HomeMy WebLinkAboutAbutter comment #2 3.16.2026To Conservation Commission
RE 10 Surfside terrace
Bill Marasco (84 abbuter)
3/16/27
At your meeting, a criterion that the raising of the retaining wall must not be more detrimental to the wetlands was stated. Based on this criteria and my explanation below, it is clear
that the raising of the retaining wall is more detrimental and ought to be denied.
If the retaining wall were elevated, it would cause immediate increased erosion, on the adjacent coastal beaches, one public and the other soon to be, during any storm water or tidal
elevation event Although the petitioner denied that any erosion of adjacent beaches would result in his presentation, increased erosion would clearly occur.
Below is my justification for the denial. I am unable to attend the April 2 nd meeting, and I would ask that it be rescheduled unless, this is not the final meeting before approval
of this petition, as I would like to make my comments in public
Raising a retaining wall (or seawall) in a flood zone typically protects the immediate property at the expense of adjacent, unprotected beaches. The increased height reflects more wave
energy, leading to accelerated erosion (known as active erosion or scouring) directly in front of and down-drift from the structure, often resulting in the loss of the neighboring beach.
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NPS.gov
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Here are the specific, detrimental effects on adjacent beaches:
Increased Down-Drift Erosion ("Flanking"):By preventing natural erosion on one property, the wall blocks the supply of sediment that normally replenishes surrounding areas. This causes
flanking erosion, where the beach on neighboring properties erodes at an accelerated rate, often leading to the "starvation" of down-drift beaches.
Active Erosion and Scour: The higher the wall, the more wave energy is reflected downward to the base of the structure. This reflected energy scours the sand in front
of the wall and on adjacent, unprotected shorelines, often resulting in the permanent loss of the beach and leaving only the hard structure.
Loss of Recreational Beach and Habitats:The increased erosion frequently causes the narrowing or complete disappearance of the sandy beach in front of and adjacent to the wall, particularly
at high tide. This destroys coastal habitats for shorebirds and other marine species.
End Effects: When a seawall ends, the wave energy that was reflected along the wall is released, resulting in intensified erosion on the immediate neighboring, unarmored property.
Passive Erosion: By fixing the shoreline in place, the raised wall prevents the beach from migrating inland as sea levels rise, eventually drowning the neighboring beach against the
new, high
Erosion diagram
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