cycle. Economic performance will be evaluated at the time of the first renourishment
following initial construction of the Federal project. The design renourishment cycle for
the Federal project is 4 years. Measurement of difference in costs to renourish structured
and non-structured groin cells (based on different volume requirements) and between
Beachsaver Reef and Double-T sill configurations will be evaluated along with the
length of time between construction and condition when the beach profile is less than the
design template (and associated renourishment cycle costs). The structure will be
successful if average annual renourishment cost savings is greater than average annual
structure cost.
Structural Performance (Measure of Structure Stability): focuses on stability of
the reef and sill structures. Structural performance will be evaluated throughout the
duration of the monitoring program by measuring the scour, settlement and alignment.
Any decrease in elevation of structure crest due to settlement, rotation, or translation will
be determined from elevation surveys along crest of structure. Change in alongshore
structure integrity, such as formation of gaps in the structure due to separation of
interlocking units or other structure failure resulting in sand loss due to higher
permeability will also be determined from elevation surveys. Scour depth of the seabed
adjacent to structure (seaward and landward sides) will be compared to initial elevation at
time of structure placement. Any excessive scour may result in failure of structure or
change sand transport patterns. The structures will be successful if the average lowering
of crest elevation is < 0.31 m, if no gaps form that result in localized sand loss through
structures and if the average scour at the base of each type of structure is < 0.61 m.
This first site in the National Shoreline Erosion Control Development and
Demonstration Program will conduct research and demonstrate prototype-scale
"innovative" or "non-traditional" methods of using prefabricated concrete structures for
shoreline erosion control and evaluate the effectiveness of these devices. This R&D
effort will aid in the assessment and advancement of the state of the art of this type of
beach erosion control technology and help in the development of these innovative
solutions to beach erosion control. The knowledge gained on this project will further the
use of well-engineered alternative approaches to beach erosion control.
Acknowledgements
Mr. William Curtis is program manager of the Section 227 Program. Additional
information on the 227 Program can be found at http://limpet.wes.army.mil/sec227/
index.htm. Messrs Randy Wise, Tim Rooney, Dwight Pakan and Jeff Gebert of the U.S.
Army Engineer District, Philadelphia, provided assistance in data collection, analysis,
and project management. Bernie Moore (ret.) and John Garofolo of the New Jersey
Department of Environmental Protection and Malcolm Fraser, Mayor of Borough of
Cape May Point, NJ, also provided assistance in project planning and implementation.
Permission to publish was granted by the Chief of Engineers.
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