barrier island status report - Coastal Protection and Restoration ...

Figure 31. Barrier island average gulf-side shoreline change rates pre-restoration (1884-2005)
and post-restoration (2005-2010/2011). Projects constructed (and years) are also listed in the
data table.
4.4.1 East Grand Terre
East Grande Terre Island is part of the original Grand Terre Island which has divided into East
and West Grand Terre Islands separated by Pass Abel. This island was restored in 2010 through
the construction of the East Grand Terre Island Restoration Project (BA-30) by the CPRA with
funding from the Coastal Impact Assistance Program (CPE, 2011). The East Grand Terre Island
Restoration Project was part of the original East and West Grand Terre Island Restoration Project
which was cooperatively designed and engineered by the CPRA and National Marine Fisheries
Service through the CWPPRA program.
Presented in Figure 32 are the average shoreline change rates for East Grand Terre. The prerestoration
erosion rates ranged from -38.9 ft/yr (BICM short-term) to -48.3 ft/yr (BICM longterm)
noting the BICM historical average was on the same order of magnitude equal to -41.7
ft/yr. East Grand Terre has experienced breaching throughout the long-term and short-term
intervals. The island experienced net accretion in the near-term interval (+85.9 ft/yr on average)
noting this period included the recently completed restoration project. The new historical
average, equal to -34.7 ft/yr, is less than the BICM time period averages. Thus restoration of the
island‟s geomorphic form and function offset a significant percentage of the erosion experienced
in the short-term period, returning the historical erosion rate to less than pre-restoration rates.
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