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| Storm surge during the great Blizzard of '78 |
By KEVIN PROFT/ecoRI.org News staff
NARRAGANSETT
— Rhode Island’s coastline is in a natural and constant state of flux. The
coastline is altered most during big storms such as hurricanes and nor’easters.
High waves wash away or damage dunes that protect land further inland. They
also pound sea cliffs saturated and weakened by rain, causing sections to
collapse.
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| Watching Blue Shutters getting eaten from waves caused by a near pass of one of last year's hurricanes |
Narrow barrier beaches, such as Ninigret Beach in Charlestown, can
dramatically shift position.
If humans weren’t part of the equation, this information
would be no cause for alarm. Dunes would recover, debris from cliff walls would
slowly erode to sand, and reoriented barrier beaches would continue to protect
wetlands and the mainland from the unrelenting ocean. But, when humans interact
with the shoreline and alter it in a fundamental way, coastal residents often
experience alarmingly problematic effects.
Matunuck is the Ocean State’s best example of what
happens when ocean and human development collide. Matunuck’s eroding coast is
threatening to undercut Matunuck Beach Road and leave 1,600 homes and
businesses with no way to enter or leave the community. To prevent the road
from being destroyed, which would create a clear public safety issue, a
220-foot sheet-pile wall will
be built in September to hold back the ocean.
At best, this is a temporary and localized solution to a
much bigger problem. It doesn’t prevent beachside establishments such as Ocean
Mist from being overtaken by the ocean, and it doesn’t halt erosion in areas
not protected by the wall — it has even been postulated that hardened
shorelines cause neighboring natural shorelines to erode faster.
This sheet-pile wall also doesn’t address the fact that
erosion is happening elsewhere in Rhode Island. A residence on the barrier
beach in Green Hill that was protected by a dune and a wide beach in 1980 had
to be moved back after the Patriots’ Day storm of 2007 when it was flooded by
the ocean. The process included segmenting the house and relocating it by
crane.
These issues, along with explanations of why erosion
happens and how Rhode Islanders should confront the consequences, were the
topic of a recent lecture given by Janet Freedman, a geologist for the Coastal
Resources Management Council (CRMC), at the University of Rhode Island Graduate
School of Oceanography.
Rhode Island is especially susceptible to coastal erosion
because more than 50 percent of the state’s coast is made of rock and sediment
that is easily eroded, according to Freedman. During storms, the combination of
storm surge — naturally higher ocean levels created when hurricane winds push
water toward the shore — and bigger waves allow water to penetrate further
inland or lash with more force against dunes and cliffs. Higher sea levels mean
more erosion during storms. Heavy rains during storms also cause slopes to
become oversaturated and more likely to fail.
This helps explain why coastal erosion is accelerating.
Today, according to Freedman, sea levels are about 3 inches higher than they
were in 1991 and are conservatively expected to reach 5 feet higher by 2100.
Freedman said parts of Westerly are already experiencing daily flooding at high
tide during the spring, when tides reach their peak height. Those additional 3
inches get added to the ocean’s height during a storm and translates into more
intense erosion.
In addition to sea level rise, climate change is generating
more frequent and intense storms. Since most erosion occurs during intense
storms, the predictable effect has been more rapidly retreating coastlines.
To combat the effects of coastal erosion, CRMC is
developing an Erosion and Inundation Special Area Management Plan. The plan
will rely on science-based data from studies scheduled to happen at multiple
sites around the state where coastal erosion is occurring.
Experimental erosion control areas have been created to
test different strategies related to controlling erosion, such as
geo-mattresses and wave attenuators. Successful strategies can then be
implemented in similar situations elsewhere in the state, according to CRMC.
Erosion
is a natural process, but humans are exacerbating it. Short-sighted development,
rising sea levels and more frequent and intense storms have resulted in
unforeseen effects that need to be dealt with sooner rather than later if
responsible solutions are to be implemented.