Tuesday, June 10, 2014

Adapting to Ongoing Erosion at Cranston’s Stillhouse Cove

FROM THE FIELD

by Wenley Ferguson
The evidence of the erosive force of Superstorm Sandy was not just confined to the south coast of Rhode Island. Stillhouse Cove, a small waterfront park in the Edgewood neighborhood of Cranston, suffered significant erosion during the storm. Bordered by a salt marsh, the park is exposed to the east, where storm-generated waves crash against a steep bank. During Sandy, the bank eroded and threatened the loss of the park. 
Coir mat "burritos" create a gentle, protective 
slope that will help prevent erosion.

After years of collaboration on restoring the Stillhouse Cove salt marsh, the Edgewood Waterfront Preservation Association (EWPA) and Save The Bay teamed up on an innovative erosion control project to address the bank erosion. 

Instead of trying to replace the lost soil along the steep shoreline, the bank was carved back to create a gentle slope that will dissipate future wave energy. Coir envelopes, coconut fiber mats filled with sand that resemble large burritos, will protect the slope from future storms. Contemporary Landscaping, a local contractor, teamed up with NETCO, a Massachusetts construction project manager that specializes in the installation of the coir mats. 

An excavator was used to carve a slope out of the bank, then three coir mats were installed in a series of steps on top of each other. The mats were covered with the excavated soil from the bank, and then covered with additional coconut fiber. 

The project was a true collaboration of a number of partners. The City of Cranston provided sand for the coir mats, and Coastal Resources Management Council, the Natural Resources Conservation Service (NRCS), and National Oceanic and Atmospheric Administration (NOAA) each provided funding and invaluable technical guidance for the project. 

Once the bank was regraded, a variety of native grasses was planted to act as a buffer between the park and the salt marsh, and to stabilize the bank. Neighborhood volunteers from EWPA, students from Johnson & WalesUniversity, Save The Bay staff and interns, and the contractor installed 6,500 plants along the cove in just one week. Due to the steepness of the slope, the fall drought and remnants of debris from historic fill along the marsh, the planting conditions were less than ideal, yet the involvement of the community was inspiring. One volunteer read about the project in The Providence Journal and stopped by to see how he could help. Moments later, he had a trowel in hand and was scrambling up and down the bank planting grasses. 

This shoreline adaptation project was part of Save The Bay’s Bay-wide effort to identify opportunities to protect shorelines naturally and create a more resilient coastline. As sea level rises, it will be important to create places where wave energy can be dissipated, and where shorelines can adapt to changing conditions.

This was published in the Spring 2014 issue of Tides, Save The Bay's biannual magazine.