would limit damage and speed recovery. Plans big and small will be advanced in the months to come to deal with the vulnerabilities exposed by Sandy, and we encourage reinforcement to be part of the recovery and repair investment.
This should be a wake-up call for other coastal communities unaffected by the storm. We would hope the events of the past several days will inspire them to look hard at their own potential weak infrastructure links and start considering what steps they can take to shore up those crucial public resources before they face the storm specter staring down at them.
As New Jersey and New York just were reminded, it's not a question of "if" but "when" and "how bad."
Ken and Kate Gooderham of The American Shore & Beach Preservation Association can be reached at asbpa.org/news/newsroom_beachnews.htm.
