Bio-engineered solution for coastal erosion protection

(Scroll down for our photo-log of project progress)

Woods Hole Group designed, permitted, and is now overseeing construction of a large non-structural erosion control solution at Bayswater Seaside LLC properties in New Seabury, MA.

Three waterfront parcels in this development have experienced long-term erosion rates of approximately one foot per year (1845-1994), but recent storms and end-effects from a nearby revetment have nearly doubled erosion rates in the short-term.  Property owners have been nourishing the beach and steep coastal bank since the 1980s, but recent nourishments of 20,000 cubic yards annually along the 250-foot shoreline made apparent the need for a more substantial solution.

We designed an innovative and effective bio-engineered solution to protect the toe and upper portions of the bank.  The measures we are implementing to prevent scour and bank slumping include:

  • Installation of eight (8) terraced biodegradable sand-filled coir envelopes at the toe of the bank, stabilized by 12-inch piles
  • Stacking of four (4) coir fiber rolls above the sand envelopes
  • 600 cubic yards of beach nourishment per year
  • Restoration of the coastal bank with high-density plantings of Cape American beach grass (Ammophilia breviligulata)

The following photos show erosion impacts at the site, and construction to date.  Our contractor, C.F. Briggs of Marion, MA, is stitching together six 13’x150′ coir mats by hand (see warehouse photos below) to create a 35’x250′ mat for each layer of coir fiber specified in the design.  Thus far, one coir envelope has been woven together, placed, and filled with sand.  Stay tuned for more updates.

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5 Responses to Bio-engineered solution for coastal erosion protection

  1. Pingback: Bio-engineered solution for coastal erosion protection, pt.2 | 2Fathom

  2. Pingback: Bio-engineered solution for coastal erosion protection, pt.5 | 2Fathom

  3. Pingback: A field guide to biodegradable erosion control | 2Fathom

  4. Jason Budsan says:

    Very good idea! Sand is used in the bags, but can recycled, fine pulverized glass be used as a 2nd choice? Is this possible to instead of using sand?
    Thank you,
    Jason Budsan

  5. We have limited experience with this material, and to our knowledge the use of glass cullet has not yet been permitted in the U.S. for beach nourishment or as a fill material for bank-stabilizing sand envelopes.

    Our understanding is that it is a viable material from an engineering standpoint, but that there is still debate over its ecological effects.

    For the purposes of our project, it would work as an alternative and ecological effects would be minimized as long as the cullet stayed inside an intact envelope. However, the demand for sand (or sand-like alternatives) is relatively small in this design and therefore glass cullet would not be cost-effective for this application.

    An interesting question, nonetheless, from an industrial ecology standpoint. We would be interested to hear from anyone having experience with glass cullet as a beach or bank fill alternative.

    Thanks for the comment!

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