APPENDIX F - PERCHED BEACHES
Perched beach sills can be built using most of the materials described for fixed breakwaters
(APPENDIX C). They must be made sand-tight to retain fill. Fill material should be chosen in
accordance with guidelines previously given for beach fills. Proper filtering should be provided beneath
and behind the sill to prevent settlement and loss of retained fill. In some cases, navigation markers may
be required.
Materials not included in APPENDIX C are discussed below.
Sheet Piling
Sheet pile sills are similar to bulkheads (APPENDIX A). Timber sheet piling will generally
require filter cloth backing on the shoreward face to prevent loss of the retained sand backfill through
joints in the structure. This is not generally a problem with steel or aluminum sheet piling. Sheet pile
sills also form an abrupt step to deeper water which would definitely be hazardous to bathers, particularly
children.
The same precautions regarding adequate ground penetration and toe protection for a bulkhead
also apply to a sheet pile sill. Figure F-1 shows a timber sheet pile sill under construction.
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