OWNER:
Atlantic Land Corporation
660 Dunlap Drive
Mobile, Alabama 36652

PROJECT ENGINEER:
Southern Earth Sciences, Inc.
P.O. Box 160745
Mobile, Alabama 36616

DESIGN/CONSTRUCT CONTRACTOR:
Synergy Earth Systems, Inc.
26240 Equity Drive
Daphne, Alabama 36526

The Atlantic Land Corporation, a subsidiary of Atlantic Marine, operates and maintains a dredge disposal impoundment on their property in Mobile, Alabama. The facility, which borders Mobile Bay, was initially constructed 1954. In 1998, the outboard slope of a section of the containment dike experienced some instability. The slide was the result of erosion of the outboard dike toe by wave action. Atlantic Land Corporation had scheduled a dredging operation and needed to repair the dike prior to beginning. Synergy Earth Systems, Inc. (SES) was retained to design and construct the repair.

Design calculations indicated that, to permanently repair the dike, reconstruction of the dike toe would be required. However, this would require a Corps of Engineers permit that could not be obtained in time to perform the scheduled dredging operation. Therefore, a temporary repair was designed to allow the dredging operation to take place while a permit was being obtained for the long-term solution. The temporary repair consisted of reconstructing an approximate 270-foot reach of the dike using geogrid soil reinforcement and geosynthetic strip drains to control seepage. About one week after construction of the temporary repair, Hurricane Georges hit the Gulf Coast and caused major erosion damage to the containment dikes. With the dredging contractor on stand-by, an emergency dike repair was designed and constructed.

The selected alternative was to set the existing dike back from the damaged area. However, this required that the dike be constructed partially over soft dredge spoil material. Geogrid reinforcement was utilized to maintain stability of the relocated dike. Approximately 1100 feet of dike was realigned in three days. Portions of the construction work were performed concurrently with the dredging operation underway resulting in minimal stand-by time.