OWNER:
Mike and Beverly Courington Bill and Diana Brogdon
1107 Lovette Lane 1201 Lovette Lane
Daphne, Alabama 36526 Daphne, Alabama 36526
DESIGN/CONSTRUCT
CONTRACTOR:
Synergy Earth Systems, LLC.
26240 Equity Drive
Daphne, Alabama 36526
This project
consisted of the repair of areas of severe erosion and slope instability
that existed along the bluff line on the Owners’ property.
The majority of the damage to the Owners’ property occurred
in July of 1997 during Hurricane Danny. The high volume of storm
water runoff generated by the storm exceeded the drainage capability
of the local infrastructure, resulting in sheet flow across the
Owners’ property towards Mobile Bay. Nearly four thousand
cubic yards of soil were eroded into the bay as a result of this
overflow. The Owners retained SES in 1998 to evaluate and design
a repair of the subject properties, and in 1999 to construct the
repair.
The repair of
the subject properties consisted of construction of a steepened
(1H:1V) slope, with the toe of the slope located just outside of
the location of a line of wooden bulkheads that were removed as
part of the new construction. The stability of the steepened slope
was achieved using geogrid reinforcing, while the face of the slope
was protected from wave action using riprap. The height, slope angle
and rip rap sizing of the rip rap slope were selected based on a
desire to provide protection against moderate hurricane strength
storm surges, such as was observed during Hurricane Danny. Another
component of the construction was the installation of horizontal
strip drains. These drains, which were installed prior to placement
of the steepened slope, functioned to provide a drainage path for
water that was observed naturally seeping out of several exposed
sand layers.
Above the riprap
slope, a 2H:1V slope was constructed. The site geometry required
that two 4-foot high cross walls be constructed along the full length
of the repair to prevent the overall slope angle of the upper slope
from being excessive. Walls were also required on each end of the
repair area due to property constraints. The walls were constructed
using modular block facing units with geogrid reinforcing for stability.
The surface of the upper slope was protected using erosion control
matting in concert with natural vegetation.
The completed
repair was over 30 feet in height and extended the entire length
of both properties, approximately 160 feet. This project was successfully
completed over a two-month span in 1999
.
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